graphify/graphify/extract.py

"""Deterministic structural extraction from source code using tree-sitter. Outputs nodes+edges dicts."""
from __future__ import annotations
import importlib
import json
import os
import re
import sys
import unicodedata
from dataclasses import dataclass, field
from pathlib import Path
from typing import Callable, Any
from .cache import load_cached, save_cached

_RECURSION_LIMIT = 10_000


def _raise_recursion_limit() -> None:
    if sys.getrecursionlimit() < _RECURSION_LIMIT:
        sys.setrecursionlimit(_RECURSION_LIMIT)


def _safe_extract(extractor: Callable, path: Path) -> dict:
    try:
        return extractor(path)
    except RecursionError:
        print(f"  warning: skipped {path} (recursion limit exceeded)", file=sys.stderr, flush=True)
        return {"nodes": [], "edges": [], "error": "recursion_limit_exceeded"}
    except Exception as e:
        print(f"  warning: skipped {path} ({type(e).__name__}: {e})", file=sys.stderr, flush=True)
        return {"nodes": [], "edges": [], "error": f"{type(e).__name__}: {e}"}


def _make_id(*parts: str) -> str:
    r"""Build a stable node ID from one or more name parts.

    Preserves Unicode letters/digits (CJK, Cyrillic, Arabic, accented Latin,
    etc.) so non-ASCII identifiers produce distinct IDs and don't collapse to
    a single per-file node (#811). NFKC normalization ensures composed and
    decomposed forms of the same character (e.g. é vs e+combining-acute)
    produce the same ID. Must stay in sync with build._normalize_id.
    """
    combined = "_".join(p.strip("_.") for p in parts if p)
    combined = unicodedata.normalize("NFKC", combined)
    cleaned = re.sub(r"[^\w]+", "_", combined, flags=re.UNICODE)
    cleaned = re.sub(r"_+", "_", cleaned)
    return cleaned.strip("_").casefold()


def _file_stem(path: Path) -> str:
    """Return a stem qualified with the parent directory name to avoid ID collisions
    when multiple files share the same filename in different directories (#550)."""
    parent = path.parent.name
    if parent and parent not in (".", ""):
        return f"{parent}.{path.stem}"
    return path.stem


_TSCONFIG_ALIAS_CACHE: dict[str, dict[str, str]] = {}


def _strip_jsonc(text: str) -> str:
    """Strip // line comments, /* */ block comments, and trailing commas from JSONC.

    Preserves string contents (including // and /* inside strings) by skipping over
    quoted spans first. Required for tsconfig.json files generated by SvelteKit,
    NestJS, Vite, T3, Astro, etc., which use JSONC by default (#700).
    """
    # Remove block and line comments while leaving string literals untouched.
    pattern = re.compile(
        r'"(?:\\.|[^"\\])*"'    # double-quoted string (with escapes)
        r"|/\*.*?\*/"           # /* block comment */
        r"|//[^\n]*",           # // line comment
        re.DOTALL,
    )

    def _replace(match: re.Match) -> str:
        token = match.group(0)
        if token.startswith('"'):
            return token
        return ""

    stripped = pattern.sub(_replace, text)
    # Remove trailing commas before } or ] (allowing whitespace between).
    stripped = re.sub(r",(\s*[}\]])", r"\1", stripped)
    return stripped


def _read_tsconfig_aliases(tsconfig: Path, base_dir: Path, seen: set) -> dict[str, str]:
    """Recursively read path aliases from a tsconfig, following extends chains.

    Child config paths override parent. Circular extends are detected via seen set.
    npm package configs (e.g. @tsconfig/svelte) are skipped since they're not on disk.
    Handles JSONC (comments + trailing commas) which is the default tsconfig format
    for SvelteKit, NestJS, Vite, T3, Astro, etc. (#700).
    """
    if str(tsconfig) in seen:
        return {}
    seen.add(str(tsconfig))
    try:
        raw = tsconfig.read_text(encoding="utf-8")
    except Exception as e:
        print(f"  warning: could not read {tsconfig} ({type(e).__name__}: {e})", file=sys.stderr, flush=True)
        return {}
    try:
        data = json.loads(raw)
    except json.JSONDecodeError:
        try:
            data = json.loads(_strip_jsonc(raw))
        except json.JSONDecodeError as e:
            print(f"  warning: failed to parse {tsconfig} as JSON/JSONC ({e.msg} at line {e.lineno} col {e.colno})", file=sys.stderr, flush=True)
            return {}
    except Exception as e:
        print(f"  warning: failed to parse {tsconfig} ({type(e).__name__}: {e})", file=sys.stderr, flush=True)
        return {}

    aliases: dict[str, str] = {}
    extends = data.get("extends")
    if extends and not extends.startswith("@"):
        extended_path = (base_dir / extends).resolve()
        if not extended_path.suffix:
            extended_path = extended_path.with_suffix(".json")
        if extended_path.exists():
            aliases.update(_read_tsconfig_aliases(extended_path, extended_path.parent, seen))

    paths = data.get("compilerOptions", {}).get("paths", {})
    for alias, targets in paths.items():
        if not targets:
            continue
        alias_prefix = alias.rstrip("/*")
        target_base = targets[0].rstrip("/*")
        aliases[alias_prefix] = str(base_dir / target_base)

    return aliases


def _load_tsconfig_aliases(start_dir: Path) -> dict[str, str]:
    """Walk up from start_dir to find tsconfig.json and return compilerOptions.paths aliases.

    Follows extends chains so SvelteKit/Nuxt/NestJS inherited aliases are included.
    Returns a dict mapping alias prefix (e.g. "@/") to resolved base dir (e.g. "src/").
    Result is cached by tsconfig path string.
    """
    current = start_dir.resolve()
    for candidate in [current, *current.parents]:
        tsconfig = candidate / "tsconfig.json"
        if tsconfig.exists():
            key = str(tsconfig)
            if key not in _TSCONFIG_ALIAS_CACHE:
                _TSCONFIG_ALIAS_CACHE[key] = _read_tsconfig_aliases(tsconfig, candidate, seen=set())
            return _TSCONFIG_ALIAS_CACHE[key]
    return {}


# ── LanguageConfig dataclass ─────────────────────────────────────────────────

@dataclass
class LanguageConfig:
    ts_module: str                                   # e.g. "tree_sitter_python"
    ts_language_fn: str = "language"                 # attr to call: e.g. tslang.language()

    class_types: frozenset = frozenset()
    function_types: frozenset = frozenset()
    import_types: frozenset = frozenset()
    call_types: frozenset = frozenset()
    static_prop_types: frozenset = frozenset()
    helper_fn_names: frozenset = frozenset()
    container_bind_methods: frozenset = frozenset()
    event_listener_properties: frozenset = frozenset()

    # Name extraction
    name_field: str = "name"
    name_fallback_child_types: tuple = ()

    # Body detection
    body_field: str = "body"
    body_fallback_child_types: tuple = ()   # e.g. ("declaration_list", "compound_statement")

    # Call name extraction
    call_function_field: str = "function"           # field on call node for callee
    call_accessor_node_types: frozenset = frozenset()  # member/attribute nodes
    call_accessor_field: str = "attribute"          # field on accessor for method name

    # Stop recursion at these types in walk_calls
    function_boundary_types: frozenset = frozenset()

    # Import handler: called for import nodes instead of generic handling
    import_handler: Callable | None = None

    # Optional custom name resolver for functions (C, C++ declarator unwrapping)
    resolve_function_name_fn: Callable | None = None

    # Extra label formatting for functions: if True, functions get "name()" label
    function_label_parens: bool = True

    # Extra walk hook called after generic dispatch (for JS arrow functions, C# namespaces, etc.)
    extra_walk_fn: Callable | None = None


# ── Generic helpers ───────────────────────────────────────────────────────────

# Vite / TypeScript resolver extensions. Used by _resolve_js_module_path()
# to map import specifiers onto real files on disk, so the resulting node
# id matches the one _extract_generic creates for the target file.
_JS_RESOLVE_EXTS = (".ts", ".tsx", ".svelte", ".js", ".jsx", ".mjs")
_JS_INDEX_FILES = ("index.ts", "index.tsx", "index.js", "index.jsx")


def _resolve_js_module_path(p: Path) -> Path:
    """Resolve a JS/TS-style import specifier path to an actual file on disk.

    TypeScript / SvelteKit / Vite let you write imports without a file
    extension and auto-resolve via a fixed extension order. The pre-existing
    .js→.ts and .jsx→.tsx rewrites only covered the TS-ESM-via-.js convention;
    every other shape produced a phantom node id and the edge was lost in
    build_from_json.

    Order, mirroring Vite's resolver:

      1. exact path, when it's a real file on disk
      2. directory → try index.{ts,tsx,js,jsx}
      3. .js  → .ts   (TS ESM convention; written as .js, file is .ts)
         .jsx → .tsx
      4. append .ts/.tsx/.svelte/.js/.jsx/.mjs to the FULL filename — not
         a suffix-swap. This handles, in one rule:
           - bare paths:               foo           → foo.ts
           - Svelte 5 rune files:      foo.svelte    → foo.svelte.ts
           - multi-dot helper files:   foo.shared    → foo.shared.ts
           - config files:             foo.config    → foo.config.ts
           - test helper files:        foo.spec      → foo.spec.ts
      5. directory variant: try ./<name>/index.{ts,tsx,js,jsx}

    Falls back to the original path on no match — preserves pre-fix behaviour
    for genuinely external modules (the edge gets dropped as external by
    build_from_json).
    """
    if p.is_file():
        return p
    # TS ESM convention: import path written with .js but the real file is .ts.
    # Apply BEFORE the generic append loop so we don't accidentally match
    # foo.js → foo.js.ts when the real file is foo.ts.
    if p.suffix == ".js":
        c = p.with_suffix(".ts")
        if c.is_file():
            return c
    if p.suffix == ".jsx":
        c = p.with_suffix(".tsx")
        if c.is_file():
            return c
    # Try appending extensions to the FULL filename BEFORE checking for a
    # directory import. Both TypeScript and Vite resolvers prefer a file
    # match over a directory match — projects routinely have a `foo.ts`
    # file living alongside a `foo/` directory of sub-modules (e.g.
    # `auth.ts` next to `auth/`). If we checked the directory first, those
    # file imports would silently lose to a directory with no `index.*`.
    for ext in _JS_RESOLVE_EXTS:
        c = p.parent / (p.name + ext)
        if c.is_file():
            return c
    # Directory imports: try ./<name>/index.{ts,tsx,js,jsx}. Reached only
    # after every file-extension candidate has been ruled out, matching the
    # resolver fallback chain.
    if p.is_dir():
        for idx in _JS_INDEX_FILES:
            c = p / idx
            if c.is_file():
                return c
    return p


def _read_text(node, source: bytes) -> str:
    return source[node.start_byte:node.end_byte].decode("utf-8", errors="replace")


def _resolve_name(node, source: bytes, config: LanguageConfig) -> str | None:
    """Get the name from a node using config.name_field, falling back to child types."""
    if config.resolve_function_name_fn is not None:
        # For C/C++ where the name is inside a declarator
        return None  # caller handles this separately
    n = node.child_by_field_name(config.name_field)
    if n:
        return _read_text(n, source)
    for child in node.children:
        if child.type in config.name_fallback_child_types:
            return _read_text(child, source)
    return None


def _find_body(node, config: LanguageConfig):
    """Find the body node using config.body_field, falling back to child types."""
    b = node.child_by_field_name(config.body_field)
    if b:
        return b
    for child in node.children:
        if child.type in config.body_fallback_child_types:
            return child
    return None


# ── Import handlers ───────────────────────────────────────────────────────────

def _import_python(node, source: bytes, file_nid: str, stem: str, edges: list, str_path: str) -> None:
    t = node.type
    if t == "import_statement":
        for child in node.children:
            if child.type in ("dotted_name", "aliased_import"):
                raw = _read_text(child, source)
                module_name = raw.split(" as ")[0].strip().lstrip(".")
                tgt_nid = _make_id(module_name)
                edges.append({
                    "source": file_nid,
                    "target": tgt_nid,
                    "relation": "imports",
                    "context": "import",
                    "confidence": "EXTRACTED",
                    "source_file": str_path,
                    "source_location": f"L{node.start_point[0] + 1}",
                    "weight": 1.0,
                })
    elif t == "import_from_statement":
        module_node = node.child_by_field_name("module_name")
        if module_node:
            raw = _read_text(module_node, source)
            if raw.startswith("."):
                # Relative import - resolve to full path so IDs match file node IDs
                dots = len(raw) - len(raw.lstrip("."))
                module_name = raw.lstrip(".")
                base = Path(str_path).parent
                for _ in range(dots - 1):
                    base = base.parent
                rel = (module_name.replace(".", "/") + ".py") if module_name else "__init__.py"
                tgt_nid = _make_id(str(base / rel))
            else:
                tgt_nid = _make_id(raw)
            edges.append({
                "source": file_nid,
                "target": tgt_nid,
                "relation": "imports_from",
                "context": "import",
                "confidence": "EXTRACTED",
                "source_file": str_path,
                "source_location": f"L{node.start_point[0] + 1}",
                "weight": 1.0,
            })


def _resolve_js_import_target(raw: str, str_path: str) -> "tuple[str, Path | None] | None":
    """Resolve a JS/TS import path string to (target_nid, resolved_path).

    Handles relative paths, tsconfig path aliases, and bare/scoped imports.
    Returns None if `raw` is empty.
    """
    if not raw:
        return None
    if raw.startswith("."):
        resolved = Path(os.path.normpath(Path(str_path).parent / raw))
        resolved = _resolve_js_module_path(resolved)
        return _make_id(str(resolved)), resolved
    aliases = _load_tsconfig_aliases(Path(str_path).parent)
    for alias_prefix, alias_base in aliases.items():
        if raw == alias_prefix or raw.startswith(alias_prefix + "/"):
            rest = raw[len(alias_prefix):].lstrip("/")
            resolved_alias = Path(os.path.normpath(Path(alias_base) / rest))
            resolved_alias = _resolve_js_module_path(resolved_alias)
            return _make_id(str(resolved_alias)), resolved_alias
    module_name = raw.split("/")[-1]
    if not module_name:
        return None
    return _make_id(module_name), None


def _import_js(node, source: bytes, file_nid: str, stem: str, edges: list, str_path: str) -> None:
    resolved_path: "Path | None" = None
    for child in node.children:
        if child.type == "string":
            raw = _read_text(child, source).strip("'\"` ")
            resolved = _resolve_js_import_target(raw, str_path)
            if resolved is None:
                break
            tgt_nid, resolved_path = resolved
            edges.append({
                "source": file_nid,
                "target": tgt_nid,
                "relation": "imports_from",
                "context": "import",
                "confidence": "EXTRACTED",
                "source_file": str_path,
                "source_location": f"L{node.start_point[0] + 1}",
                "weight": 1.0,
            })
            break

    # Emit symbol-level edges for named imports from local/aliased files.
    # e.g. `import { Foo, type Bar } from './bar'` → file → Foo, file → Bar (EXTRACTED)
    # Uses the same _make_id(target_stem, name) key that _extract_generic emits when
    # defining the symbol, so these edges wire importers directly to existing symbol nodes.
    if resolved_path is not None:
        target_stem = _file_stem(resolved_path)
        line = node.start_point[0] + 1
        for child in node.children:
            if child.type == "import_clause":
                for sub in child.children:
                    if sub.type == "named_imports":
                        for spec in sub.children:
                            if spec.type == "import_specifier":
                                name_node = spec.child_by_field_name("name")
                                if name_node:
                                    sym = _read_text(name_node, source)
                                    edges.append({
                                        "source": file_nid,
                                        "target": _make_id(target_stem, sym),
                                        "relation": "imports",
                                        "context": "import",
                                        "confidence": "EXTRACTED",
                                        "source_file": str_path,
                                        "source_location": f"L{line}",
                                        "weight": 1.0,
                                    })


def _dynamic_import_js(node, source: bytes, caller_nid: str, str_path: str, edges: list,
                       seen_dyn_pairs: set) -> bool:
    """Detect dynamic import() calls in JS/TS and emit imports_from edges.

    Handles patterns like:
      await import('./foo.js')
      import('./foo.js').then(...)
      const m = await import(`./foo`)

    Returns True if the node was a dynamic import (caller should skip normal call handling).
    """
    # Dynamic import is a call_expression whose function child is the keyword "import".
    # tree-sitter-typescript parses `import('...')` as call_expression with first child
    # being an "import" token (type="import").
    func_node = node.child_by_field_name("function")
    if func_node is None:
        # Fallback: check first child directly (some TS versions)
        if node.children and _read_text(node.children[0], source) == "import":
            func_node = node.children[0]
        else:
            return False
    if _read_text(func_node, source) != "import":
        return False

    # Extract the module path from the arguments
    args = node.child_by_field_name("arguments")
    if args is None:
        return True  # It's an import() but no args — skip
    for arg in args.children:
        if arg.type == "template_string":
            # Skip dynamic template literals — path can't be statically resolved
            if any(c.type == "template_substitution" for c in arg.children):
                break
            raw = _read_text(arg, source).strip("`")
        elif arg.type == "string":
            raw = _read_text(arg, source).strip("'\" ")
        else:
            continue
        if not raw:
            break
        # Resolve path using the same logic as static imports
        if raw.startswith("."):
            resolved = Path(os.path.normpath(Path(str_path).parent / raw))
            # Same TS/SvelteKit resolver fixups static imports use, so
            # `await import('./foo')` (bare path), `import('./bar.shared')`
            # (multi-dot helper), and Svelte 5 rune-file dynamic imports
            # all land on real file nodes.
            resolved = _resolve_js_module_path(resolved)
            tgt_nid = _make_id(str(resolved))
        else:
            aliases = _load_tsconfig_aliases(Path(str_path).parent)
            resolved_alias = None
            for alias_prefix, alias_base in aliases.items():
                if raw == alias_prefix or raw.startswith(alias_prefix + "/"):
                    rest = raw[len(alias_prefix):].lstrip("/")
                    resolved_alias = Path(os.path.normpath(Path(alias_base) / rest))
                    break
            if resolved_alias is not None:
                resolved_alias = _resolve_js_module_path(resolved_alias)
                tgt_nid = _make_id(str(resolved_alias))
            else:
                module_name = raw.split("/")[-1]
                if not module_name:
                    break
                tgt_nid = _make_id(module_name)
        pair = (caller_nid, tgt_nid)
        if pair not in seen_dyn_pairs:
            seen_dyn_pairs.add(pair)
            edges.append({
                "source": caller_nid,
                "target": tgt_nid,
                "relation": "imports_from",
                "confidence": "EXTRACTED",
                "source_file": str_path,
                "source_location": f"L{node.start_point[0] + 1}",
                "weight": 1.0,
            })
        break
    return True


def _import_java(node, source: bytes, file_nid: str, stem: str, edges: list, str_path: str) -> None:
    def _walk_scoped(n) -> str:
        parts: list[str] = []
        cur = n
        while cur:
            if cur.type == "scoped_identifier":
                name_node = cur.child_by_field_name("name")
                if name_node:
                    parts.append(_read_text(name_node, source))
                cur = cur.child_by_field_name("scope")
            elif cur.type == "identifier":
                parts.append(_read_text(cur, source))
                break
            else:
                break
        parts.reverse()
        return ".".join(parts)

    for child in node.children:
        if child.type in ("scoped_identifier", "identifier"):
            path_str = _walk_scoped(child)
            module_name = path_str.split(".")[-1].strip("*").strip(".") or (
                path_str.split(".")[-2] if len(path_str.split(".")) > 1 else path_str
            )
            if module_name:
                tgt_nid = _make_id(module_name)
                edges.append({
                    "source": file_nid,
                    "target": tgt_nid,
                    "relation": "imports",
                    "context": "import",
                    "confidence": "EXTRACTED",
                    "source_file": str_path,
                    "source_location": f"L{node.start_point[0] + 1}",
                    "weight": 1.0,
                })
            break


def _resolve_c_include_path(raw: str, str_path: str) -> "Path | None":
    """Resolve a quoted #include path to a real file on disk.

    Searches relative to the including file's directory. Returns None for
    system headers (<...>) or paths that don't exist on disk.
    """
    if not raw:
        return None
    candidate = (Path(str_path).parent / raw).resolve()
    if candidate.is_file():
        return candidate
    return None


def _import_c(node, source: bytes, file_nid: str, stem: str, edges: list, str_path: str) -> None:
    for child in node.children:
        if child.type in ("string_literal", "system_lib_string", "string"):
            raw = _read_text(child, source).strip('"<> ')
            # Quoted includes: try to resolve to a real file so the target ID
            # matches the node ID _extract_generic creates for that file.
            if child.type != "system_lib_string":
                resolved = _resolve_c_include_path(raw, str_path)
                if resolved is not None:
                    tgt_nid = _make_id(str(resolved))
                    edges.append({
                        "source": file_nid,
                        "target": tgt_nid,
                        "relation": "imports",
                        "context": "import",
                        "confidence": "EXTRACTED",
                        "source_file": str_path,
                        "source_location": f"L{node.start_point[0] + 1}",
                        "weight": 1.0,
                    })
                    break
            module_name = raw.split("/")[-1].split(".")[0]
            if module_name:
                tgt_nid = _make_id(module_name)
                edges.append({
                    "source": file_nid,
                    "target": tgt_nid,
                    "relation": "imports",
                    "context": "import",
                    "confidence": "EXTRACTED",
                    "source_file": str_path,
                    "source_location": f"L{node.start_point[0] + 1}",
                    "weight": 1.0,
                })
            break


def _import_csharp(node, source: bytes, file_nid: str, stem: str, edges: list, str_path: str) -> None:
    for child in node.children:
        if child.type in ("qualified_name", "identifier", "name_equals"):
            raw = _read_text(child, source)
            module_name = raw.split(".")[-1].strip()
            if module_name:
                tgt_nid = _make_id(module_name)
                edges.append({
                    "source": file_nid,
                    "target": tgt_nid,
                    "relation": "imports",
                    "context": "import",
                    "confidence": "EXTRACTED",
                    "source_file": str_path,
                    "source_location": f"L{node.start_point[0] + 1}",
                    "weight": 1.0,
                })
            break


def _import_kotlin(node, source: bytes, file_nid: str, stem: str, edges: list, str_path: str) -> None:
    path_node = node.child_by_field_name("path")
    if path_node:
        raw = _read_text(path_node, source)
        module_name = raw.split(".")[-1].strip()
        if module_name:
            tgt_nid = _make_id(module_name)
            edges.append({
                "source": file_nid,
                "target": tgt_nid,
                "relation": "imports",
                "context": "import",
                "confidence": "EXTRACTED",
                "source_file": str_path,
                "source_location": f"L{node.start_point[0] + 1}",
                "weight": 1.0,
            })
        return
    # Fallback: find identifier child
    for child in node.children:
        if child.type == "identifier":
            raw = _read_text(child, source)
            tgt_nid = _make_id(raw)
            edges.append({
                "source": file_nid,
                "target": tgt_nid,
                "relation": "imports",
                "context": "import",
                "confidence": "EXTRACTED",
                "source_file": str_path,
                "source_location": f"L{node.start_point[0] + 1}",
                "weight": 1.0,
            })
            break


def _import_scala(node, source: bytes, file_nid: str, stem: str, edges: list, str_path: str) -> None:
    for child in node.children:
        if child.type in ("stable_id", "identifier"):
            raw = _read_text(child, source)
            module_name = raw.split(".")[-1].strip("{} ")
            if module_name and module_name != "_":
                tgt_nid = _make_id(module_name)
                edges.append({
                    "source": file_nid,
                    "target": tgt_nid,
                    "relation": "imports",
                    "context": "import",
                    "confidence": "EXTRACTED",
                    "source_file": str_path,
                    "source_location": f"L{node.start_point[0] + 1}",
                    "weight": 1.0,
                })
            break


def _import_php(node, source: bytes, file_nid: str, stem: str, edges: list, str_path: str) -> None:
    for child in node.children:
        if child.type in ("qualified_name", "name", "identifier"):
            raw = _read_text(child, source)
            module_name = raw.split("\\")[-1].strip()
            if module_name:
                tgt_nid = _make_id(module_name)
                edges.append({
                    "source": file_nid,
                    "target": tgt_nid,
                    "relation": "imports",
                    "context": "import",
                    "confidence": "EXTRACTED",
                    "source_file": str_path,
                    "source_location": f"L{node.start_point[0] + 1}",
                    "weight": 1.0,
                })
            break


# ── C/C++ function name helpers ───────────────────────────────────────────────

def _get_c_func_name(node, source: bytes) -> str | None:
    """Recursively unwrap declarator to find the innermost identifier (C)."""
    if node.type == "identifier":
        return _read_text(node, source)
    decl = node.child_by_field_name("declarator")
    if decl:
        return _get_c_func_name(decl, source)
    for child in node.children:
        if child.type == "identifier":
            return _read_text(child, source)
    return None


def _get_cpp_func_name(node, source: bytes) -> str | None:
    """Recursively unwrap declarator to find the innermost identifier (C++)."""
    if node.type == "identifier":
        return _read_text(node, source)
    if node.type in ("field_identifier", "destructor_name", "operator_name"):
        return _read_text(node, source)
    if node.type == "qualified_identifier":
        name_node = node.child_by_field_name("name")
        if name_node:
            return _read_text(name_node, source)
    decl = node.child_by_field_name("declarator")
    if decl:
        return _get_cpp_func_name(decl, source)
    for child in node.children:
        if child.type == "identifier":
            return _read_text(child, source)
    return None


# ── JS/TS extra walk for arrow functions ──────────────────────────────────────

def _find_require_call(value_node):
    """Return the call_expression node if `value_node` is a `require(...)` call
    or `require(...).x` member access. Otherwise None."""
    if value_node is None:
        return None
    if value_node.type == "call_expression":
        fn = value_node.child_by_field_name("function")
        if fn is not None and fn.type == "identifier":
            return value_node
    if value_node.type == "member_expression":
        obj = value_node.child_by_field_name("object")
        return _find_require_call(obj)
    return None


def _require_imports_js(node, source: bytes, file_nid: str, stem: str, edges: list, str_path: str) -> bool:
    """Detect CommonJS require imports inside lexical_declaration / variable_declaration.

    Handles three patterns:
      const { foo, bar } = require('./mod')   → file → mod (imports_from), file → foo, file → bar
      const mod         = require('./mod')   → file → mod (imports_from)
      const x           = require('./mod').y → file → mod (imports_from), file → y

    Returns True if any require import was found.
    """
    if node.type not in ("lexical_declaration", "variable_declaration"):
        return False
    found = False
    for child in node.children:
        if child.type != "variable_declarator":
            continue
        value = child.child_by_field_name("value")
        call = _find_require_call(value)
        if call is None:
            continue
        fn = call.child_by_field_name("function")
        if fn is None or _read_text(fn, source) != "require":
            continue
        args = call.child_by_field_name("arguments")
        if args is None:
            continue
        raw = None
        for arg in args.children:
            if arg.type == "string":
                raw = _read_text(arg, source).strip("'\"` ")
                break
        if not raw:
            continue
        resolved = _resolve_js_import_target(raw, str_path)
        if resolved is None:
            continue
        tgt_nid, resolved_path = resolved
        line = node.start_point[0] + 1
        edges.append({
            "source": file_nid,
            "target": tgt_nid,
            "relation": "imports_from",
            "context": "import",
            "confidence": "EXTRACTED",
            "source_file": str_path,
            "source_location": f"L{line}",
            "weight": 1.0,
        })
        found = True

        # Symbol-level edges for destructured / accessor binders.
        target_stem = _file_stem(resolved_path) if resolved_path is not None else None
        name_node = child.child_by_field_name("name")
        sym_names: list[str] = []
        if name_node is not None and name_node.type == "object_pattern":
            # `const { a, b: alias } = require('./m')` — emit edges for each property key
            for prop in name_node.children:
                if prop.type == "shorthand_property_identifier_pattern":
                    sym_names.append(_read_text(prop, source))
                elif prop.type == "pair_pattern":
                    key = prop.child_by_field_name("key")
                    if key is not None:
                        sym_names.append(_read_text(key, source))
        elif value is not None and value.type == "member_expression":
            # `const x = require('./m').y` — symbol is the property accessed
            prop = value.child_by_field_name("property")
            if prop is not None:
                sym_names.append(_read_text(prop, source))
        if target_stem is not None:
            for sym in sym_names:
                edges.append({
                    "source": file_nid,
                    "target": _make_id(target_stem, sym),
                    "relation": "imports",
                    "context": "import",
                    "confidence": "EXTRACTED",
                    "source_file": str_path,
                    "source_location": f"L{line}",
                    "weight": 1.0,
                })
    return found


def _js_extra_walk(node, source: bytes, file_nid: str, stem: str, str_path: str,
                   nodes: list, edges: list, seen_ids: set, function_bodies: list,
                   parent_class_nid: str | None, add_node_fn, add_edge_fn) -> bool:
    """Handle lexical_declaration (arrow functions, CJS requires, module-level const literals) for JS/TS. Returns True if handled."""
    if node.type in ("lexical_declaration", "variable_declaration"):
        # CJS require imports — emit edges, do not block other lexical_declaration handling
        require_found = _require_imports_js(node, source, file_nid, stem, edges, str_path)

        # Arrow function declarations and module-level const literals (lexical_declaration only)
        arrow_found = False
        const_found = False
        if node.type == "lexical_declaration":
            for child in node.children:
                if child.type == "variable_declarator":
                    value = child.child_by_field_name("value")
                    if value and value.type == "arrow_function":
                        name_node = child.child_by_field_name("name")
                        if name_node:
                            func_name = _read_text(name_node, source)
                            line = child.start_point[0] + 1
                            func_nid = _make_id(stem, func_name)
                            add_node_fn(func_nid, f"{func_name}()", line)
                            add_edge_fn(file_nid, func_nid, "contains", line)
                            body = value.child_by_field_name("body")
                            if body:
                                function_bodies.append((func_nid, body))
                            arrow_found = True
                    elif value and value.type in (
                        "object", "array", "as_expression", "call_expression", "new_expression",
                    ):
                        # Module-level const with literal/object/array/factory value
                        name_node = child.child_by_field_name("name")
                        if name_node:
                            const_name = _read_text(name_node, source)
                            line = child.start_point[0] + 1
                            const_nid = _make_id(stem, const_name)
                            add_node_fn(const_nid, const_name, line)
                            add_edge_fn(file_nid, const_nid, "contains", line)
                            const_found = True
        if arrow_found:
            return True
        if const_found:
            return True
        if require_found:
            return True
    return False


# ── C# extra walk for namespace declarations ──────────────────────────────────

def _csharp_extra_walk(node, source: bytes, file_nid: str, stem: str, str_path: str,
                       nodes: list, edges: list, seen_ids: set, function_bodies: list,
                       parent_class_nid: str | None, add_node_fn, add_edge_fn,
                       walk_fn) -> bool:
    """Handle namespace_declaration for C#. Returns True if handled."""
    if node.type == "namespace_declaration":
        name_node = node.child_by_field_name("name")
        if name_node:
            ns_name = _read_text(name_node, source)
            ns_nid = _make_id(stem, ns_name)
            line = node.start_point[0] + 1
            add_node_fn(ns_nid, ns_name, line)
            add_edge_fn(file_nid, ns_nid, "contains", line)
        body = node.child_by_field_name("body")
        if body:
            for child in body.children:
                walk_fn(child, parent_class_nid)
        return True
    return False


# ── Swift extra walk for enum cases ──────────────────────────────────────────

def _swift_extra_walk(node, source: bytes, file_nid: str, stem: str, str_path: str,
                      nodes: list, edges: list, seen_ids: set, function_bodies: list,
                      parent_class_nid: str | None, add_node_fn, add_edge_fn) -> bool:
    """Handle enum_entry for Swift. Returns True if handled."""
    if node.type == "enum_entry" and parent_class_nid:
        for child in node.children:
            if child.type == "simple_identifier":
                case_name = _read_text(child, source)
                case_nid = _make_id(parent_class_nid, case_name)
                line = node.start_point[0] + 1
                add_node_fn(case_nid, case_name, line)
                add_edge_fn(parent_class_nid, case_nid, "case_of", line)
        return True
    return False


# ── Language configs ──────────────────────────────────────────────────────────

_PYTHON_CONFIG = LanguageConfig(
    ts_module="tree_sitter_python",
    class_types=frozenset({"class_definition"}),
    function_types=frozenset({"function_definition"}),
    import_types=frozenset({"import_statement", "import_from_statement"}),
    call_types=frozenset({"call"}),
    call_function_field="function",
    call_accessor_node_types=frozenset({"attribute"}),
    call_accessor_field="attribute",
    function_boundary_types=frozenset({"function_definition"}),
    import_handler=_import_python,
)

_JS_CONFIG = LanguageConfig(
    ts_module="tree_sitter_javascript",
    class_types=frozenset({"class_declaration"}),
    function_types=frozenset({"function_declaration", "method_definition"}),
    import_types=frozenset({"import_statement"}),
    call_types=frozenset({"call_expression", "new_expression"}),
    call_function_field="function",
    call_accessor_node_types=frozenset({"member_expression"}),
    call_accessor_field="property",
    function_boundary_types=frozenset({"function_declaration", "arrow_function", "method_definition"}),
    import_handler=_import_js,
)

_TS_CONFIG = LanguageConfig(
    ts_module="tree_sitter_typescript",
    ts_language_fn="language_typescript",
    class_types=frozenset({
        "class_declaration",
        "interface_declaration",   # parity with Java/C#
        "enum_declaration",        # named enums
        "type_alias_declaration",  # named type aliases
    }),
    function_types=frozenset({"function_declaration", "method_definition"}),
    import_types=frozenset({"import_statement"}),
    call_types=frozenset({"call_expression", "new_expression"}),
    call_function_field="function",
    call_accessor_node_types=frozenset({"member_expression"}),
    call_accessor_field="property",
    function_boundary_types=frozenset({"function_declaration", "arrow_function", "method_definition"}),
    import_handler=_import_js,
)

# .tsx files must use the TSX grammar (JSX-aware), not the plain TypeScript grammar.
# tree-sitter-typescript ships two languages: language_typescript (for .ts) and
# language_tsx (for .tsx). Parsing .tsx with language_typescript silently fails on
# JSX expressions, dropping any call_expression nested inside JSX (e.g. {fmtDate(x)}).
_TSX_CONFIG = LanguageConfig(
    ts_module="tree_sitter_typescript",
    ts_language_fn="language_tsx",
    class_types=_TS_CONFIG.class_types,
    function_types=_TS_CONFIG.function_types,
    import_types=_TS_CONFIG.import_types,
    call_types=_TS_CONFIG.call_types,
    call_function_field=_TS_CONFIG.call_function_field,
    call_accessor_node_types=_TS_CONFIG.call_accessor_node_types,
    call_accessor_field=_TS_CONFIG.call_accessor_field,
    function_boundary_types=_TS_CONFIG.function_boundary_types,
    import_handler=_TS_CONFIG.import_handler,
)

_JAVA_CONFIG = LanguageConfig(
    ts_module="tree_sitter_java",
    class_types=frozenset({"class_declaration", "interface_declaration"}),
    function_types=frozenset({"method_declaration", "constructor_declaration"}),
    import_types=frozenset({"import_declaration"}),
    call_types=frozenset({"method_invocation"}),
    call_function_field="name",
    call_accessor_node_types=frozenset(),
    function_boundary_types=frozenset({"method_declaration", "constructor_declaration"}),
    import_handler=_import_java,
)

_GROOVY_CONFIG = LanguageConfig(
    ts_module="tree_sitter_groovy",
    class_types=frozenset({"class_declaration", "interface_declaration"}),
    function_types=frozenset({"method_declaration", "constructor_declaration"}),
    import_types=frozenset({"import_declaration"}),
    call_types=frozenset({"method_invocation"}),
    call_function_field="name",
    call_accessor_node_types=frozenset(),
    function_boundary_types=frozenset({"method_declaration", "constructor_declaration"}),
    import_handler=_import_java,
)

_C_CONFIG = LanguageConfig(
    ts_module="tree_sitter_c",
    class_types=frozenset(),
    function_types=frozenset({"function_definition"}),
    import_types=frozenset({"preproc_include"}),
    call_types=frozenset({"call_expression"}),
    call_function_field="function",
    call_accessor_node_types=frozenset({"field_expression"}),
    call_accessor_field="field",
    function_boundary_types=frozenset({"function_definition"}),
    import_handler=_import_c,
    resolve_function_name_fn=_get_c_func_name,
)

_CPP_CONFIG = LanguageConfig(
    ts_module="tree_sitter_cpp",
    class_types=frozenset({"class_specifier", "struct_specifier"}),
    function_types=frozenset({"function_definition"}),
    import_types=frozenset({"preproc_include"}),
    call_types=frozenset({"call_expression"}),
    call_function_field="function",
    call_accessor_node_types=frozenset({"field_expression", "qualified_identifier"}),
    call_accessor_field="field",
    function_boundary_types=frozenset({"function_definition"}),
    import_handler=_import_c,
    resolve_function_name_fn=_get_cpp_func_name,
)

_RUBY_CONFIG = LanguageConfig(
    ts_module="tree_sitter_ruby",
    class_types=frozenset({"class"}),
    function_types=frozenset({"method", "singleton_method"}),
    import_types=frozenset(),
    call_types=frozenset({"call"}),
    call_function_field="method",
    call_accessor_node_types=frozenset(),
    name_fallback_child_types=("constant", "scope_resolution", "identifier"),
    body_fallback_child_types=("body_statement",),
    function_boundary_types=frozenset({"method", "singleton_method"}),
)

_CSHARP_CONFIG = LanguageConfig(
    ts_module="tree_sitter_c_sharp",
    class_types=frozenset({"class_declaration", "interface_declaration"}),
    function_types=frozenset({"method_declaration"}),
    import_types=frozenset({"using_directive"}),
    call_types=frozenset({"invocation_expression"}),
    call_function_field="function",
    call_accessor_node_types=frozenset({"member_access_expression"}),
    call_accessor_field="name",
    body_fallback_child_types=("declaration_list",),
    function_boundary_types=frozenset({"method_declaration"}),
    import_handler=_import_csharp,
)

_KOTLIN_CONFIG = LanguageConfig(
    ts_module="tree_sitter_kotlin",
    class_types=frozenset({"class_declaration", "object_declaration"}),
    function_types=frozenset({"function_declaration"}),
    import_types=frozenset({"import_header"}),
    call_types=frozenset({"call_expression"}),
    call_function_field="",
    call_accessor_node_types=frozenset({"navigation_expression"}),
    call_accessor_field="",
    # Different tree-sitter-kotlin grammar versions name plain identifier
    # nodes differently: PyPI's `tree_sitter_kotlin` uses `identifier`,
    # older forks use `simple_identifier`. Accept both so the extractor
    # works across grammar generations.
    name_fallback_child_types=("simple_identifier", "identifier"),
    body_fallback_child_types=("function_body", "class_body"),
    function_boundary_types=frozenset({"function_declaration"}),
    import_handler=_import_kotlin,
)

_SCALA_CONFIG = LanguageConfig(
    ts_module="tree_sitter_scala",
    class_types=frozenset({"class_definition", "object_definition"}),
    function_types=frozenset({"function_definition"}),
    import_types=frozenset({"import_declaration"}),
    call_types=frozenset({"call_expression"}),
    call_function_field="",
    call_accessor_node_types=frozenset({"field_expression"}),
    call_accessor_field="field",
    name_fallback_child_types=("identifier",),
    body_fallback_child_types=("template_body",),
    function_boundary_types=frozenset({"function_definition"}),
    import_handler=_import_scala,
)

_PHP_CONFIG = LanguageConfig(
    ts_module="tree_sitter_php",
    ts_language_fn="language_php",
    class_types=frozenset({"class_declaration"}),
    function_types=frozenset({"function_definition", "method_declaration"}),
    import_types=frozenset({"namespace_use_clause"}),
    call_types=frozenset({"function_call_expression", "member_call_expression", "scoped_call_expression", "class_constant_access_expression"}),
    static_prop_types=frozenset({"scoped_property_access_expression"}),
    helper_fn_names=frozenset({"config"}),
    container_bind_methods=frozenset({"bind", "singleton", "scoped", "instance"}),
    event_listener_properties=frozenset({"listen", "subscribe"}),
    call_function_field="function",
    call_accessor_node_types=frozenset({"member_call_expression"}),
    call_accessor_field="name",
    name_fallback_child_types=("name",),
    body_fallback_child_types=("declaration_list", "compound_statement"),
    function_boundary_types=frozenset({"function_definition", "method_declaration"}),
    import_handler=_import_php,
)


def _import_lua(node, source: bytes, file_nid: str, stem: str, edges: list, str_path: str) -> None:
    """Extract require('module') from Lua variable_declaration nodes."""
    text = _read_text(node, source)
    import re
    m = re.search(r"""require\s*[\('"]\s*['"]?([^'")\s]+)""", text)
    if m:
        module_name = m.group(1).split(".")[-1]
        if module_name:
            edges.append({
                "source": file_nid,
                "target": module_name,
                "relation": "imports",
                "context": "import",
                "confidence": "EXTRACTED",
                "confidence_score": 1.0,
                "source_file": str_path,
                "source_location": str(node.start_point[0] + 1),
                "weight": 1.0,
            })


_LUA_CONFIG = LanguageConfig(
    ts_module="tree_sitter_lua",
    ts_language_fn="language",
    class_types=frozenset(),
    function_types=frozenset({"function_declaration"}),
    import_types=frozenset({"variable_declaration"}),
    call_types=frozenset({"function_call"}),
    call_function_field="name",
    call_accessor_node_types=frozenset({"method_index_expression"}),
    call_accessor_field="name",
    name_fallback_child_types=("identifier", "method_index_expression"),
    body_fallback_child_types=("block",),
    function_boundary_types=frozenset({"function_declaration"}),
    import_handler=_import_lua,
)


def _import_swift(node, source: bytes, file_nid: str, stem: str, edges: list, str_path: str) -> None:
    for child in node.children:
        if child.type == "identifier":
            raw = _read_text(child, source)
            tgt_nid = _make_id(raw)
            edges.append({
                "source": file_nid,
                "target": tgt_nid,
                "relation": "imports",
                "context": "import",
                "confidence": "EXTRACTED",
                "source_file": str_path,
                "source_location": f"L{node.start_point[0] + 1}",
                "weight": 1.0,
            })
            break


def _read_csharp_type_name(node, source: bytes) -> str | None:
    """Resolve a readable C# type name from a field/type node."""
    if node is None:
        return None
    if node.type in ("identifier", "predefined_type"):
        return _read_text(node, source)
    if node.type == "qualified_name":
        return _read_text(node, source).split(".")[-1]
    if node.type == "generic_name":
        name_node = node.child_by_field_name("name")
        if name_node is not None:
            return _read_text(name_node, source)
    for child in node.children:
        if not child.is_named:
            continue
        name = _read_csharp_type_name(child, source)
        if name:
            return name
    return None


_SWIFT_CONFIG = LanguageConfig(
    ts_module="tree_sitter_swift",
    class_types=frozenset({"class_declaration", "protocol_declaration"}),
    function_types=frozenset({"function_declaration", "init_declaration", "deinit_declaration", "subscript_declaration"}),
    import_types=frozenset({"import_declaration"}),
    call_types=frozenset({"call_expression"}),
    call_function_field="",
    call_accessor_node_types=frozenset({"navigation_expression"}),
    call_accessor_field="",
    name_fallback_child_types=("simple_identifier", "type_identifier", "user_type"),
    body_fallback_child_types=("class_body", "protocol_body", "function_body", "enum_class_body"),
    function_boundary_types=frozenset({"function_declaration", "init_declaration", "deinit_declaration", "subscript_declaration"}),
    import_handler=_import_swift,
)

# ── Generic extractor ─────────────────────────────────────────────────────────

def _extract_generic(path: Path, config: LanguageConfig) -> dict:
    """Generic AST extractor driven by LanguageConfig."""
    try:
        mod = importlib.import_module(config.ts_module)
        from tree_sitter import Language, Parser
        lang_fn = getattr(mod, config.ts_language_fn, None)
        if lang_fn is None:
            # Fallback for PHP: try "language_php" then "language"
            lang_fn = getattr(mod, "language", None)
        if lang_fn is None:
            return {"nodes": [], "edges": [], "error": f"No language function in {config.ts_module}"}
        language = Language(lang_fn())
    except ImportError:
        return {"nodes": [], "edges": [], "error": f"{config.ts_module} not installed"}
    except TypeError as e:
        # tree-sitter version mismatch: old Language() expects (lib_path),
        # new Language() expects (language_capsule, name). Surface a hint
        # so users see the upgrade path instead of a bare TypeError.
        hint = (
            f"tree-sitter version mismatch for {config.ts_module}: {e}. "
            "Try: pip install --upgrade tree-sitter tree-sitter-languages"
        )
        return {"nodes": [], "edges": [], "error": hint}
    except Exception as e:
        return {"nodes": [], "edges": [], "error": str(e)}

    try:
        parser = Parser(language)
        source = path.read_bytes()
        tree = parser.parse(source)
        root = tree.root_node
    except Exception as e:
        return {"nodes": [], "edges": [], "error": str(e)}

    stem = _file_stem(path)
    str_path = str(path)
    nodes: list[dict] = []
    edges: list[dict] = []
    seen_ids: set[str] = set()
    function_bodies: list[tuple[str, object]] = []
    pending_listen_edges: list[tuple[str, str, int]] = []
    # tree-sitter-swift parses both `class Foo` and `extension Foo` as
    # `class_declaration`. Same-file pairs collapse via seen_ids, but cross-file
    # extensions don't (file stem is part of the id), so they're collected here
    # for a corpus-level merge after every file has been parsed.
    swift_extensions: list[dict] = []

    def add_node(nid: str, label: str, line: int) -> None:
        if nid not in seen_ids:
            seen_ids.add(nid)
            nodes.append({
                "id": nid,
                "label": label,
                "file_type": "code",
                "source_file": str_path,
                "source_location": f"L{line}",
            })

    def add_edge(src: str, tgt: str, relation: str, line: int,
                 confidence: str = "EXTRACTED", weight: float = 1.0,
                 context: str | None = None) -> None:
        edge = {
            "source": src,
            "target": tgt,
            "relation": relation,
            "confidence": confidence,
            "source_file": str_path,
            "source_location": f"L{line}",
            "weight": weight,
        }
        if context:
            edge["context"] = context
        edges.append(edge)

    def ensure_named_node(name: str, line: int) -> str:
        nid = _make_id(stem, name)
        if nid in seen_ids:
            return nid
        nid = _make_id(name)
        if nid not in seen_ids:
            add_node(nid, name, line)
        return nid

    file_nid = _make_id(str(path))
    add_node(file_nid, path.name, 1)

    def walk(node, parent_class_nid: str | None = None) -> None:
        t = node.type

        # Import types
        if t in config.import_types:
            if config.import_handler:
                config.import_handler(node, source, file_nid, stem, edges, str_path)
            return

        # Class types
        if t in config.class_types:
            # Resolve class name
            name_node = node.child_by_field_name(config.name_field)
            if name_node is None:
                for child in node.children:
                    if child.type in config.name_fallback_child_types:
                        name_node = child
                        break
            if not name_node:
                return
            class_name = _read_text(name_node, source)
            class_nid = _make_id(stem, class_name)
            line = node.start_point[0] + 1
            add_node(class_nid, class_name, line)
            add_edge(file_nid, class_nid, "contains", line)

            if config.ts_module == "tree_sitter_swift" and any(
                c.type == "extension" for c in node.children
            ):
                swift_extensions.append({"nid": class_nid, "label": class_name})

            # Python-specific: inheritance
            if config.ts_module == "tree_sitter_python":
                args = node.child_by_field_name("superclasses")
                if args:
                    for arg in args.children:
                        if arg.type == "identifier":
                            base = _read_text(arg, source)
                            base_nid = _make_id(stem, base)
                            if base_nid not in seen_ids:
                                base_nid = _make_id(base)
                                if base_nid not in seen_ids:
                                    nodes.append({
                                        "id": base_nid,
                                        "label": base,
                                        "file_type": "code",
                                        "source_file": "",
                                        "source_location": "",
                                    })
                                    seen_ids.add(base_nid)
                            add_edge(class_nid, base_nid, "inherits", line)

            # Swift-specific: conformance / inheritance
            if config.ts_module == "tree_sitter_swift":
                for child in node.children:
                    if child.type == "inheritance_specifier":
                        for sub in child.children:
                            if sub.type in ("user_type", "type_identifier"):
                                base = _read_text(sub, source)
                                base_nid = _make_id(stem, base)
                                if base_nid not in seen_ids:
                                    base_nid = _make_id(base)
                                    if base_nid not in seen_ids:
                                        nodes.append({
                                            "id": base_nid,
                                            "label": base,
                                            "file_type": "code",
                                            "source_file": "",
                                            "source_location": "",
                                        })
                                        seen_ids.add(base_nid)
                                add_edge(class_nid, base_nid, "inherits", line)

            # C#-specific: inheritance / interface implementation via base_list
            if config.ts_module == "tree_sitter_c_sharp":
                for child in node.children:
                    if child.type == "base_list":
                        for sub in child.children:
                            if sub.type in ("identifier", "generic_name"):
                                if sub.type == "generic_name":
                                    name_child = sub.child_by_field_name("name")
                                    base = _read_text(name_child, source) if name_child else _read_text(sub.children[0], source)
                                else:
                                    base = _read_text(sub, source)
                                base_nid = _make_id(stem, base)
                                if base_nid not in seen_ids:
                                    base_nid = _make_id(base)
                                    if base_nid not in seen_ids:
                                        nodes.append({
                                            "id": base_nid,
                                            "label": base,
                                            "file_type": "code",
                                            "source_file": "",
                                            "source_location": "",
                                        })
                                        seen_ids.add(base_nid)
                                add_edge(class_nid, base_nid, "inherits", line)

            # Java-specific: extends (superclass) / implements (interfaces) / interface-extends
            if config.ts_module == "tree_sitter_java":
                def _emit_java_parent(base_name: str, rel: str, at_line: int) -> None:
                    if not base_name:
                        return
                    base_nid = _make_id(stem, base_name)
                    if base_nid not in seen_ids:
                        base_nid = _make_id(base_name)
                        if base_nid not in seen_ids:
                            nodes.append({
                                "id": base_nid,
                                "label": base_name,
                                "file_type": "code",
                                "source_file": "",
                                "source_location": "",
                            })
                            seen_ids.add(base_nid)
                    add_edge(class_nid, base_nid, rel, at_line)

                sup = node.child_by_field_name("superclass")
                if sup is not None:
                    for sub in sup.children:
                        if sub.type == "type_identifier":
                            _emit_java_parent(_read_text(sub, source), "extends", line)
                            break

                ifs = node.child_by_field_name("interfaces")
                if ifs is not None:
                    for sub in ifs.children:
                        if sub.type == "type_list":
                            for tid in sub.children:
                                if tid.type == "type_identifier":
                                    _emit_java_parent(_read_text(tid, source), "implements", line)

                if t == "interface_declaration":
                    for child in node.children:
                        if child.type == "extends_interfaces":
                            for sub in child.children:
                                if sub.type == "type_list":
                                    for tid in sub.children:
                                        if tid.type == "type_identifier":
                                            _emit_java_parent(_read_text(tid, source), "extends", line)

            # C++-specific: inheritance via base_class_clause (class and struct).
            # tree-sitter-cpp shape:
            #   class_specifier / struct_specifier
            #     base_class_clause
            #       access_specifier? ("public"/"protected"/"private")  -- skip
            #       "virtual"?                                          -- skip
            #       type_identifier                                     -- "Base"
            #       qualified_identifier                                -- "ns::Base"
            #       template_type                                       -- "Vec<int>"
            # Multiple bases are siblings separated by ',' tokens.
            if config.ts_module == "tree_sitter_cpp":
                for child in node.children:
                    if child.type != "base_class_clause":
                        continue
                    for sub in child.children:
                        base = ""
                        if sub.type == "type_identifier":
                            base = _read_text(sub, source)
                        elif sub.type == "qualified_identifier":
                            # Use the unqualified tail so "std::vector" matches
                            # a "vector" node id if one exists in the graph;
                            # fall back to the full qualified text otherwise.
                            tail = sub.child_by_field_name("name")
                            base = _read_text(tail, source) if tail else _read_text(sub, source)
                        elif sub.type == "template_type":
                            tname = sub.child_by_field_name("name")
                            base = _read_text(tname, source) if tname else _read_text(sub, source)
                        else:
                            continue
                        if not base:
                            continue
                        base_nid = _make_id(stem, base)
                        if base_nid not in seen_ids:
                            base_nid = _make_id(base)
                            if base_nid not in seen_ids:
                                nodes.append({
                                    "id": base_nid,
                                    "label": base,
                                    "file_type": "code",
                                    "source_file": "",
                                    "source_location": "",
                                })
                                seen_ids.add(base_nid)
                        add_edge(class_nid, base_nid, "inherits", line)

            # Find body and recurse
            body = _find_body(node, config)
            if body:
                for child in body.children:
                    walk(child, parent_class_nid=class_nid)
            return

        # Event listener property arrays: $listen = [Event::class => [Listener::class]]
        if (t == "property_declaration"
                and parent_class_nid
                and config.event_listener_properties):
            for element in node.children:
                if element.type != "property_element":
                    continue
                prop_name: str | None = None
                array_node = None
                for c in element.children:
                    if c.type == "variable_name":
                        for sc in c.children:
                            if sc.type == "name":
                                prop_name = _read_text(sc, source)
                                break
                    elif c.type == "array_creation_expression":
                        array_node = c
                if (prop_name is None
                        or prop_name not in config.event_listener_properties
                        or array_node is None):
                    continue
                for entry in array_node.children:
                    if entry.type != "array_element_initializer":
                        continue
                    event_cls: str | None = None
                    listener_arr = None
                    for sub in entry.children:
                        if sub.type == "class_constant_access_expression" and event_cls is None:
                            for sc in sub.children:
                                if sc.is_named and sc.type in ("name", "qualified_name"):
                                    event_cls = _read_text(sc, source)
                                    break
                        elif sub.type == "array_creation_expression":
                            listener_arr = sub
                    if not event_cls or listener_arr is None:
                        continue
                    for listener_entry in listener_arr.children:
                        if listener_entry.type != "array_element_initializer":
                            continue
                        for item in listener_entry.children:
                            if item.type != "class_constant_access_expression":
                                continue
                            for sc in item.children:
                                if sc.is_named and sc.type in ("name", "qualified_name"):
                                    listener_cls = _read_text(sc, source)
                                    line_no = item.start_point[0] + 1
                                    pending_listen_edges.append((event_cls, listener_cls, line_no))
                                    break
                            break
            return

        if (config.ts_module == "tree_sitter_c_sharp"
                and t == "field_declaration"
                and parent_class_nid):
            type_node = node.child_by_field_name("type")
            if type_node is None:
                for child in node.children:
                    if child.type == "variable_declaration":
                        type_node = child.child_by_field_name("type")
                        if type_node is not None:
                            break
            type_name = _read_csharp_type_name(type_node, source)
            if type_name:
                line = node.start_point[0] + 1
                add_edge(parent_class_nid, ensure_named_node(type_name, line),
                         "references", line, context="field")
            return

        if (config.ts_module == "tree_sitter_cpp"
                and t == "field_declaration"
                and parent_class_nid):
            # Emit a node for each data member. Use children_by_field_name so we
            # only visit declarator children, not the type node (which would give
            # us the type name, not the field name). Handles int x, y; via
            # multiple declarator fields and static const int MAX = 100; via the
            # init_declarator → field_identifier recursion in _get_cpp_func_name.
            for decl in node.children_by_field_name("declarator"):
                name = _get_cpp_func_name(decl, source)
                if name:
                    line = decl.start_point[0] + 1
                    field_nid = _make_id(parent_class_nid, name)
                    add_node(field_nid, name, line)
                    add_edge(parent_class_nid, field_nid, "defines", line, context="field")
            return

        # Function types
        if t in config.function_types:
            # Swift deinit/subscript have no name field — resolve before generic fallback
            if t == "deinit_declaration":
                func_name: str | None = "deinit"
            elif t == "subscript_declaration":
                func_name = "subscript"
            elif config.resolve_function_name_fn is not None:
                # C/C++ style: use declarator
                declarator = node.child_by_field_name("declarator")
                func_name = None
                if declarator:
                    func_name = config.resolve_function_name_fn(declarator, source)
            else:
                name_node = node.child_by_field_name(config.name_field)
                if name_node is None:
                    for child in node.children:
                        if child.type in config.name_fallback_child_types:
                            name_node = child
                            break
                func_name = _read_text(name_node, source) if name_node else None

            if not func_name:
                return

            line = node.start_point[0] + 1
            if parent_class_nid:
                func_nid = _make_id(parent_class_nid, func_name)
                add_node(func_nid, f".{func_name}()", line)
                add_edge(parent_class_nid, func_nid, "method", line)
            else:
                func_nid = _make_id(stem, func_name)
                add_node(func_nid, f"{func_name}()", line)
                add_edge(file_nid, func_nid, "contains", line)

            body = _find_body(node, config)
            if body:
                function_bodies.append((func_nid, body))
            return

        # JS/TS arrow functions and C# namespaces — language-specific extra handling
        if config.ts_module in ("tree_sitter_javascript", "tree_sitter_typescript"):
            if _js_extra_walk(node, source, file_nid, stem, str_path,
                              nodes, edges, seen_ids, function_bodies,
                              parent_class_nid, add_node, add_edge):
                return

        if config.ts_module == "tree_sitter_c_sharp":
            if _csharp_extra_walk(node, source, file_nid, stem, str_path,
                                   nodes, edges, seen_ids, function_bodies,
                                   parent_class_nid, add_node, add_edge, walk):
                return

        if config.ts_module == "tree_sitter_swift":
            if _swift_extra_walk(node, source, file_nid, stem, str_path,
                                  nodes, edges, seen_ids, function_bodies,
                                  parent_class_nid, add_node, add_edge):
                return

        # Default: recurse
        for child in node.children:
            walk(child, parent_class_nid=None)

    walk(root)

    # ── Call-graph pass ───────────────────────────────────────────────────────
    label_to_nid: dict[str, str] = {}
    for n in nodes:
        raw = n["label"]
        normalised = raw.strip("()").lstrip(".")
        label_to_nid[normalised.lower()] = n["id"]

    seen_call_pairs: set[tuple[str, str]] = set()
    seen_dyn_import_pairs: set[tuple[str, str]] = set()
    seen_static_ref_pairs: set[tuple[str, str, str]] = set()
    seen_helper_ref_pairs: set[tuple[str, str, str]] = set()
    seen_bind_pairs: set[tuple[str, str, str]] = set()
    raw_calls: list[dict] = []  # unresolved calls for cross-file resolution in extract()

    def _php_class_const_scope(n) -> str | None:
        scope = n.child_by_field_name("scope")
        if scope is None:
            for c in n.children:
                if c.is_named and c.type in ("name", "qualified_name", "identifier"):
                    scope = c
                    break
        if scope is None:
            return None
        return _read_text(scope, source)

    def walk_calls(node, caller_nid: str) -> None:
        if node.type in config.function_boundary_types:
            return

        if node.type in config.call_types:
            # JS/TS dynamic imports: await import('./foo.js')
            if config.ts_module in ("tree_sitter_javascript", "tree_sitter_typescript"):
                if _dynamic_import_js(node, source, caller_nid, str_path,
                                      edges, seen_dyn_import_pairs):
                    # Still recurse into children (import().then(...) may have calls)
                    for child in node.children:
                        walk_calls(child, caller_nid)
                    return

            callee_name: str | None = None
            is_member_call: bool = False

            # Special handling per language
            if config.ts_module == "tree_sitter_swift":
                # Swift: first child may be simple_identifier or navigation_expression
                first = node.children[0] if node.children else None
                if first:
                    if first.type == "simple_identifier":
                        callee_name = _read_text(first, source)
                    elif first.type == "navigation_expression":
                        is_member_call = True
                        for child in first.children:
                            if child.type == "navigation_suffix":
                                for sc in child.children:
                                    if sc.type == "simple_identifier":
                                        callee_name = _read_text(sc, source)
            elif config.ts_module == "tree_sitter_kotlin":
                # Kotlin: first child may be simple_identifier/identifier or
                # navigation_expression. PyPI's `tree_sitter_kotlin` produces
                # `identifier` for plain identifier nodes; older grammar
                # versions (including the JVM `io.github.bonede:tree-sitter-kotlin`
                # binding) produce `simple_identifier`. Accept both.
                first = node.children[0] if node.children else None
                if first:
                    if first.type in ("simple_identifier", "identifier"):
                        callee_name = _read_text(first, source)
                    elif first.type == "navigation_expression":
                        is_member_call = True
                        for child in reversed(first.children):
                            if child.type in ("simple_identifier", "identifier"):
                                callee_name = _read_text(child, source)
                                break
            elif config.ts_module == "tree_sitter_scala":
                # Scala: first child
                first = node.children[0] if node.children else None
                if first:
                    if first.type == "identifier":
                        callee_name = _read_text(first, source)
                    elif first.type == "field_expression":
                        is_member_call = True
                        field = first.child_by_field_name("field")
                        if field:
                            callee_name = _read_text(field, source)
                        else:
                            for child in reversed(first.children):
                                if child.type == "identifier":
                                    callee_name = _read_text(child, source)
                                    break
            elif config.ts_module == "tree_sitter_c_sharp" and node.type == "invocation_expression":
                # C#: try name field, then first named child
                name_node = node.child_by_field_name("name")
                if name_node:
                    callee_name = _read_text(name_node, source)
                else:
                    for child in node.children:
                        if child.is_named:
                            raw = _read_text(child, source)
                            if "." in raw:
                                callee_name = raw.split(".")[-1]
                                is_member_call = True
                            else:
                                callee_name = raw
                            break
            elif config.ts_module == "tree_sitter_php":
                # PHP: distinguish call expression subtypes
                if node.type == "function_call_expression":
                    func_node = node.child_by_field_name("function")
                    if func_node:
                        callee_name = _read_text(func_node, source)
                elif node.type == "scoped_call_expression":
                    # Static method call: Helper::format() → callee = "Helper"
                    scope_node = node.child_by_field_name("scope")
                    if scope_node:
                        callee_name = _read_text(scope_node, source)
                else:
                    # member_call_expression: $obj->method()
                    is_member_call = True
                    name_node = node.child_by_field_name("name")
                    if name_node:
                        callee_name = _read_text(name_node, source)
            elif config.ts_module == "tree_sitter_cpp":
                # C++: function field, then field_expression/qualified_identifier
                func_node = node.child_by_field_name(config.call_function_field) if config.call_function_field else None
                if func_node:
                    if func_node.type == "identifier":
                        callee_name = _read_text(func_node, source)
                    elif func_node.type in ("field_expression", "qualified_identifier"):
                        is_member_call = True
                        name = func_node.child_by_field_name("field") or func_node.child_by_field_name("name")
                        if name:
                            callee_name = _read_text(name, source)
            else:
                # Generic: get callee from call_function_field
                func_node = node.child_by_field_name(config.call_function_field) if config.call_function_field else None
                if func_node:
                    if func_node.type == "identifier":
                        callee_name = _read_text(func_node, source)
                    elif func_node.type in config.call_accessor_node_types:
                        is_member_call = True
                        if config.call_accessor_field:
                            attr = func_node.child_by_field_name(config.call_accessor_field)
                            if attr:
                                callee_name = _read_text(attr, source)
                    else:
                        # Try reading the node directly (e.g. Java name field is the callee)
                        callee_name = _read_text(func_node, source)

            if callee_name:
                tgt_nid = label_to_nid.get(callee_name.lower())
                if tgt_nid and tgt_nid != caller_nid:
                    pair = (caller_nid, tgt_nid)
                    if pair not in seen_call_pairs:
                        seen_call_pairs.add(pair)
                        line = node.start_point[0] + 1
                        edges.append({
                            "source": caller_nid,
                            "target": tgt_nid,
                            "relation": "calls",
                            "context": "call",
                            "confidence": "EXTRACTED",
                            "source_file": str_path,
                            "source_location": f"L{line}",
                            "weight": 1.0,
                        })
                elif callee_name and not tgt_nid:
                    # Callee not in this file — save for cross-file resolution in extract()
                    raw_calls.append({
                        "caller_nid": caller_nid,
                        "callee": callee_name,
                        "is_member_call": is_member_call,
                        "source_file": str_path,
                        "source_location": f"L{node.start_point[0] + 1}",
                    })

            # Helper function calls: config('foo.bar') → uses_config edge to "foo"
            if (callee_name and callee_name in config.helper_fn_names):
                args_node = node.child_by_field_name("arguments")
                first_key: str | None = None
                if args_node:
                    for arg in args_node.children:
                        if arg.type != "argument":
                            continue
                        for inner in arg.children:
                            if inner.type == "string":
                                for sc in inner.children:
                                    if sc.type == "string_content":
                                        first_key = _read_text(sc, source)
                                        break
                                break
                        if first_key:
                            break
                if first_key:
                    segment = first_key.split(".")[0]
                    tgt_nid = (label_to_nid.get(segment.lower())
                               or label_to_nid.get(f"{segment}.php".lower()))
                    if tgt_nid and tgt_nid != caller_nid:
                        relation = f"uses_{callee_name}"
                        pair3 = (caller_nid, tgt_nid, relation)
                        if pair3 not in seen_helper_ref_pairs:
                            seen_helper_ref_pairs.add(pair3)
                            line = node.start_point[0] + 1
                            edges.append({
                                "source": caller_nid,
                                "target": tgt_nid,
                                "relation": relation,
                                "confidence": "EXTRACTED",
                                "confidence_score": 1.0,
                                "source_file": str_path,
                                "source_location": f"L{line}",
                                "weight": 1.0,
                            })

            # Service container bindings: $this->app->bind(Foo::class, Bar::class)
            if (node.type == "member_call_expression"
                    and callee_name
                    and callee_name in config.container_bind_methods):
                args_node = node.child_by_field_name("arguments")
                class_args: list[str] = []
                if args_node:
                    for arg in args_node.children:
                        if arg.type != "argument":
                            continue
                        for inner in arg.children:
                            if inner.type == "class_constant_access_expression":
                                cls = _php_class_const_scope(inner)
                                if cls:
                                    class_args.append(cls)
                                break
                        if len(class_args) >= 2:
                            break
                if len(class_args) == 2:
                    contract_name, impl_name = class_args
                    contract_nid = label_to_nid.get(contract_name.lower())
                    impl_nid = label_to_nid.get(impl_name.lower())
                    if contract_nid and impl_nid and contract_nid != impl_nid:
                        pair3 = (contract_nid, impl_nid, "bound_to")
                        if pair3 not in seen_bind_pairs:
                            seen_bind_pairs.add(pair3)
                            line = node.start_point[0] + 1
                            edges.append({
                                "source": contract_nid,
                                "target": impl_nid,
                                "relation": "bound_to",
                                "confidence": "EXTRACTED",
                                "confidence_score": 1.0,
                                "source_file": str_path,
                                "source_location": f"L{line}",
                                "weight": 1.0,
                            })

        # Static property access: Foo::$bar → uses_static_prop edge
        if node.type in config.static_prop_types:
            scope_node = node.child_by_field_name("scope")
            if scope_node is None:
                for child in node.children:
                    if child.is_named and child.type in ("name", "qualified_name", "identifier"):
                        scope_node = child
                        break
            if scope_node is not None:
                class_name = _read_text(scope_node, source)
                tgt_nid = label_to_nid.get(class_name.lower())
                if tgt_nid and tgt_nid != caller_nid:
                    pair3 = (caller_nid, tgt_nid, "uses_static_prop")
                    if pair3 not in seen_static_ref_pairs:
                        seen_static_ref_pairs.add(pair3)
                        line = node.start_point[0] + 1
                        edges.append({
                            "source": caller_nid,
                            "target": tgt_nid,
                            "relation": "uses_static_prop",
                            "confidence": "EXTRACTED",
                            "confidence_score": 1.0,
                            "source_file": str_path,
                            "source_location": f"L{line}",
                            "weight": 1.0,
                        })

        # PHP class constant access: Foo::BAR → references_constant edge
        if config.ts_module == "tree_sitter_php" and node.type == "class_constant_access_expression":
            class_name = _php_class_const_scope(node)
            if class_name:
                tgt_nid = label_to_nid.get(class_name.lower())
                if tgt_nid and tgt_nid != caller_nid:
                    pair3 = (caller_nid, tgt_nid, "references_constant")
                    if pair3 not in seen_static_ref_pairs:
                        seen_static_ref_pairs.add(pair3)
                        line = node.start_point[0] + 1
                        edges.append({
                            "source": caller_nid,
                            "target": tgt_nid,
                            "relation": "references_constant",
                            "confidence": "EXTRACTED",
                            "confidence_score": 1.0,
                            "source_file": str_path,
                            "source_location": f"L{line}",
                            "weight": 1.0,
                        })

        for child in node.children:
            walk_calls(child, caller_nid)

    for caller_nid, body_node in function_bodies:
        walk_calls(body_node, caller_nid)

    # ── Event listener pass ───────────────────────────────────────────────────
    seen_listen_pairs: set[tuple[str, str]] = set()
    for event_name, listener_name, line in pending_listen_edges:
        event_nid = label_to_nid.get(event_name.lower())
        listener_nid = label_to_nid.get(listener_name.lower())
        if not event_nid or not listener_nid or event_nid == listener_nid:
            continue
        pair2 = (event_nid, listener_nid)
        if pair2 in seen_listen_pairs:
            continue
        seen_listen_pairs.add(pair2)
        edges.append({
            "source": event_nid,
            "target": listener_nid,
            "relation": "listened_by",
            "confidence": "EXTRACTED",
            "confidence_score": 1.0,
            "source_file": str_path,
            "source_location": f"L{line}",
            "weight": 1.0,
        })

    # ── Clean edges ───────────────────────────────────────────────────────────
    valid_ids = seen_ids
    clean_edges = []
    for edge in edges:
        src, tgt = edge["source"], edge["target"]
        if src in valid_ids and (tgt in valid_ids or edge["relation"] in ("imports", "imports_from")):
            clean_edges.append(edge)

    result = {"nodes": nodes, "edges": clean_edges, "raw_calls": raw_calls}
    if swift_extensions:
        result["swift_extensions"] = swift_extensions
    return result


# ── Python rationale extraction ───────────────────────────────────────────────

_RATIONALE_PREFIXES = ("# NOTE:", "# IMPORTANT:", "# HACK:", "# WHY:", "# RATIONALE:", "# TODO:", "# FIXME:")


def _is_autogenerated_python(source: bytes) -> bool:
    """Return True if this Python file is auto-generated and its module docstring is noise.

    Covers: Alembic/Flask-Migrate revisions, Django migrations, protobuf/gRPC/OpenAPI stubs.
    Module docstrings in these files are change annotations or boilerplate, not rationale.
    """
    head = source[:2048].decode("utf-8", errors="replace")
    # Generic generated-file markers (protobuf, gRPC, OpenAPI codegen, etc.)
    if any(m in head for m in ("DO NOT EDIT", "@generated", "Generated by the protocol buffer")):
        return True
    # Alembic / Flask-Migrate revision files
    if (re.search(r"^revision\s*[:=]", head, re.MULTILINE)
            and "def upgrade(" in head
            and "down_revision" in head):
        return True
    # Django migrations
    if "class Migration(migrations.Migration)" in head and "operations" in head:
        return True
    return False


def _extract_python_rationale(path: Path, result: dict) -> None:
    """Post-pass: extract docstrings and rationale comments from Python source.
    Mutates result in-place by appending to result['nodes'] and result['edges'].
    """
    try:
        import tree_sitter_python as tspython
        from tree_sitter import Language, Parser
        language = Language(tspython.language())
        parser = Parser(language)
        source = path.read_bytes()
        tree = parser.parse(source)
        root = tree.root_node
    except Exception:
        return

    stem = _file_stem(path)
    str_path = str(path)
    nodes = result["nodes"]
    edges = result["edges"]
    seen_ids = {n["id"] for n in nodes}
    file_nid = _make_id(str(path))

    def _get_docstring(body_node) -> tuple[str, int] | None:
        if not body_node:
            return None
        for child in body_node.children:
            if child.type == "expression_statement":
                for sub in child.children:
                    if sub.type in ("string", "concatenated_string"):
                        text = source[sub.start_byte:sub.end_byte].decode("utf-8", errors="replace")
                        text = text.strip("\"'").strip('"""').strip("'''").strip()
                        if len(text) > 20:
                            return text, child.start_point[0] + 1
            break
        return None

    def _add_rationale(text: str, line: int, parent_nid: str) -> None:
        label = text[:80].replace("\r\n", " ").replace("\r", " ").replace("\n", " ").strip()
        rid = _make_id(stem, "rationale", str(line))
        if rid not in seen_ids:
            seen_ids.add(rid)
            nodes.append({
                "id": rid,
                "label": label,
                "file_type": "rationale",
                "source_file": str_path,
                "source_location": f"L{line}",
            })
        edges.append({
            "source": rid,
            "target": parent_nid,
            "relation": "rationale_for",
            "confidence": "EXTRACTED",
            "source_file": str_path,
            "source_location": f"L{line}",
            "weight": 1.0,
        })

    # Module-level docstring — skip for auto-generated files (Alembic, Django
    # migrations, protobuf stubs, etc.) whose module docstrings are revision
    # annotations, not architectural rationale.
    if not _is_autogenerated_python(source):
        ds = _get_docstring(root)
        if ds:
            _add_rationale(ds[0], ds[1], file_nid)

    # Class and function docstrings
    def walk_docstrings(node, parent_nid: str) -> None:
        t = node.type
        if t == "class_definition":
            name_node = node.child_by_field_name("name")
            body = node.child_by_field_name("body")
            if name_node and body:
                class_name = source[name_node.start_byte:name_node.end_byte].decode("utf-8", errors="replace")
                nid = _make_id(stem, class_name)
                ds = _get_docstring(body)
                if ds:
                    _add_rationale(ds[0], ds[1], nid)
                for child in body.children:
                    walk_docstrings(child, nid)
            return
        if t == "function_definition":
            name_node = node.child_by_field_name("name")
            body = node.child_by_field_name("body")
            if name_node and body:
                func_name = source[name_node.start_byte:name_node.end_byte].decode("utf-8", errors="replace")
                nid = _make_id(parent_nid, func_name) if parent_nid != file_nid else _make_id(stem, func_name)
                ds = _get_docstring(body)
                if ds:
                    _add_rationale(ds[0], ds[1], nid)
            return
        for child in node.children:
            walk_docstrings(child, parent_nid)

    walk_docstrings(root, file_nid)

    # Rationale comments (# NOTE:, # IMPORTANT:, etc.)
    source_text = source.decode("utf-8", errors="replace")
    for lineno, line_text in enumerate(source_text.splitlines(), start=1):
        stripped = line_text.strip()
        if any(stripped.startswith(p) for p in _RATIONALE_PREFIXES):
            _add_rationale(stripped, lineno, file_nid)


# ── Public API ────────────────────────────────────────────────────────────────

def extract_python(path: Path) -> dict:
    """Extract classes, functions, and imports from a .py file via tree-sitter AST."""
    result = _extract_generic(path, _PYTHON_CONFIG)
    if "error" not in result:
        _extract_python_rationale(path, result)
    return result


def extract_js(path: Path) -> dict:
    """Extract classes, functions, arrow functions, and imports from a .js/.ts/.tsx file."""
    if path.suffix == ".tsx":
        config = _TSX_CONFIG
    elif path.suffix == ".ts":
        config = _TS_CONFIG
    else:
        config = _JS_CONFIG
    return _extract_generic(path, config)


def extract_svelte(path: Path) -> dict:
    """Extract imports from .svelte files: script-block via JS AST + template regex fallback.

    Tree-sitter only sees the <script> block. Svelte template syntax like
    {#await import('./X.svelte')} lives in the markup layer and is invisible
    to the JS parser, so a regex pass covers those dynamic imports.
    """
    result = _extract_generic(path, _JS_CONFIG)
    try:
        import re as _re
        src = path.read_text(encoding="utf-8", errors="replace")
        existing_ids = {n["id"] for n in result.get("nodes", [])}
        # Source file node ID must match the one _extract_generic creates:
        # _make_id(str(path)) - single arg, no stem prefix. Otherwise the source
        # endpoint is a phantom node and build_from_json drops the edge (#701).
        file_node_id = _make_id(str(path))
        aliases = _load_tsconfig_aliases(path.parent)
        for m in _re.finditer(r"""import\(\s*['"]([^'"]+)['"]\s*\)""", src):
            raw = m.group(1)
            if not raw:
                continue
            if raw.startswith("."):
                # Relative import - resolve to full path so IDs match file node IDs.
                resolved = Path(os.path.normpath(path.parent / raw))
                # Apply same TS/Svelte resolver fixups as static imports so dynamic
                # imports of bare paths and .svelte.ts rune files land on real
                # file nodes instead of phantom ids (#716).
                resolved = _resolve_js_module_path(resolved)
                node_id = _make_id(str(resolved))
                stub_source_file = str(resolved)
            else:
                # Check tsconfig.json path aliases (e.g. "$lib/" -> "src/lib/", "@/" -> "src/")
                # before treating as external. Mirrors _import_js logic so SvelteKit alias
                # imports resolve to the same file node IDs the extractor creates (#701).
                resolved_alias = None
                for alias_prefix, alias_base in aliases.items():
                    if raw == alias_prefix or raw.startswith(alias_prefix + "/"):
                        rest = raw[len(alias_prefix):].lstrip("/")
                        resolved_alias = Path(os.path.normpath(Path(alias_base) / rest))
                        break
                if resolved_alias is not None:
                    resolved_alias = _resolve_js_module_path(resolved_alias)
                    node_id = _make_id(str(resolved_alias))
                    stub_source_file = str(resolved_alias)
                else:
                    # Bare/scoped import (node_modules) - use last segment;
                    # build_from_json drops as external if no matching node exists.
                    module_name = raw.split("/")[-1]
                    if not module_name:
                        continue
                    node_id = _make_id(module_name)
                    stub_source_file = raw
            if node_id in existing_ids:
                # Edge target already a real node - just add the edge, don't add a node.
                result.setdefault("edges", []).append({
                    "source": file_node_id, "target": node_id,
                    "relation": "dynamic_import", "confidence": "EXTRACTED",
                    "source_file": str(path),
                })
                continue
            result.setdefault("nodes", []).append({
                "id": node_id, "label": raw,
                "file_type": "code", "source_file": stub_source_file,
                "confidence": "EXTRACTED",
            })
            result.setdefault("edges", []).append({
                "source": file_node_id, "target": node_id,
                "relation": "dynamic_import", "confidence": "EXTRACTED",
                "source_file": str(path),
            })
            existing_ids.add(node_id)
        # Static imports inside <script> blocks. The JS tree-sitter parser fed
        # the full .svelte file produces a top-level ERROR node (HTML markup
        # is not valid JS), so import_statement nodes are never reached and
        # static imports are silently dropped (#713). Regex over each script
        # body recovers them.
        script_re = _re.compile(
            r"<script\b[^>]*>([\s\S]*?)</script\s*>", _re.IGNORECASE
        )
        static_import_re = _re.compile(
            r"""import\s+(?:[^'"`;]+?\s+from\s+)?['"]([^'"]+)['"]"""
        )
        for script_match in script_re.finditer(src):
            script_body = script_match.group(1)
            for m in static_import_re.finditer(script_body):
                raw = m.group(1)
                if not raw:
                    continue
                if raw.startswith("."):
                    resolved = Path(os.path.normpath(path.parent / raw))
                    if resolved.suffix == ".js":
                        resolved = resolved.with_suffix(".ts")
                    elif resolved.suffix == ".jsx":
                        resolved = resolved.with_suffix(".tsx")
                    node_id = _make_id(str(resolved))
                    stub_source_file = str(resolved)
                else:
                    resolved_alias = None
                    for alias_prefix, alias_base in aliases.items():
                        if raw == alias_prefix or raw.startswith(alias_prefix + "/"):
                            rest = raw[len(alias_prefix):].lstrip("/")
                            resolved_alias = Path(os.path.normpath(Path(alias_base) / rest))
                            break
                    if resolved_alias is not None:
                        node_id = _make_id(str(resolved_alias))
                        stub_source_file = str(resolved_alias)
                    else:
                        module_name = raw.split("/")[-1]
                        if not module_name:
                            continue
                        node_id = _make_id(module_name)
                        stub_source_file = raw
                if node_id in existing_ids:
                    result.setdefault("edges", []).append({
                        "source": file_node_id, "target": node_id,
                        "relation": "imports_from", "confidence": "EXTRACTED",
                        "source_file": str(path),
                    })
                    continue
                result.setdefault("nodes", []).append({
                    "id": node_id, "label": raw,
                    "file_type": "code", "source_file": stub_source_file,
                    "confidence": "EXTRACTED",
                })
                result.setdefault("edges", []).append({
                    "source": file_node_id, "target": node_id,
                    "relation": "imports_from", "confidence": "EXTRACTED",
                    "source_file": str(path),
                })
                existing_ids.add(node_id)
    except Exception:
        pass
    return result


def extract_astro(path: Path) -> dict:
    """Extract imports from .astro files: frontmatter (TS) + template regex fallback.

    Astro files start with a ``---\\n...\\n---`` frontmatter block of TypeScript
    setup code (where almost all imports live), followed by an HTML-with-expressions
    template body, and optionally ``<script>`` blocks for client-side JS. Tree-sitter
    only sees the file usefully through the frontmatter — feeding the whole file to
    the JS parser produces a top-level ERROR node because the template is not valid
    JS, so ``import_statement`` nodes are never reached and static imports are
    silently dropped (#850). Mirrors :func:`extract_svelte` — same regex-rescue
    approach, scanning the frontmatter block and any client-side ``<script>`` blocks
    for static and dynamic imports.
    """
    result = _extract_generic(path, _JS_CONFIG)
    try:
        import re as _re
        src = path.read_text(encoding="utf-8", errors="replace")
        existing_ids = {n["id"] for n in result.get("nodes", [])}
        file_node_id = _make_id(str(path))
        aliases = _load_tsconfig_aliases(path.parent)
        # Dynamic imports anywhere in the file: `import('./X.astro')` is legal in
        # frontmatter setup code and inside expression slots.
        for m in _re.finditer(r"""import\(\s*['"]([^'"]+)['"]\s*\)""", src):
            raw = m.group(1)
            if not raw:
                continue
            if raw.startswith("."):
                resolved = Path(os.path.normpath(path.parent / raw))
                resolved = _resolve_js_module_path(resolved)
                node_id = _make_id(str(resolved))
                stub_source_file = str(resolved)
            else:
                resolved_alias = None
                for alias_prefix, alias_base in aliases.items():
                    if raw == alias_prefix or raw.startswith(alias_prefix + "/"):
                        rest = raw[len(alias_prefix):].lstrip("/")
                        resolved_alias = Path(os.path.normpath(Path(alias_base) / rest))
                        break
                if resolved_alias is not None:
                    resolved_alias = _resolve_js_module_path(resolved_alias)
                    node_id = _make_id(str(resolved_alias))
                    stub_source_file = str(resolved_alias)
                else:
                    module_name = raw.split("/")[-1]
                    if not module_name:
                        continue
                    node_id = _make_id(module_name)
                    stub_source_file = raw
            if node_id in existing_ids:
                result.setdefault("edges", []).append({
                    "source": file_node_id, "target": node_id,
                    "relation": "dynamic_import", "confidence": "EXTRACTED",
                    "source_file": str(path),
                })
                continue
            result.setdefault("nodes", []).append({
                "id": node_id, "label": raw,
                "file_type": "code", "source_file": stub_source_file,
                "confidence": "EXTRACTED",
            })
            result.setdefault("edges", []).append({
                "source": file_node_id, "target": node_id,
                "relation": "dynamic_import", "confidence": "EXTRACTED",
                "source_file": str(path),
            })
            existing_ids.add(node_id)
        # Static imports: scan the `---...---` frontmatter at the file head plus any
        # client-side <script> blocks. Both are TS/JS regions but live inside a file
        # the JS tree-sitter parser cannot validate as a whole.
        frontmatter_re = _re.compile(
            r"\A\s*---\s*\r?\n([\s\S]*?)\r?\n---\s*(?:\r?\n|\Z)"
        )
        script_re = _re.compile(
            r"<script\b[^>]*>([\s\S]*?)</script\s*>", _re.IGNORECASE
        )
        static_import_re = _re.compile(
            r"""import\s+(?:[^'"`;]+?\s+from\s+)?['"]([^'"]+)['"]"""
        )
        regions: list[str] = []
        fm = frontmatter_re.search(src)
        if fm:
            regions.append(fm.group(1))
        for script_match in script_re.finditer(src):
            regions.append(script_match.group(1))
        for region in regions:
            for m in static_import_re.finditer(region):
                raw = m.group(1)
                if not raw:
                    continue
                if raw.startswith("."):
                    resolved = Path(os.path.normpath(path.parent / raw))
                    if resolved.suffix == ".js":
                        resolved = resolved.with_suffix(".ts")
                    elif resolved.suffix == ".jsx":
                        resolved = resolved.with_suffix(".tsx")
                    node_id = _make_id(str(resolved))
                    stub_source_file = str(resolved)
                else:
                    resolved_alias = None
                    for alias_prefix, alias_base in aliases.items():
                        if raw == alias_prefix or raw.startswith(alias_prefix + "/"):
                            rest = raw[len(alias_prefix):].lstrip("/")
                            resolved_alias = Path(os.path.normpath(Path(alias_base) / rest))
                            break
                    if resolved_alias is not None:
                        node_id = _make_id(str(resolved_alias))
                        stub_source_file = str(resolved_alias)
                    else:
                        module_name = raw.split("/")[-1]
                        if not module_name:
                            continue
                        node_id = _make_id(module_name)
                        stub_source_file = raw
                if node_id in existing_ids:
                    result.setdefault("edges", []).append({
                        "source": file_node_id, "target": node_id,
                        "relation": "imports_from", "confidence": "EXTRACTED",
                        "source_file": str(path),
                    })
                    continue
                result.setdefault("nodes", []).append({
                    "id": node_id, "label": raw,
                    "file_type": "code", "source_file": stub_source_file,
                    "confidence": "EXTRACTED",
                })
                result.setdefault("edges", []).append({
                    "source": file_node_id, "target": node_id,
                    "relation": "imports_from", "confidence": "EXTRACTED",
                    "source_file": str(path),
                })
                existing_ids.add(node_id)
    except Exception:
        pass
    return result


def extract_java(path: Path) -> dict:
    """Extract classes, interfaces, methods, constructors, and imports from a .java file."""
    return _extract_generic(path, _JAVA_CONFIG)


def _is_spock_file(path: Path, ts_result: dict) -> bool:
    """Return True when the file contains Spock-style ``def "feature"()`` methods
    that tree-sitter-groovy cannot parse, detected by checking the raw source."""
    import re as _re
    _SPOCK_FEATURE_RE = _re.compile(r"""^\s*def\s+[\"']""", _re.MULTILINE)
    try:
        return bool(_SPOCK_FEATURE_RE.search(path.read_text(errors="replace")))
    except OSError:
        return False


def _extract_spock_fallback(path: Path, ts_result: dict) -> dict:
    """Regex-based fallback for Spock spec files where tree-sitter-groovy cannot parse
    ``def "feature name"()`` methods. Merges import edges from the tree-sitter pass
    (which survive reliably) with class and feature-method nodes extracted via regex.
    """
    import re as _re
    source = path.read_text(errors="replace")
    str_path = str(path)
    stem = _file_stem(path)

    # Only keep the file node from the tree-sitter pass (guaranteed present and
    # correctly IDed) plus all import edges.  All other ts nodes are discarded to
    # avoid orphaned method/constructor nodes whose parent edges were dropped.
    file_node = next((n for n in ts_result.get("nodes", []) if n.get("label") == path.name), None)
    nodes: list[dict] = [file_node] if file_node else []
    edges: list[dict] = [e for e in ts_result.get("edges", []) if e.get("context") == "import"]
    seen_ids: set[str] = {n["id"] for n in nodes}

    def _add_node(nid: str, label: str, line: int) -> None:
        if nid not in seen_ids:
            seen_ids.add(nid)
            nodes.append({
                "id": nid,
                "label": label,
                "file_type": "code",
                "source_file": str_path,
                "source_location": f"L{line}",
            })

    def _add_edge(src: str, tgt: str, relation: str, line: int,
                  confidence: str = "EXTRACTED") -> None:
        edges.append({
            "source": src,
            "target": tgt,
            "relation": relation,
            "confidence": confidence,
            "source_file": str_path,
            "source_location": f"L{line}",
            "weight": 1.0,
        })

    lines_text = source.splitlines()

    # Extract class declarations
    class_re = _re.compile(r"^\s*(?:[\w@]+\s+)*class\s+(\w+)")
    # Extract Spock feature methods: def "..." () or def '...' ()
    # Two separate capture groups per quote style so apostrophes inside
    # double-quoted names (e.g. "shouldn't") are captured correctly.
    feature_re = _re.compile(r"""^\s*def\s+(?:\"([^\"]+)\"|'([^']+)')\s*\(""")
    # Extract plain def methods (non-string names) as well
    plain_method_re = _re.compile(r"""^\s*def\s+(\w+)\s*\(""")

    current_class_nid: str | None = None
    file_nid = _make_id(str_path)

    # Ensure the file node exists (tree-sitter pass may have emitted it)
    if file_nid not in seen_ids:
        _add_node(file_nid, path.name, 1)

    for lineno, line_text in enumerate(lines_text, start=1):
        cm = class_re.match(line_text)
        if cm:
            class_name = cm.group(1)
            class_nid = _make_id(stem, class_name)
            _add_node(class_nid, class_name, lineno)
            _add_edge(file_nid, class_nid, "contains", lineno)
            current_class_nid = class_nid
            continue

        if current_class_nid is None:
            continue

        fm = feature_re.match(line_text)
        if fm:
            method_name = fm.group(1) or fm.group(2)
            method_label = f'"{method_name}"'
            method_nid = _make_id(current_class_nid, method_name)
            _add_node(method_nid, method_label, lineno)
            _add_edge(current_class_nid, method_nid, "method", lineno)
            continue

        pm = plain_method_re.match(line_text)
        if pm:
            method_name = pm.group(1)
            if method_name not in ("if", "while", "for", "switch", "catch"):
                method_label = f".{method_name}()"
                method_nid = _make_id(current_class_nid, method_name)
                _add_node(method_nid, method_label, lineno)
                _add_edge(current_class_nid, method_nid, "method", lineno)

    return {"nodes": nodes, "edges": edges}


def extract_groovy(path: Path) -> dict:
    """Extract classes, methods, constructors, and imports from a .groovy/.gradle file.

    Falls back to a regex-based Spock extractor when tree-sitter-groovy cannot parse
    ``def "feature name"()`` methods (common in Spock specification classes).
    """
    result = _extract_generic(path, _GROOVY_CONFIG)
    if _is_spock_file(path, result):
        result = _extract_spock_fallback(path, result)
    return result


def extract_c(path: Path) -> dict:
    """Extract functions and includes from a .c/.h file."""
    return _extract_generic(path, _C_CONFIG)


def extract_cpp(path: Path) -> dict:
    """Extract functions, classes, and includes from a .cpp/.cc/.cxx/.hpp file."""
    return _extract_generic(path, _CPP_CONFIG)


def extract_ruby(path: Path) -> dict:
    """Extract classes, methods, singleton methods, and calls from a .rb file."""
    return _extract_generic(path, _RUBY_CONFIG)


def extract_csharp(path: Path) -> dict:
    """Extract classes, interfaces, methods, namespaces, and usings from a .cs file."""
    return _extract_generic(path, _CSHARP_CONFIG)


def extract_kotlin(path: Path) -> dict:
    """Extract classes, objects, functions, and imports from a .kt/.kts file."""
    return _extract_generic(path, _KOTLIN_CONFIG)


def extract_scala(path: Path) -> dict:
    """Extract classes, objects, functions, and imports from a .scala file."""
    return _extract_generic(path, _SCALA_CONFIG)


def extract_php(path: Path) -> dict:
    """Extract classes, functions, methods, namespace uses, and calls from a .php file."""
    return _extract_generic(path, _PHP_CONFIG)


def extract_blade(path: Path) -> dict:
    """Extract @include, <livewire:> components, and wire:click bindings from Blade templates."""
    import re
    try:
        src = path.read_text(encoding="utf-8", errors="replace")
    except OSError:
        return {"error": f"cannot read {path}"}

    file_nid = _make_id(str(path))
    nodes = [{"id": file_nid, "label": path.name, "file_type": "code",
              "source_file": str(path), "source_location": None}]
    edges = []

    # @include('path.to.partial') or @include("path.to.partial")
    for m in re.finditer(r"@include\(['\"]([^'\"]+)['\"]", src):
        tgt = m.group(1).replace(".", "/")
        tgt_nid = _make_id(tgt)
        if tgt_nid not in {n["id"] for n in nodes}:
            nodes.append({"id": tgt_nid, "label": m.group(1), "file_type": "code",
                          "source_file": str(path), "source_location": None})
        edges.append({"source": file_nid, "target": tgt_nid, "relation": "includes",
                      "confidence": "EXTRACTED", "confidence_score": 1.0,
                      "source_file": str(path), "source_location": None, "weight": 1.0})

    # <livewire:component.name /> or <livewire:component.name>
    for m in re.finditer(r"<livewire:([\w.\-]+)", src):
        tgt_nid = _make_id(m.group(1))
        if tgt_nid not in {n["id"] for n in nodes}:
            nodes.append({"id": tgt_nid, "label": m.group(1), "file_type": "code",
                          "source_file": str(path), "source_location": None})
        edges.append({"source": file_nid, "target": tgt_nid, "relation": "uses_component",
                      "confidence": "EXTRACTED", "confidence_score": 1.0,
                      "source_file": str(path), "source_location": None, "weight": 1.0})

    # wire:click="methodName"
    for m in re.finditer(r'wire:click=["\']([^"\']+)["\']', src):
        tgt_nid = _make_id(m.group(1))
        if tgt_nid not in {n["id"] for n in nodes}:
            nodes.append({"id": tgt_nid, "label": m.group(1), "file_type": "code",
                          "source_file": str(path), "source_location": None})
        edges.append({"source": file_nid, "target": tgt_nid, "relation": "binds_method",
                      "confidence": "EXTRACTED", "confidence_score": 1.0,
                      "source_file": str(path), "source_location": None, "weight": 1.0})

    return {"nodes": nodes, "edges": edges}


def extract_dart(path: Path) -> dict:
    """Extract classes, mixins, functions, imports, and calls from a .dart file using regex."""
    try:
        src = path.read_text(encoding="utf-8", errors="replace")
    except OSError:
        return {"error": f"cannot read {path}"}

    file_nid = _make_id(str(path))
    nodes = [{"id": file_nid, "label": path.name, "file_type": "code",
              "source_file": str(path), "source_location": None}]
    edges = []
    defined: set[str] = set()

    # Classes and mixins
    for m in re.finditer(r"^\s*(?:abstract\s+)?(?:class|mixin)\s+(\w+)", src, re.MULTILINE):
        nid = _make_id(str(path), m.group(1))
        if nid not in defined:
            nodes.append({"id": nid, "label": m.group(1), "file_type": "code",
                          "source_file": str(path), "source_location": None})
            edges.append({"source": file_nid, "target": nid, "relation": "defines",
                          "confidence": "EXTRACTED", "confidence_score": 1.0,
                          "source_file": str(path), "source_location": None, "weight": 1.0})
            defined.add(nid)

    # Top-level and member functions/methods
    for m in re.finditer(r"^\s*(?:static\s+|async\s+)?(?:\w+\s+)+(\w+)\s*\(", src, re.MULTILINE):
        name = m.group(1)
        if name in {"if", "for", "while", "switch", "catch", "return"}:
            continue
        nid = _make_id(str(path), name)
        if nid not in defined:
            nodes.append({"id": nid, "label": name, "file_type": "code",
                          "source_file": str(path), "source_location": None})
            edges.append({"source": file_nid, "target": nid, "relation": "defines",
                          "confidence": "EXTRACTED", "confidence_score": 1.0,
                          "source_file": str(path), "source_location": None, "weight": 1.0})
            defined.add(nid)

    # import 'package:...' or import '...'
    for m in re.finditer(r"""^import\s+['"]([^'"]+)['"]""", src, re.MULTILINE):
        pkg = m.group(1)
        tgt_nid = _make_id(pkg)
        if tgt_nid not in defined:
            nodes.append({"id": tgt_nid, "label": pkg, "file_type": "code",
                          "source_file": str(path), "source_location": None})
            defined.add(tgt_nid)
        edges.append({"source": file_nid, "target": tgt_nid, "relation": "imports",
                      "confidence": "EXTRACTED", "confidence_score": 1.0,
                      "source_file": str(path), "source_location": None, "weight": 1.0})

    return {"nodes": nodes, "edges": edges}


def extract_verilog(path: Path) -> dict:
    """Extract modules, functions, tasks, package imports, and instantiations from .v/.sv files."""
    try:
        import tree_sitter_verilog as tsverilog
        from tree_sitter import Language, Parser
    except ImportError:
        return {"nodes": [], "edges": [], "error": "tree_sitter_verilog not installed"}

    try:
        language = Language(tsverilog.language())
        parser = Parser(language)
        source = path.read_bytes()
        tree = parser.parse(source)
        root = tree.root_node
    except Exception as e:
        return {"nodes": [], "edges": [], "error": str(e)}

    stem = _file_stem(path)
    str_path = str(path)
    nodes: list[dict] = []
    edges: list[dict] = []
    seen_ids: set[str] = set()

    def add_node(nid: str, label: str, line: int) -> None:
        if nid not in seen_ids:
            seen_ids.add(nid)
            nodes.append({"id": nid, "label": label, "file_type": "code",
                          "source_file": str_path, "source_location": f"L{line}",
                          "confidence_score": 1.0})

    def add_edge(src: str, tgt: str, relation: str, line: int,
                 confidence: str = "EXTRACTED", score: float = 1.0) -> None:
        edges.append({"source": src, "target": tgt, "relation": relation,
                      "confidence": confidence, "confidence_score": score,
                      "source_file": str_path, "source_location": f"L{line}", "weight": 1.0})

    file_nid = _make_id(str(path))
    add_node(file_nid, path.name, 1)

    def walk(node, module_nid: str | None = None) -> None:
        t = node.type

        if t == "module_declaration":
            name_node = node.child_by_field_name("name")
            if name_node:
                mod_name = _read_text(name_node, source)
                line = node.start_point[0] + 1
                nid = _make_id(stem, mod_name)
                add_node(nid, mod_name, line)
                add_edge(file_nid, nid, "defines", line)
                for child in node.children:
                    walk(child, nid)
                return

        elif t in ("function_declaration", "function_prototype"):
            name_node = node.child_by_field_name("name")
            if name_node:
                func_name = _read_text(name_node, source)
                line = node.start_point[0] + 1
                parent = module_nid or file_nid
                nid = _make_id(parent, func_name)
                add_node(nid, f"{func_name}()", line)
                add_edge(parent, nid, "contains", line)

        elif t == "task_declaration":
            name_node = node.child_by_field_name("name")
            if name_node:
                task_name = _read_text(name_node, source)
                line = node.start_point[0] + 1
                parent = module_nid or file_nid
                nid = _make_id(parent, task_name)
                add_node(nid, task_name, line)
                add_edge(parent, nid, "contains", line)

        elif t == "package_import_declaration":
            for child in node.children:
                if child.type == "package_import_item":
                    pkg_text = _read_text(child, source)
                    pkg_name = pkg_text.split("::")[0].strip()
                    if pkg_name:
                        line = node.start_point[0] + 1
                        tgt_nid = _make_id(pkg_name)
                        add_node(tgt_nid, pkg_name, line)
                        src = module_nid or file_nid
                        add_edge(src, tgt_nid, "imports_from", line)

        elif t == "module_instantiation":
            # module_type instantiates another module
            type_node = node.child_by_field_name("module_type")
            if type_node and module_nid:
                inst_type = _read_text(type_node, source).strip()
                if inst_type:
                    line = node.start_point[0] + 1
                    tgt_nid = _make_id(inst_type)
                    add_node(tgt_nid, inst_type, line)
                    add_edge(module_nid, tgt_nid, "instantiates", line)

        for child in node.children:
            walk(child, module_nid)

    walk(root)
    return {"nodes": nodes, "edges": edges}


def extract_sql(path: Path) -> dict:
    """Extract tables, views, functions, and relationships from .sql files via tree-sitter."""
    try:
        import tree_sitter_sql as tssql
        from tree_sitter import Language, Parser
    except ImportError:
        return {"nodes": [], "edges": [], "error": "tree_sitter_sql not installed. Run: pip install tree-sitter-sql"}

    try:
        language = Language(tssql.language())
        parser = Parser(language)
        source = path.read_bytes()
        tree = parser.parse(source)
        root = tree.root_node
    except Exception as e:
        return {"nodes": [], "edges": [], "error": str(e)}

    stem = _file_stem(path)
    str_path = str(path)
    file_nid = _make_id(str_path)
    nodes: list[dict] = [{"id": file_nid, "label": path.name, "file_type": "code",
                           "source_file": str_path, "source_location": None}]
    edges: list[dict] = []
    seen_ids: set[str] = {file_nid}
    table_nids: dict[str, str] = {}  # name → nid for reference resolution

    def _read(n) -> str:
        return source[n.start_byte:n.end_byte].decode("utf-8", errors="replace")

    def _obj_name(n) -> str | None:
        for c in n.children:
            if c.type == "object_reference":
                return _read(c)
        return None

    def _add_node(nid: str, label: str, line: int) -> None:
        if nid not in seen_ids:
            seen_ids.add(nid)
            nodes.append({"id": nid, "label": label, "file_type": "code",
                           "source_file": str_path, "source_location": f"L{line}"})
            edges.append({"source": file_nid, "target": nid, "relation": "contains",
                           "confidence": "EXTRACTED", "source_file": str_path,
                           "source_location": f"L{line}", "weight": 1.0})

    def _add_edge(src: str, tgt: str, relation: str, line: int) -> None:
        edges.append({"source": src, "target": tgt, "relation": relation,
                       "confidence": "EXTRACTED", "source_file": str_path,
                       "source_location": f"L{line}", "weight": 1.0})

    def walk(node) -> None:
        t = node.type
        line = node.start_point[0] + 1

        if t == "create_table":
            name = _obj_name(node)
            if name:
                nid = _make_id(stem, name)
                _add_node(nid, name, line)
                table_nids[name.lower()] = nid
                # Foreign key REFERENCES
                for col in node.children:
                    if col.type == "column_definitions":
                        has_error = any(cd.type == "ERROR" for cd in col.children)
                        seen_refs: set[str] = set()
                        for cd in col.children:
                            if cd.type == "column_definition":
                                # Inline column-level REFERENCES
                                ref_name: str | None = None
                                found_ref = False
                                for cc in cd.children:
                                    if cc.type == "keyword_references":
                                        found_ref = True
                                    elif found_ref and cc.type == "object_reference":
                                        ref_name = _read(cc)
                                        break
                                if ref_name:
                                    ref_nid = table_nids.get(ref_name.lower()) or _make_id(stem, ref_name)
                                    _add_edge(nid, ref_nid, "references", line)
                                    seen_refs.add(ref_name.lower())
                            elif cd.type == "constraints":
                                # Table-level FOREIGN KEY ... REFERENCES ... constraints
                                for constraint in cd.children:
                                    if constraint.type != "constraint":
                                        continue
                                    ref_name = None
                                    found_ref = False
                                    for cc in constraint.children:
                                        if cc.type == "keyword_references":
                                            found_ref = True
                                        elif found_ref and cc.type == "object_reference":
                                            ref_name = _read(cc)
                                            break
                                    if ref_name:
                                        ref_nid = table_nids.get(ref_name.lower()) or _make_id(stem, ref_name)
                                        _add_edge(nid, ref_nid, "references", line)
                                        seen_refs.add(ref_name.lower())
                        if has_error:
                            # Dialect-specific syntax (e.g. Firebird COMPUTED BY) causes ERROR
                            # nodes that make the parser drop the trailing constraints block.
                            # Regex-scan the raw column_definitions text as fallback.
                            col_text = _read(col)
                            for rm in re.finditer(r"\bREFERENCES\s+([\w$]+)", col_text, re.IGNORECASE):
                                ref_name = rm.group(1)
                                if ref_name.lower() not in seen_refs:
                                    ref_nid = table_nids.get(ref_name.lower()) or _make_id(stem, ref_name)
                                    _add_edge(nid, ref_nid, "references", line)
                                    seen_refs.add(ref_name.lower())

        elif t == "create_view":
            name = _obj_name(node)
            if name:
                nid = _make_id(stem, name)
                _add_node(nid, name, line)
                table_nids[name.lower()] = nid
                # FROM/JOIN table references inside view body
                _walk_from_refs(node, nid, line)

        elif t == "create_function":
            name = _obj_name(node)
            if name:
                nid = _make_id(stem, name)
                _add_node(nid, f"{name}()", line)
                _walk_from_refs(node, nid, line)

        elif t == "create_procedure":
            name = _obj_name(node)
            if name:
                nid = _make_id(stem, name)
                _add_node(nid, f"{name}()", line)
                _walk_from_refs(node, nid, line)

        elif t == "alter_table":
            name = _obj_name(node)
            if name:
                src_nid = table_nids.get(name.lower())
                if not src_nid:
                    src_nid = _make_id(stem, name)
                    _add_node(src_nid, name, line)
                    table_nids[name.lower()] = src_nid
                for child in node.children:
                    if child.type == "add_constraint":
                        for cc in child.children:
                            if cc.type != "constraint":
                                continue
                            found_ref = False
                            ref_name: str | None = None
                            for ccc in cc.children:
                                if ccc.type == "keyword_references":
                                    found_ref = True
                                elif found_ref and ccc.type == "object_reference":
                                    ref_name = _read(ccc)
                                    break
                            if ref_name:
                                ref_nid = table_nids.get(ref_name.lower())
                                if not ref_nid:
                                    ref_nid = _make_id(stem, ref_name)
                                _add_edge(src_nid, ref_nid, "references", line)

        elif t == "create_trigger":
            trig_name: str | None = None
            tbl_name: str | None = None
            after_trigger = False
            after_for = False
            for c in node.children:
                if c.type == "keyword_trigger":
                    after_trigger = True
                elif after_trigger and not trig_name and c.type == "object_reference":
                    trig_name = _read(c)
                elif c.type == "keyword_for":
                    after_for = True
                elif after_for and not tbl_name and c.type == "object_reference":
                    tbl_name = _read(c)
            if trig_name:
                trig_nid = _make_id(stem, trig_name)
                _add_node(trig_nid, trig_name, line)
                if tbl_name:
                    tbl_nid = table_nids.get(tbl_name.lower()) or _make_id(stem, tbl_name)
                    _add_edge(trig_nid, tbl_nid, "triggers", line)

        elif t == "fb_proc_or_trigger":
            text = _read(node)
            m = re.match(
                r"CREATE\s+(?:OR\s+(?:REPLACE|ALTER)\s+)?"
                r"(PROCEDURE|TRIGGER|FUNCTION)\s+([\w$]+)",
                text, re.IGNORECASE,
            )
            if m:
                obj_type = m.group(1).upper()
                obj_name = m.group(2)
                obj_nid = _make_id(stem, obj_name)
                label = obj_name if obj_type == "TRIGGER" else f"{obj_name}()"
                _add_node(obj_nid, label, line)
                if obj_type == "TRIGGER":
                    fm = re.search(r"\bFOR\s+([\w$]+)", text, re.IGNORECASE)
                    if fm:
                        tbl = fm.group(1)
                        tbl_nid = table_nids.get(tbl.lower()) or _make_id(stem, tbl)
                        _add_edge(obj_nid, tbl_nid, "triggers", line)
                _NON_TABLES = {
                    "select", "where", "set", "dual", "null", "true", "false",
                    "first", "skip", "rows", "next", "only", "lateral",
                }
                seen_tbls: set[str] = set()
                for rm in re.finditer(r"\b(?:FROM|JOIN|INTO)\s+([\w$]+)", text, re.IGNORECASE):
                    tbl = rm.group(1)
                    if tbl.lower() not in _NON_TABLES and tbl.lower() not in seen_tbls:
                        seen_tbls.add(tbl.lower())
                        tbl_nid = table_nids.get(tbl.lower()) or _make_id(stem, tbl)
                        _add_edge(obj_nid, tbl_nid, "reads_from", line)
                for rm in re.finditer(r"\bUPDATE\s+([\w$]+)", text, re.IGNORECASE):
                    tbl = rm.group(1)
                    if tbl.lower() not in _NON_TABLES and tbl.lower() not in seen_tbls:
                        seen_tbls.add(tbl.lower())
                        tbl_nid = table_nids.get(tbl.lower()) or _make_id(stem, tbl)
                        _add_edge(obj_nid, tbl_nid, "reads_from", line)

        for child in node.children:
            walk(child)

    def _walk_from_refs(node, caller_nid: str, line: int) -> None:
        """Recursively find FROM/JOIN table references inside a node."""
        if node.type in ("from", "join"):
            for c in node.children:
                if c.type == "relation":
                    for cc in c.children:
                        if cc.type == "object_reference":
                            tbl = _read(cc)
                            tbl_nid = _make_id(stem, tbl)
                            _add_edge(caller_nid, tbl_nid, "reads_from",
                                      c.start_point[0] + 1)
        for child in node.children:
            _walk_from_refs(child, caller_nid, line)

    for stmt in root.children:
        if stmt.type == "statement":
            for child in stmt.children:
                walk(child)
        elif stmt.type in ("fb_proc_or_trigger", "set_term", "declare_external_function"):
            walk(stmt)

    # Global regex fallback: catch any REFERENCES missed due to ERROR nodes in the parse tree
    # (e.g. Firebird COMPUTED BY columns push constraints out of the tree entirely).
    # Snapshot after tree walk so we don't re-emit edges already captured above.
    emitted = {(e["source"], e["target"]) for e in edges if e["relation"] == "references"}
    src_text = source.decode("utf-8", errors="replace")
    for m in re.finditer(r"CREATE\s+TABLE\s+([\w$]+)\s*\(", src_text, re.IGNORECASE):
        tbl_name = m.group(1)
        tbl_nid = table_nids.get(tbl_name.lower())
        if tbl_nid is None:
            continue
        tbl_line = src_text[: m.start()].count("\n") + 1
        tail = src_text[m.start():]
        end = re.search(r"(?:^|\n)(?:CREATE|SET\s+TERM|ALTER)\s", tail[1:], re.IGNORECASE)
        block = tail[: end.start() + 1] if end else tail
        for rm in re.finditer(r"\bREFERENCES\s+([\w$]+)", block, re.IGNORECASE):
            ref_name = rm.group(1)
            ref_nid = table_nids.get(ref_name.lower()) or _make_id(stem, ref_name)
            if (tbl_nid, ref_nid) not in emitted:
                _add_edge(tbl_nid, ref_nid, "references", tbl_line)
                emitted.add((tbl_nid, ref_nid))

    return {"nodes": nodes, "edges": edges}


def extract_lua(path: Path) -> dict:
    """Extract functions, methods, require() imports, and calls from a .lua file."""
    return _extract_generic(path, _LUA_CONFIG)


def extract_swift(path: Path) -> dict:
    """Extract classes, structs, protocols, functions, imports, and calls from a .swift file."""
    return _extract_generic(path, _SWIFT_CONFIG)


# ── Julia extractor (custom walk) ────────────────────────────────────────────

def extract_julia(path: Path) -> dict:
    """Extract modules, structs, functions, imports, and calls from a .jl file."""
    try:
        import tree_sitter_julia as tsjulia
        from tree_sitter import Language, Parser
    except ImportError:
        return {"nodes": [], "edges": [], "error": "tree-sitter-julia not installed"}

    try:
        language = Language(tsjulia.language())
        parser = Parser(language)
        source = path.read_bytes()
        tree = parser.parse(source)
        root = tree.root_node
    except Exception as e:
        return {"nodes": [], "edges": [], "error": str(e)}

    stem = _file_stem(path)
    str_path = str(path)
    nodes: list[dict] = []
    edges: list[dict] = []
    seen_ids: set[str] = set()
    function_bodies: list[tuple[str, object]] = []

    def add_node(nid: str, label: str, line: int) -> None:
        if nid not in seen_ids:
            seen_ids.add(nid)
            nodes.append({
                "id": nid,
                "label": label,
                "file_type": "code",
                "source_file": str_path,
                "source_location": f"L{line}",
            })

    def add_edge(src: str, tgt: str, relation: str, line: int,
                 confidence: str = "EXTRACTED", weight: float = 1.0,
                 context: str | None = None) -> None:
        edge = {
            "source": src,
            "target": tgt,
            "relation": relation,
            "confidence": confidence,
            "source_file": str_path,
            "source_location": f"L{line}",
            "weight": weight,
        }
        if context:
            edge["context"] = context
        edges.append(edge)

    file_nid = _make_id(str(path))
    add_node(file_nid, path.name, 1)

    def _func_name_from_signature(sig_node) -> str | None:
        """Extract function name from a Julia signature node (call_expression > identifier)."""
        for child in sig_node.children:
            if child.type == "call_expression":
                callee = child.children[0] if child.children else None
                if callee and callee.type == "identifier":
                    return _read_text(callee, source)
        return None

    def walk_calls(body_node, func_nid: str) -> None:
        if body_node is None:
            return
        t = body_node.type
        if t in ("function_definition", "short_function_definition"):
            return
        if t == "call_expression" and body_node.children:
            callee = body_node.children[0]
            # Direct call: foo(...)
            if callee.type == "identifier":
                callee_name = _read_text(callee, source)
                target_nid = _make_id(stem, callee_name)
                add_edge(func_nid, target_nid, "calls", body_node.start_point[0] + 1,
                         confidence="EXTRACTED", context="call")
            # Method call: obj.method(...)
            elif callee.type == "field_expression" and len(callee.children) >= 3:
                method_node = callee.children[-1]
                method_name = _read_text(method_node, source)
                target_nid = _make_id(stem, method_name)
                add_edge(func_nid, target_nid, "calls", body_node.start_point[0] + 1,
                         confidence="EXTRACTED", context="call")
        for child in body_node.children:
            walk_calls(child, func_nid)

    def walk(node, scope_nid: str) -> None:
        t = node.type

        # Module
        if t == "module_definition":
            name_node = next((c for c in node.children if c.type == "identifier"), None)
            if name_node:
                mod_name = _read_text(name_node, source)
                mod_nid = _make_id(stem, mod_name)
                line = node.start_point[0] + 1
                add_node(mod_nid, mod_name, line)
                add_edge(file_nid, mod_nid, "defines", line)
                for child in node.children:
                    walk(child, mod_nid)
            return

        # Struct (struct / mutable struct — both map to struct_definition in tree-sitter-julia)
        if t == "struct_definition":
            # type_head may contain: identifier (simple) or binary_expression (Foo <: Bar)
            type_head = next((c for c in node.children if c.type == "type_head"), None)
            if type_head:
                bin_expr = next((c for c in type_head.children if c.type == "binary_expression"), None)
                if bin_expr:
                    # First identifier is the struct name, last is the supertype
                    identifiers = [c for c in bin_expr.children if c.type == "identifier"]
                    if identifiers:
                        struct_name = _read_text(identifiers[0], source)
                        struct_nid = _make_id(stem, struct_name)
                        line = node.start_point[0] + 1
                        add_node(struct_nid, struct_name, line)
                        add_edge(scope_nid, struct_nid, "defines", line)
                        if len(identifiers) >= 2:
                            super_name = _read_text(identifiers[-1], source)
                            add_edge(struct_nid, _make_id(stem, super_name), "inherits",
                                     line, confidence="EXTRACTED")
                else:
                    name_node = next((c for c in type_head.children if c.type == "identifier"), None)
                    if name_node:
                        struct_name = _read_text(name_node, source)
                        struct_nid = _make_id(stem, struct_name)
                        line = node.start_point[0] + 1
                        add_node(struct_nid, struct_name, line)
                        add_edge(scope_nid, struct_nid, "defines", line)
            return

        # Abstract type
        if t == "abstract_definition":
            # type_head > identifier
            type_head = next((c for c in node.children if c.type == "type_head"), None)
            if type_head:
                name_node = next((c for c in type_head.children if c.type == "identifier"), None)
                if name_node:
                    abs_name = _read_text(name_node, source)
                    abs_nid = _make_id(stem, abs_name)
                    line = node.start_point[0] + 1
                    add_node(abs_nid, abs_name, line)
                    add_edge(scope_nid, abs_nid, "defines", line)
            return

        # Function: function foo(...) ... end
        if t == "function_definition":
            sig_node = next((c for c in node.children if c.type == "signature"), None)
            if sig_node:
                func_name = _func_name_from_signature(sig_node)
                if func_name:
                    func_nid = _make_id(stem, func_name)
                    line = node.start_point[0] + 1
                    add_node(func_nid, f"{func_name}()", line)
                    add_edge(scope_nid, func_nid, "defines", line)
                    function_bodies.append((func_nid, node))
            return

        # Short function: foo(x) = expr
        if t == "assignment":
            lhs = node.children[0] if node.children else None
            if lhs and lhs.type == "call_expression" and lhs.children:
                callee = lhs.children[0]
                if callee.type == "identifier":
                    func_name = _read_text(callee, source)
                    func_nid = _make_id(stem, func_name)
                    line = node.start_point[0] + 1
                    add_node(func_nid, f"{func_name}()", line)
                    add_edge(scope_nid, func_nid, "defines", line)
                    # Only walk the RHS (index 2 after lhs and operator) to avoid self-loops
                    rhs = node.children[-1] if len(node.children) >= 3 else None
                    if rhs:
                        function_bodies.append((func_nid, rhs))
            return

        # Using / Import
        if t in ("using_statement", "import_statement"):
            line = node.start_point[0] + 1
            for child in node.children:
                if child.type == "identifier":
                    mod_name = _read_text(child, source)
                    imp_nid = _make_id(mod_name)
                    add_node(imp_nid, mod_name, line)
                    add_edge(scope_nid, imp_nid, "imports", line, context="import")
                elif child.type == "selected_import":
                    identifiers = [c for c in child.children if c.type == "identifier"]
                    if identifiers:
                        pkg_name = _read_text(identifiers[0], source)
                        pkg_nid = _make_id(pkg_name)
                        add_node(pkg_nid, pkg_name, line)
                        add_edge(scope_nid, pkg_nid, "imports", line, context="import")
            return

        for child in node.children:
            walk(child, scope_nid)

    walk(root, file_nid)

    for func_nid, body_node in function_bodies:
        # For function_definition nodes, walk children directly to avoid
        # the boundary check returning early on the top-level node itself.
        # Skip the "signature" child — it contains the function's own call_expression
        # which would create a self-loop.
        if body_node.type == "function_definition":
            for child in body_node.children:
                if child.type != "signature":
                    walk_calls(child, func_nid)
        else:
            walk_calls(body_node, func_nid)

    return {"nodes": nodes, "edges": edges}


_FORTRAN_CPP_EXTS = {".F", ".F90", ".F95", ".F03", ".F08"}


def _cpp_preprocess(path: Path) -> bytes:
    """Run cpp -w -P on a capital-F Fortran file and return preprocessed bytes.

    Falls back to raw file bytes if cpp is not available. Capital-F extensions
    conventionally require C preprocessor expansion (#ifdef MPI, #define REAL8, etc.)
    before parsing.

    Security (F-007): we pass `-nostdinc` and `-I /dev/null` so a malicious
    source file containing `#include "/home/victim/.ssh/id_rsa"` (or any other
    include directive) cannot inline arbitrary host files into the output that
    we then ship to an LLM. Without these flags `cpp` happily resolves any
    relative or absolute include path it can read, which is a corpus-side
    file-exfiltration vector.
    """
    import shutil
    import subprocess
    if not shutil.which("cpp"):
        return path.read_bytes()
    try:
        result = subprocess.run(
            ["cpp", "-w", "-P", "-nostdinc", "-I", "/dev/null", str(path)],
            capture_output=True,
            timeout=30,
        )
        if result.returncode == 0 and result.stdout:
            return result.stdout
    except Exception:
        pass
    return path.read_bytes()


def extract_fortran(path: Path) -> dict:
    """Extract programs, modules, subroutines, functions, use statements, and calls from Fortran files.

    Capital-F extensions (.F, .F90, etc.) are run through the C preprocessor before
    parsing so #ifdef/#define macros are resolved.
    """
    try:
        import tree_sitter_fortran as tsfortran
        from tree_sitter import Language, Parser
    except ImportError:
        return {"nodes": [], "edges": [], "error": "tree-sitter-fortran not installed"}

    try:
        language = Language(tsfortran.language())
        parser = Parser(language)
        source = _cpp_preprocess(path) if path.suffix in _FORTRAN_CPP_EXTS else path.read_bytes()
        tree = parser.parse(source)
        root = tree.root_node
    except Exception as e:
        return {"nodes": [], "edges": [], "error": str(e)}

    stem = _file_stem(path)
    str_path = str(path)
    nodes: list[dict] = []
    edges: list[dict] = []
    seen_ids: set[str] = set()
    scope_bodies: list[tuple[str, object]] = []

    def add_node(nid: str, label: str, line: int) -> None:
        if nid not in seen_ids:
            seen_ids.add(nid)
            nodes.append({
                "id": nid,
                "label": label,
                "file_type": "code",
                "source_file": str_path,
                "source_location": f"L{line}",
            })

    def add_edge(src: str, tgt: str, relation: str, line: int,
                 confidence: str = "EXTRACTED", weight: float = 1.0,
                 context: str | None = None) -> None:
        edge = {
            "source": src,
            "target": tgt,
            "relation": relation,
            "confidence": confidence,
            "source_file": str_path,
            "source_location": f"L{line}",
            "weight": weight,
        }
        if context:
            edge["context"] = context
        edges.append(edge)

    file_nid = _make_id(str(path))
    add_node(file_nid, path.name, 1)

    def _fortran_name(stmt_node) -> str | None:
        """Extract name from a *_statement node. Fortran is case-insensitive; lowercase."""
        for child in stmt_node.children:
            if child.type in ("name", "identifier"):
                return _read_text(child, source).lower()
        return None

    def walk_calls(node, scope_nid: str) -> None:
        if node is None:
            return
        t = node.type
        if t in ("subroutine", "function", "module", "program", "internal_procedures"):
            return
        # call FOO(args) — tree-sitter-fortran uses subroutine_call
        if t == "subroutine_call":
            name_node = next((c for c in node.children if c.type == "identifier"), None)
            if name_node:
                callee = _read_text(name_node, source).lower()
                target_nid = _make_id(stem, callee)
                add_edge(scope_nid, target_nid, "calls", node.start_point[0] + 1,
                         confidence="EXTRACTED", context="call")
        for child in node.children:
            walk_calls(child, scope_nid)

    def walk(node, scope_nid: str) -> None:
        t = node.type

        if t == "program":
            stmt = next((c for c in node.children if c.type == "program_statement"), None)
            name = _fortran_name(stmt) if stmt else None
            if name:
                nid = _make_id(stem, name)
                line = node.start_point[0] + 1
                add_node(nid, name, line)
                add_edge(file_nid, nid, "defines", line)
                scope_bodies.append((nid, node))
                for child in node.children:
                    walk(child, nid)
            return

        if t == "module":
            stmt = next((c for c in node.children if c.type == "module_statement"), None)
            name = _fortran_name(stmt) if stmt else None
            if name:
                nid = _make_id(stem, name)
                line = node.start_point[0] + 1
                add_node(nid, name, line)
                add_edge(file_nid, nid, "defines", line)
                for child in node.children:
                    walk(child, nid)
            return

        # subroutines/functions inside a module live under internal_procedures
        if t == "internal_procedures":
            for child in node.children:
                walk(child, scope_nid)
            return

        if t == "subroutine":
            stmt = next((c for c in node.children if c.type == "subroutine_statement"), None)
            name = _fortran_name(stmt) if stmt else None
            if name:
                nid = _make_id(stem, name)
                line = node.start_point[0] + 1
                add_node(nid, f"{name}()", line)
                add_edge(scope_nid, nid, "defines", line)
                scope_bodies.append((nid, node))
                for child in node.children:
                    walk(child, nid)
            return

        if t == "function":
            stmt = next((c for c in node.children if c.type == "function_statement"), None)
            name = _fortran_name(stmt) if stmt else None
            if name:
                nid = _make_id(stem, name)
                line = node.start_point[0] + 1
                add_node(nid, f"{name}()", line)
                add_edge(scope_nid, nid, "defines", line)
                scope_bodies.append((nid, node))
                for child in node.children:
                    walk(child, nid)
            return

        if t == "use_statement":
            line = node.start_point[0] + 1
            # tree-sitter-fortran uses module_name node for the used module
            name_node = next((c for c in node.children if c.type in ("module_name", "name", "identifier")), None)
            if name_node:
                mod_name = _read_text(name_node, source).lower()
                imp_nid = _make_id(mod_name)
                add_node(imp_nid, mod_name, line)
                add_edge(scope_nid, imp_nid, "imports", line, context="use")
            return

        for child in node.children:
            walk(child, scope_nid)

    walk(root, file_nid)

    _stmt_headers = {
        "subroutine_statement", "function_statement",
        "program_statement", "module_statement",
    }
    for scope_nid, body_node in scope_bodies:
        for child in body_node.children:
            if child.type not in _stmt_headers:
                walk_calls(child, scope_nid)

    return {"nodes": nodes, "edges": edges}


# ── Go extractor (custom walk) ────────────────────────────────────────────────

def extract_go(path: Path) -> dict:
    """Extract functions, methods, type declarations, and imports from a .go file."""
    try:
        import tree_sitter_go as tsgo
        from tree_sitter import Language, Parser
    except ImportError:
        return {"nodes": [], "edges": [], "error": "tree-sitter-go not installed"}

    try:
        language = Language(tsgo.language())
        parser = Parser(language)
        source = path.read_bytes()
        tree = parser.parse(source)
        root = tree.root_node
    except Exception as e:
        return {"nodes": [], "edges": [], "error": str(e)}

    stem = _file_stem(path)
    # Use directory name as package scope so methods on the same type across
    # multiple files in a package share one canonical type node.
    pkg_scope = path.parent.name or stem
    str_path = str(path)
    nodes: list[dict] = []
    edges: list[dict] = []
    seen_ids: set[str] = set()
    function_bodies: list[tuple[str, object]] = []
    go_imported_pkgs: set[str] = set()  # local names of imported packages

    def add_node(nid: str, label: str, line: int) -> None:
        if nid not in seen_ids:
            seen_ids.add(nid)
            nodes.append({
                "id": nid,
                "label": label,
                "file_type": "code",
                "source_file": str_path,
                "source_location": f"L{line}",
            })

    def add_edge(src: str, tgt: str, relation: str, line: int,
                 confidence: str = "EXTRACTED", weight: float = 1.0,
                 context: str | None = None) -> None:
        edge = {
            "source": src,
            "target": tgt,
            "relation": relation,
            "confidence": confidence,
            "source_file": str_path,
            "source_location": f"L{line}",
            "weight": weight,
        }
        if context:
            edge["context"] = context
        edges.append(edge)

    file_nid = _make_id(str(path))
    add_node(file_nid, path.name, 1)

    def walk(node) -> None:
        t = node.type

        if t == "function_declaration":
            name_node = node.child_by_field_name("name")
            if name_node:
                func_name = _read_text(name_node, source)
                line = node.start_point[0] + 1
                func_nid = _make_id(stem, func_name)
                add_node(func_nid, f"{func_name}()", line)
                add_edge(file_nid, func_nid, "contains", line)
                body = node.child_by_field_name("body")
                if body:
                    function_bodies.append((func_nid, body))
            return

        if t == "method_declaration":
            receiver = node.child_by_field_name("receiver")
            receiver_type: str | None = None
            if receiver:
                for param in receiver.children:
                    if param.type == "parameter_declaration":
                        type_node = param.child_by_field_name("type")
                        if type_node:
                            raw = _read_text(type_node, source).lstrip("*").strip()
                            receiver_type = raw
                        break
            name_node = node.child_by_field_name("name")
            if name_node:
                method_name = _read_text(name_node, source)
                line = node.start_point[0] + 1
                if receiver_type:
                    parent_nid = _make_id(pkg_scope, receiver_type)
                    add_node(parent_nid, receiver_type, line)
                    method_nid = _make_id(parent_nid, method_name)
                    add_node(method_nid, f".{method_name}()", line)
                    add_edge(parent_nid, method_nid, "method", line)
                else:
                    method_nid = _make_id(stem, method_name)
                    add_node(method_nid, f"{method_name}()", line)
                    add_edge(file_nid, method_nid, "contains", line)
                body = node.child_by_field_name("body")
                if body:
                    function_bodies.append((method_nid, body))
            return

        if t == "type_declaration":
            for child in node.children:
                if child.type == "type_spec":
                    name_node = child.child_by_field_name("name")
                    if name_node:
                        type_name = _read_text(name_node, source)
                        line = child.start_point[0] + 1
                        type_nid = _make_id(pkg_scope, type_name)
                        add_node(type_nid, type_name, line)
                        add_edge(file_nid, type_nid, "contains", line)
            return

        if t == "import_declaration":
            for child in node.children:
                if child.type == "import_spec_list":
                    for spec in child.children:
                        if spec.type == "import_spec":
                            path_node = spec.child_by_field_name("path")
                            if path_node:
                                raw = _read_text(path_node, source).strip('"')
                                # Prefix with go_pkg_ so stdlib names (e.g. "context")
                                # don't collide with local files of the same basename.
                                tgt_nid = _make_id("go", "pkg", raw)
                                add_edge(file_nid, tgt_nid, "imports_from", spec.start_point[0] + 1, context="import")
                                # Track local name (alias or last path segment)
                                alias = spec.child_by_field_name("name")
                                local_name = _read_text(alias, source) if alias else raw.split("/")[-1]
                                if local_name and local_name != "_" and local_name != ".":
                                    go_imported_pkgs.add(local_name)
                elif child.type == "import_spec":
                    path_node = child.child_by_field_name("path")
                    if path_node:
                        raw = _read_text(path_node, source).strip('"')
                        tgt_nid = _make_id("go", "pkg", raw)
                        add_edge(file_nid, tgt_nid, "imports_from", child.start_point[0] + 1, context="import")
                        alias = child.child_by_field_name("name")
                        local_name = _read_text(alias, source) if alias else raw.split("/")[-1]
                        if local_name and local_name != "_" and local_name != ".":
                            go_imported_pkgs.add(local_name)
            return

        for child in node.children:
            walk(child)

    walk(root)

    label_to_nid: dict[str, str] = {}
    for n in nodes:
        raw = n["label"]
        normalised = raw.strip("()").lstrip(".")
        label_to_nid[normalised.lower()] = n["id"]

    seen_call_pairs: set[tuple[str, str]] = set()
    raw_calls: list[dict] = []

    def walk_calls(node, caller_nid: str) -> None:
        if node.type in ("function_declaration", "method_declaration"):
            return
        if node.type == "call_expression":
            func_node = node.child_by_field_name("function")
            callee_name: str | None = None
            is_member_call: bool = False
            if func_node:
                if func_node.type == "identifier":
                    callee_name = _read_text(func_node, source)
                elif func_node.type == "selector_expression":
                    field = func_node.child_by_field_name("field")
                    operand = func_node.child_by_field_name("operand")
                    receiver_name = _read_text(operand, source) if operand else ""
                    # Package-qualified call (e.g. fmt.Println) → allow cross-file resolution.
                    # Receiver method call (e.g. s.logger.Log) → skip, no import evidence.
                    is_member_call = receiver_name not in go_imported_pkgs
                    if field:
                        callee_name = _read_text(field, source)
            if callee_name:
                tgt_nid = label_to_nid.get(callee_name.lower())
                if tgt_nid and tgt_nid != caller_nid:
                    pair = (caller_nid, tgt_nid)
                    if pair not in seen_call_pairs:
                        seen_call_pairs.add(pair)
                        line = node.start_point[0] + 1
                        edges.append({
                            "source": caller_nid,
                            "target": tgt_nid,
                            "relation": "calls",
                            "context": "call",
                            "confidence": "EXTRACTED",
                            "source_file": str_path,
                            "source_location": f"L{line}",
                            "weight": 1.0,
                        })
                elif callee_name:
                    raw_calls.append({
                        "caller_nid": caller_nid,
                        "callee": callee_name,
                        "is_member_call": is_member_call,
                        "source_file": str_path,
                        "source_location": f"L{node.start_point[0] + 1}",
                    })
        for child in node.children:
            walk_calls(child, caller_nid)

    for caller_nid, body_node in function_bodies:
        walk_calls(body_node, caller_nid)

    valid_ids = seen_ids
    clean_edges = []
    for edge in edges:
        src, tgt = edge["source"], edge["target"]
        if src in valid_ids and (tgt in valid_ids or edge["relation"] in ("imports", "imports_from")):
            clean_edges.append(edge)

    return {"nodes": nodes, "edges": clean_edges, "raw_calls": raw_calls}


# ── Rust extractor (custom walk) ──────────────────────────────────────────────

# Common Rust trait/stdlib method names that appear in virtually every codebase.
# Resolving these cross-file produces spurious INFERRED edges across crate
# boundaries (issue #908) — skip them from the unresolved-call queue entirely.
_RUST_TRAIT_METHOD_BLOCKLIST: frozenset[str] = frozenset({
    "new", "default", "parse", "from_str", "now", "clone", "into", "from",
    "to_string", "to_owned", "len", "is_empty", "iter", "next", "build",
    "start", "run", "init", "app", "get", "set", "push", "pop", "insert",
    "remove", "contains", "collect", "map", "filter", "unwrap", "expect",
    "ok", "err", "some", "none", "send", "recv", "lock", "read", "write",
})

def extract_rust(path: Path) -> dict:
    """Extract functions, structs, enums, traits, impl methods, and use declarations from a .rs file."""
    try:
        import tree_sitter_rust as tsrust
        from tree_sitter import Language, Parser
    except ImportError:
        return {"nodes": [], "edges": [], "error": "tree-sitter-rust not installed"}

    try:
        language = Language(tsrust.language())
        parser = Parser(language)
        source = path.read_bytes()
        tree = parser.parse(source)
        root = tree.root_node
    except Exception as e:
        return {"nodes": [], "edges": [], "error": str(e)}

    stem = _file_stem(path)
    str_path = str(path)
    nodes: list[dict] = []
    edges: list[dict] = []
    seen_ids: set[str] = set()
    function_bodies: list[tuple[str, object]] = []

    def add_node(nid: str, label: str, line: int) -> None:
        if nid not in seen_ids:
            seen_ids.add(nid)
            nodes.append({
                "id": nid,
                "label": label,
                "file_type": "code",
                "source_file": str_path,
                "source_location": f"L{line}",
            })

    def add_edge(src: str, tgt: str, relation: str, line: int,
                 confidence: str = "EXTRACTED", weight: float = 1.0,
                 context: str | None = None) -> None:
        edge = {
            "source": src,
            "target": tgt,
            "relation": relation,
            "confidence": confidence,
            "source_file": str_path,
            "source_location": f"L{line}",
            "weight": weight,
        }
        if context:
            edge["context"] = context
        edges.append(edge)

    file_nid = _make_id(str(path))
    add_node(file_nid, path.name, 1)

    def walk(node, parent_impl_nid: str | None = None) -> None:
        t = node.type

        if t == "function_item":
            name_node = node.child_by_field_name("name")
            if name_node:
                func_name = _read_text(name_node, source)
                line = node.start_point[0] + 1
                if parent_impl_nid:
                    func_nid = _make_id(parent_impl_nid, func_name)
                    add_node(func_nid, f".{func_name}()", line)
                    add_edge(parent_impl_nid, func_nid, "method", line)
                else:
                    func_nid = _make_id(stem, func_name)
                    add_node(func_nid, f"{func_name}()", line)
                    add_edge(file_nid, func_nid, "contains", line)
                body = node.child_by_field_name("body")
                if body:
                    function_bodies.append((func_nid, body))
            return

        if t in ("struct_item", "enum_item", "trait_item"):
            name_node = node.child_by_field_name("name")
            if name_node:
                item_name = _read_text(name_node, source)
                line = node.start_point[0] + 1
                item_nid = _make_id(stem, item_name)
                add_node(item_nid, item_name, line)
                add_edge(file_nid, item_nid, "contains", line)
            return

        if t == "impl_item":
            type_node = node.child_by_field_name("type")
            impl_nid: str | None = None
            if type_node:
                type_name = _read_text(type_node, source).strip()
                impl_nid = _make_id(stem, type_name)
                add_node(impl_nid, type_name, node.start_point[0] + 1)
            body = node.child_by_field_name("body")
            if body:
                for child in body.children:
                    walk(child, parent_impl_nid=impl_nid)
            return

        if t == "use_declaration":
            arg = node.child_by_field_name("argument")
            if arg:
                raw = _read_text(arg, source)
                clean = raw.split("{")[0].rstrip(":").rstrip("*").rstrip(":")
                module_name = clean.split("::")[-1].strip()
                if module_name:
                    tgt_nid = _make_id(module_name)
                    add_edge(file_nid, tgt_nid, "imports_from", node.start_point[0] + 1, context="import")
            return

        for child in node.children:
            walk(child, parent_impl_nid=None)

    walk(root)

    label_to_nid: dict[str, str] = {}
    for n in nodes:
        raw = n["label"]
        normalised = raw.strip("()").lstrip(".")
        label_to_nid[normalised.lower()] = n["id"]

    seen_call_pairs: set[tuple[str, str]] = set()
    raw_calls: list[dict] = []

    def walk_calls(node, caller_nid: str) -> None:
        if node.type == "function_item":
            return
        if node.type == "call_expression":
            func_node = node.child_by_field_name("function")
            callee_name: str | None = None
            is_member_call: bool = False
            is_scoped_call: bool = False
            if func_node:
                if func_node.type == "identifier":
                    callee_name = _read_text(func_node, source)
                elif func_node.type == "field_expression":
                    is_member_call = True
                    field = func_node.child_by_field_name("field")
                    if field:
                        callee_name = _read_text(field, source)
                elif func_node.type == "scoped_identifier":
                    # Type::method() — still allow in-file EXTRACTED match, but
                    # skip cross-file resolution: bare last-segment lookup ignores
                    # crate boundaries and produces spurious INFERRED edges (#908).
                    is_scoped_call = True
                    name = func_node.child_by_field_name("name")
                    if name:
                        callee_name = _read_text(name, source)
            if callee_name:
                tgt_nid = label_to_nid.get(callee_name.lower())
                if tgt_nid and tgt_nid != caller_nid:
                    pair = (caller_nid, tgt_nid)
                    if pair not in seen_call_pairs:
                        seen_call_pairs.add(pair)
                        line = node.start_point[0] + 1
                        edges.append({
                            "source": caller_nid,
                            "target": tgt_nid,
                            "relation": "calls",
                            "context": "call",
                            "confidence": "EXTRACTED",
                            "source_file": str_path,
                            "source_location": f"L{line}",
                            "weight": 1.0,
                        })
                elif not is_scoped_call and callee_name.lower() not in _RUST_TRAIT_METHOD_BLOCKLIST:
                    raw_calls.append({
                        "caller_nid": caller_nid,
                        "callee": callee_name,
                        "is_member_call": is_member_call,
                        "source_file": str_path,
                        "source_location": f"L{node.start_point[0] + 1}",
                    })
        for child in node.children:
            walk_calls(child, caller_nid)

    for caller_nid, body_node in function_bodies:
        walk_calls(body_node, caller_nid)

    valid_ids = seen_ids
    clean_edges = []
    for edge in edges:
        src, tgt = edge["source"], edge["target"]
        if src in valid_ids and (tgt in valid_ids or edge["relation"] in ("imports", "imports_from")):
            clean_edges.append(edge)

    return {"nodes": nodes, "edges": clean_edges, "raw_calls": raw_calls}


# ── Zig ───────────────────────────────────────────────────────────────────────

def extract_zig(path: Path) -> dict:
    """Extract functions, structs, enums, unions, and imports from a .zig file."""
    try:
        import tree_sitter_zig as tszig
        from tree_sitter import Language, Parser
    except ImportError:
        return {"nodes": [], "edges": [], "error": "tree_sitter_zig not installed"}

    try:
        language = Language(tszig.language())
        parser = Parser(language)
        source = path.read_bytes()
        tree = parser.parse(source)
        root = tree.root_node
    except Exception as e:
        return {"nodes": [], "edges": [], "error": str(e)}

    stem = _file_stem(path)
    str_path = str(path)
    nodes: list[dict] = []
    edges: list[dict] = []
    seen_ids: set[str] = set()
    function_bodies: list[tuple[str, Any]] = []

    def add_node(nid: str, label: str, line: int) -> None:
        if nid not in seen_ids:
            seen_ids.add(nid)
            nodes.append({"id": nid, "label": label, "file_type": "code",
                          "source_file": str_path, "source_location": f"L{line}"})

    def add_edge(src: str, tgt: str, relation: str, line: int,
                 confidence: str = "EXTRACTED", weight: float = 1.0,
                 context: str | None = None) -> None:
        edge = {"source": src, "target": tgt, "relation": relation,
                "confidence": confidence, "source_file": str_path,
                "source_location": f"L{line}", "weight": weight}
        if context:
            edge["context"] = context
        edges.append(edge)

    file_nid = _make_id(str(path))
    add_node(file_nid, path.name, 1)

    def _extract_import(node) -> None:
        for child in node.children:
            if child.type == "builtin_function":
                bi = None
                args = None
                for c in child.children:
                    if c.type == "builtin_identifier":
                        bi = _read_text(c, source)
                    elif c.type == "arguments":
                        args = c
                if bi in ("@import", "@cImport") and args:
                    for arg in args.children:
                        if arg.type in ("string_literal", "string"):
                            raw = _read_text(arg, source).strip('"')
                            module_name = raw.split("/")[-1].split(".")[0]
                            if module_name:
                                tgt_nid = _make_id(module_name)
                                add_edge(file_nid, tgt_nid, "imports_from",
                                         node.start_point[0] + 1)
                            return
            elif child.type == "field_expression":
                _extract_import(child)
                return

    def walk(node, parent_struct_nid: str | None = None) -> None:
        t = node.type

        if t == "function_declaration":
            name_node = node.child_by_field_name("name")
            if name_node:
                func_name = _read_text(name_node, source)
                line = node.start_point[0] + 1
                if parent_struct_nid:
                    func_nid = _make_id(parent_struct_nid, func_name)
                    add_node(func_nid, f".{func_name}()", line)
                    add_edge(parent_struct_nid, func_nid, "method", line)
                else:
                    func_nid = _make_id(stem, func_name)
                    add_node(func_nid, f"{func_name}()", line)
                    add_edge(file_nid, func_nid, "contains", line)
                body = node.child_by_field_name("body")
                if body:
                    function_bodies.append((func_nid, body))
            return

        if t == "variable_declaration":
            name_node = None
            value_node = None
            for child in node.children:
                if child.type == "identifier":
                    name_node = child
                elif child.type in ("struct_declaration", "enum_declaration",
                                    "union_declaration", "builtin_function",
                                    "field_expression"):
                    value_node = child

            if value_node and value_node.type == "struct_declaration":
                if name_node:
                    struct_name = _read_text(name_node, source)
                    line = node.start_point[0] + 1
                    struct_nid = _make_id(stem, struct_name)
                    add_node(struct_nid, struct_name, line)
                    add_edge(file_nid, struct_nid, "contains", line)
                    for child in value_node.children:
                        walk(child, parent_struct_nid=struct_nid)
                return

            if value_node and value_node.type in ("enum_declaration", "union_declaration"):
                if name_node:
                    type_name = _read_text(name_node, source)
                    line = node.start_point[0] + 1
                    type_nid = _make_id(stem, type_name)
                    add_node(type_nid, type_name, line)
                    add_edge(file_nid, type_nid, "contains", line)
                return

            if value_node and value_node.type in ("builtin_function", "field_expression"):
                _extract_import(node)
            return

        for child in node.children:
            walk(child, parent_struct_nid)

    walk(root)

    seen_call_pairs: set[tuple[str, str]] = set()
    raw_calls: list[dict] = []

    def walk_calls(node, caller_nid: str) -> None:
        if node.type == "function_declaration":
            return
        if node.type == "call_expression":
            fn = node.child_by_field_name("function")
            if fn:
                fn_text = _read_text(fn, source)
                callee = fn_text.split(".")[-1]
                is_member_call = "." in fn_text
                tgt_nid = next((n["id"] for n in nodes if n["label"] in
                                (f"{callee}()", f".{callee}()")), None)
                if tgt_nid and tgt_nid != caller_nid:
                    pair = (caller_nid, tgt_nid)
                    if pair not in seen_call_pairs:
                        seen_call_pairs.add(pair)
                        add_edge(caller_nid, tgt_nid, "calls",
                                 node.start_point[0] + 1,
                                 confidence="EXTRACTED", weight=1.0)
                elif callee:
                    raw_calls.append({
                        "caller_nid": caller_nid,
                        "callee": callee,
                        "is_member_call": is_member_call,
                        "source_file": str_path,
                        "source_location": f"L{node.start_point[0] + 1}",
                    })
        for child in node.children:
            walk_calls(child, caller_nid)

    for caller_nid, body_node in function_bodies:
        walk_calls(body_node, caller_nid)

    clean_edges = [e for e in edges if e["source"] in seen_ids and
                   (e["target"] in seen_ids or e["relation"] == "imports_from")]
    return {"nodes": nodes, "edges": clean_edges, "raw_calls": raw_calls}


# ── PowerShell ────────────────────────────────────────────────────────────────

def extract_powershell(path: Path) -> dict:
    """Extract functions, classes, methods, and using statements from a .ps1 file."""
    try:
        import tree_sitter_powershell as tsps
        from tree_sitter import Language, Parser
    except ImportError:
        return {"nodes": [], "edges": [], "error": "tree_sitter_powershell not installed"}

    try:
        language = Language(tsps.language())
        parser = Parser(language)
        source = path.read_bytes()
        tree = parser.parse(source)
        root = tree.root_node
    except Exception as e:
        return {"nodes": [], "edges": [], "error": str(e)}

    stem = _file_stem(path)
    str_path = str(path)
    nodes: list[dict] = []
    edges: list[dict] = []
    seen_ids: set[str] = set()
    function_bodies: list[tuple[str, Any]] = []

    def add_node(nid: str, label: str, line: int) -> None:
        if nid not in seen_ids:
            seen_ids.add(nid)
            nodes.append({"id": nid, "label": label, "file_type": "code",
                          "source_file": str_path, "source_location": f"L{line}"})

    def add_edge(src: str, tgt: str, relation: str, line: int,
                 confidence: str = "EXTRACTED", weight: float = 1.0,
                 context: str | None = None) -> None:
        edge = {"source": src, "target": tgt, "relation": relation,
                "confidence": confidence, "source_file": str_path,
                "source_location": f"L{line}", "weight": weight}
        if context:
            edge["context"] = context
        edges.append(edge)

    file_nid = _make_id(str(path))
    add_node(file_nid, path.name, 1)

    _PS_SKIP = frozenset({
        "using", "return", "if", "else", "elseif", "foreach", "for",
        "while", "do", "switch", "try", "catch", "finally", "throw",
        "break", "continue", "exit", "param", "begin", "process", "end",
    })

    def _find_script_block_body(node):
        for child in node.children:
            if child.type == "script_block":
                for sc in child.children:
                    if sc.type == "script_block_body":
                        return sc
                return child
        return None

    def walk(node, parent_class_nid: str | None = None) -> None:
        t = node.type

        if t == "function_statement":
            name_node = next((c for c in node.children if c.type == "function_name"), None)
            if name_node:
                func_name = _read_text(name_node, source)
                line = node.start_point[0] + 1
                func_nid = _make_id(stem, func_name)
                add_node(func_nid, f"{func_name}()", line)
                add_edge(file_nid, func_nid, "contains", line)
                body = _find_script_block_body(node)
                if body:
                    function_bodies.append((func_nid, body))
            return

        if t == "class_statement":
            name_node = next((c for c in node.children if c.type == "simple_name"), None)
            if name_node:
                class_name = _read_text(name_node, source)
                line = node.start_point[0] + 1
                class_nid = _make_id(stem, class_name)
                add_node(class_nid, class_name, line)
                add_edge(file_nid, class_nid, "contains", line)
                for child in node.children:
                    walk(child, parent_class_nid=class_nid)
            return

        if t == "class_method_definition":
            name_node = next((c for c in node.children if c.type == "simple_name"), None)
            if name_node:
                method_name = _read_text(name_node, source)
                line = node.start_point[0] + 1
                if parent_class_nid:
                    method_nid = _make_id(parent_class_nid, method_name)
                    add_node(method_nid, f".{method_name}()", line)
                    add_edge(parent_class_nid, method_nid, "method", line)
                else:
                    method_nid = _make_id(stem, method_name)
                    add_node(method_nid, f"{method_name}()", line)
                    add_edge(file_nid, method_nid, "contains", line)
                body = _find_script_block_body(node)
                if body:
                    function_bodies.append((method_nid, body))
            return

        if t == "command":
            cmd_name_node = next((c for c in node.children if c.type == "command_name"), None)
            if cmd_name_node:
                cmd_text = _read_text(cmd_name_node, source).lower()
                if cmd_text == "using":
                    tokens = []
                    for child in node.children:
                        if child.type == "command_elements":
                            for el in child.children:
                                if el.type == "generic_token":
                                    tokens.append(_read_text(el, source))
                    module_tokens = [t for t in tokens
                                     if t.lower() not in ("namespace", "module", "assembly")]
                    if module_tokens:
                        module_name = module_tokens[-1].split(".")[-1]
                        add_edge(file_nid, _make_id(module_name), "imports_from",
                                 node.start_point[0] + 1)
            return

        for child in node.children:
            walk(child, parent_class_nid)

    walk(root)

    label_to_nid = {n["label"].strip("()").lstrip(".").lower(): n["id"] for n in nodes}
    seen_call_pairs: set[tuple[str, str]] = set()
    raw_calls: list[dict] = []

    def walk_calls(node, caller_nid: str) -> None:
        if node.type in ("function_statement", "class_statement"):
            return
        if node.type == "command":
            cmd_name_node = next((c for c in node.children if c.type == "command_name"), None)
            if cmd_name_node:
                cmd_text = _read_text(cmd_name_node, source)
                if cmd_text.lower() not in _PS_SKIP:
                    tgt_nid = label_to_nid.get(cmd_text.lower())
                    if tgt_nid and tgt_nid != caller_nid:
                        pair = (caller_nid, tgt_nid)
                        if pair not in seen_call_pairs:
                            seen_call_pairs.add(pair)
                            add_edge(caller_nid, tgt_nid, "calls",
                                     node.start_point[0] + 1,
                                     confidence="EXTRACTED", weight=1.0)
                    elif cmd_text:
                        raw_calls.append({
                            "caller_nid": caller_nid,
                            "callee": cmd_text,
                            "is_member_call": False,
                            "source_file": str_path,
                            "source_location": f"L{node.start_point[0] + 1}",
                        })
        for child in node.children:
            walk_calls(child, caller_nid)

    for caller_nid, body_node in function_bodies:
        walk_calls(body_node, caller_nid)

    clean_edges = [e for e in edges if e["source"] in seen_ids and
                   (e["target"] in seen_ids or e["relation"] == "imports_from")]
    return {"nodes": nodes, "edges": clean_edges, "raw_calls": raw_calls}


# ── Cross-file import resolution ──────────────────────────────────────────────

def _resolve_cross_file_imports(
    per_file: list[dict],
    paths: list[Path],
) -> list[dict]:
    """
    Two-pass import resolution: turn file-level imports into class-level edges.

    Pass 1 - build a global map: class/function name → node_id, per stem.
    Pass 2 - for each `from .module import Name`, look up Name in the global
              map and add a direct INFERRED edge from each class in the
              importing file to the imported entity.

    This turns:
        auth.py --imports_from--> models.py          (obvious, filtered out)
    Into:
        DigestAuth --uses--> Response  [INFERRED]    (cross-file, interesting!)
        BasicAuth  --uses--> Request   [INFERRED]
    """
    try:
        import tree_sitter_python as tspython
        from tree_sitter import Language, Parser
    except ImportError:
        return []

    language = Language(tspython.language())
    parser = Parser(language)

    # Pass 1: _file_stem(path) → {ClassName: node_id}
    # Keyed by directory-qualified stem (e.g. "auth_models") to avoid collisions
    # when multiple files share the same filename in different directories.
    # A secondary bare-stem index handles absolute imports where only the module
    # name is known — first writer wins when names collide (inherently ambiguous).
    stem_to_entities: dict[str, dict[str, str]] = {}
    bare_to_qualified: dict[str, str] = {}
    for file_result in per_file:
        for node in file_result.get("nodes", []):
            src = node.get("source_file", "")
            if not src:
                continue
            src_path = Path(src)
            fq_stem = _file_stem(src_path)
            label = node.get("label", "")
            nid = node.get("id", "")
            # Index class-level entities only. Function/method labels end in "()"
            # so are excluded by the `endswith(")")` filter; file nodes end in ".py";
            # private/internal labels start with "_"; rationale nodes carry
            # file_type=="rationale" and must never participate in cross-file
            # import resolution (#563).
            if (
                label
                and not label.endswith((")", ".py"))
                and "_" not in label[:1]
                and node.get("file_type") != "rationale"
            ):
                stem_to_entities.setdefault(fq_stem, {})[label] = nid
                if src_path.stem not in bare_to_qualified:
                    bare_to_qualified[src_path.stem] = fq_stem

    # Pass 2: for each file, find `from .X import A, B, C` and resolve
    new_edges: list[dict] = []
    stem_to_path: dict[str, Path] = {_file_stem(p): p for p in paths}

    for file_result, path in zip(per_file, paths):
        stem = _file_stem(path)
        str_path = str(path)

        # Find all classes defined in this file (the importers).
        # Excludes rationale nodes whose labels happen not to end in ")" or ".py"
        # but which must never be treated as importing entities (#563).
        local_classes = [
            n["id"] for n in file_result.get("nodes", [])
            if n.get("source_file") == str_path
            and not n["label"].endswith((")", ".py"))
            and n["id"] != _make_id(stem)  # exclude file-level node
            and n.get("file_type") != "rationale"
        ]
        if not local_classes:
            continue

        # Parse imports from this file
        try:
            source = path.read_bytes()
            tree = parser.parse(source)
        except Exception:
            continue

        def walk_imports(node) -> None:
            if node.type == "import_from_statement":
                # Find the module name - handles both absolute and relative imports.
                # Relative: `from .models import X` → relative_import → dotted_name
                # Absolute: `from models import X`  → module_name field
                # target_fq is the directory-qualified stem used as the key in
                # stem_to_entities. Relative imports are resolved exactly via the
                # importing file's directory; absolute imports fall back to the
                # bare-stem secondary index (first-writer-wins when names collide).
                target_fq: str | None = None
                for child in node.children:
                    if child.type == "relative_import":
                        for sub in child.children:
                            if sub.type == "dotted_name":
                                raw = source[sub.start_byte:sub.end_byte].decode("utf-8", errors="replace")
                                bare = raw.split(".")[-1]
                                # Resolve relative import to exact qualified stem.
                                candidate = path.parent / f"{bare}.py"
                                target_fq = _file_stem(candidate)
                                break
                        break
                    if child.type == "dotted_name" and target_fq is None:
                        raw = source[child.start_byte:child.end_byte].decode("utf-8", errors="replace")
                        bare = raw.split(".")[-1]
                        target_fq = bare_to_qualified.get(bare)

                if not target_fq or target_fq not in stem_to_entities:
                    return

                # Collect imported names: dotted_name children of import_from_statement
                # that come AFTER the 'import' keyword token.
                imported_names: list[str] = []
                past_import_kw = False
                for child in node.children:
                    if child.type == "import":
                        past_import_kw = True
                        continue
                    if not past_import_kw:
                        continue
                    if child.type == "dotted_name":
                        imported_names.append(
                            source[child.start_byte:child.end_byte].decode("utf-8", errors="replace")
                        )
                    elif child.type == "aliased_import":
                        # `import X as Y` - take the original name
                        name_node = child.child_by_field_name("name")
                        if name_node:
                            imported_names.append(
                                source[name_node.start_byte:name_node.end_byte].decode("utf-8", errors="replace")
                            )

                line = node.start_point[0] + 1
                for name in imported_names:
                    tgt_nid = stem_to_entities[target_fq].get(name)
                    if tgt_nid:
                        for src_class_nid in local_classes:
                            new_edges.append({
                                "source": src_class_nid,
                                "target": tgt_nid,
                                "relation": "uses",
                                "confidence": "INFERRED",
                                "source_file": str_path,
                                "source_location": f"L{line}",
                                "weight": 0.8,
                            })
            for child in node.children:
                walk_imports(child)

        walk_imports(tree.root_node)

    return new_edges


def _merge_swift_extensions(
    per_file: list[dict],
    all_nodes: list[dict],
    all_edges: list[dict],
) -> None:
    """Collapse cross-file Swift `extension Foo` nodes into the canonical `Foo`.

    tree-sitter-swift reuses `class_declaration` for both `class Foo` and
    `extension Foo`, and node ids carry the file stem, so each file that
    extends `Foo` produces its own `Foo` node. The match is done by label:
    when exactly one non-extension declaration shares the label, extension
    nodes redirect onto it. Extensions of types outside the corpus (no match)
    and ambiguous labels (more than one match) are left untouched — picking
    arbitrarily would invent edges.
    """
    extension_nids: set[str] = set()
    extension_labels: dict[str, str] = {}
    for result in per_file:
        for ext in result.get("swift_extensions", []) or []:
            extension_nids.add(ext["nid"])
            extension_labels[ext["nid"]] = ext["label"]

    if not extension_nids:
        return

    label_to_canonical: dict[str, list[str]] = {}
    for n in all_nodes:
        if n.get("id") in extension_nids:
            continue
        label = n.get("label")
        if not label:
            continue
        label_to_canonical.setdefault(label, []).append(n["id"])

    remap: dict[str, str] = {}
    for ext_nid in extension_nids:
        candidates = label_to_canonical.get(extension_labels[ext_nid], [])
        if len(candidates) != 1:
            continue
        canonical_nid = candidates[0]
        if canonical_nid != ext_nid:
            remap[ext_nid] = canonical_nid

    if not remap:
        return

    all_nodes[:] = [n for n in all_nodes if n.get("id") not in remap]

    # Each extension file's `contains` edge ends up pointing at the canonical
    # type — multiple files containing the same node is the intended shape:
    # the type owns the methods, the files own their slice. Self-loops are
    # dropped (e.g. an in-file extension method whose call already pointed at
    # the canonical type).
    rewritten: list[dict] = []
    seen_keys: set[tuple] = set()
    for e in all_edges:
        src = remap.get(e.get("source"), e.get("source"))
        tgt = remap.get(e.get("target"), e.get("target"))
        if src == tgt:
            continue
        e["source"] = src
        e["target"] = tgt
        key = (src, tgt, e.get("relation"), e.get("source_file"), e.get("source_location"))
        if key in seen_keys:
            continue
        seen_keys.add(key)
        rewritten.append(e)
    all_edges[:] = rewritten


def _resolve_cross_file_java_imports(
    per_file: list[dict],
    paths: list[Path],
) -> list[dict]:
    """Two-pass Java import resolution.

    Pass 1: build a global index {ClassName: [node_id, ...]} across all Java nodes.
    Pass 2: re-parse each Java file; for every `import a.b.C;`, resolve C against
    the index. Wildcard and stdlib imports produce no edge.
    """
    try:
        import tree_sitter_java as tsjava
        from tree_sitter import Language, Parser
    except ImportError:
        return []

    language = Language(tsjava.language())
    parser = Parser(language)

    # Pass 1: class-name → node_id index (only internal, uppercase-starting names)
    name_to_ids: dict[str, list[str]] = {}
    for file_result in per_file:
        for node in file_result.get("nodes", []):
            label = node.get("label", "")
            nid = node.get("id", "")
            src = node.get("source_file", "")
            if not label or not nid or not src:
                continue
            if label.endswith(")") or label.endswith(".java"):
                continue
            if not label[0].isalpha() or not label[0].isupper():
                continue
            name_to_ids.setdefault(label, []).append(nid)

    # Pass 2: resolve imports to real node IDs
    new_edges: list[dict] = []
    seen_pairs: set[tuple[str, str]] = set()
    for path in paths:
        file_nid = _make_id(str(path))
        try:
            source = path.read_bytes()
            tree = parser.parse(source)
        except Exception:
            continue

        def walk(n) -> None:
            if n.type == "import_declaration":
                raw = _read_text(n, source).strip()
                body = raw[len("import"):].strip().rstrip(";").strip()
                if body.startswith("static "):
                    body = body[len("static "):].strip()
                if body.endswith(".*"):
                    return
                parts = body.split(".")
                if not parts:
                    return
                last = parts[-1]
                if last and last[0].islower() and len(parts) >= 2:
                    last = parts[-2]
                at_line = n.start_point[0] + 1
                for tgt_nid in name_to_ids.get(last, []):
                    if tgt_nid == file_nid:
                        continue
                    key = (file_nid, tgt_nid)
                    if key in seen_pairs:
                        continue
                    seen_pairs.add(key)
                    new_edges.append({
                        "source": file_nid,
                        "target": tgt_nid,
                        "relation": "imports",
                        "confidence": "EXTRACTED",
                        "confidence_score": 1.0,
                        "source_file": str(path),
                        "source_location": f"L{at_line}",
                        "weight": 1.0,
                    })
            for child in n.children:
                walk(child)

        walk(tree.root_node)

    return new_edges


def extract_objc(path: Path) -> dict:
    """Extract interfaces, implementations, protocols, methods, and imports from .m/.mm/.h files."""
    try:
        import tree_sitter_objc as tsobjc
        from tree_sitter import Language, Parser
    except ImportError:
        return {"nodes": [], "edges": [], "error": "tree_sitter_objc not installed"}

    try:
        language = Language(tsobjc.language())
        parser = Parser(language)
        source = path.read_bytes()
        tree = parser.parse(source)
        root = tree.root_node
    except Exception as e:
        return {"nodes": [], "edges": [], "error": str(e)}

    stem = _file_stem(path)
    str_path = str(path)
    nodes: list[dict] = []
    edges: list[dict] = []
    seen_ids: set[str] = set()
    method_bodies: list[tuple[str, Any]] = []

    def add_node(nid: str, label: str, line: int) -> None:
        if nid not in seen_ids:
            seen_ids.add(nid)
            nodes.append({"id": nid, "label": label, "file_type": "code",
                          "source_file": str_path, "source_location": f"L{line}"})

    def add_edge(src: str, tgt: str, relation: str, line: int,
                 confidence: str = "EXTRACTED", weight: float = 1.0,
                 context: str | None = None) -> None:
        edge = {"source": src, "target": tgt, "relation": relation,
                "confidence": confidence, "source_file": str_path,
                "source_location": f"L{line}", "weight": weight}
        if context:
            edge["context"] = context
        edges.append(edge)

    file_nid = _make_id(str(path))
    add_node(file_nid, path.name, 1)

    def _read(node) -> str:
        return source[node.start_byte:node.end_byte].decode("utf-8", errors="replace")

    def _get_name(node, field: str) -> str | None:
        n = node.child_by_field_name(field)
        return _read(n) if n else None

    def walk(node, parent_nid: str | None = None) -> None:
        t = node.type
        line = node.start_point[0] + 1

        if t == "preproc_include":
            # #import <Foundation/Foundation.h> or #import "MyClass.h"
            for child in node.children:
                if child.type == "system_lib_string":
                    raw = _read(child).strip("<>")
                    module = raw.split("/")[-1].replace(".h", "")
                    if module:
                        tgt_nid = _make_id(module)
                        add_edge(file_nid, tgt_nid, "imports", line, context="import")
                elif child.type == "string_literal":
                    # recurse into string_literal to find string_content
                    for sub in child.children:
                        if sub.type == "string_content":
                            raw = _read(sub)
                            module = raw.split("/")[-1].replace(".h", "")
                            if module:
                                tgt_nid = _make_id(module)
                                add_edge(file_nid, tgt_nid, "imports", line, context="import")
            return

        if t == "class_interface":
            # @interface ClassName : SuperClass <Protocols>
            # children: @interface, identifier(name), ':', identifier(super), parameterized_arguments, ...
            identifiers = [c for c in node.children if c.type == "identifier"]
            if not identifiers:
                for child in node.children:
                    walk(child, parent_nid)
                return
            name = _read(identifiers[0])
            cls_nid = _make_id(stem, name)
            add_node(cls_nid, name, line)
            add_edge(file_nid, cls_nid, "contains", line)
            # superclass is second identifier after ':'
            colon_seen = False
            for child in node.children:
                if child.type == ":":
                    colon_seen = True
                elif colon_seen and child.type == "identifier":
                    super_nid = _make_id(_read(child))
                    add_edge(cls_nid, super_nid, "inherits", line)
                    colon_seen = False
                elif child.type == "parameterized_arguments":
                    # protocols adopted
                    for sub in child.children:
                        if sub.type == "type_name":
                            for s in sub.children:
                                if s.type == "type_identifier":
                                    proto_nid = _make_id(_read(s))
                                    add_edge(cls_nid, proto_nid, "imports", line, context="import")
                elif child.type == "method_declaration":
                    walk(child, cls_nid)
            return

        if t == "class_implementation":
            # @implementation ClassName
            name = None
            for child in node.children:
                if child.type == "identifier":
                    name = _read(child)
                    break
            if not name:
                for child in node.children:
                    walk(child, parent_nid)
                return
            impl_nid = _make_id(stem, name)
            if impl_nid not in seen_ids:
                add_node(impl_nid, name, line)
                add_edge(file_nid, impl_nid, "contains", line)
            for child in node.children:
                if child.type == "implementation_definition":
                    for sub in child.children:
                        walk(sub, impl_nid)
            return

        if t == "protocol_declaration":
            name = None
            for child in node.children:
                if child.type == "identifier":
                    name = _read(child)
                    break
            if name:
                proto_nid = _make_id(stem, name)
                add_node(proto_nid, f"<{name}>", line)
                add_edge(file_nid, proto_nid, "contains", line)
                for child in node.children:
                    walk(child, proto_nid)
            return

        if t in ("method_declaration", "method_definition"):
            container = parent_nid or file_nid
            # method name is the first identifier child (simple selector)
            # for compound selectors: identifier + method_parameter pairs
            parts = []
            for child in node.children:
                if child.type == "identifier":
                    parts.append(_read(child))
                elif child.type == "method_parameter":
                    for sub in child.children:
                        if sub.type == "identifier":
                            # selector keyword before ':'
                            pass
            method_name = "".join(parts) if parts else None
            if method_name:
                method_nid = _make_id(container, method_name)
                add_node(method_nid, f"-{method_name}", line)
                add_edge(container, method_nid, "method", line)
                if t == "method_definition":
                    method_bodies.append((method_nid, node))
            return

        for child in node.children:
            walk(child, parent_nid)

    walk(root)

    # Second pass: resolve calls inside method bodies
    all_method_nids = {n["id"] for n in nodes if n["id"] != file_nid}
    seen_calls: set[tuple[str, str]] = set()
    for caller_nid, body_node in method_bodies:
        def walk_calls(n) -> None:
            if n.type == "message_expression":
                # [receiver selector]
                for child in n.children:
                    if child.type in ("selector", "keyword_argument_list"):
                        sel = []
                        if child.type == "selector":
                            sel.append(_read(child))
                        else:
                            for sub in child.children:
                                if sub.type == "keyword_argument":
                                    for s in sub.children:
                                        if s.type == "selector":
                                            sel.append(_read(s))
                        method_name = "".join(sel)
                        for candidate in all_method_nids:
                            if candidate.endswith(_make_id("", method_name).lstrip("_")):
                                pair = (caller_nid, candidate)
                                if pair not in seen_calls and caller_nid != candidate:
                                    seen_calls.add(pair)
                                    add_edge(caller_nid, candidate, "calls", body_node.start_point[0] + 1,
                                             confidence="EXTRACTED", weight=1.0, context="call")
            for child in n.children:
                walk_calls(child)
        walk_calls(body_node)

    return {"nodes": nodes, "edges": edges, "input_tokens": 0, "output_tokens": 0}


def extract_elixir(path: Path) -> dict:
    """Extract modules, functions, imports, and calls from a .ex/.exs file."""
    try:
        import tree_sitter_elixir as tselixir
        from tree_sitter import Language, Parser
    except ImportError:
        return {"nodes": [], "edges": [], "error": "tree_sitter_elixir not installed"}

    try:
        language = Language(tselixir.language())
        parser = Parser(language)
        source = path.read_bytes()
        tree = parser.parse(source)
        root = tree.root_node
    except Exception as e:
        return {"nodes": [], "edges": [], "error": str(e)}

    stem = _file_stem(path)
    str_path = str(path)
    nodes: list[dict] = []
    edges: list[dict] = []
    seen_ids: set[str] = set()
    function_bodies: list[tuple[str, Any]] = []

    def add_node(nid: str, label: str, line: int) -> None:
        if nid not in seen_ids:
            seen_ids.add(nid)
            nodes.append({"id": nid, "label": label, "file_type": "code",
                          "source_file": str_path, "source_location": f"L{line}"})

    def add_edge(src: str, tgt: str, relation: str, line: int,
                 confidence: str = "EXTRACTED", weight: float = 1.0,
                 context: str | None = None) -> None:
        edge = {"source": src, "target": tgt, "relation": relation,
                "confidence": confidence, "source_file": str_path,
                "source_location": f"L{line}", "weight": weight}
        if context:
            edge["context"] = context
        edges.append(edge)

    file_nid = _make_id(str(path))
    add_node(file_nid, path.name, 1)

    _IMPORT_KEYWORDS = frozenset({"alias", "import", "require", "use"})

    def _get_alias_text(node) -> str | None:
        for child in node.children:
            if child.type == "alias":
                return source[child.start_byte:child.end_byte].decode("utf-8", errors="replace")
        return None

    def walk(node, parent_module_nid: str | None = None) -> None:
        if node.type != "call":
            for child in node.children:
                walk(child, parent_module_nid)
            return

        identifier_node = None
        arguments_node = None
        do_block_node = None
        for child in node.children:
            if child.type == "identifier":
                identifier_node = child
            elif child.type == "arguments":
                arguments_node = child
            elif child.type == "do_block":
                do_block_node = child

        if identifier_node is None:
            for child in node.children:
                walk(child, parent_module_nid)
            return

        keyword = source[identifier_node.start_byte:identifier_node.end_byte].decode("utf-8", errors="replace")
        line = node.start_point[0] + 1

        if keyword == "defmodule":
            module_name = _get_alias_text(arguments_node) if arguments_node else None
            if not module_name:
                return
            module_nid = _make_id(stem, module_name)
            add_node(module_nid, module_name, line)
            add_edge(file_nid, module_nid, "contains", line)
            if do_block_node:
                for child in do_block_node.children:
                    walk(child, parent_module_nid=module_nid)
            return

        if keyword in ("def", "defp"):
            func_name = None
            if arguments_node:
                for child in arguments_node.children:
                    if child.type == "call":
                        for sub in child.children:
                            if sub.type == "identifier":
                                func_name = source[sub.start_byte:sub.end_byte].decode("utf-8", errors="replace")
                                break
                    elif child.type == "identifier":
                        func_name = source[child.start_byte:child.end_byte].decode("utf-8", errors="replace")
                        break
            if not func_name:
                return
            container = parent_module_nid or file_nid
            func_nid = _make_id(container, func_name)
            add_node(func_nid, f"{func_name}()", line)
            if parent_module_nid:
                add_edge(parent_module_nid, func_nid, "method", line)
            else:
                add_edge(file_nid, func_nid, "contains", line)
            if do_block_node:
                function_bodies.append((func_nid, do_block_node))
            return

        if keyword in _IMPORT_KEYWORDS and arguments_node:
            module_name = _get_alias_text(arguments_node)
            if module_name:
                tgt_nid = _make_id(module_name)
                add_edge(file_nid, tgt_nid, "imports", line, context="import")
            return

        for child in node.children:
            walk(child, parent_module_nid)

    walk(root)

    label_to_nid: dict[str, str] = {}
    for n in nodes:
        normalised = n["label"].strip("()").lstrip(".")
        label_to_nid[normalised.lower()] = n["id"]

    seen_call_pairs: set[tuple[str, str]] = set()
    raw_calls: list[dict] = []
    _SKIP_KEYWORDS = frozenset({
        "def", "defp", "defmodule", "defmacro", "defmacrop",
        "defstruct", "defprotocol", "defimpl", "defguard",
        "alias", "import", "require", "use",
        "if", "unless", "case", "cond", "with", "for",
    })

    def walk_calls(node, caller_nid: str) -> None:
        if node.type != "call":
            for child in node.children:
                walk_calls(child, caller_nid)
            return
        for child in node.children:
            if child.type == "identifier":
                kw = source[child.start_byte:child.end_byte].decode("utf-8", errors="replace")
                if kw in _SKIP_KEYWORDS:
                    for c in node.children:
                        walk_calls(c, caller_nid)
                    return
                break
        callee_name: str | None = None
        is_member_call: bool = False
        for child in node.children:
            if child.type == "dot":
                is_member_call = True
                dot_text = source[child.start_byte:child.end_byte].decode("utf-8", errors="replace")
                parts = dot_text.rstrip(".").split(".")
                if parts:
                    callee_name = parts[-1]
                break
            if child.type == "identifier":
                callee_name = source[child.start_byte:child.end_byte].decode("utf-8", errors="replace")
                break
        if callee_name:
            tgt_nid = label_to_nid.get(callee_name.lower())
            if tgt_nid and tgt_nid != caller_nid:
                pair = (caller_nid, tgt_nid)
                if pair not in seen_call_pairs:
                    seen_call_pairs.add(pair)
                    add_edge(caller_nid, tgt_nid, "calls",
                             node.start_point[0] + 1, confidence="EXTRACTED", weight=1.0,
                             context="call")
            else:
                raw_calls.append({
                    "caller_nid": caller_nid,
                    "callee": callee_name,
                    "is_member_call": is_member_call,
                    "source_file": str_path,
                    "source_location": f"L{node.start_point[0] + 1}",
                })
        for child in node.children:
            walk_calls(child, caller_nid)

    for caller_nid, body in function_bodies:
        walk_calls(body, caller_nid)

    clean_edges = [e for e in edges if e["source"] in seen_ids and
                   (e["target"] in seen_ids or e["relation"] == "imports")]
    return {"nodes": nodes, "edges": clean_edges, "raw_calls": raw_calls, "input_tokens": 0, "output_tokens": 0}


def extract_markdown(path: Path) -> dict:
    """Extract structural nodes and edges from a Markdown file.

    Produces nodes for:
    - The file itself
    - Each heading (# / ## / ### etc.)
    - Each fenced code block (``` ... ```)

    Produces edges for:
    - file --contains--> heading
    - parent heading --contains--> child heading (nesting by level)
    - heading --contains--> code block
    - heading --references--> other node (when backtick `Name` matches a known pattern)

    No tree-sitter dependency — pure line-by-line parsing.
    """
    try:
        source = path.read_text(encoding="utf-8", errors="replace")
    except Exception as e:
        return {"nodes": [], "edges": [], "error": str(e)}

    stem = _file_stem(path)
    str_path = str(path)
    nodes: list[dict] = []
    edges: list[dict] = []
    seen_ids: set[str] = set()

    def add_node(nid: str, label: str, line: int, file_type: str = "document") -> None:
        if nid not in seen_ids:
            seen_ids.add(nid)
            nodes.append({"id": nid, "label": label, "file_type": file_type,
                          "source_file": str_path, "source_location": f"L{line}"})

    def add_edge(src: str, tgt: str, relation: str, line: int,
                 confidence: str = "EXTRACTED", weight: float = 1.0) -> None:
        edges.append({"source": src, "target": tgt, "relation": relation,
                      "confidence": confidence, "source_file": str_path,
                      "source_location": f"L{line}", "weight": weight})

    file_nid = _make_id(str(path))
    add_node(file_nid, path.name, 1)

    # Track heading stack for nesting: [(level, nid), ...]
    heading_stack: list[tuple[int, str]] = []
    in_code_block = False
    code_block_lang: str | None = None
    code_block_start: int = 0
    code_block_lines: list[str] = []
    code_block_count = 0

    lines = source.splitlines()
    for line_num_0, line_text in enumerate(lines):
        line_num = line_num_0 + 1

        # Toggle fenced code blocks
        stripped = line_text.strip()
        if stripped.startswith("```"):
            if not in_code_block:
                in_code_block = True
                code_block_lang = stripped[3:].strip().split()[0] if len(stripped) > 3 else None
                code_block_start = line_num
                code_block_lines = []
                continue
            else:
                # End of code block — create a node
                in_code_block = False
                code_block_count += 1
                snippet = "\n".join(code_block_lines[:3])  # first 3 lines as preview
                label = f"code:{code_block_lang}" if code_block_lang else f"code:block{code_block_count}"
                if snippet:
                    # Use first meaningful line as label hint
                    first_line = code_block_lines[0].strip()[:60] if code_block_lines else ""
                    if first_line:
                        label = f"{label} ({first_line})"
                cb_nid = _make_id(stem, f"codeblock_{code_block_count}")
                add_node(cb_nid, label, code_block_start)
                # Attach to nearest heading or file
                parent = heading_stack[-1][1] if heading_stack else file_nid
                add_edge(parent, cb_nid, "contains", code_block_start)
                continue

        if in_code_block:
            code_block_lines.append(line_text)
            continue

        # Detect headings: # Heading, ## Heading, etc.
        heading_match = re.match(r'^(#{1,6})\s+(.+)', line_text)
        if heading_match:
            level = len(heading_match.group(1))
            title = heading_match.group(2).strip()
            h_nid = _make_id(stem, title)
            # Avoid duplicate heading IDs by appending line number
            if h_nid in seen_ids:
                h_nid = _make_id(stem, title, str(line_num))
            add_node(h_nid, title, line_num)

            # Pop headings at same or deeper level
            while heading_stack and heading_stack[-1][0] >= level:
                heading_stack.pop()

            # Connect to parent heading or file
            parent = heading_stack[-1][1] if heading_stack else file_nid
            add_edge(parent, h_nid, "contains", line_num)

            heading_stack.append((level, h_nid))
            continue

    return {"nodes": nodes, "edges": edges, "input_tokens": 0, "output_tokens": 0}


# ── Pascal / Delphi extractor ─────────────────────────────────────────────────

_pascal_unit_cache: dict[str, dict[str, str]] = {}
_pascal_class_stem_cache: dict[str, dict[str, str]] = {}  # root_key → {stem_lower: _file_stem}


def _pascal_project_root(from_path: Path) -> Path:
    """Return the highest ancestor directory that looks like a Pascal project root.

    Walks up the directory tree and tracks the topmost directory that:
      - is NOT a filesystem root (e.g. D:/, C:/, /)
      - has at least 2 .pas files OR at least 1 .dpr file as direct children

    The minimum-2 threshold avoids treating a level as the root just because a
    single stray .pas file was copied there.  The filesystem-root exclusion
    prevents overshoot on drives that have a stray file directly at D:/.

    Falls back to from_path.parent if nothing better is found.
    """
    best = from_path.parent
    current = from_path.parent
    for _ in range(12):
        if len(current.parts) <= 1:
            break  # never use a filesystem root (D:/, C:/, /)
        pas_count = sum(1 for _ in current.glob("*.pas"))
        dpr_count = sum(1 for _ in current.glob("*.dpr"))
        if pas_count >= 2 or dpr_count >= 1:
            best = current
        parent = current.parent
        if parent == current:
            break
        current = parent
    return best


def _pascal_resolve_unit(from_path: Path, unit_name: str) -> str:
    """Resolve a Pascal unit name to the graphify node ID of its source file.

    Scans all Pascal files under the project root (the highest ancestor that
    directly contains .pas/.dpr files) and returns _make_id(str(matched_path)).
    Result is cached per project root so the rglob runs at most once per
    project.  Falls back to _make_id(unit_name) for units not found on disk
    (e.g. standard RTL units like SysUtils, Windows).
    """
    root = _pascal_project_root(from_path)
    root_key = str(root)
    if root_key not in _pascal_unit_cache:
        unit_map: dict[str, str] = {}
        for ext in (".pas", ".pp", ".dpr", ".dpk", ".inc"):
            for f in root.rglob("*" + ext):
                unit_map[f.stem.lower()] = _make_id(str(f))
        _pascal_unit_cache[root_key] = unit_map
    return _pascal_unit_cache[root_key].get(unit_name.lower(), _make_id(unit_name))


def _pascal_resolve_class(from_path: Path, class_name: str) -> str | None:
    """Resolve a Pascal class/interface name to the node ID of its defining file's class node.

    Pascal convention: TFooBar is defined in FooBar.pas, IFooBar in FooBar.pas.
    Strips the leading T/I prefix, finds the file, and returns
    _make_id(_file_stem(found_file), class_name).

    Returns None when no matching file is found on disk (RTL, stdlib, or
    unconventionally-named class — caller should create a stub node).
    """
    prefix = class_name[:1]
    unit_name = class_name[1:] if prefix in ("T", "I") else class_name

    root = _pascal_project_root(from_path)
    root_key = str(root)
    if root_key not in _pascal_class_stem_cache:
        stem_map: dict[str, str] = {}
        for ext in (".pas", ".pp", ".dpr", ".dpk"):
            for f in root.rglob("*" + ext):
                stem_map[f.stem.lower()] = _file_stem(f)
        _pascal_class_stem_cache[root_key] = stem_map

    file_stem = _pascal_class_stem_cache[root_key].get(unit_name.lower())
    if file_stem:
        return _make_id(file_stem, class_name)
    return None


_PAS_TOKEN_RE = re.compile(
    r"'(?:''|[^'])*'"
    r"|\{[^}]*\}"
    r"|\(\*.*?\*\)"
    r"|//[^\n]*",
    re.DOTALL,
)
_PAS_MODULE_RE = re.compile(
    r"\b(unit|program|library)\s+([A-Za-z_][\w.]*)\s*;",
    re.IGNORECASE,
)
_PAS_USES_RE = re.compile(
    r"\buses\b\s*([^;]+);",
    re.IGNORECASE | re.DOTALL,
)
_PAS_TYPE_HEADER_RE = re.compile(
    r"\b(?P<name>[A-Za-z_]\w*)(?:\s*<[^>]+>)?\s*=\s*(?:packed\s+)?"
    r"(?P<kind>class|interface)\b"
    r"(?:\s*\(\s*(?P<bases>[^)]*)\s*\))?",
    re.IGNORECASE,
)
_PAS_END_SEMI_RE = re.compile(r"\bend\s*;", re.IGNORECASE)
_PAS_METHOD_DECL_RE = re.compile(
    r"\b(?:procedure|function|constructor|destructor)\s+"
    r"(?P<name>[A-Za-z_]\w*)"
    r"(?:\s*\([^)]*\))?"
    r"(?:\s*:\s*[\w<>,\s.]+)?"
    r"\s*;",
    re.IGNORECASE,
)
_PAS_IMPL_HEADER_RE = re.compile(
    r"\b(?:procedure|function|constructor|destructor)\s+"
    r"(?P<qual>[A-Za-z_]\w*(?:\.[A-Za-z_]\w*)?)"
    r"(?:\s*<[^>]+>)?"
    r"(?:\s*\([^)]*\))?"
    r"(?:\s*:\s*[\w<>,\s.]+)?"
    r"\s*;",
    re.IGNORECASE,
)
_PAS_BEGIN_END_TOKEN_RE = re.compile(
    r"\b(begin|end|case|try|asm|record)\b", re.IGNORECASE
)
_PAS_CALL_RE = re.compile(r"\b([A-Za-z_]\w*(?:\.[A-Za-z_]\w*)*)\s*[(;]")
_PAS_KEYWORDS = frozenset({
    "begin", "end", "if", "then", "else", "while", "do", "for", "to",
    "downto", "repeat", "until", "case", "of", "try", "finally", "except",
    "with", "inherited", "result", "var", "const", "type", "nil", "true",
    "false", "exit", "break", "continue", "uses", "unit", "program",
    "library", "interface", "implementation", "initialization", "finalization",
    "procedure", "function", "constructor", "destructor", "class", "record",
    "object", "array", "string", "integer", "boolean", "real", "char",
    "writeln", "write", "readln", "read", "assigned", "length", "high",
    "low", "inc", "dec", "new", "dispose", "setlength", "copy", "pos",
    "trim", "format", "inttostr", "strtoint", "ord", "chr", "sizeof",
    "create", "free", "destroy",
})


def _pascal_strip_comments(text: str) -> str:
    """Strip Pascal comments ({}, (* *), //) while preserving newlines."""
    def _sub(m: re.Match) -> str:
        tok = m.group(0)
        if tok.startswith("'"):
            return tok
        return "".join(c if c == "\n" else " " for c in tok)
    return _PAS_TOKEN_RE.sub(_sub, text)


def _pascal_split_sections(text: str) -> tuple[str, int, str, int]:
    """Split into (iface_text, iface_offset, impl_text, impl_offset).
    Files without interface/implementation sections (dpr/lpr/inc) return
    the whole text as impl with offset 0.
    """
    iface_m = re.search(r"\binterface\b", text, re.IGNORECASE)
    impl_m = re.search(r"\bimplementation\b", text, re.IGNORECASE)
    if iface_m and impl_m:
        iface_off = iface_m.end()
        impl_off = impl_m.end()
        end_m = re.search(
            r"\b(initialization|finalization)\b", text[impl_off:], re.IGNORECASE
        )
        impl_end = impl_off + end_m.start() if end_m else len(text)
        return text[iface_off:impl_m.start()], iface_off, text[impl_off:impl_end], impl_off
    return "", 0, text, 0


def _pascal_split_uses(s: str) -> list[str]:
    """Split a uses list string, handling 'Foo in ''bar.pas''' syntax."""
    out = []
    for chunk in s.split(","):
        name = re.split(r"\s+in\s+", chunk.strip(), maxsplit=1, flags=re.IGNORECASE)[0]
        name = name.strip().strip(";")
        if name and re.match(r"[A-Za-z_][\w.]*$", name):
            out.append(name)
    return out


def _pascal_split_bases(s: str) -> list[str]:
    """Split inheritance list, handling generics like TList<T, U>."""
    out, depth, buf = [], 0, []
    for ch in s:
        if ch == "<":
            depth += 1
            buf.append(ch)
        elif ch == ">":
            depth -= 1
            buf.append(ch)
        elif ch == "," and depth == 0:
            name = re.sub(r"<.*$", "", "".join(buf).strip())
            if name:
                out.append(name)
            buf = []
        else:
            buf.append(ch)
    name = re.sub(r"<.*$", "", "".join(buf).strip())
    if name:
        out.append(name)
    return [n for n in out if re.match(r"[A-Za-z_]\w*$", n)]


def _pascal_find_body(text: str, start: int) -> tuple[int, int]:
    """Find balanced begin..end after start. Returns (body_start, body_end).
    Returns (0, 0) if no begin found.
    """
    m = re.search(r"\bbegin\b", text[start:], re.IGNORECASE)
    if not m:
        return (0, 0)
    body_start = start + m.end()
    depth = 1
    for tok in _PAS_BEGIN_END_TOKEN_RE.finditer(text, body_start):
        kw = tok.group(1).lower()
        if kw in ("begin", "case", "try", "asm", "record"):
            depth += 1
        elif kw == "end":
            depth -= 1
            if depth == 0:
                return (body_start, tok.start())
    return (body_start, len(text))


def _extract_pascal_regex(path: Path) -> dict:
    """Regex fallback for Pascal/Delphi extraction when tree-sitter-pascal
    is unavailable. Produces the same node/edge schema as the tree-sitter pass.
    """
    try:
        raw = path.read_text(encoding="utf-8", errors="replace")
    except Exception as exc:
        return {"nodes": [], "edges": [], "error": str(exc)}

    str_path = str(path)
    stem = _file_stem(path)
    nodes: list[dict] = []
    edges: list[dict] = []
    seen_ids: set[str] = set()
    seen_call_pairs: set[tuple[str, str]] = set()

    def _add_node(nid: str, label: str, line: int) -> None:
        if nid not in seen_ids:
            seen_ids.add(nid)
            nodes.append({
                "id": nid,
                "label": label,
                "file_type": "code",
                "source_file": str_path,
                "source_location": f"L{line}",
            })

    def _add_edge(src: str, tgt: str, relation: str, line: int, context: str | None = None) -> None:
        edge: dict = {
            "source": src,
            "target": tgt,
            "relation": relation,
            "confidence": "EXTRACTED",
            "source_file": str_path,
            "source_location": f"L{line}",
            "weight": 1.0,
        }
        if context:
            edge["context"] = context
        edges.append(edge)

    def _lineno(text: str, offset: int) -> int:
        return text.count("\n", 0, offset) + 1

    file_nid = _make_id(str_path)
    _add_node(file_nid, path.name, 1)

    stripped = _pascal_strip_comments(raw)

    # Module header
    module_nid = file_nid
    mod_m = _PAS_MODULE_RE.search(stripped)
    if mod_m:
        mod_name = mod_m.group(2)
        module_nid = _make_id(stem, mod_name)
        _add_node(module_nid, mod_name, _lineno(stripped, mod_m.start()))
        _add_edge(file_nid, module_nid, "contains", _lineno(stripped, mod_m.start()))

    iface_text, iface_off, impl_text, impl_off = _pascal_split_sections(stripped)

    # Uses clauses
    for section_text, section_off in ((iface_text, iface_off), (impl_text, impl_off)):
        for um in _PAS_USES_RE.finditer(section_text):
            line = _lineno(stripped, section_off + um.start())
            for unit_name in _pascal_split_uses(um.group(1)):
                tgt_nid = _pascal_resolve_unit(path, unit_name)
                _add_edge(module_nid, tgt_nid, "imports", line, context="import")

    # Type declarations (classes / interfaces) in interface section
    search_text = iface_text if iface_text else stripped
    search_off = iface_off if iface_text else 0
    pos = 0
    while pos < len(search_text):
        hm = _PAS_TYPE_HEADER_RE.search(search_text, pos)
        if not hm:
            break
        type_name = hm.group("name")
        bases_raw = hm.group("bases") or ""
        line = _lineno(stripped, search_off + hm.start())
        cls_nid = _make_id(stem, type_name)
        _add_node(cls_nid, type_name, line)
        _add_edge(module_nid, cls_nid, "contains", line)

        for base_name in _pascal_split_bases(bases_raw):
            resolved = _pascal_resolve_class(path, base_name)
            base_nid = resolved if resolved else _make_id(base_name)
            if base_nid not in seen_ids:
                _add_node(base_nid, base_name, line)
            _add_edge(cls_nid, base_nid, "inherits", line)

        # Find class body (up to next end;)
        end_m = _PAS_END_SEMI_RE.search(search_text, hm.end())
        body_text = search_text[hm.end():end_m.start()] if end_m else ""
        body_off = search_off + hm.end()

        # Forward method declarations inside the class body
        for mm in _PAS_METHOD_DECL_RE.finditer(body_text):
            mname = mm.group("name")
            mline = _lineno(stripped, body_off + mm.start())
            method_nid = _make_id(cls_nid, mname)
            _add_node(method_nid, f"{mname}()", mline)
            _add_edge(cls_nid, method_nid, "method", mline)

        pos = end_m.end() if end_m else len(search_text)

    # Implementation headers (procedure/function/constructor/destructor)
    impl_records: list[tuple[str, int, str]] = []
    for fm in _PAS_IMPL_HEADER_RE.finditer(impl_text):
        qualified = fm.group("qual")
        line = _lineno(stripped, impl_off + fm.start())
        if "." in qualified:
            cls_part, method_part = qualified.split(".", 1)
            cls_nid = _make_id(stem, cls_part)
            container = cls_nid if cls_nid in seen_ids else module_nid
            relation = "method" if cls_nid in seen_ids else "contains"
            label = f"{method_part}()"
        else:
            container, relation = module_nid, "contains"
            label = f"{qualified}()"
        proc_nid = _make_id(stem, qualified)
        _add_node(proc_nid, label, line)
        _add_edge(container, proc_nid, relation, line)

        body_start, body_end = _pascal_find_body(impl_text, fm.end())
        body_text = impl_text[body_start:body_end] if body_start else ""
        impl_records.append((proc_nid, line, body_text))

    # Intra-file call edges
    all_procs: dict[str, str] = {
        n["label"].removesuffix("()").lower(): n["id"]
        for n in nodes
        if n["id"] != file_nid and n["label"].endswith("()")
    }
    for caller_nid, caller_line, body_text in impl_records:
        for cm in _PAS_CALL_RE.finditer(body_text):
            callee_name = cm.group(1).split(".")[-1].lower()
            if callee_name in _PAS_KEYWORDS:
                continue
            callee_nid = all_procs.get(callee_name)
            if not callee_nid or callee_nid == caller_nid:
                continue
            pair = (caller_nid, callee_nid)
            if pair in seen_call_pairs:
                continue
            seen_call_pairs.add(pair)
            call_line = caller_line + body_text.count("\n", 0, cm.start())
            _add_edge(caller_nid, callee_nid, "calls", call_line, context="call")

    return {"nodes": nodes, "edges": edges, "input_tokens": 0, "output_tokens": 0}


def extract_pascal(path: Path) -> dict:
    """Extract units, classes, procedures, uses-imports, and calls from Pascal/Delphi files.

    Produces nodes for:
    - The file itself
    - unit / program / library declarations
    - class and interface type declarations
    - procedure / function implementations (including qualified TClass.Method names)

    Produces edges for:
    - file --contains--> module
    - module --imports--> other file node (via uses clause, resolved to path-based IDs)
    - class --inherits--> base class
    - class/module --contains--> method forward declaration
    - class/module --contains--> procedure/function implementation
    - procedure --calls--> other procedure (within the same file)

    Uses tree-sitter-pascal when available; falls back to a regex-based extractor
    (_extract_pascal_regex) when it isn't installed or fails to parse, so Pascal
    extraction works out of the box without an extra pip install.
    """
    try:
        import tree_sitter_pascal as tspascal
        from tree_sitter import Language, Parser
    except ImportError:
        return _extract_pascal_regex(path)

    try:
        language = Language(tspascal.language())
        parser = Parser(language)
        source = path.read_bytes()
        tree = parser.parse(source)
        root = tree.root_node
    except Exception:
        return _extract_pascal_regex(path)

    stem = _file_stem(path)
    str_path = str(path)
    nodes: list[dict] = []
    edges: list[dict] = []
    seen_ids: set[str] = set()
    proc_bodies: list[tuple[str, Any]] = []

    def _read(node) -> str:  # type: ignore[no-untyped-def]
        return source[node.start_byte:node.end_byte].decode("utf-8", errors="replace")

    def add_node(nid: str, label: str, line: int) -> None:
        if nid not in seen_ids:
            seen_ids.add(nid)
            nodes.append({
                "id": nid, "label": label, "file_type": "code",
                "source_file": str_path, "source_location": f"L{line}",
            })

    def add_edge(
        src: str, tgt: str, relation: str, line: int,
        confidence: str = "EXTRACTED", weight: float = 1.0,
        context: str | None = None,
    ) -> None:
        edge: dict[str, Any] = {
            "source": src, "target": tgt, "relation": relation,
            "confidence": confidence, "source_file": str_path,
            "source_location": f"L{line}", "weight": weight,
        }
        if context:
            edge["context"] = context
        edges.append(edge)

    file_nid = _make_id(str(path))
    add_node(file_nid, path.name, 1)
    module_nid = file_nid

    def _proc_name(header_node) -> str | None:  # type: ignore[no-untyped-def]
        name_node = header_node.child_by_field_name("name")
        if name_node:
            return _read(name_node)
        for child in header_node.children:
            if child.type in ("identifier", "genericDot", "genericTpl"):
                return _read(child)
        return None

    def walk(node, parent_nid: str) -> None:  # type: ignore[no-untyped-def]
        nonlocal module_nid
        t = node.type
        line = node.start_point[0] + 1

        if t in ("unit", "program", "library"):
            name_node = next((c for c in node.children if c.type == "moduleName"), None)
            mod_name = _read(name_node) if name_node else path.stem
            mod_nid = _make_id(stem, mod_name)
            add_node(mod_nid, mod_name, line)
            add_edge(file_nid, mod_nid, "contains", line)
            module_nid = mod_nid
            for child in node.children:
                walk(child, mod_nid)
            return

        if t == "declUses":
            for child in node.children:
                if child.type == "moduleName":
                    mod_name = _read(child)
                    tgt_nid = _pascal_resolve_unit(path, mod_name)
                    add_edge(parent_nid, tgt_nid, "imports", line, context="import")
            return

        if t == "declType":
            type_name = None
            kind_node = None
            for child in node.children:
                if child.type == "identifier" and type_name is None:
                    type_name = _read(child)
                elif child.type in ("declClass", "declIntf", "declHelper") and kind_node is None:
                    kind_node = child
            if type_name and kind_node:
                cls_nid = _make_id(stem, type_name)
                add_node(cls_nid, type_name, line)
                add_edge(parent_nid, cls_nid, "contains", line)
                for child in kind_node.children:
                    if child.type == "typeref":
                        base_name = _read(child)
                        base_nid = _make_id(stem, base_name)
                        if base_nid not in seen_ids:
                            # Try cross-file resolution (TFooBar → FooBar.pas)
                            resolved = _pascal_resolve_class(path, base_name)
                            base_nid = resolved if resolved else _make_id(base_name)
                            if base_nid not in seen_ids:
                                # Stub for RTL/external/cross-file base classes
                                add_node(base_nid, base_name, line)
                        add_edge(cls_nid, base_nid, "inherits", line)
                for child in kind_node.children:
                    walk(child, cls_nid)
                return
            for child in node.children:
                walk(child, parent_nid)
            return

        if t == "declProcFwd":
            header = next((c for c in node.children if c.type == "declProc"), None)
            if header:
                name = _proc_name(header)
                if name and "." not in name:
                    method_nid = _make_id(parent_nid, name)
                    add_node(method_nid, f"{name}()", line)
                    add_edge(parent_nid, method_nid, "method", line)
            return

        if t == "defProc":
            header = next((c for c in node.children if c.type == "declProc"), None)
            body_node = next((c for c in node.children if c.type == "block"), None)
            if not header:
                for child in node.children:
                    walk(child, parent_nid)
                return
            name = _proc_name(header)
            if not name:
                for child in node.children:
                    walk(child, parent_nid)
                return
            container = parent_nid
            if "." in name:
                parts = name.split(".", 1)
                cls_nid = _make_id(stem, parts[0])
                if cls_nid in seen_ids:
                    container = cls_nid
                label = f"{parts[-1]}()"
            else:
                label = f"{name}()"
            proc_nid = _make_id(stem, name)
            add_node(proc_nid, label, line)
            add_edge(
                container, proc_nid,
                "method" if container != parent_nid else "contains",
                line,
            )
            if body_node:
                proc_bodies.append((proc_nid, body_node))
            return

        for child in node.children:
            walk(child, parent_nid)

    walk(root, file_nid)

    # Second pass: resolve calls inside procedure/function bodies
    all_procs: dict[str, str] = {
        n["label"].removesuffix("()").lower(): n["id"]
        for n in nodes if n["id"] != file_nid
    }
    seen_call_pairs: set[tuple[str, str]] = set()

    def walk_calls(node, caller_nid: str) -> None:  # type: ignore[no-untyped-def]
        if node.type == "exprCall":
            callee_text = None
            for child in node.children:
                if child.is_named and child.type not in ("exprArgs",):
                    callee_text = _read(child).split(".")[-1]
                    break
            if callee_text:
                callee_nid = all_procs.get(callee_text.lower())
                if callee_nid and callee_nid != caller_nid:
                    pair = (caller_nid, callee_nid)
                    if pair not in seen_call_pairs:
                        seen_call_pairs.add(pair)
                        add_edge(
                            caller_nid, callee_nid, "calls",
                            node.start_point[0] + 1, context="call",
                        )
        elif node.type == "statement":
            # Pascal bare procedure calls with no args: `Reset;`
            # tree-sitter represents these as statement → identifier (no exprCall wrapper)
            named = [c for c in node.children if c.is_named]
            if len(named) == 1 and named[0].type == "identifier":
                callee_text = _read(named[0])
                callee_nid = all_procs.get(callee_text.lower())
                if callee_nid and callee_nid != caller_nid:
                    pair = (caller_nid, callee_nid)
                    if pair not in seen_call_pairs:
                        seen_call_pairs.add(pair)
                        add_edge(
                            caller_nid, callee_nid, "calls",
                            node.start_point[0] + 1, context="call",
                        )
        for child in node.children:
            walk_calls(child, caller_nid)

    for proc_nid, body_node in proc_bodies:
        walk_calls(body_node, proc_nid)

    return {"nodes": nodes, "edges": edges, "input_tokens": 0, "output_tokens": 0}


def extract_lazarus_form(path: Path) -> dict:
    """Extract component hierarchy from Lazarus .lfm form files.

    .lfm is a text-based declarative format for UI component trees, structured as:
        object ComponentName: TClassName
          PropertyName = Value
          OnEvent = HandlerName
          object ChildName: TChildClass
            ...
          end
        end

    Produces nodes for:
    - The form file itself
    - Each component class encountered (TForm1, TButton, TPanel, ...)
    - Event handler names referenced by OnXxx properties

    Produces edges for:
    - file --contains--> root form class
    - parent component --contains--> child component class
    - component --references--> event handler (context: "event")
    """
    try:
        text = path.read_text(encoding="utf-8", errors="replace")
    except Exception as e:
        return {"nodes": [], "edges": [], "error": str(e)}

    import re
    str_path = str(path)
    stem = _file_stem(path)
    nodes: list[dict] = []
    edges: list[dict] = []
    seen_ids: set[str] = set()
    seen_edge_pairs: set[tuple[str, str, str]] = set()

    def add_node(nid: str, label: str, line: int) -> None:
        if nid not in seen_ids:
            seen_ids.add(nid)
            nodes.append({
                "id": nid, "label": label, "file_type": "code",
                "source_file": str_path, "source_location": f"L{line}",
            })

    def add_edge(
        src: str, tgt: str, relation: str, line: int,
        context: str | None = None,
    ) -> None:
        key = (src, tgt, relation)
        if key in seen_edge_pairs:
            return
        seen_edge_pairs.add(key)
        edge: dict[str, Any] = {
            "source": src, "target": tgt, "relation": relation,
            "confidence": "EXTRACTED", "source_file": str_path,
            "source_location": f"L{line}", "weight": 1.0,
        }
        if context:
            edge["context"] = context
        edges.append(edge)

    file_nid = _make_id(str(path))
    add_node(file_nid, path.name, 1)

    obj_re = re.compile(r"^\s*object\s+\w+\s*:\s*(\w+)", re.IGNORECASE)
    event_re = re.compile(r"^\s*On\w+\s*=\s*(\w+)", re.IGNORECASE)
    end_re = re.compile(r"^\s*end\s*$", re.IGNORECASE)

    # Stack of node IDs representing the nesting of object...end blocks
    stack: list[str] = [file_nid]

    for lineno, line in enumerate(text.splitlines(), 1):
        m = obj_re.match(line)
        if m:
            class_name = m.group(1)
            nid = _make_id(stem, class_name)
            add_node(nid, class_name, lineno)
            add_edge(stack[-1], nid, "contains", lineno)
            stack.append(nid)
            continue

        m = event_re.match(line)
        if m and len(stack) > 1:
            handler = m.group(1)
            handler_nid = _make_id(stem, handler)
            add_node(handler_nid, f"{handler}()", lineno)
            add_edge(stack[-1], handler_nid, "references", lineno, context="event")
            continue

        if end_re.match(line) and len(stack) > 1:
            stack.pop()

    return {"nodes": nodes, "edges": edges, "input_tokens": 0, "output_tokens": 0}


def extract_delphi_form(path: Path) -> dict:
    """Extract component hierarchy from Delphi .dfm form files.

    .dfm files come in two formats:
    - Text (same `object Name: TClassName ... end` syntax as .lfm)
    - Binary (starts with a TPF0/FF0A magic header — unreadable as text)

    Binary .dfm files are skipped gracefully: an empty result is returned
    so the rest of the pipeline is unaffected.  Convert binary forms to
    text in the Delphi IDE via File → Save As (Text DFM) if you want them
    indexed.

    Text .dfm files are parsed identically to .lfm: component containment
    (`contains`) and event handler references (`references`, context "event").
    """
    try:
        raw = path.read_bytes()
    except Exception as e:
        return {"nodes": [], "edges": [], "error": str(e)}

    # Detect binary DFM: Delphi binary resource streams start with FF 0A
    if raw[:2] == b"\xff\x0a":
        return {
            "nodes": [], "edges": [],
            "error": f"binary DFM (convert to text in Delphi IDE to index): {path.name}",
        }

    # Text DFM — delegate to the shared form parser (same syntax as .lfm)
    try:
        text = raw.decode("utf-8", errors="replace")
    except Exception as e:
        return {"nodes": [], "edges": [], "error": str(e)}

    import re
    str_path = str(path)
    stem = _file_stem(path)
    nodes: list[dict] = []
    edges: list[dict] = []
    seen_ids: set[str] = set()
    seen_edge_pairs: set[tuple[str, str, str]] = set()

    def add_node(nid: str, label: str, line: int) -> None:
        if nid not in seen_ids:
            seen_ids.add(nid)
            nodes.append({
                "id": nid, "label": label, "file_type": "code",
                "source_file": str_path, "source_location": f"L{line}",
            })

    def add_edge(
        src: str, tgt: str, relation: str, line: int,
        context: str | None = None,
    ) -> None:
        key = (src, tgt, relation)
        if key in seen_edge_pairs:
            return
        seen_edge_pairs.add(key)
        edge: dict[str, Any] = {
            "source": src, "target": tgt, "relation": relation,
            "confidence": "EXTRACTED", "source_file": str_path,
            "source_location": f"L{line}", "weight": 1.0,
        }
        if context:
            edge["context"] = context
        edges.append(edge)

    file_nid = _make_id(str(path))
    add_node(file_nid, path.name, 1)

    obj_re   = re.compile(r"^\s*object\s+\w+\s*:\s*(\w+)", re.IGNORECASE)
    event_re = re.compile(r"^\s*On\w+\s*=\s*(\w+)", re.IGNORECASE)
    end_re   = re.compile(r"^\s*end\s*$", re.IGNORECASE)
    stack: list[str] = [file_nid]

    for lineno, line in enumerate(text.splitlines(), 1):
        m = obj_re.match(line)
        if m:
            class_name = m.group(1)
            nid = _make_id(stem, class_name)
            add_node(nid, class_name, lineno)
            add_edge(stack[-1], nid, "contains", lineno)
            stack.append(nid)
            continue
        m = event_re.match(line)
        if m and len(stack) > 1:
            handler = m.group(1)
            handler_nid = _make_id(stem, handler)
            add_node(handler_nid, f"{handler}()", lineno)
            add_edge(stack[-1], handler_nid, "references", lineno, context="event")
            continue
        if end_re.match(line) and len(stack) > 1:
            stack.pop()

    return {"nodes": nodes, "edges": edges, "input_tokens": 0, "output_tokens": 0}


def extract_lazarus_package(path: Path) -> dict:
    """Extract package metadata from Lazarus .lpk package files (XML format).

    .lpk is an XML file listing the package name, required dependencies,
    and the Pascal units that belong to the package.

    Produces nodes for:
    - The package file itself
    - The package (by name)
    - Each required package (dependency)
    - Each listed unit file (resolved to path-based IDs where possible)

    Produces edges for:
    - file --contains--> package
    - package --imports--> required dependency (context: "import")
    - package --contains--> listed unit
    """
    try:
        import xml.etree.ElementTree as ET
        text = path.read_text(encoding="utf-8", errors="replace")
        xml_root = ET.fromstring(text)
    except Exception as e:
        return {"nodes": [], "edges": [], "error": str(e)}

    str_path = str(path)
    stem = _file_stem(path)
    nodes: list[dict] = []
    edges: list[dict] = []
    seen_ids: set[str] = set()

    def add_node(nid: str, label: str) -> None:
        if nid not in seen_ids:
            seen_ids.add(nid)
            nodes.append({
                "id": nid, "label": label, "file_type": "code",
                "source_file": str_path, "source_location": "L1",
            })

    def add_edge(src: str, tgt: str, relation: str, context: str | None = None) -> None:
        edge: dict[str, Any] = {
            "source": src, "target": tgt, "relation": relation,
            "confidence": "EXTRACTED", "source_file": str_path,
            "source_location": "L1", "weight": 1.0,
        }
        if context:
            edge["context"] = context
        edges.append(edge)

    file_nid = _make_id(str(path))
    add_node(file_nid, path.name)

    name_elem = xml_root.find(".//Package/Name")
    pkg_name = name_elem.get("Value") if name_elem is not None else path.stem
    pkg_nid = _make_id(stem, pkg_name)
    add_node(pkg_nid, pkg_name)
    add_edge(file_nid, pkg_nid, "contains")

    # Required packages → imports edges
    for item in xml_root.findall(".//RequiredPkgs/"):
        dep_elem = item.find("PackageName")
        if dep_elem is not None:
            dep_name = dep_elem.get("Value", "")
            if dep_name:
                dep_nid = _make_id(dep_name)
                add_node(dep_nid, dep_name)
                add_edge(pkg_nid, dep_nid, "imports", context="import")

    # Listed units → contains edges, resolved to path-based IDs where possible
    for item in xml_root.findall(".//Files/"):
        unit_elem = item.find("UnitName")
        if unit_elem is not None:
            unit_name = unit_elem.get("Value", "")
            if unit_name:
                unit_nid = _pascal_resolve_unit(path, unit_name)
                add_node(unit_nid, unit_name)
                add_edge(pkg_nid, unit_nid, "contains")

    return {"nodes": nodes, "edges": edges, "input_tokens": 0, "output_tokens": 0}


# ── Main extract and collect_files ────────────────────────────────────────────


def _check_tree_sitter_version() -> None:
    """Raise a clear error if tree-sitter is too old for the new Language API."""
    try:
        from tree_sitter import LANGUAGE_VERSION
    except ImportError:
        raise ImportError(
            "tree-sitter is not installed. Run: pip install 'tree-sitter>=0.23.0'"
        )
    # Language API v2 starts at LANGUAGE_VERSION 14
    if LANGUAGE_VERSION < 14:
        import tree_sitter as _ts
        raise RuntimeError(
            f"tree-sitter {getattr(_ts, '__version__', 'unknown')} is too old. "
            f"graphify requires tree-sitter >= 0.23.0 (Language API v2). "
            f"Run: pip install --upgrade tree-sitter"
        )


def extract_bash(path: Path) -> dict:
    """Extract functions, source imports, and cross-function calls from a .sh file."""
    try:
        import tree_sitter_bash as tsbash
        from tree_sitter import Language, Parser
    except ImportError:
        return {"nodes": [], "edges": [], "error": "tree-sitter-bash not installed"}

    try:
        language = Language(tsbash.language())
        parser = Parser(language)
        source = path.read_bytes()
        tree = parser.parse(source)
        root = tree.root_node
    except Exception as e:
        return {"nodes": [], "edges": [], "error": str(e)}

    stem = _file_stem(path)
    str_path = str(path)
    nodes: list[dict] = []
    edges: list[dict] = []
    seen_ids: set[str] = set()
    function_bodies: list[tuple[str, Any]] = []
    defined_functions: set[str] = set()

    from graphify.security import sanitize_metadata  # module-level cached import

    def add_node(nid: str, label: str, line: int, kind: str = "code") -> None:
        if nid and nid not in seen_ids:
            seen_ids.add(nid)
            nodes.append({"id": nid, "label": label, "file_type": "code",
                          "source_file": str_path, "source_location": f"L{line}",
                          "metadata": sanitize_metadata({"language": "bash", "kind": kind})})  # noqa: E501

    def add_edge(src: str, tgt: str, relation: str, line: int,
                 confidence: str = "EXTRACTED", weight: float = 1.0,
                 context: str | None = None) -> None:
        if not src or not tgt or src == tgt:
            return
        edge = {"source": src, "target": tgt, "relation": relation,
                "confidence": confidence, "source_file": str_path,
                "source_location": f"L{line}", "weight": weight}
        if context:
            edge["context"] = context
        edges.append(edge)

    file_nid = _make_id(str(path))
    # file_nid is fully path-derived and never produced by _make_id(stem, func_name),
    # so appending "__entry" guarantees a distinct ID from any function node.
    entry_nid = file_nid + "__entry"
    add_node(file_nid, path.name, 1, kind="file")
    add_node(entry_nid, f"{path.name} script", 1, kind="bash_entrypoint")
    add_edge(file_nid, entry_nid, "contains", 1)

    _BASH_SOURCE_COMMANDS = frozenset({"source", "."})
    # Parent node types that mean a contained command is part of a substitution
    # or expansion, not a real function call. Token-level filtering misses
    # these because `$(build)` exposes `build` as a child command whose name
    # token has no metacharacters — only the parent does.
    _BASH_EXPANSION_PARENTS = frozenset({
        "command_substitution",
        "process_substitution",
    })

    def text(node) -> str:
        return source[node.start_byte:node.end_byte].decode("utf-8", errors="replace")

    def is_inside_expansion(node) -> bool:
        parent = node.parent
        while parent is not None:
            if parent.type in _BASH_EXPANSION_PARENTS:
                return True
            parent = parent.parent
        return False

    def literal(node) -> str | None:
        # Token-level filter: rejects names containing shell metacharacters.
        # Combined with `is_inside_expansion` for parent-context rejection.
        raw = text(node).strip()
        if not raw:
            return None
        if raw[0:1] in {"'", '"'} and raw[-1:] == raw[0]:
            raw = raw[1:-1]
        if any(token in raw for token in ("$", "`", "$(", "<(", ">", "|", ";", "&")):
            return None
        return raw

    def _bash_func_name(node) -> str | None:
        """Get the name from a function_definition node."""
        # bash grammar: function_definition has a word child (the name)
        for child in node.children:
            if child.type == "word":
                return literal(child)
        return None

    def walk_calls(body_node, func_nid: str, seen_calls: set) -> None:
        if body_node is None:
            return
        for child in body_node.children:
            if child.type == "function_definition":
                # Skip nested function definitions — their bodies are walked
                # separately, so we don't attribute their calls to the
                # enclosing scope.
                continue
            if child.type == "command" and not is_inside_expansion(child):
                cmd_name_node = child.child_by_field_name("name")
                if cmd_name_node is None and child.children:
                    cmd_name_node = child.children[0]
                if cmd_name_node:
                    name = literal(cmd_name_node)
                    # Defined-functions wins. Skip-lists for external commands
                    # would create false negatives when a user defines a
                    # function shadowing an external (`install`, `find`, etc.).
                    if name and name in defined_functions:
                        tgt = _make_id(stem, name)
                        key = (func_nid, tgt)
                        if tgt and key not in seen_calls:
                            seen_calls.add(key)
                            add_edge(func_nid, tgt, "calls",
                                     child.start_point[0] + 1,
                                     confidence="EXTRACTED", context="call")
            walk_calls(child, func_nid, seen_calls)

    def walk(node, parent_nid: str) -> None:
        t = node.type
        if t == "function_definition":
            name = _bash_func_name(node)
            if name:
                fn_nid = _make_id(stem, name)
                line = node.start_point[0] + 1
                add_node(fn_nid, f"{name}()", line, kind="bash_function")
                add_edge(parent_nid, fn_nid, "defines", line)
                defined_functions.add(name)
                # find the compound_statement body
                body = None
                for child in node.children:
                    if child.type == "compound_statement":
                        body = child
                        break
                function_bodies.append((fn_nid, body))
                # Recurse into the body so nested function definitions are discovered
                # and added to function_bodies for the second-pass walk_calls.
                if body is not None:
                    walk(body, fn_nid)
            return

        if t == "command":
            if is_inside_expansion(node):
                return
            cmd_name_node = node.child_by_field_name("name")
            if cmd_name_node is None and node.children:
                cmd_name_node = node.children[0]
            if cmd_name_node:
                cmd = literal(cmd_name_node)
                if cmd in _BASH_SOURCE_COMMANDS and cmd not in defined_functions:
                    # find the path argument (first word after command name)
                    args = [c for c in node.children
                            if c.type in ("word", "string", "concatenation")
                            and c != cmd_name_node]
                    if args:
                        raw = _read_text(args[0], source).strip().strip("'\"")
                        line = node.start_point[0] + 1
                        if raw.startswith((".", "/")):
                            resolved = (path.parent / raw).resolve()
                            # Only emit the edge if the target actually exists on
                            # disk — prevents graph pollution from crafted paths
                            # like `source ../../etc/passwd` that traverse outside
                            # the project tree (B-1).
                            if resolved.exists():
                                tgt_nid = _make_id(str(resolved))
                                add_edge(file_nid, tgt_nid, "imports_from", line,
                                         context="import")
                        else:
                            tgt_nid = _make_id(raw)
                            if tgt_nid:
                                add_edge(file_nid, tgt_nid, "imports", line,
                                         context="import")
            return

        if t == "declaration_command":
            # export/declare/readonly VAR=value at program level
            if node.parent and node.parent.type == "program":
                for child in node.children:
                    if child.type == "variable_assignment":
                        var_node = child.child_by_field_name("name")
                        if var_node:
                            var = _read_text(var_node, source).strip()
                            if var:
                                var_nid = _make_id(stem, var)
                                line = child.start_point[0] + 1
                                add_node(var_nid, var, line)
                                add_edge(file_nid, var_nid, "defines", line)
            return

        for child in node.children:
            walk(child, parent_nid)

    # Pre-pass: collect all defined function names so the source-command handler
    # in walk() can detect user-defined functions that shadow 'source' / '.'
    # regardless of definition order in the file.
    def _prescan_functions(node) -> None:
        if node.type == "function_definition":
            name = _bash_func_name(node)
            if name:
                defined_functions.add(name)
            for child in node.children:
                _prescan_functions(child)
        else:
            for child in node.children:
                _prescan_functions(child)

    _prescan_functions(root)
    walk(root, file_nid)

    # Second pass: cross-function calls
    top_seen: set = set()
    walk_calls(root, entry_nid, top_seen)  # top-level calls attributed to the entrypoint
    for fn_nid, body in function_bodies:
        walk_calls(body, fn_nid, set())

    return {"nodes": nodes, "edges": edges}


def extract_json(path: Path) -> dict:
    """Extract top-level keys, nested structure, and dependency edges from a .json file."""
    _JSON_MAX_BYTES = 1_048_576  # 1 MiB — skip large fixture dumps / GeoJSON blobs

    try:
        import tree_sitter_json as tsjson
        from tree_sitter import Language, Parser
    except ImportError:
        return {"nodes": [], "edges": [], "error": "tree-sitter-json not installed"}

    try:
        # Bounded read instead of stat()+read() to eliminate TOCTOU (J-1):
        # read one byte beyond the limit so we can detect oversized files even
        # if the file grows between stat and read.
        with path.open("rb") as _f:
            source = _f.read(_JSON_MAX_BYTES + 1)
        if len(source) > _JSON_MAX_BYTES:
            return {"nodes": [], "edges": [], "error": "json file too large to index"}
        language = Language(tsjson.language())
        parser = Parser(language)
        tree = parser.parse(source)
        root = tree.root_node
    except Exception as e:
        return {"nodes": [], "edges": [], "error": str(e)}

    stem = _file_stem(path)
    str_path = str(path)
    nodes: list[dict] = []
    edges: list[dict] = []
    seen_ids: set[str] = set()

    # Keys whose string values become imports (package.json dep blocks)
    _DEP_KEYS = frozenset({
        "dependencies", "devDependencies", "peerDependencies",
        "optionalDependencies", "bundleDependencies", "bundledDependencies",
    })

    def add_node(nid: str, label: str, line: int) -> None:
        if nid and nid not in seen_ids:
            seen_ids.add(nid)
            nodes.append({"id": nid, "label": label, "file_type": "code",
                          "source_file": str_path, "source_location": f"L{line}"})

    def add_edge(src: str, tgt: str, relation: str, line: int,
                 context: str | None = None) -> None:
        if not src or not tgt or src == tgt:
            return
        edge = {"source": src, "target": tgt, "relation": relation,
                "confidence": "EXTRACTED", "source_file": str_path,
                "source_location": f"L{line}", "weight": 1.0}
        if context:
            edge["context"] = context
        edges.append(edge)

    file_nid = _make_id(str(path))
    add_node(file_nid, path.name, 1)

    def _key_text(pair_node) -> str | None:
        """Extract the string content of a pair's key."""
        key_node = pair_node.child_by_field_name("key")
        if key_node is None:
            return None
        if key_node.type == "string":
            content = key_node.child_by_field_name("string_content")
            if content:
                return _read_text(content, source)
            # fallback: strip surrounding quotes
            raw = _read_text(key_node, source)
            return raw.strip('"\'')
        return _read_text(key_node, source)

    def _val_node(pair_node):
        return pair_node.child_by_field_name("value")

    def walk_object(obj_node, parent_nid: str, parent_key: str | None,
                    depth: int, pair_count: list) -> None:
        if depth > 6:
            return
        for child in obj_node.children:
            if child.type != "pair":
                continue
            if pair_count[0] >= 500:  # check per-pair so the cap is honoured exactly (J-3)
                return
            pair_count[0] += 1
            key = _key_text(child)
            if not key:
                continue
            key_nid = _make_id(stem, *(([parent_key] if parent_key else []) + [key]))
            if not key_nid:
                continue
            line = child.start_point[0] + 1
            add_node(key_nid, key, line)
            add_edge(parent_nid, key_nid, "contains", line)

            val = _val_node(child)
            if val is None:
                continue

            if val.type == "object":
                walk_object(val, key_nid, key, depth + 1, pair_count)

            elif val.type == "array":
                # For "extends" arrays (tsconfig, eslint): each string element.
                # Prefix with "ref_" so external refs don't collide with real
                # code/file node IDs that share the same collapsed _make_id (J-4).
                for item in val.children:
                    if item.type == "string":
                        content = item.child_by_field_name("string_content")
                        ref = _read_text(content, source) if content else _read_text(item, source).strip('"\'')
                        if ref:
                            ref_nid = _make_id("ref", ref)
                            if ref_nid:
                                add_edge(key_nid, ref_nid, "extends", line, context="import")

            elif val.type == "string":
                content = val.child_by_field_name("string_content")
                val_text = _read_text(content, source) if content else _read_text(val, source).strip('"\'')

                if key == "extends" and val_text:
                    # Namespace external refs to avoid ID collision with file nodes (J-4)
                    ref_nid = _make_id("ref", val_text)
                    if ref_nid:
                        add_edge(file_nid, ref_nid, "extends", line, context="import")

                elif key == "$ref" and val_text:
                    # Namespace $ref values to prevent edge hijacking into code nodes (J-4)
                    ref_nid = _make_id("ref", val_text)
                    if ref_nid:
                        add_edge(parent_nid, ref_nid, "references", line)

                elif parent_key in _DEP_KEYS and val_text:
                    dep_nid = _make_id(key)
                    if dep_nid:
                        add_edge(key_nid, dep_nid, "imports", line, context="import")

    # Entry: find root document → object
    doc = root
    if doc.type == "document" and doc.child_count > 0:
        doc = doc.children[0]
    if doc.type == "object":
        walk_object(doc, file_nid, None, 0, [0])

    return {"nodes": nodes, "edges": edges}


_DISPATCH: dict[str, Any] = {
    ".py": extract_python,
    ".js": extract_js,
    ".jsx": extract_js,
    ".mjs": extract_js,
    ".ts": extract_js,
    ".tsx": extract_js,
    ".go": extract_go,
    ".rs": extract_rust,
    ".java": extract_java,
    ".groovy": extract_groovy,
    ".gradle": extract_groovy,
    ".c": extract_c,
    ".h": extract_c,
    ".cpp": extract_cpp,
    ".cc": extract_cpp,
    ".cxx": extract_cpp,
    ".hpp": extract_cpp,
    ".rb": extract_ruby,
    ".cs": extract_csharp,
    ".kt": extract_kotlin,
    ".kts": extract_kotlin,
    ".scala": extract_scala,
    ".php": extract_php,
    ".swift": extract_swift,
    ".lua": extract_lua,
    ".luau": extract_lua,
    ".toc": extract_lua,
    ".zig": extract_zig,
    ".ps1": extract_powershell,
    ".ex": extract_elixir,
    ".exs": extract_elixir,
    ".m": extract_objc,
    ".mm": extract_objc,
    ".jl": extract_julia,
    ".f": extract_fortran,
    ".F": extract_fortran,
    ".f90": extract_fortran,
    ".F90": extract_fortran,
    ".f95": extract_fortran,
    ".F95": extract_fortran,
    ".f03": extract_fortran,
    ".F03": extract_fortran,
    ".f08": extract_fortran,
    ".F08": extract_fortran,
    ".vue": extract_js,
    ".svelte": extract_svelte,
    ".astro": extract_astro,
    ".dart": extract_dart,
    ".v": extract_verilog,
    ".sv": extract_verilog,
    ".sql": extract_sql,
    ".md": extract_markdown,
    ".mdx": extract_markdown,
    ".qmd": extract_markdown,
    ".pas": extract_pascal,
    ".pp": extract_pascal,
    ".dpr": extract_pascal,
    ".dpk": extract_pascal,
    ".lpr": extract_pascal,
    ".inc": extract_pascal,
    ".dfm": extract_delphi_form,
    ".lfm": extract_lazarus_form,
    ".lpk": extract_lazarus_package,
    ".sh": extract_bash,
    ".bash": extract_bash,
    ".json": extract_json,
}


def _get_extractor(path: Path) -> Any | None:
    """Return the correct extractor function for a file, or None if unsupported."""
    if path.name.endswith(".blade.php"):
        return extract_blade
    return _DISPATCH.get(path.suffix)


def _extract_single_file(args: tuple) -> tuple[int, dict]:
    """Worker function for parallel extraction. Runs in a subprocess.

    Must be at module level (not a closure) so it can be pickled by
    ProcessPoolExecutor.

    Args:
        args: (index, path_str, cache_root_str) tuple

    Returns:
        (index, result_dict) so results can be placed back in order.
    """
    idx, path_str, cache_root_str = args
    path = Path(path_str)
    cache_root = Path(cache_root_str)
    _raise_recursion_limit()

    # Check cache first (avoid re-extraction)
    cached = load_cached(path, cache_root)
    if cached is not None:
        return idx, cached

    extractor = _get_extractor(path)
    if extractor is None:
        return idx, {"nodes": [], "edges": []}

    result = _safe_extract(extractor, path)
    if "error" not in result:
        save_cached(path, result, cache_root)
    return idx, result


def _extract_parallel(
    uncached_work: list[tuple[int, Path]],
    per_file: list[dict | None],
    effective_root: Path,
    max_workers: int | None,
    total_files: int,
) -> bool:
    """Extract uncached files in parallel using ProcessPoolExecutor.

    Returns True if the pool ran to completion. Returns False if the pool
    failed in a recoverable way (typically Windows-spawn without an
    ``if __name__ == "__main__"`` guard in the calling script, which causes
    BrokenProcessPool); the caller should fall back to sequential extraction.
    """
    import concurrent.futures

    if max_workers is None:
        # Honour GRAPHIFY_MAX_WORKERS env override; otherwise scale to the
        # full CPU. The historical `, 8)` cap was a safety bound for laptops
        # in 2023 — on a 32-thread workstation it costs a 4x slowdown
        # (issue #792). Capping at len(uncached_work) keeps small jobs
        # from spawning useless idle workers.
        env_raw = os.environ.get("GRAPHIFY_MAX_WORKERS", "").strip()
        env_cap = None
        if env_raw:
            try:
                v = int(env_raw)
                if v > 0:
                    env_cap = v
            except ValueError:
                pass
        cpu_cap = env_cap if env_cap is not None else (os.cpu_count() or 4)
        max_workers = min(cpu_cap, len(uncached_work))

    root_str = str(effective_root)
    work_items = [(idx, str(path), root_str) for idx, path in uncached_work]

    done_count = 0
    _PROGRESS_INTERVAL = 100
    try:
        with concurrent.futures.ProcessPoolExecutor(max_workers=max_workers) as pool:
            futures = {
                pool.submit(_extract_single_file, item): item[0] for item in work_items
            }
            for future in concurrent.futures.as_completed(futures):
                idx, result = future.result()
                per_file[idx] = result
                done_count += 1
                if (
                    total_files >= _PROGRESS_INTERVAL
                    and done_count % _PROGRESS_INTERVAL == 0
                ):
                    print(
                        f"  AST extraction: {done_count}/{len(uncached_work)} uncached files "
                        f"({done_count * 100 // len(uncached_work)}%) [{max_workers} workers]",
                        flush=True,
                    )
    except concurrent.futures.process.BrokenProcessPool:
        # On Windows (spawn start method) the worker subprocesses re-import the
        # caller's __main__. Inline invocations like `python -c "..."` have no
        # __main__ guard, so worker bootstrap raises and the pool dies before
        # any work completes. Fall back to in-process sequential extraction —
        # slower but correct.
        print(
            "  warning: parallel extraction failed (BrokenProcessPool); "
            "falling back to sequential. On Windows this usually means the "
            'caller is missing an `if __name__ == "__main__":` guard. Pass '
            "parallel=False to extract() to skip the pool entirely.",
            flush=True,
        )
        return False
    if total_files >= _PROGRESS_INTERVAL:
        print(
            f"  AST extraction: {total_files}/{total_files} files (100%) [{max_workers} workers]",
            flush=True,
        )
    return True


def _extract_sequential(
    uncached_work: list[tuple[int, Path]],
    per_file: list[dict | None],
    effective_root: Path,
    total_files: int,
) -> None:
    """Extract uncached files sequentially (fallback for small batches)."""
    _PROGRESS_INTERVAL = 100
    for work_idx, (idx, path) in enumerate(uncached_work):
        if (
            total_files >= _PROGRESS_INTERVAL
            and work_idx % _PROGRESS_INTERVAL == 0
            and work_idx > 0
        ):
            print(
                f"  AST extraction: {work_idx}/{len(uncached_work)} uncached files ({work_idx * 100 // len(uncached_work)}%)",
                flush=True,
            )
        extractor = _get_extractor(path)
        if extractor is None:
            per_file[idx] = {"nodes": [], "edges": []}
            continue
        result = _safe_extract(extractor, path)
        if "error" not in result:
            save_cached(path, result, effective_root)
        per_file[idx] = result
    if total_files >= _PROGRESS_INTERVAL:
        print(f"  AST extraction: {total_files}/{total_files} files (100%)", flush=True)


_PARALLEL_THRESHOLD = 20


def extract(
    paths: list[Path],
    cache_root: Path | None = None,
    *,
    parallel: bool = True,
    max_workers: int | None = None,
) -> dict:
    """Extract AST nodes and edges from a list of code files.

    Two-pass process:
    1. Per-file structural extraction (classes, functions, imports)
    2. Cross-file import resolution: turns file-level imports into
       class-level INFERRED edges (DigestAuth --uses--> Response)

    Args:
        paths: files to extract from
        cache_root: explicit root for graphify-out/cache/ (overrides the
            inferred common path prefix). Pass Path('.') when running on a
            subdirectory so the cache stays at ./graphify-out/cache/.
        parallel: if True and there are >= _PARALLEL_THRESHOLD uncached files,
            use ProcessPoolExecutor for multi-core extraction.
        max_workers: max subprocess count. Defaults to cpu_count (or the
            value of GRAPHIFY_MAX_WORKERS if set), bounded by len(uncached_work).
    """
    _check_tree_sitter_version()
    _raise_recursion_limit()

    # Infer a common root for cache keys (use first diverging segment, not sum of all matches)
    try:
        if not paths:
            root = Path(".")
        elif len(paths) == 1:
            root = paths[0].parent
        else:
            min_parts = min(len(p.parts) for p in paths)
            common_len = 0
            for i in range(min_parts):
                if len({p.parts[i] for p in paths}) == 1:
                    common_len += 1
                else:
                    break
            root = Path(*paths[0].parts[:common_len]) if common_len else Path(".")
    except Exception:
        root = Path(".")
    root = root.resolve()

    effective_root = cache_root or root
    total = len(paths)

    # Phase 1: separate cached hits from uncached work
    per_file: list[dict | None] = [None] * total
    uncached_work: list[tuple[int, Path]] = []

    for i, path in enumerate(paths):
        if _get_extractor(path) is None:
            per_file[i] = {"nodes": [], "edges": []}
            continue
        cached = load_cached(path, effective_root)
        if cached is not None:
            per_file[i] = cached
            continue
        uncached_work.append((i, path))

    # Phase 2: extract uncached files (parallel or sequential)
    if uncached_work:
        ran_parallel = False
        if parallel and len(uncached_work) >= _PARALLEL_THRESHOLD:
            ran_parallel = _extract_parallel(
                uncached_work, per_file, effective_root, max_workers, total
            )
        if not ran_parallel:
            _extract_sequential(uncached_work, per_file, effective_root, total)

    # Fill any remaining None slots (shouldn't happen, but defensive)
    for i in range(total):
        if per_file[i] is None:
            per_file[i] = {"nodes": [], "edges": []}

    all_nodes: list[dict] = []
    all_edges: list[dict] = []
    for result in per_file:
        all_nodes.extend(result.get("nodes", []))
        all_edges.extend(result.get("edges", []))

    # Remap file node IDs from absolute-path-derived to project-relative so
    # graph.json edge endpoints are stable across machines (#502)
    id_remap: dict[str, str] = {}
    for path in paths:
        old_id = _make_id(str(path))
        try:
            new_id = _make_id(str(path.relative_to(root)))
        except ValueError:
            continue
        if old_id != new_id:
            id_remap[old_id] = new_id
    if id_remap:
        for n in all_nodes:
            if n.get("id") in id_remap:
                n["id"] = id_remap[n["id"]]
        for e in all_edges:
            if e.get("source") in id_remap:
                e["source"] = id_remap[e["source"]]
            if e.get("target") in id_remap:
                e["target"] = id_remap[e["target"]]

    _merge_swift_extensions(per_file, all_nodes, all_edges)

    # Add cross-file class-level edges (Python only - uses Python parser internally)
    py_paths = [p for p in paths if p.suffix == ".py"]
    if py_paths:
        py_results = [r for r, p in zip(per_file, paths) if p.suffix == ".py"]
        try:
            cross_file_edges = _resolve_cross_file_imports(py_results, py_paths)
            all_edges.extend(cross_file_edges)
        except Exception as exc:
            import logging
            logging.getLogger(__name__).warning("Cross-file import resolution failed, skipping: %s", exc)

    # Cross-file Java import resolution
    java_paths = [p for p in paths if p.suffix == ".java"]
    if java_paths:
        java_results = [r for r, p in zip(per_file, paths) if p.suffix == ".java"]
        try:
            all_edges.extend(_resolve_cross_file_java_imports(java_results, java_paths))
        except Exception as exc:
            import logging
            logging.getLogger(__name__).warning("Java cross-file import resolution failed, skipping: %s", exc)

    # Cross-file call resolution for all languages
    # Each extractor saved unresolved calls in raw_calls. Now that we have all
    # nodes from all files, resolve any callee that exists in another file.
    # Build name → ALL matching node IDs so we can skip ambiguous common names
    # (e.g. "log", "execute", "find") that appear in multiple files — resolving
    # those inflates god_nodes ranking with spurious cross-file edges.
    # Build label -> node_id index for cross-file call resolution.
    # Skip rationale nodes (their labels are docstring text, not callable
    # identifiers, and they were polluting matches for short names — #563).
    global_label_to_nids: dict[str, list[str]] = {}
    for n in all_nodes:
        if n.get("file_type") == "rationale":
            continue
        raw = n.get("label", "")
        normalised = raw.strip("()").lstrip(".")
        if normalised:
            key = normalised.lower()
            global_label_to_nids.setdefault(key, []).append(n["id"])

    # Build evidence index from import edges so cross-file calls backed by an
    # explicit import statement can be promoted from INFERRED to EXTRACTED.
    # Direct symbol imports (`import { foo }` / `const { foo } = require()`) are
    # the strongest evidence — caller's file_id has an `imports` edge directly to
    # the callee's symbol id. Module imports (`imports_from`) are weaker but still
    # confirm the caller pulled in the callee's source file.
    file_to_symbol_imports: dict[str, set[str]] = {}
    file_to_module_imports: dict[str, set[str]] = {}
    for e in all_edges:
        if e.get("relation") == "imports":
            file_to_symbol_imports.setdefault(e["source"], set()).add(e["target"])
        elif e.get("relation") == "imports_from":
            file_to_module_imports.setdefault(e["source"], set()).add(e["target"])

    # Map each node back to its containing file_id so we can ask
    # "did the caller's file import the callee's file?"
    # Use relativized paths to match how file node IDs were remapped above (#502).
    nid_to_file_nid: dict[str, str] = {}
    for n in all_nodes:
        sf = n.get("source_file")
        if not sf:
            continue
        sf_path = Path(sf)
        try:
            sf_rel = sf_path.relative_to(root) if sf_path.is_absolute() else sf_path
        except ValueError:
            sf_rel = sf_path
        nid_to_file_nid[n["id"]] = _make_id(str(sf_rel))

    existing_pairs = {(e["source"], e["target"]) for e in all_edges}
    for result in per_file:
        for rc in result.get("raw_calls", []):
            callee = rc.get("callee", "")
            if not callee:
                continue
            # Skip member-call callees: obj.log() → "log" has no import evidence
            # and collides with any top-level function named "log" in the corpus.
            if rc.get("is_member_call"):
                continue
            candidates = global_label_to_nids.get(callee.lower(), [])
            # Skip ambiguous names that resolve to multiple nodes — these are
            # common short names (log, execute, find) with no import evidence
            # to pick the right target; emitting all edges inflates god_nodes.
            if len(candidates) != 1:
                continue
            tgt = candidates[0]
            caller = rc["caller_nid"]
            if tgt != caller and (caller, tgt) not in existing_pairs:
                existing_pairs.add((caller, tgt))
                # Promote to EXTRACTED when there's a direct import edge from the
                # caller's file pointing at either the callee symbol itself or the
                # file the callee lives in.
                caller_file_nid = nid_to_file_nid.get(caller)
                callee_file_nid = nid_to_file_nid.get(tgt)
                imported_symbols = file_to_symbol_imports.get(caller_file_nid, set())
                imported_modules = file_to_module_imports.get(caller_file_nid, set())
                has_import_evidence = (
                    tgt in imported_symbols
                    or (callee_file_nid is not None and callee_file_nid in imported_modules)
                )
                if has_import_evidence:
                    confidence = "EXTRACTED"
                    confidence_score = 1.0
                else:
                    confidence = "INFERRED"
                    confidence_score = 0.8
                all_edges.append({
                    "source": caller,
                    "target": tgt,
                    "relation": "calls",
                    "context": "call",
                    "confidence": confidence,
                    "confidence_score": confidence_score,
                    "source_file": rc.get("source_file", ""),
                    "source_location": rc.get("source_location"),
                    "weight": 1.0,
                })

    # Relativize source_file fields so paths are portable across machines (#555)
    for item in all_nodes + all_edges:
        sf = item.get("source_file")
        if not sf:
            continue
        sf_path = Path(sf)
        if not sf_path.is_absolute():
            continue
        try:
            item["source_file"] = str(sf_path.relative_to(root))
        except ValueError:
            pass

    return {
        "nodes": all_nodes,
        "edges": all_edges,
        "input_tokens": 0,
        "output_tokens": 0,
    }


def collect_files(target: Path, *, follow_symlinks: bool = False, root: Path | None = None) -> list[Path]:
    if target.is_file():
        return [target]
    _EXTENSIONS = set(_DISPATCH.keys())
    from graphify.detect import _load_graphifyignore, _is_ignored, _is_noise_dir
    ignore_root = root if root is not None else target
    patterns = _load_graphifyignore(ignore_root)

    def _ignored(p: Path) -> bool:
        return bool(patterns and _is_ignored(p, ignore_root, patterns))

    if not follow_symlinks:
        results: list[Path] = []
        for ext in sorted(_EXTENSIONS):
            results.extend(
                p for p in target.rglob(f"*{ext}")
                if not any(_is_noise_dir(part) for part in p.parts)
                and not _ignored(p)
            )
        return sorted(results)
    # Walk with symlink following + cycle detection
    results = []
    for dirpath, dirnames, filenames in os.walk(target, followlinks=True):
        if os.path.islink(dirpath):
            real = os.path.realpath(dirpath)
            parent_real = os.path.realpath(os.path.dirname(dirpath))
            if parent_real == real or parent_real.startswith(real + os.sep):
                dirnames.clear()
                continue
        dp = Path(dirpath)
        dirnames[:] = [d for d in dirnames if not _is_noise_dir(d)]
        for fname in filenames:
            p = dp / fname
            if p.suffix in _EXTENSIONS and not _ignored(p):
                results.append(p)
    return sorted(results)


if __name__ == "__main__":
    if len(sys.argv) < 2:
        print("Usage: python -m graphify.extract <file_or_dir> ...", file=sys.stderr)
        sys.exit(1)

    paths: list[Path] = []
    for arg in sys.argv[1:]:
        paths.extend(collect_files(Path(arg)))

    result = extract(paths)
    print(json.dumps(result, indent=2))