first commit

cli/internal/runtime/sgr.go

@@ -0,0 +1,71 @@
+package runtime
+
+import (
+	"bytes"
+	"strconv"
+)
+
+// rewriteSGRParams converts colon-separated SGR sub-parameters to semicolon-
+// separated equivalents. Each semicolon-delimited group is processed:
+//
+//   - 4:x         -> 4          (underline style -> basic underline)
+//   - 38:2:cs:r:g:b -> 38;2;r;g;b (fg true-color, drop colorspace)
+//   - 48:2:cs:r:g:b -> 48;2;r;g;b (bg true-color, drop colorspace)
+//   - 38:5:n      -> 38;5;n     (fg 256-color)
+//   - 48:5:n      -> 48;5;n     (bg 256-color)
+//   - 58:...      -> (dropped - underline color, unsupported by vt10x)
+//   - other:x     -> other      (keep first sub-param only)
+func rewriteSGRParams(params []byte) []byte {
+	parts := bytes.Split(params, []byte{';'})
+	var out [][]byte
+	for _, part := range parts {
+		if !bytes.ContainsRune(part, ':') {
+			out = append(out, part)
+			continue
+		}
+		subs := bytes.Split(part, []byte{':'})
+		if len(subs) == 0 {
+			continue
+		}
+		code, err := strconv.Atoi(string(subs[0]))
+		if err != nil {
+			out = append(out, subs[0])
+			continue
+		}
+		switch code {
+		case 4: // underline style -> basic underline
+			out = append(out, []byte("4"))
+		case 38, 48: // fg/bg color
+			if len(subs) >= 2 {
+				switch string(subs[1]) {
+				case "2": // true-color: code:2[:cs]:r:g:b
+					// Find r,g,b - skip optional colorspace id.
+					if len(subs) >= 6 {
+						// code:2:cs:r:g:b
+						out = append(out, subs[0], []byte("2"), subs[3], subs[4], subs[5])
+					} else if len(subs) >= 5 {
+						// code:2:r:g:b (no colorspace)
+						out = append(out, subs[0], []byte("2"), subs[2], subs[3], subs[4])
+					} else {
+						out = append(out, subs[0])
+					}
+				case "5": // 256-color: code:5:n
+					if len(subs) >= 3 {
+						out = append(out, subs[0], []byte("5"), subs[2])
+					} else {
+						out = append(out, subs[0])
+					}
+				default:
+					out = append(out, subs[0])
+				}
+			} else {
+				out = append(out, subs[0])
+			}
+		case 58: // underline color - not supported by vt10x, drop entirely
+			continue
+		default:
+			out = append(out, subs[0])
+		}
+	}
+	return bytes.Join(out, []byte{';'})
+}