package governance

import (
	"context"
	"fmt"
	"testing"
	"time"

	"github.com/google/cel-go/cel"
	bifrost "github.com/maximhq/bifrost/core"
	"github.com/maximhq/bifrost/core/schemas"
	"github.com/maximhq/bifrost/framework/configstore"
	configstoreTables "github.com/maximhq/bifrost/framework/configstore/tables"
	"github.com/maximhq/bifrost/framework/routing"
	"github.com/stretchr/testify/assert"
	"github.com/stretchr/testify/require"
)

// TestBuildScopeChain_GlobalOnly tests scope chain with no VirtualKey
func TestBuildScopeChain_GlobalOnly(t *testing.T) {
	chain := buildScopeChain(nil)

	require.Equal(t, 1, len(chain))
	assert.Equal(t, "global", chain[0].ScopeName)
	assert.Equal(t, "", chain[0].ScopeID)
}

// TestBuildScopeChain_VirtualKeyOnly tests scope chain with only VirtualKey
func TestBuildScopeChain_VirtualKeyOnly(t *testing.T) {
	vk := &configstoreTables.TableVirtualKey{
		ID:   "vk-123",
		Name: "test-vk",
	}

	chain := buildScopeChain(vk)

	require.Equal(t, 2, len(chain))
	assert.Equal(t, "virtual_key", chain[0].ScopeName)
	assert.Equal(t, "vk-123", chain[0].ScopeID)
	assert.Equal(t, "global", chain[1].ScopeName)
	assert.Equal(t, "", chain[1].ScopeID)
}

// TestBuildScopeChain_WithTeam tests scope chain with VirtualKey and Team
func TestBuildScopeChain_WithTeam(t *testing.T) {
	team := &configstoreTables.TableTeam{
		ID:   "team-456",
		Name: "premium-team",
	}

	vk := &configstoreTables.TableVirtualKey{
		ID:   "vk-123",
		Name: "test-vk",
		Team: team,
	}

	chain := buildScopeChain(vk)

	require.Equal(t, 3, len(chain))
	assert.Equal(t, "virtual_key", chain[0].ScopeName)
	assert.Equal(t, "vk-123", chain[0].ScopeID)
	assert.Equal(t, "team", chain[1].ScopeName)
	assert.Equal(t, "team-456", chain[1].ScopeID)
	assert.Equal(t, "global", chain[2].ScopeName)
}

// TestBuildScopeChain_FullHierarchy tests scope chain with full hierarchy
func TestBuildScopeChain_FullHierarchy(t *testing.T) {
	customer := &configstoreTables.TableCustomer{
		ID:   "cust-789",
		Name: "acme-corp",
	}

	team := &configstoreTables.TableTeam{
		ID:       "team-456",
		Name:     "premium-team",
		Customer: customer,
	}

	vk := &configstoreTables.TableVirtualKey{
		ID:   "vk-123",
		Name: "test-vk",
		Team: team,
	}

	chain := buildScopeChain(vk)

	require.Equal(t, 4, len(chain))
	assert.Equal(t, "virtual_key", chain[0].ScopeName)
	assert.Equal(t, "vk-123", chain[0].ScopeID)
	assert.Equal(t, "team", chain[1].ScopeName)
	assert.Equal(t, "team-456", chain[1].ScopeID)
	assert.Equal(t, "customer", chain[2].ScopeName)
	assert.Equal(t, "cust-789", chain[2].ScopeID)
	assert.Equal(t, "global", chain[3].ScopeName)
	assert.Equal(t, "", chain[3].ScopeID)
}

// TestGetDefaultRouting tests getting default routing from context
func TestGetDefaultRouting(t *testing.T) {
	ctx := &RoutingContext{
		Provider: schemas.OpenAI,
		Model:    "gpt-4o",
	}

	decision := getDefaultRouting(ctx)

	assert.NotNil(t, decision)
	assert.Equal(t, "openai", decision.Provider)
	assert.Equal(t, "gpt-4o", decision.Model)
	assert.Equal(t, 0, len(decision.Fallbacks))
	assert.Equal(t, "0", decision.MatchedRuleID)
}

// TestGetDefaultRouting_NilContext tests GetDefaultRouting with nil context
func TestGetDefaultRouting_NilContext(t *testing.T) {
	decision := getDefaultRouting(nil)
	assert.Nil(t, decision)
}

// TestApplyRoutingDecision tests applying a routing decision to context
func TestApplyRoutingDecision(t *testing.T) {
	ctx := &RoutingContext{
		Provider: schemas.OpenAI,
		Model:    "gpt-4o",
	}

	decision := &RoutingDecision{
		Provider: "azure",
		Model:    "gpt-4-turbo",
	}

	updated := applyRoutingDecision(ctx, decision)

	assert.Equal(t, schemas.Azure, updated.Provider)
	assert.Equal(t, "gpt-4-turbo", updated.Model)
	// Original context should not be modified
	assert.Equal(t, schemas.OpenAI, ctx.Provider)
	assert.Equal(t, "gpt-4o", ctx.Model)
}

// TestApplyRoutingDecision_NilDecision tests applyRoutingDecision with nil decision
func TestApplyRoutingDecision_NilDecision(t *testing.T) {
	ctx := &RoutingContext{
		Provider: schemas.OpenAI,
		Model:    "gpt-4o",
	}

	updated := applyRoutingDecision(ctx, nil)
	assert.Equal(t, ctx, updated)
}

// TestValidateRoutingDecision_Valid tests validating a valid decision
func TestValidateRoutingDecision_Valid(t *testing.T) {
	decision := &RoutingDecision{
		Provider: "openai",
		Model:    "gpt-4o",
	}

	err := validateRoutingDecision(decision)
	assert.NoError(t, err)
}

// TestValidateRoutingDecision_NilDecision tests validating nil decision
func TestValidateRoutingDecision_NilDecision(t *testing.T) {
	err := validateRoutingDecision(nil)
	assert.Error(t, err)
	assert.Contains(t, err.Error(), "cannot be nil")
}

// TestValidateRoutingDecision_MissingProvider tests validating with missing provider
func TestValidateRoutingDecision_MissingProvider(t *testing.T) {
	decision := &RoutingDecision{
		Model: "gpt-4o",
	}

	err := validateRoutingDecision(decision)
	assert.Error(t, err)
	assert.Contains(t, err.Error(), "provider")
}

// TestValidateRoutingDecision_MissingModel tests validating with missing model
func TestValidateRoutingDecision_MissingModel(t *testing.T) {
	decision := &RoutingDecision{
		Provider: "openai",
	}

	err := validateRoutingDecision(decision)
	assert.Error(t, err)
	assert.Contains(t, err.Error(), "model")
}

// TestEvaluateRoutingRules_NilContext tests EvaluateRoutingRules with nil context
func TestEvaluateRoutingRules_NilContext(t *testing.T) {
	store, err := NewLocalGovernanceStore(context.Background(), NewMockLogger(), nil, &configstore.GovernanceConfig{}, nil)
	require.NoError(t, err)

	engine, err := NewRoutingEngine(store, NewMockLogger(), schemas.Ptr(10))
	require.NoError(t, err)

	_, err = engine.EvaluateRoutingRules(schemas.NewBifrostContext(context.Background(), time.Now()), nil)
	assert.Error(t, err)
	assert.Contains(t, err.Error(), "context cannot be nil")
}

// TestEvaluateRoutingRules_NoRulesMatch tests EvaluateRoutingRules when no rules match
func TestEvaluateRoutingRules_NoRulesMatch(t *testing.T) {
	store, err := NewLocalGovernanceStore(context.Background(), NewMockLogger(), nil, &configstore.GovernanceConfig{}, nil)
	require.NoError(t, err)

	engine, err := NewRoutingEngine(store, NewMockLogger(), schemas.Ptr(10))
	require.NoError(t, err)

	ctx := &RoutingContext{
		Provider:    schemas.OpenAI,
		Model:       "gpt-4o",
		Headers:     map[string]string{},
		QueryParams: map[string]string{},
	}

	decision, err := engine.EvaluateRoutingRules(schemas.NewBifrostContext(context.Background(), time.Now()), ctx)
	assert.NoError(t, err)
	assert.Nil(t, decision)
}

// TestEvaluateRoutingRules_GlobalRuleMatches tests global scope rule matching
func TestEvaluateRoutingRules_GlobalRuleMatches(t *testing.T) {
	store, err := NewLocalGovernanceStore(context.Background(), NewMockLogger(), nil, &configstore.GovernanceConfig{}, nil)
	require.NoError(t, err)
	bgCtx := schemas.NewBifrostContext(context.Background(), time.Now())

	engine, err := NewRoutingEngine(store, NewMockLogger(), schemas.Ptr(10))
	require.NoError(t, err)

	// Create a global routing rule
	rule := &configstoreTables.TableRoutingRule{
		ID:            "1",
		Name:          "Global Rule",
		CelExpression: "model == 'gpt-4o'",
		Targets: []configstoreTables.TableRoutingTarget{
			{Provider: bifrost.Ptr("azure"), Model: bifrost.Ptr("gpt-4-turbo"), Weight: 1.0},
		},
		Enabled:  true,
		Scope:    "global",
		Priority: 0,
	}

	// Store the rule
	require.NoError(t, store.UpdateRoutingRuleInMemory(context.Background(), rule))

	// Create routing context
	ctx := &RoutingContext{
		Provider:    schemas.OpenAI,
		Model:       "gpt-4o",
		Headers:     map[string]string{},
		QueryParams: map[string]string{},
	}

	// Evaluate rules
	decision, err := engine.EvaluateRoutingRules(bgCtx, ctx)
	require.NoError(t, err)
	require.NotNil(t, decision)

	assert.Equal(t, "azure", decision.Provider)
	assert.Equal(t, "gpt-4-turbo", decision.Model)
	assert.Equal(t, "1", decision.MatchedRuleID)
	assert.Equal(t, "Global Rule", decision.MatchedRuleName)
}

// TestEvaluateRoutingRules_MultiTargetDeterministicWithPinnedKey tests weighted target selection
// with a seeded/stubbed approach: one target carries all the weight (1.0) and the other carries
// none (0.0). Because selectWeightedTarget accumulates weights and picks the first target whose
// cumulative sum exceeds the random draw — and rand.Float64()*1.0 always lies in [0,1) — the
// 1.0-weight target is always chosen regardless of the RNG state.  This gives us fully
// deterministic selection without modifying production code or reaching for a global-rand seed.
// The test also verifies that the pinned key_id from the winning target propagates into the
// RoutingDecision and, when applied the same way governance/main.go does it, into the
// BifrostContext under BifrostContextKeyAPIKeyID.
func TestEvaluateRoutingRules_MultiTargetDeterministicWithPinnedKey(t *testing.T) {
	store, err := NewLocalGovernanceStore(context.Background(), NewMockLogger(), nil, &configstore.GovernanceConfig{}, nil)
	require.NoError(t, err)

	engine, err := NewRoutingEngine(store, NewMockLogger(), schemas.Ptr(10))
	require.NoError(t, err)

	bgCtx := schemas.NewBifrostContext(context.Background(), time.Now())

	const pinnedKeyID = "pinned-key-abc-123"

	// Two-target fixture: azure gets weight 1.0 (always wins), openai gets weight 0.0
	// (included in valid[] per the >= 0 filter but contributes 0 to cumulative, so it can
	// never be selected).  No RNG seeding is required — the outcome is guaranteed by the
	// weight distribution alone.
	rule := &configstoreTables.TableRoutingRule{
		ID:            "multi-1",
		Name:          "Multi-Target Rule",
		CelExpression: "model == 'gpt-4o'",
		Targets: []configstoreTables.TableRoutingTarget{
			{
				Provider: bifrost.Ptr("azure"),
				Model:    bifrost.Ptr("gpt-4-turbo"),
				KeyID:    bifrost.Ptr(pinnedKeyID),
				Weight:   1.0,
			},
			{
				Provider: bifrost.Ptr("openai"),
				Model:    bifrost.Ptr("gpt-3.5"),
				Weight:   0.0,
			},
		},
		Enabled:  true,
		Scope:    "global",
		Priority: 0,
	}
	require.NoError(t, store.UpdateRoutingRuleInMemory(context.Background(), rule))

	routingCtx := &RoutingContext{
		Provider:    schemas.OpenAI,
		Model:       "gpt-4o",
		Headers:     map[string]string{},
		QueryParams: map[string]string{},
	}

	decision, err := engine.EvaluateRoutingRules(bgCtx, routingCtx)
	require.NoError(t, err)
	require.NotNil(t, decision)

	// The 1.0-weight azure target must always be selected.
	assert.Equal(t, "azure", decision.Provider)
	assert.Equal(t, "gpt-4-turbo", decision.Model)
	assert.Equal(t, "multi-1", decision.MatchedRuleID)
	assert.Equal(t, "Multi-Target Rule", decision.MatchedRuleName)

	// KeyID must be propagated through the routing decision.
	assert.Equal(t, pinnedKeyID, decision.KeyID)

	// Simulate the propagation step performed by governance/main.go so that we can
	// assert the pinned key_id is visible in the BifrostContext.
	if decision.KeyID != "" {
		bgCtx.SetValue(schemas.BifrostContextKeyAPIKeyID, decision.KeyID)
	}
	ctxKeyID, _ := bgCtx.Value(schemas.BifrostContextKeyAPIKeyID).(string)
	assert.Equal(t, pinnedKeyID, ctxKeyID)
}

// TestEvaluateRoutingRules_ScopePrecedence tests virtual_key scope takes precedence over global
func TestEvaluateRoutingRules_ScopePrecedence(t *testing.T) {
	store, err := NewLocalGovernanceStore(context.Background(), NewMockLogger(), nil, &configstore.GovernanceConfig{}, nil)
	require.NoError(t, err)
	bgCtx := schemas.NewBifrostContext(context.Background(), time.Now())

	engine, err := NewRoutingEngine(store, NewMockLogger(), schemas.Ptr(10))
	require.NoError(t, err)

	// Create global rule
	globalRule := &configstoreTables.TableRoutingRule{
		ID:            "1",
		Name:          "Global Rule",
		CelExpression: "model == 'gpt-4o'",
		Targets: []configstoreTables.TableRoutingTarget{
			{Provider: bifrost.Ptr("openai"), Model: bifrost.Ptr("gpt-4o"), Weight: 1.0},
		},
		Enabled:  true,
		Scope:    "global",
		Priority: 0,
	}
	require.NoError(t, store.UpdateRoutingRuleInMemory(context.Background(), globalRule))

	// Create VK-specific rule (should take precedence)
	vkRule := &configstoreTables.TableRoutingRule{
		ID:            "2",
		Name:          "VK Rule",
		CelExpression: "model == 'gpt-4o'",
		Targets: []configstoreTables.TableRoutingTarget{
			{Provider: bifrost.Ptr("azure"), Model: bifrost.Ptr("gpt-4-turbo"), Weight: 1.0},
		},
		Enabled:  true,
		Scope:    "virtual_key",
		ScopeID:  bifrost.Ptr("vk-123"),
		Priority: 10,
	}
	require.NoError(t, store.UpdateRoutingRuleInMemory(context.Background(), vkRule))

	// Create routing context with VirtualKey
	vk := &configstoreTables.TableVirtualKey{
		ID:   "vk-123",
		Name: "test-vk",
	}

	ctx := &RoutingContext{
		VirtualKey:  vk,
		Provider:    schemas.OpenAI,
		Model:       "gpt-4o",
		Headers:     map[string]string{},
		QueryParams: map[string]string{},
	}

	// Evaluate rules
	decision, err := engine.EvaluateRoutingRules(bgCtx, ctx)
	require.NoError(t, err)
	require.NotNil(t, decision)

	// Should match VK rule, not global
	assert.Equal(t, "azure", decision.Provider)
	assert.Equal(t, "gpt-4-turbo", decision.Model)
	assert.Equal(t, "2", decision.MatchedRuleID)
}

// TestEvaluateRoutingRules_PriorityOrdering tests rules within scope are evaluated by priority.
// Lower numeric Priority is higher precedence (model/UI semantics); rules are ordered ASC.
func TestEvaluateRoutingRules_PriorityOrdering(t *testing.T) {
	store, err := NewLocalGovernanceStore(context.Background(), NewMockLogger(), nil, &configstore.GovernanceConfig{}, nil)
	require.NoError(t, err)
	bgCtx := schemas.NewBifrostContext(context.Background(), time.Now())

	engine, err := NewRoutingEngine(store, NewMockLogger(), schemas.Ptr(10))
	require.NoError(t, err)

	// Low precedence rule (evaluated second): higher priority number
	rule1 := &configstoreTables.TableRoutingRule{
		ID:            "1",
		Name:          "Low Priority",
		CelExpression: "true",
		Targets: []configstoreTables.TableRoutingTarget{
			{Provider: bifrost.Ptr("openai"), Model: bifrost.Ptr("gpt-4o"), Weight: 1.0},
		},
		Enabled:  true,
		Scope:    "global",
		Priority: 10,
	}
	require.NoError(t, store.UpdateRoutingRuleInMemory(context.Background(), rule1))

	// High precedence rule (evaluated first): lower priority number
	rule2 := &configstoreTables.TableRoutingRule{
		ID:            "2",
		Name:          "High Priority",
		CelExpression: "true",
		Targets: []configstoreTables.TableRoutingTarget{
			{Provider: bifrost.Ptr("azure"), Model: bifrost.Ptr("gpt-4-turbo"), Weight: 1.0},
		},
		Enabled:  true,
		Scope:    "global",
		Priority: 0,
	}
	require.NoError(t, store.UpdateRoutingRuleInMemory(context.Background(), rule2))

	ctx := &RoutingContext{
		Provider:    schemas.OpenAI,
		Model:       "gpt-4o",
		Headers:     map[string]string{},
		QueryParams: map[string]string{},
	}

	decision, err := engine.EvaluateRoutingRules(bgCtx, ctx)
	require.NoError(t, err)
	require.NotNil(t, decision)

	// Lower Priority value = higher precedence: "High Priority" (0) is evaluated first and matches
	assert.Equal(t, "azure", decision.Provider)
	assert.Equal(t, "2", decision.MatchedRuleID)
}

// TestResolveRoutingWithFallback_RuleMatches tests resolving with matching rule
func TestResolveRoutingWithFallback_RuleMatches(t *testing.T) {
	store, err := NewLocalGovernanceStore(context.Background(), NewMockLogger(), nil, &configstore.GovernanceConfig{}, nil)
	require.NoError(t, err)
	bgCtx := schemas.NewBifrostContext(context.Background(), time.Now())

	rule := &configstoreTables.TableRoutingRule{
		ID:            "1",
		Name:          "Test Rule",
		CelExpression: "model == 'gpt-4o'",
		Targets: []configstoreTables.TableRoutingTarget{
			{Provider: bifrost.Ptr("azure"), Model: bifrost.Ptr("gpt-4-turbo"), Weight: 1.0},
		},
		Enabled:  true,
		Scope:    "global",
		Priority: 0,
	}
	require.NoError(t, store.UpdateRoutingRuleInMemory(context.Background(), rule))

	ctx := &RoutingContext{
		Provider:    schemas.OpenAI,
		Model:       "gpt-4o",
		Headers:     map[string]string{},
		QueryParams: map[string]string{},
	}

	engine, err := NewRoutingEngine(store, NewMockLogger(), schemas.Ptr(10))
	require.NoError(t, err)

	decision, err := resolveRoutingWithFallback(bgCtx, ctx, engine)
	require.NoError(t, err)
	require.NotNil(t, decision)

	assert.Equal(t, "azure", decision.Provider)
	assert.Equal(t, "gpt-4-turbo", decision.Model)
}

// TestResolveRoutingWithFallback_NoMatch tests resolving when no rule matches
func TestResolveRoutingWithFallback_NoMatch(t *testing.T) {
	store, err := NewLocalGovernanceStore(context.Background(), NewMockLogger(), nil, &configstore.GovernanceConfig{}, nil)
	require.NoError(t, err)

	ctx := &RoutingContext{
		Provider:    schemas.OpenAI,
		Model:       "gpt-4o",
		Headers:     map[string]string{},
		QueryParams: map[string]string{},
	}

	engine, err := NewRoutingEngine(store, NewMockLogger(), schemas.Ptr(10))
	require.NoError(t, err)

	decision, err := resolveRoutingWithFallback(schemas.NewBifrostContext(context.Background(), time.Now()), ctx, engine)
	require.NoError(t, err)
	require.NotNil(t, decision)

	// Should return default routing
	assert.Equal(t, "openai", decision.Provider)
	assert.Equal(t, "gpt-4o", decision.Model)
	assert.Equal(t, "0", decision.MatchedRuleID)
}

// TestEvaluateRoutingRules_DisabledRulesIgnored tests that disabled rules are ignored
func TestEvaluateRoutingRules_DisabledRulesIgnored(t *testing.T) {
	store, err := NewLocalGovernanceStore(context.Background(), NewMockLogger(), nil, &configstore.GovernanceConfig{}, nil)
	require.NoError(t, err)
	bgCtx := schemas.NewBifrostContext(context.Background(), time.Now())

	engine, err := NewRoutingEngine(store, NewMockLogger(), schemas.Ptr(10))
	require.NoError(t, err)

	// Create disabled rule
	disabledRule := &configstoreTables.TableRoutingRule{
		ID:            "1",
		Name:          "Disabled Rule",
		CelExpression: "model == 'gpt-4o'",
		Targets: []configstoreTables.TableRoutingTarget{
			{Provider: bifrost.Ptr("azure"), Model: bifrost.Ptr("gpt-4-turbo"), Weight: 1.0},
		},
		Enabled:  false,
		Scope:    "global",
		Priority: 10,
	}
	require.NoError(t, store.UpdateRoutingRuleInMemory(context.Background(), disabledRule))

	// Create enabled rule
	enabledRule := &configstoreTables.TableRoutingRule{
		ID:            "2",
		Name:          "Enabled Rule",
		CelExpression: "model == 'gpt-4o'",
		Targets: []configstoreTables.TableRoutingTarget{
			{Provider: bifrost.Ptr("openai"), Model: bifrost.Ptr("gpt-4o"), Weight: 1.0},
		},
		Enabled:  true,
		Scope:    "global",
		Priority: 0,
	}
	require.NoError(t, store.UpdateRoutingRuleInMemory(context.Background(), enabledRule))

	ctx := &RoutingContext{
		Provider:    schemas.OpenAI,
		Model:       "gpt-4o",
		Headers:     map[string]string{},
		QueryParams: map[string]string{},
	}

	decision, err := engine.EvaluateRoutingRules(bgCtx, ctx)
	require.NoError(t, err)
	require.NotNil(t, decision)

	// Should match enabled rule, not disabled
	assert.Equal(t, "2", decision.MatchedRuleID)
}

// TestEvaluateRoutingRules_ComplexExpression tests evaluation with complex CEL expression
func TestEvaluateRoutingRules_ComplexExpression(t *testing.T) {
	store, err := NewLocalGovernanceStore(context.Background(), NewMockLogger(), nil, &configstore.GovernanceConfig{}, nil)
	require.NoError(t, err)
	bgCtx := schemas.NewBifrostContext(context.Background(), time.Now())

	engine, err := NewRoutingEngine(store, NewMockLogger(), schemas.Ptr(10))
	require.NoError(t, err)

	rule := &configstoreTables.TableRoutingRule{
		ID:            "1",
		Name:          "Complex Rule",
		CelExpression: "model == 'gpt-4o' && headers['x-tier'] == 'premium'",
		Targets: []configstoreTables.TableRoutingTarget{
			{Provider: bifrost.Ptr("azure"), Model: bifrost.Ptr("gpt-4-turbo"), Weight: 1.0},
		},
		Enabled:  true,
		Scope:    "global",
		Priority: 0,
	}
	require.NoError(t, store.UpdateRoutingRuleInMemory(context.Background(), rule))

	// Test with matching headers
	ctx := &RoutingContext{
		Provider: schemas.OpenAI,
		Model:    "gpt-4o",
		Headers: map[string]string{
			"x-tier": "premium",
		},
		QueryParams: map[string]string{},
	}

	decision, err := engine.EvaluateRoutingRules(bgCtx, ctx)
	require.NoError(t, err)
	require.NotNil(t, decision)
	assert.Equal(t, "azure", decision.Provider)

	// Test with non-matching headers
	ctx.Headers["x-tier"] = "free"
	decision, err = engine.EvaluateRoutingRules(bgCtx, ctx)
	require.NoError(t, err)
	assert.Nil(t, decision)
}

// TestEvaluateRoutingRules_NilVirtualKey tests evaluation without VirtualKey
func TestEvaluateRoutingRules_NilVirtualKey(t *testing.T) {
	store, err := NewLocalGovernanceStore(context.Background(), NewMockLogger(), nil, &configstore.GovernanceConfig{}, nil)
	require.NoError(t, err)
	bgCtx := schemas.NewBifrostContext(context.Background(), time.Now())

	engine, err := NewRoutingEngine(store, NewMockLogger(), schemas.Ptr(10))
	require.NoError(t, err)

	rule := &configstoreTables.TableRoutingRule{
		ID:            "1",
		Name:          "Global Rule",
		CelExpression: "true",
		Targets: []configstoreTables.TableRoutingTarget{
			{Provider: bifrost.Ptr("azure"), Model: bifrost.Ptr("gpt-4-turbo"), Weight: 1.0},
		},
		Enabled:  true,
		Scope:    "global",
		Priority: 0,
	}
	require.NoError(t, store.UpdateRoutingRuleInMemory(context.Background(), rule))

	ctx := &RoutingContext{
		Provider:    schemas.OpenAI,
		Model:       "gpt-4o",
		Headers:     map[string]string{},
		QueryParams: map[string]string{},
	}

	decision, err := engine.EvaluateRoutingRules(bgCtx, ctx)
	require.NoError(t, err)
	require.NotNil(t, decision)

	assert.Equal(t, "azure", decision.Provider)
}

// TestEvaluateRoutingRules_MissingHeaderGracefully tests that missing headers don't cause evaluation errors
func TestEvaluateRoutingRules_MissingHeaderGracefully(t *testing.T) {
	store, err := NewLocalGovernanceStore(context.Background(), NewMockLogger(), nil, &configstore.GovernanceConfig{}, nil)
	require.NoError(t, err)
	bgCtx := schemas.NewBifrostContext(context.Background(), time.Now())

	engine, err := NewRoutingEngine(store, NewMockLogger(), schemas.Ptr(10))
	require.NoError(t, err)

	// Create a rule that checks for a header that may not be present
	rule := &configstoreTables.TableRoutingRule{
		ID:            "1",
		Name:          "Header Check Rule",
		CelExpression: "headers[\"x-custom-header\"] == \"premium\"",
		Targets: []configstoreTables.TableRoutingTarget{
			{Provider: bifrost.Ptr("azure"), Model: bifrost.Ptr("gpt-4-turbo"), Weight: 1.0},
		},
		Enabled:  true,
		Scope:    "global",
		Priority: 0,
	}
	require.NoError(t, store.UpdateRoutingRuleInMemory(context.Background(), rule))

	// Create context WITHOUT the header
	ctx := &RoutingContext{
		Provider:    schemas.OpenAI,
		Model:       "gpt-4o",
		Headers:     map[string]string{}, // No x-custom-header
		QueryParams: map[string]string{},
	}

	// Should not error, should just not match
	decision, err := engine.EvaluateRoutingRules(bgCtx, ctx)
	require.NoError(t, err)
	assert.Nil(t, decision) // Rule didn't match because header was missing

	// Now provide the header with correct value
	ctx.Headers = map[string]string{"x-custom-header": "premium"}
	decision, err = engine.EvaluateRoutingRules(bgCtx, ctx)
	require.NoError(t, err)
	assert.NotNil(t, decision) // Rule matches now
	assert.Equal(t, "azure", decision.Provider)
}

// TestEvaluateRoutingRules_ChainRuleReEvaluation tests that chain_rule=true causes re-evaluation
// with the resolved provider/model fed back into the engine.
func TestEvaluateRoutingRules_ChainRuleReEvaluation(t *testing.T) {
	store, err := NewLocalGovernanceStore(context.Background(), NewMockLogger(), nil, &configstore.GovernanceConfig{}, nil)
	require.NoError(t, err)
	bgCtx := schemas.NewBifrostContext(context.Background(), time.Now())

	engine, err := NewRoutingEngine(store, NewMockLogger(), schemas.Ptr(10))
	require.NoError(t, err)

	// Rule A: matches gpt-4o → routes to gpt-4-turbo, chain_rule=true so re-evaluation continues.
	ruleA := &configstoreTables.TableRoutingRule{
		ID:            "chain-a",
		Name:          "Chain Rule A",
		CelExpression: "model == 'gpt-4o'",
		Targets: []configstoreTables.TableRoutingTarget{
			{Provider: bifrost.Ptr("openai"), Model: bifrost.Ptr("gpt-4-turbo"), Weight: 1.0},
		},
		Enabled:   true,
		Scope:     "global",
		Priority:  0,
		ChainRule: true,
	}
	require.NoError(t, store.UpdateRoutingRuleInMemory(context.Background(), ruleA))

	// Rule B: matches gpt-4-turbo → routes to azure/gpt-4, terminal (chain_rule=false).
	ruleB := &configstoreTables.TableRoutingRule{
		ID:            "chain-b",
		Name:          "Chain Rule B",
		CelExpression: "model == 'gpt-4-turbo'",
		Targets: []configstoreTables.TableRoutingTarget{
			{Provider: bifrost.Ptr("azure"), Model: bifrost.Ptr("gpt-4"), Weight: 1.0},
		},
		Enabled:   true,
		Scope:     "global",
		Priority:  1,
		ChainRule: false,
	}
	require.NoError(t, store.UpdateRoutingRuleInMemory(context.Background(), ruleB))

	ctx := &RoutingContext{
		Provider:    schemas.OpenAI,
		Model:       "gpt-4o",
		Headers:     map[string]string{},
		QueryParams: map[string]string{},
	}

	decision, err := engine.EvaluateRoutingRules(bgCtx, ctx)
	require.NoError(t, err)
	require.NotNil(t, decision)

	// Rule A matched first, but chain_rule=true caused re-evaluation.
	// Rule B then matched the updated model (gpt-4-turbo) and produced the final result.
	assert.Equal(t, "azure", decision.Provider)
	assert.Equal(t, "gpt-4", decision.Model)
	assert.Equal(t, "chain-b", decision.MatchedRuleID)
}

// TestEvaluateRoutingRules_TerminalRuleStopsChain tests that a terminal rule (chain_rule=false)
// halts the chaining loop immediately without re-evaluation.
func TestEvaluateRoutingRules_TerminalRuleStopsChain(t *testing.T) {
	store, err := NewLocalGovernanceStore(context.Background(), NewMockLogger(), nil, &configstore.GovernanceConfig{}, nil)
	require.NoError(t, err)
	bgCtx := schemas.NewBifrostContext(context.Background(), time.Now())

	engine, err := NewRoutingEngine(store, NewMockLogger(), schemas.Ptr(10))
	require.NoError(t, err)

	// Rule A: matches gpt-4o → routes to gpt-4-turbo, terminal (chain_rule=false).
	ruleA := &configstoreTables.TableRoutingRule{
		ID:            "terminal-a",
		Name:          "Terminal Rule A",
		CelExpression: "model == 'gpt-4o'",
		Targets: []configstoreTables.TableRoutingTarget{
			{Provider: bifrost.Ptr("openai"), Model: bifrost.Ptr("gpt-4-turbo"), Weight: 1.0},
		},
		Enabled:   true,
		Scope:     "global",
		Priority:  0,
		ChainRule: false,
	}
	require.NoError(t, store.UpdateRoutingRuleInMemory(context.Background(), ruleA))

	// Rule B: would match gpt-4-turbo, but should never be reached because Rule A is terminal.
	ruleB := &configstoreTables.TableRoutingRule{
		ID:            "terminal-b",
		Name:          "Terminal Rule B",
		CelExpression: "model == 'gpt-4-turbo'",
		Targets: []configstoreTables.TableRoutingTarget{
			{Provider: bifrost.Ptr("azure"), Model: bifrost.Ptr("gpt-4"), Weight: 1.0},
		},
		Enabled:   true,
		Scope:     "global",
		Priority:  1,
		ChainRule: false,
	}
	require.NoError(t, store.UpdateRoutingRuleInMemory(context.Background(), ruleB))

	ctx := &RoutingContext{
		Provider:    schemas.OpenAI,
		Model:       "gpt-4o",
		Headers:     map[string]string{},
		QueryParams: map[string]string{},
	}

	decision, err := engine.EvaluateRoutingRules(bgCtx, ctx)
	require.NoError(t, err)
	require.NotNil(t, decision)

	// Only Rule A should have matched; chain stopped immediately at terminal rule.
	assert.Equal(t, "openai", decision.Provider)
	assert.Equal(t, "gpt-4-turbo", decision.Model)
	assert.Equal(t, "terminal-a", decision.MatchedRuleID)
}

// TestEvaluateRoutingRules_ConvergenceStopsChain tests that the cycle-detection mechanism stops
// the chain when a chain_rule=true rule resolves to a provider/model already visited (no-op loop).
func TestEvaluateRoutingRules_ConvergenceStopsChain(t *testing.T) {
	store, err := NewLocalGovernanceStore(context.Background(), NewMockLogger(), nil, &configstore.GovernanceConfig{}, nil)
	require.NoError(t, err)
	bgCtx := schemas.NewBifrostContext(context.Background(), time.Now())

	engine, err := NewRoutingEngine(store, NewMockLogger(), schemas.Ptr(10))
	require.NoError(t, err)

	// Rule A: chain_rule=true but resolves back to the initial provider/model — creates a cycle.
	ruleA := &configstoreTables.TableRoutingRule{
		ID:            "converge-a",
		Name:          "Convergence Rule A",
		CelExpression: "model == 'gpt-4o'",
		Targets: []configstoreTables.TableRoutingTarget{
			{Provider: bifrost.Ptr("openai"), Model: bifrost.Ptr("gpt-4o"), Weight: 1.0},
		},
		Enabled:   true,
		Scope:     "global",
		Priority:  0,
		ChainRule: true,
	}
	require.NoError(t, store.UpdateRoutingRuleInMemory(context.Background(), ruleA))

	ctx := &RoutingContext{
		Provider:    schemas.OpenAI,
		Model:       "gpt-4o",
		Headers:     map[string]string{},
		QueryParams: map[string]string{},
	}

	decision, err := engine.EvaluateRoutingRules(bgCtx, ctx)
	require.NoError(t, err)
	require.NotNil(t, decision)

	// Cycle detected after the first match; the last matched decision (openai/gpt-4o) is returned.
	assert.Equal(t, "openai", decision.Provider)
	assert.Equal(t, "gpt-4o", decision.Model)
	assert.Equal(t, "converge-a", decision.MatchedRuleID)
}

// TestEvaluateRoutingRules_MaxDepthCutoff tests that the chain stops once chainMaxDepth is reached,
// returning the last successfully resolved decision rather than continuing further.
func TestEvaluateRoutingRules_MaxDepthCutoff(t *testing.T) {
	store, err := NewLocalGovernanceStore(context.Background(), NewMockLogger(), nil, &configstore.GovernanceConfig{}, nil)
	require.NoError(t, err)
	bgCtx := schemas.NewBifrostContext(context.Background(), time.Now())

	// Use maxDepth=2: steps 0 and 1 are allowed; step 2 is cut off before any rule is evaluated.
	engine, err := NewRoutingEngine(store, NewMockLogger(), schemas.Ptr(2))
	require.NoError(t, err)

	// Rule A: gpt-4o → gpt-4-turbo, chain continues.
	ruleA := &configstoreTables.TableRoutingRule{
		ID:            "depth-a",
		Name:          "Depth Rule A",
		CelExpression: "model == 'gpt-4o'",
		Targets: []configstoreTables.TableRoutingTarget{
			{Provider: bifrost.Ptr("openai"), Model: bifrost.Ptr("gpt-4-turbo"), Weight: 1.0},
		},
		Enabled:   true,
		Scope:     "global",
		Priority:  0,
		ChainRule: true,
	}
	require.NoError(t, store.UpdateRoutingRuleInMemory(context.Background(), ruleA))

	// Rule B: gpt-4-turbo → azure/gpt-4, chain continues (would proceed to step 2 if depth allowed).
	ruleB := &configstoreTables.TableRoutingRule{
		ID:            "depth-b",
		Name:          "Depth Rule B",
		CelExpression: "model == 'gpt-4-turbo'",
		Targets: []configstoreTables.TableRoutingTarget{
			{Provider: bifrost.Ptr("azure"), Model: bifrost.Ptr("gpt-4"), Weight: 1.0},
		},
		Enabled:   true,
		Scope:     "global",
		Priority:  1,
		ChainRule: true,
	}
	require.NoError(t, store.UpdateRoutingRuleInMemory(context.Background(), ruleB))

	// Rule C: gpt-4 → anthropic/claude-3, would match at step 2 but max depth is 2.
	ruleC := &configstoreTables.TableRoutingRule{
		ID:            "depth-c",
		Name:          "Depth Rule C",
		CelExpression: "model == 'gpt-4'",
		Targets: []configstoreTables.TableRoutingTarget{
			{Provider: bifrost.Ptr("anthropic"), Model: bifrost.Ptr("claude-3"), Weight: 1.0},
		},
		Enabled:   true,
		Scope:     "global",
		Priority:  2,
		ChainRule: false,
	}
	require.NoError(t, store.UpdateRoutingRuleInMemory(context.Background(), ruleC))

	ctx := &RoutingContext{
		Provider:    schemas.OpenAI,
		Model:       "gpt-4o",
		Headers:     map[string]string{},
		QueryParams: map[string]string{},
	}

	decision, err := engine.EvaluateRoutingRules(bgCtx, ctx)
	require.NoError(t, err)
	require.NotNil(t, decision)

	// Step 0: Rule A matched → openai/gpt-4-turbo (finalDecision updated)
	// Step 1: Rule B matched → azure/gpt-4 (finalDecision updated)
	// Step 2: chainStep (2) >= maxDepth (2) → cut off before Rule C can match
	// Final result is the last successful decision: azure/gpt-4
	assert.Equal(t, "azure", decision.Provider)
	assert.Equal(t, "gpt-4", decision.Model)
	assert.Equal(t, "depth-b", decision.MatchedRuleID)
}

// TestCompileAndCacheProgram_ValidExpression_Routing tests compiling and caching a valid CEL expression
func TestCompileAndCacheProgram_ValidExpression_Routing(t *testing.T) {
	ctx := context.Background()
	logger := NewMockLogger()
	store, err := NewLocalGovernanceStore(ctx, logger, nil, &configstore.GovernanceConfig{}, nil)
	require.NoError(t, err)

	rule := &configstoreTables.TableRoutingRule{
		ID:            "1",
		Name:          "Test Rule",
		CelExpression: "model == 'gpt-4o'",
		Targets: []configstoreTables.TableRoutingTarget{
			{Provider: bifrost.Ptr("openai"), Weight: 1.0},
		},
		Enabled: true,
	}

	program, err := store.GetRoutingProgram(context.Background(), rule)
	require.NoError(t, err)
	assert.NotNil(t, program)

	// Verify caching works - second call should return cached program
	cached, err := store.GetRoutingProgram(context.Background(), rule)
	require.NoError(t, err)
	assert.NotNil(t, cached)
}

// TestCompileAndCacheProgram_EmptyExpression_Routing tests compiling with empty expression (defaults to "true")
func TestCompileAndCacheProgram_EmptyExpression_Routing(t *testing.T) {
	ctx := context.Background()
	logger := NewMockLogger()
	store, err := NewLocalGovernanceStore(ctx, logger, nil, &configstore.GovernanceConfig{}, nil)
	require.NoError(t, err)

	rule := &configstoreTables.TableRoutingRule{
		ID:            "1",
		Name:          "Default Rule",
		CelExpression: "",
		Targets: []configstoreTables.TableRoutingTarget{
			{Provider: bifrost.Ptr("openai"), Weight: 1.0},
		},
		Enabled: true,
	}

	program, err := store.GetRoutingProgram(context.Background(), rule)
	require.NoError(t, err)
	assert.NotNil(t, program)
}

// TestCompileAndCacheProgram_InvalidExpression_Routing tests compiling an invalid expression
func TestCompileAndCacheProgram_InvalidExpression_Routing(t *testing.T) {
	ctx := context.Background()
	logger := NewMockLogger()
	store, err := NewLocalGovernanceStore(ctx, logger, nil, &configstore.GovernanceConfig{}, nil)
	require.NoError(t, err)

	rule := &configstoreTables.TableRoutingRule{
		ID:            "1",
		Name:          "Invalid Rule",
		CelExpression: "model == gpt-4o'", // Missing opening quote
		Targets: []configstoreTables.TableRoutingTarget{
			{Provider: bifrost.Ptr("openai"), Weight: 1.0},
		},
		Enabled: true,
	}

	_, err = store.GetRoutingProgram(context.Background(), rule)
	assert.Error(t, err)
}

// TestCompileAndCacheProgram_NilRule tests compiling nil rule
func TestCompileAndCacheProgram_NilRule(t *testing.T) {
	ctx := context.Background()
	logger := NewMockLogger()
	store, err := NewLocalGovernanceStore(ctx, logger, nil, &configstore.GovernanceConfig{}, nil)
	require.NoError(t, err)

	_, err = store.GetRoutingProgram(context.Background(), nil)
	assert.Error(t, err)
	assert.Contains(t, err.Error(), "cannot be nil")
}

// TestCompileAndCacheProgram_ListExpression tests compiling list membership expression
func TestCompileAndCacheProgram_ListExpression(t *testing.T) {
	ctx := context.Background()
	logger := NewMockLogger()
	store, err := NewLocalGovernanceStore(ctx, logger, nil, &configstore.GovernanceConfig{}, nil)
	require.NoError(t, err)

	rule := &configstoreTables.TableRoutingRule{
		ID:            "1",
		Name:          "List Rule",
		CelExpression: "model in ['gpt-4o', 'gpt-4-turbo']",
		Targets: []configstoreTables.TableRoutingTarget{
			{Provider: bifrost.Ptr("openai"), Weight: 1.0},
		},
		Enabled: true,
	}

	program, err := store.GetRoutingProgram(context.Background(), rule)
	require.NoError(t, err)
	assert.NotNil(t, program)
}

// TestCompileAndCacheProgram_RegexExpression tests compiling regex expression
func TestCompileAndCacheProgram_RegexExpression(t *testing.T) {
	ctx := context.Background()
	logger := NewMockLogger()
	store, err := NewLocalGovernanceStore(ctx, logger, nil, &configstore.GovernanceConfig{}, nil)
	require.NoError(t, err)

	rule := &configstoreTables.TableRoutingRule{
		ID:            "1",
		Name:          "Regex Rule",
		CelExpression: "model.matches('^gpt-4.*')",
		Targets: []configstoreTables.TableRoutingTarget{
			{Provider: bifrost.Ptr("openai"), Weight: 1.0},
		},
		Enabled: true,
	}

	program, err := store.GetRoutingProgram(context.Background(), rule)
	require.NoError(t, err)
	assert.NotNil(t, program)
}

// TestCompileAndCacheProgram_HeaderExpression tests compiling header-based expression
func TestCompileAndCacheProgram_HeaderExpression(t *testing.T) {
	ctx := context.Background()
	logger := NewMockLogger()
	store, err := NewLocalGovernanceStore(ctx, logger, nil, &configstore.GovernanceConfig{}, nil)
	require.NoError(t, err)

	rule := &configstoreTables.TableRoutingRule{
		ID:            "1",
		Name:          "Header Rule",
		CelExpression: "headers['x-tier'] == 'premium'",
		Targets: []configstoreTables.TableRoutingTarget{
			{Provider: bifrost.Ptr("openai"), Weight: 1.0},
		},
		Enabled: true,
	}

	program, err := store.GetRoutingProgram(context.Background(), rule)
	require.NoError(t, err)
	assert.NotNil(t, program)
}

// TestCompileAndCacheProgram_RateLimitExpression tests compiling rate limit expression
func TestCompileAndCacheProgram_RateLimitExpression(t *testing.T) {
	ctx := context.Background()
	logger := NewMockLogger()
	store, err := NewLocalGovernanceStore(ctx, logger, nil, &configstore.GovernanceConfig{}, nil)
	require.NoError(t, err)

	rule := &configstoreTables.TableRoutingRule{
		ID:            "1",
		Name:          "Rate Limit Rule",
		CelExpression: "tokens_used >= 80.0",
		Targets: []configstoreTables.TableRoutingTarget{
			{Provider: bifrost.Ptr("openai"), Weight: 1.0},
		},
		Enabled: true,
	}

	program, err := store.GetRoutingProgram(context.Background(), rule)
	require.NoError(t, err)
	assert.NotNil(t, program)
}

// TestCompileAndCacheProgram_BudgetExpression tests compiling budget expression
func TestCompileAndCacheProgram_BudgetExpression(t *testing.T) {
	ctx := context.Background()
	logger := NewMockLogger()
	store, err := NewLocalGovernanceStore(ctx, logger, nil, &configstore.GovernanceConfig{}, nil)
	require.NoError(t, err)

	rule := &configstoreTables.TableRoutingRule{
		ID:            "1",
		Name:          "Budget Rule",
		CelExpression: "budget_used < 100.0",
		Targets: []configstoreTables.TableRoutingTarget{
			{Provider: bifrost.Ptr("openai"), Weight: 1.0},
		},
		Enabled: true,
	}

	program, err := store.GetRoutingProgram(context.Background(), rule)
	require.NoError(t, err)
	assert.NotNil(t, program)
}

// TestCompileAndCacheProgram_ComplexExpression tests compiling complex expression
func TestCompileAndCacheProgram_ComplexExpression(t *testing.T) {
	ctx := context.Background()
	logger := NewMockLogger()
	store, err := NewLocalGovernanceStore(ctx, logger, nil, &configstore.GovernanceConfig{}, nil)
	require.NoError(t, err)

	rule := &configstoreTables.TableRoutingRule{
		ID:            "1",
		Name:          "Complex Rule",
		CelExpression: "model == 'gpt-4o' && team_name == 'premium' && tokens_used >= 80.0",
		Targets: []configstoreTables.TableRoutingTarget{
			{Provider: bifrost.Ptr("openai"), Weight: 1.0},
		},
		Enabled: true,
	}

	program, err := store.GetRoutingProgram(context.Background(), rule)
	require.NoError(t, err)
	assert.NotNil(t, program)
}

// TestValidateCELExpression_Valid tests validating valid expressions
func TestValidateCELExpression_Valid(t *testing.T) {
	tests := []string{
		"model == 'gpt-4o'",
		"model in ['gpt-4o', 'gpt-4-turbo']",
		"model.matches('^gpt.*')",
		"headers['x-tier'] == 'premium'",
		"rate_limit['openai'].percent_used >= 80",
		"!budget['openai'].is_exhausted",
		"true",
		"false",
		"",
	}

	for _, expr := range tests {
		err := routing.ValidateCELExpression(expr)
		assert.NoError(t, err, "expression should be valid: %s", expr)
	}
}

// TestValidateCELExpression_Invalid tests validating invalid expressions
func TestValidateCELExpression_Invalid(t *testing.T) {
	tests := []string{
		"somevariable", // No operator
		"model",        // No operator
		"gpt-4o",       // No operator
	}

	for _, expr := range tests {
		err := routing.ValidateCELExpression(expr)
		assert.Error(t, err, "expression should be invalid: %s", expr)
	}
}

// TestEvaluateCELExpression_TrueResult tests evaluating expression that returns true
func TestEvaluateCELExpression_TrueResult(t *testing.T) {
	ctx := context.Background()
	logger := NewMockLogger()
	store, err := NewLocalGovernanceStore(ctx, logger, nil, &configstore.GovernanceConfig{}, nil)
	require.NoError(t, err)

	rule := &configstoreTables.TableRoutingRule{
		ID:            "1",
		CelExpression: "model == 'gpt-4o'",
		Targets: []configstoreTables.TableRoutingTarget{
			{Provider: bifrost.Ptr("openai"), Weight: 1.0},
		},
		Enabled: true,
	}

	program, err := store.GetRoutingProgram(context.Background(), rule)
	require.NoError(t, err)

	variables := map[string]interface{}{
		"model":    "gpt-4o",
		"provider": "openai",
		"headers":  map[string]string{},
		"params":   map[string]string{},
	}

	result, err := evaluateCELExpression(program, variables)
	require.NoError(t, err)
	assert.True(t, result)
}

// TestEvaluateCELExpression_FalseResult tests evaluating expression that returns false
func TestEvaluateCELExpression_FalseResult(t *testing.T) {
	ctx := context.Background()
	logger := NewMockLogger()
	store, err := NewLocalGovernanceStore(ctx, logger, nil, &configstore.GovernanceConfig{}, nil)
	require.NoError(t, err)

	rule := &configstoreTables.TableRoutingRule{
		ID:            "1",
		CelExpression: "model == 'gpt-4o'",
		Targets: []configstoreTables.TableRoutingTarget{
			{Provider: bifrost.Ptr("openai"), Weight: 1.0},
		},
		Enabled: true,
	}

	program, err := store.GetRoutingProgram(context.Background(), rule)
	require.NoError(t, err)

	variables := map[string]interface{}{
		"model":    "gpt-4-turbo",
		"provider": "openai",
		"headers":  map[string]string{},
		"params":   map[string]string{},
	}

	result, err := evaluateCELExpression(program, variables)
	require.NoError(t, err)
	assert.False(t, result)
}

// TestEvaluateCELExpression_ListMembership tests list membership evaluation
func TestEvaluateCELExpression_ListMembership(t *testing.T) {
	ctx := context.Background()
	logger := NewMockLogger()
	store, err := NewLocalGovernanceStore(ctx, logger, nil, &configstore.GovernanceConfig{}, nil)
	require.NoError(t, err)

	rule := &configstoreTables.TableRoutingRule{
		ID:            "1",
		CelExpression: "model in ['gpt-4o', 'gpt-4-turbo']",
		Targets: []configstoreTables.TableRoutingTarget{
			{Provider: bifrost.Ptr("openai"), Weight: 1.0},
		},
		Enabled: true,
	}

	program, err := store.GetRoutingProgram(context.Background(), rule)
	require.NoError(t, err)

	// Test: model in list
	variables := map[string]interface{}{
		"model":    "gpt-4o",
		"provider": "openai",
		"headers":  map[string]string{},
		"params":   map[string]string{},
	}

	result, err := evaluateCELExpression(program, variables)
	require.NoError(t, err)
	assert.True(t, result)

	// Test: model not in list
	variables["model"] = "claude-3"
	result, err = evaluateCELExpression(program, variables)
	require.NoError(t, err)
	assert.False(t, result)
}

// TestEvaluateCELExpression_HeaderAccess tests accessing headers
func TestEvaluateCELExpression_HeaderAccess(t *testing.T) {
	ctx := context.Background()
	logger := NewMockLogger()
	store, err := NewLocalGovernanceStore(ctx, logger, nil, &configstore.GovernanceConfig{}, nil)
	require.NoError(t, err)

	rule := &configstoreTables.TableRoutingRule{
		ID:            "1",
		CelExpression: "headers['x-tier'] == 'premium'",
		Targets: []configstoreTables.TableRoutingTarget{
			{Provider: bifrost.Ptr("openai"), Weight: 1.0},
		},
		Enabled: true,
	}

	program, err := store.GetRoutingProgram(context.Background(), rule)
	require.NoError(t, err)

	variables := map[string]interface{}{
		"model":    "gpt-4o",
		"provider": "openai",
		"headers": map[string]string{
			"x-tier": "premium",
		},
		"params": map[string]string{},
	}

	result, err := evaluateCELExpression(program, variables)
	require.NoError(t, err)
	assert.True(t, result)
}

// TestEvaluateCELExpression_NilProgram tests evaluating nil program
func TestEvaluateCELExpression_NilProgram(t *testing.T) {
	_, err := evaluateCELExpression(nil, map[string]interface{}{})
	assert.Error(t, err)
	assert.Contains(t, err.Error(), "nil")
}

// TestCreateCELEnvironment tests creating CEL environment
func TestCreateCELEnvironment(t *testing.T) {
	env, err := cel.NewEnv(
		cel.Variable("model", cel.StringType),
		cel.Variable("provider", cel.StringType),
		cel.Variable("headers", cel.MapType(cel.StringType, cel.StringType)),
		cel.Variable("params", cel.MapType(cel.StringType, cel.StringType)),
		cel.Variable("virtual_key_id", cel.StringType),
		cel.Variable("virtual_key_name", cel.StringType),
		cel.Variable("team_id", cel.StringType),
		cel.Variable("team_name", cel.StringType),
		cel.Variable("customer_id", cel.StringType),
		cel.Variable("customer_name", cel.StringType),
		cel.Variable("rate_limit", cel.MapType(cel.StringType, cel.AnyType)),
		cel.Variable("budget", cel.MapType(cel.StringType, cel.AnyType)),
	)
	require.NoError(t, err)
	require.NotNil(t, env)
}

// TestExtractRoutingVariables_BasicContext tests extracting variables from basic context
func TestExtractRoutingVariables_BasicContext(t *testing.T) {
	ctx := &RoutingContext{
		Provider:    schemas.OpenAI,
		Model:       "gpt-4o",
		Headers:     map[string]string{"x-tier": "premium"},
		QueryParams: map[string]string{"key": "value"},
	}

	variables, err := extractRoutingVariables(ctx)
	require.NoError(t, err)

	assert.Equal(t, "gpt-4o", variables["model"])
	assert.Equal(t, "openai", variables["provider"])
	assert.Equal(t, map[string]string{"x-tier": "premium"}, variables["headers"])
	assert.Equal(t, map[string]string{"key": "value"}, variables["params"])
}

// TestExtractRoutingVariables_WithVirtualKey tests extracting with VirtualKey context
func TestExtractRoutingVariables_WithVirtualKey(t *testing.T) {
	vk := &configstoreTables.TableVirtualKey{
		ID:   "vk-123",
		Name: "test-vk",
	}

	ctx := &RoutingContext{
		VirtualKey: vk,
		Provider:   schemas.OpenAI,
		Model:      "gpt-4o",
	}

	variables, err := extractRoutingVariables(ctx)
	require.NoError(t, err)

	assert.Equal(t, "vk-123", variables["virtual_key_id"])
	assert.Equal(t, "test-vk", variables["virtual_key_name"])
	assert.Equal(t, "", variables["team_id"])
	assert.Equal(t, "", variables["team_name"])
}

// TestExtractRoutingVariables_WithTeam tests extracting with Team context
func TestExtractRoutingVariables_WithTeam(t *testing.T) {
	team := &configstoreTables.TableTeam{
		ID:   "team-456",
		Name: "premium-team",
	}

	vk := &configstoreTables.TableVirtualKey{
		ID:   "vk-123",
		Name: "test-vk",
		Team: team,
	}

	ctx := &RoutingContext{
		VirtualKey: vk,
		Provider:   schemas.OpenAI,
		Model:      "gpt-4o",
	}

	variables, err := extractRoutingVariables(ctx)
	require.NoError(t, err)

	assert.Equal(t, "vk-123", variables["virtual_key_id"])
	assert.Equal(t, "team-456", variables["team_id"])
	assert.Equal(t, "premium-team", variables["team_name"])
}

// TestExtractRoutingVariables_WithCustomer tests extracting with Customer context
func TestExtractRoutingVariables_WithCustomer(t *testing.T) {
	customer := &configstoreTables.TableCustomer{
		ID:   "cust-789",
		Name: "acme-corp",
	}

	team := &configstoreTables.TableTeam{
		ID:       "team-456",
		Name:     "premium-team",
		Customer: customer,
	}

	vk := &configstoreTables.TableVirtualKey{
		ID:   "vk-123",
		Name: "test-vk",
		Team: team,
	}

	ctx := &RoutingContext{
		VirtualKey: vk,
		Provider:   schemas.OpenAI,
		Model:      "gpt-4o",
	}

	variables, err := extractRoutingVariables(ctx)
	require.NoError(t, err)

	assert.Equal(t, "cust-789", variables["customer_id"])
	assert.Equal(t, "acme-corp", variables["customer_name"])
}

// TestExtractRoutingVariables_WithRateLimits tests extracting with rate limit data
func TestExtractRoutingVariables_WithRateLimits(t *testing.T) {
	ctx := &RoutingContext{
		Provider: schemas.OpenAI,
		Model:    "gpt-4o",
		BudgetAndRateLimitStatus: &BudgetAndRateLimitStatus{
			BudgetPercentUsed:           75.5,
			RateLimitTokenPercentUsed:   75.5,
			RateLimitRequestPercentUsed: 75.5,
		},
	}

	variables, err := extractRoutingVariables(ctx)
	require.NoError(t, err)

	// Variables should contain budget and rate limit percentages
	assert.Equal(t, 75.5, variables["budget_used"])
	assert.Equal(t, 75.5, variables["tokens_used"])
	assert.Equal(t, 75.5, variables["request"])
}

// TestExtractRoutingVariables_WithBudgets tests extracting with budget data
func TestExtractRoutingVariables_WithBudgets(t *testing.T) {
	ctx := &RoutingContext{
		Provider: schemas.OpenAI,
		Model:    "gpt-4o",
		BudgetAndRateLimitStatus: &BudgetAndRateLimitStatus{
			BudgetPercentUsed:           45.0,
			RateLimitTokenPercentUsed:   45.0,
			RateLimitRequestPercentUsed: 45.0,
		},
	}

	variables, err := extractRoutingVariables(ctx)
	require.NoError(t, err)

	// Variables should contain budget percentage
	assert.Equal(t, 45.0, variables["budget_used"])
}

// TestExtractRoutingVariables_NilContext tests with nil context
func TestExtractRoutingVariables_NilContext(t *testing.T) {
	_, err := extractRoutingVariables(nil)
	assert.Error(t, err)
	assert.Contains(t, err.Error(), "cannot be nil")
}

// TestExtractRoutingVariables_NilMaps tests with nil maps in context
func TestExtractRoutingVariables_NilMaps(t *testing.T) {
	ctx := &RoutingContext{
		Provider:                 schemas.OpenAI,
		Model:                    "gpt-4o",
		Headers:                  nil,
		QueryParams:              nil,
		BudgetAndRateLimitStatus: nil,
	}

	variables, err := extractRoutingVariables(ctx)
	require.NoError(t, err)

	assert.NotNil(t, variables["headers"])
	assert.NotNil(t, variables["params"])

	// Headers and params should be empty maps
	assert.Equal(t, 0, len(variables["headers"].(map[string]string)))
	assert.Equal(t, 0, len(variables["params"].(map[string]string)))

	// Budget and rate limit defaults should be 0.0
	assert.Equal(t, 0.0, variables["budget_used"])
	assert.Equal(t, 0.0, variables["tokens_used"])
	assert.Equal(t, 0.0, variables["request"])
}

// TestExtractRoutingVariables_MultipleProviders tests with multiple rate limits
func TestExtractRoutingVariables_MultipleProviders(t *testing.T) {
	ctx := &RoutingContext{
		Provider: schemas.OpenAI,
		Model:    "gpt-4o",
		BudgetAndRateLimitStatus: &BudgetAndRateLimitStatus{
			BudgetPercentUsed:           25.0,
			RateLimitTokenPercentUsed:   25.0,
			RateLimitRequestPercentUsed: 25.0,
		},
	}

	variables, err := extractRoutingVariables(ctx)
	require.NoError(t, err)

	// Should contain budget and rate limit percentages
	assert.Equal(t, 25.0, variables["budget_used"])
	assert.Equal(t, 25.0, variables["tokens_used"])
	assert.Equal(t, 25.0, variables["request"])
}

// TestBuildRoutingContext tests the convenience builder function
func TestBuildRoutingContext(t *testing.T) {
	vk := &configstoreTables.TableVirtualKey{
		ID:   "vk-123",
		Name: "test-vk",
	}

	headers := map[string]string{"x-tier": "premium"}
	params := map[string]string{"org": "test"}

	ctx := &RoutingContext{
		VirtualKey:               vk,
		Provider:                 schemas.OpenAI,
		Model:                    "gpt-4o",
		Headers:                  headers,
		QueryParams:              params,
		BudgetAndRateLimitStatus: &BudgetAndRateLimitStatus{},
	}

	assert.Equal(t, vk, ctx.VirtualKey)
	assert.Equal(t, schemas.OpenAI, ctx.Provider)
	assert.Equal(t, "gpt-4o", ctx.Model)
	assert.Equal(t, headers, ctx.Headers)
	assert.Equal(t, params, ctx.QueryParams)
}

// TestExtractRoutingVariables_ComplexHierarchy tests full organizational hierarchy
func TestExtractRoutingVariables_ComplexHierarchy(t *testing.T) {
	customer := &configstoreTables.TableCustomer{
		ID:   "cust-789",
		Name: "acme-corp",
	}

	team := &configstoreTables.TableTeam{
		ID:       "team-456",
		Name:     "premium-team",
		Customer: customer,
	}

	vk := &configstoreTables.TableVirtualKey{
		ID:   "vk-123",
		Name: "test-vk",
		Team: team,
	}

	ctx := &RoutingContext{
		VirtualKey:  vk,
		Provider:    schemas.OpenAI,
		Model:       "gpt-4o",
		Headers:     map[string]string{"X-Tier": "premium", "X-Org": "acme"},
		QueryParams: map[string]string{"Region": "us-east-1"},
		BudgetAndRateLimitStatus: &BudgetAndRateLimitStatus{
			BudgetPercentUsed:           60.0,
			RateLimitTokenPercentUsed:   60.0,
			RateLimitRequestPercentUsed: 60.0,
		},
	}

	variables, err := extractRoutingVariables(ctx)
	require.NoError(t, err)

	// Verify all hierarchy levels
	assert.Equal(t, "vk-123", variables["virtual_key_id"])
	assert.Equal(t, "test-vk", variables["virtual_key_name"])
	assert.Equal(t, "team-456", variables["team_id"])
	assert.Equal(t, "premium-team", variables["team_name"])
	assert.Equal(t, "cust-789", variables["customer_id"])
	assert.Equal(t, "acme-corp", variables["customer_name"])

	// Verify request context
	assert.Equal(t, "gpt-4o", variables["model"])
	assert.Equal(t, "openai", variables["provider"])

	// Verify dynamic data
	headers := variables["headers"].(map[string]string)
	assert.Equal(t, "premium", headers["x-tier"])
	assert.Equal(t, "acme", headers["x-org"])

	params := variables["params"].(map[string]string)
	assert.Equal(t, "us-east-1", params["region"])

	// Verify capacity metrics
	assert.Equal(t, 60.0, variables["budget_used"])
	assert.Equal(t, 60.0, variables["tokens_used"])
	assert.Equal(t, 60.0, variables["request"])
}

func TestNormalizeMapKeysInCEL(t *testing.T) {
	tests := []struct {
		name     string
		input    string
		expected string
	}{
		// Header bracket access
		{
			name:     "header double quotes uppercase",
			input:    `headers["X-Api-Key"] == "secret"`,
			expected: `headers["x-api-key"] == "secret"`,
		},
		{
			name:     "header single quotes uppercase",
			input:    `headers['X-Api-Key'] == 'secret'`,
			expected: `headers['x-api-key'] == 'secret'`,
		},
		{
			name:     "header mixed case with other conditions",
			input:    `model == "gpt-4o" && headers["X-Tier"] == "premium"`,
			expected: `model == "gpt-4o" && headers["x-tier"] == "premium"`,
		},
		{
			name:     "header already lowercase",
			input:    `headers["x-tier"] == "premium"`,
			expected: `headers["x-tier"] == "premium"`,
		},
		{
			name:     "multiple header accesses",
			input:    `headers["X-Org"] == "acme" && headers["X-Tier"] == "premium"`,
			expected: `headers["x-org"] == "acme" && headers["x-tier"] == "premium"`,
		},
		{
			name:     "no headers or params",
			input:    `model == "gpt-4o"`,
			expected: `model == "gpt-4o"`,
		},
		// Header "in" operator
		{
			name:     "header in operator with double quotes",
			input:    `"X-Test" in headers`,
			expected: `"x-test" in headers`,
		},
		{
			name:     "header in operator with single quotes",
			input:    `'X-Api-Key' in headers`,
			expected: `'x-api-key' in headers`,
		},
		{
			name:     "header negated in operator",
			input:    `!("X-Test" in headers)`,
			expected: `!("x-test" in headers)`,
		},
		{
			name:     "header in operator combined with bracket access",
			input:    `"X-Tier" in headers && headers["X-Tier"] == "premium"`,
			expected: `"x-tier" in headers && headers["x-tier"] == "premium"`,
		},
		// Param bracket access
		{
			name:     "param double quotes uppercase",
			input:    `params["Region"] == "us-east-1"`,
			expected: `params["region"] == "us-east-1"`,
		},
		{
			name:     "param single quotes uppercase",
			input:    `params['Region'] == 'us-east-1'`,
			expected: `params['region'] == 'us-east-1'`,
		},
		{
			name:     "param already lowercase",
			input:    `params["region"] == "us-east-1"`,
			expected: `params["region"] == "us-east-1"`,
		},
		{
			name:     "multiple param accesses",
			input:    `params["Region"] == "us-east-1" && params["Env"] == "prod"`,
			expected: `params["region"] == "us-east-1" && params["env"] == "prod"`,
		},
		// Param "in" operator
		{
			name:     "param in operator with double quotes",
			input:    `"Region" in params`,
			expected: `"region" in params`,
		},
		{
			name:     "param in operator with single quotes",
			input:    `'Region' in params`,
			expected: `'region' in params`,
		},
		{
			name:     "param negated in operator",
			input:    `!("Region" in params)`,
			expected: `!("region" in params)`,
		},
		{
			name:     "param in operator combined with bracket access",
			input:    `"Region" in params && params["Region"] == "us-east-1"`,
			expected: `"region" in params && params["region"] == "us-east-1"`,
		},
		// Mixed headers and params
		{
			name:     "mixed headers and params",
			input:    `"X-Tier" in headers && headers["X-Tier"] == "premium" && params["Region"] == "us-east-1"`,
			expected: `"x-tier" in headers && headers["x-tier"] == "premium" && params["region"] == "us-east-1"`,
		},
		{
			name:     "mixed in operators for headers and params",
			input:    `"X-Test" in headers && "Region" in params`,
			expected: `"x-test" in headers && "region" in params`,
		},
	}

	for _, tt := range tests {
		t.Run(tt.name, func(t *testing.T) {
			result := routing.NormalizeMapKeysInCEL(tt.input)
			assert.Equal(t, tt.expected, result)
		})
	}
}

// resolveRoutingWithFallback evaluates routing rules and returns decision with fallback chain
// If primary rule doesn't match, attempts fallback providers in order
func resolveRoutingWithFallback(
	ctx *schemas.BifrostContext,
	routingCtx *RoutingContext,
	engine *RoutingEngine,
) (*RoutingDecision, error) {
	if routingCtx == nil {
		return nil, fmt.Errorf("routing context cannot be nil")
	}

	// Evaluate routing rules for primary decision
	decision, err := engine.EvaluateRoutingRules(ctx, routingCtx)
	if err != nil {
		return nil, err
	}

	// If a rule matched, return the decision
	if decision != nil {
		return decision, nil
	}

	// No rule matched - use default routing
	decision = getDefaultRouting(routingCtx)
	if decision == nil {
		return nil, fmt.Errorf("failed to create default routing decision")
	}

	return decision, nil
}

// applyRoutingDecision applies a routing decision by modifying the routing context
// Returns updated context with new provider/model/fallbacks
func applyRoutingDecision(ctx *RoutingContext, decision *RoutingDecision) *RoutingContext {
	if ctx == nil || decision == nil {
		return ctx
	}

	// Create a copy of the context
	updated := *ctx

	// Apply routing decision
	updated.Provider = schemas.ModelProvider(decision.Provider)
	updated.Model = decision.Model

	return &updated
}

// validateRoutingDecision validates that a routing decision has required fields
func validateRoutingDecision(decision *RoutingDecision) error {
	if decision == nil {
		return fmt.Errorf("routing decision cannot be nil")
	}

	if decision.Provider == "" {
		return fmt.Errorf("routing decision provider cannot be empty")
	}

	if decision.Model == "" {
		return fmt.Errorf("routing decision model cannot be empty")
	}

	return nil
}

// getDefaultRouting returns a default routing decision using provider/model from context
// Used when no routing rule matches
func getDefaultRouting(ctx *RoutingContext) *RoutingDecision {
	if ctx == nil {
		return nil
	}

	return &RoutingDecision{
		Provider:      string(ctx.Provider),
		Model:         ctx.Model,
		Fallbacks:     ctx.Fallbacks,
		MatchedRuleID: "0",
	}
}