package auth

import (
	"context"
	"encoding/json"
	"errors"
	"fmt"
	"net/http"
	"strings"
	"sync"
	"testing"
	"time"

	cliproxyexecutor "github.com/router-for-me/CLIProxyAPI/v7/sdk/cliproxy/executor"
)

func TestFillFirstSelectorPick_Deterministic(t *testing.T) {
	t.Parallel()

	selector := &FillFirstSelector{}
	auths := []*Auth{
		{ID: "b"},
		{ID: "a"},
		{ID: "c"},
	}

	got, err := selector.Pick(context.Background(), "gemini", "", cliproxyexecutor.Options{}, auths)
	if err != nil {
		t.Fatalf("Pick() error = %v", err)
	}
	if got == nil {
		t.Fatalf("Pick() auth = nil")
	}
	if got.ID != "a" {
		t.Fatalf("Pick() auth.ID = %q, want %q", got.ID, "a")
	}
}

func TestRoundRobinSelectorPick_CyclesDeterministic(t *testing.T) {
	t.Parallel()

	selector := &RoundRobinSelector{}
	auths := []*Auth{
		{ID: "b"},
		{ID: "a"},
		{ID: "c"},
	}

	want := []string{"a", "b", "c", "a", "b"}
	for i, id := range want {
		got, err := selector.Pick(context.Background(), "gemini", "", cliproxyexecutor.Options{}, auths)
		if err != nil {
			t.Fatalf("Pick() #%d error = %v", i, err)
		}
		if got == nil {
			t.Fatalf("Pick() #%d auth = nil", i)
		}
		if got.ID != id {
			t.Fatalf("Pick() #%d auth.ID = %q, want %q", i, got.ID, id)
		}
	}
}

func TestRoundRobinSelectorPick_PriorityBuckets(t *testing.T) {
	t.Parallel()

	selector := &RoundRobinSelector{}
	auths := []*Auth{
		{ID: "c", Attributes: map[string]string{"priority": "0"}},
		{ID: "a", Attributes: map[string]string{"priority": "10"}},
		{ID: "b", Attributes: map[string]string{"priority": "10"}},
	}

	want := []string{"a", "b", "a", "b"}
	for i, id := range want {
		got, err := selector.Pick(context.Background(), "mixed", "", cliproxyexecutor.Options{}, auths)
		if err != nil {
			t.Fatalf("Pick() #%d error = %v", i, err)
		}
		if got == nil {
			t.Fatalf("Pick() #%d auth = nil", i)
		}
		if got.ID != id {
			t.Fatalf("Pick() #%d auth.ID = %q, want %q", i, got.ID, id)
		}
		if got.ID == "c" {
			t.Fatalf("Pick() #%d unexpectedly selected lower priority auth", i)
		}
	}
}

func TestFillFirstSelectorPick_PriorityFallbackCooldown(t *testing.T) {
	t.Parallel()

	selector := &FillFirstSelector{}
	now := time.Now()
	model := "test-model"

	high := &Auth{
		ID:         "high",
		Attributes: map[string]string{"priority": "10"},
		ModelStates: map[string]*ModelState{
			model: {
				Status:         StatusActive,
				Unavailable:    true,
				NextRetryAfter: now.Add(30 * time.Minute),
				Quota: QuotaState{
					Exceeded: true,
				},
			},
		},
	}
	low := &Auth{ID: "low", Attributes: map[string]string{"priority": "0"}}

	got, err := selector.Pick(context.Background(), "mixed", model, cliproxyexecutor.Options{}, []*Auth{high, low})
	if err != nil {
		t.Fatalf("Pick() error = %v", err)
	}
	if got == nil {
		t.Fatalf("Pick() auth = nil")
	}
	if got.ID != "low" {
		t.Fatalf("Pick() auth.ID = %q, want %q", got.ID, "low")
	}
}

func TestRoundRobinSelectorPick_Concurrent(t *testing.T) {
	selector := &RoundRobinSelector{}
	auths := []*Auth{
		{ID: "b"},
		{ID: "a"},
		{ID: "c"},
	}

	start := make(chan struct{})
	var wg sync.WaitGroup
	errCh := make(chan error, 1)

	goroutines := 32
	iterations := 100
	for i := 0; i < goroutines; i++ {
		wg.Add(1)
		go func() {
			defer wg.Done()
			<-start
			for j := 0; j < iterations; j++ {
				got, err := selector.Pick(context.Background(), "gemini", "", cliproxyexecutor.Options{}, auths)
				if err != nil {
					select {
					case errCh <- err:
					default:
					}
					return
				}
				if got == nil {
					select {
					case errCh <- errors.New("Pick() returned nil auth"):
					default:
					}
					return
				}
				if got.ID == "" {
					select {
					case errCh <- errors.New("Pick() returned auth with empty ID"):
					default:
					}
					return
				}
			}
		}()
	}

	close(start)
	wg.Wait()

	select {
	case err := <-errCh:
		t.Fatalf("concurrent Pick() error = %v", err)
	default:
	}
}

func TestSelectorPick_AllCooldownReturnsModelCooldownError(t *testing.T) {
	t.Parallel()

	model := "test-model"
	now := time.Now()
	next := now.Add(60 * time.Second)
	auths := []*Auth{
		{
			ID: "a",
			ModelStates: map[string]*ModelState{
				model: {
					Status:         StatusActive,
					Unavailable:    true,
					NextRetryAfter: next,
					Quota: QuotaState{
						Exceeded:      true,
						NextRecoverAt: next,
					},
				},
			},
		},
		{
			ID: "b",
			ModelStates: map[string]*ModelState{
				model: {
					Status:         StatusActive,
					Unavailable:    true,
					NextRetryAfter: next,
					Quota: QuotaState{
						Exceeded:      true,
						NextRecoverAt: next,
					},
				},
			},
		},
	}

	t.Run("mixed provider redacts provider field", func(t *testing.T) {
		t.Parallel()

		selector := &FillFirstSelector{}
		_, err := selector.Pick(context.Background(), "mixed", model, cliproxyexecutor.Options{}, auths)
		if err == nil {
			t.Fatalf("Pick() error = nil")
		}

		var mce *modelCooldownError
		if !errors.As(err, &mce) {
			t.Fatalf("Pick() error = %T, want *modelCooldownError", err)
		}
		if mce.StatusCode() != http.StatusTooManyRequests {
			t.Fatalf("StatusCode() = %d, want %d", mce.StatusCode(), http.StatusTooManyRequests)
		}

		headers := mce.Headers()
		if got := headers.Get("Retry-After"); got == "" {
			t.Fatalf("Headers().Get(Retry-After) = empty")
		}

		var payload map[string]any
		if err := json.Unmarshal([]byte(mce.Error()), &payload); err != nil {
			t.Fatalf("json.Unmarshal(Error()) error = %v", err)
		}
		rawErr, ok := payload["error"].(map[string]any)
		if !ok {
			t.Fatalf("Error() payload missing error object: %v", payload)
		}
		if got, _ := rawErr["code"].(string); got != "model_cooldown" {
			t.Fatalf("Error().error.code = %q, want %q", got, "model_cooldown")
		}
		if _, ok := rawErr["provider"]; ok {
			t.Fatalf("Error().error.provider exists for mixed provider: %v", rawErr["provider"])
		}
	})

	t.Run("non-mixed provider includes provider field", func(t *testing.T) {
		t.Parallel()

		selector := &FillFirstSelector{}
		_, err := selector.Pick(context.Background(), "gemini", model, cliproxyexecutor.Options{}, auths)
		if err == nil {
			t.Fatalf("Pick() error = nil")
		}

		var mce *modelCooldownError
		if !errors.As(err, &mce) {
			t.Fatalf("Pick() error = %T, want *modelCooldownError", err)
		}

		var payload map[string]any
		if err := json.Unmarshal([]byte(mce.Error()), &payload); err != nil {
			t.Fatalf("json.Unmarshal(Error()) error = %v", err)
		}
		rawErr, ok := payload["error"].(map[string]any)
		if !ok {
			t.Fatalf("Error() payload missing error object: %v", payload)
		}
		if got, _ := rawErr["provider"].(string); got != "gemini" {
			t.Fatalf("Error().error.provider = %q, want %q", got, "gemini")
		}
	})
}

func TestIsAuthBlockedForModel_UnavailableWithoutNextRetryIsNotBlocked(t *testing.T) {
	t.Parallel()

	now := time.Now()
	model := "test-model"
	auth := &Auth{
		ID: "a",
		ModelStates: map[string]*ModelState{
			model: {
				Status:      StatusActive,
				Unavailable: true,
				Quota: QuotaState{
					Exceeded: true,
				},
			},
		},
	}

	blocked, reason, next := isAuthBlockedForModel(auth, model, now)
	if blocked {
		t.Fatalf("blocked = true, want false")
	}
	if reason != blockReasonNone {
		t.Fatalf("reason = %v, want %v", reason, blockReasonNone)
	}
	if !next.IsZero() {
		t.Fatalf("next = %v, want zero", next)
	}
}

func TestFillFirstSelectorPick_ThinkingSuffixFallsBackToBaseModelState(t *testing.T) {
	t.Parallel()

	selector := &FillFirstSelector{}
	now := time.Now()

	baseModel := "test-model"
	requestedModel := "test-model(high)"

	high := &Auth{
		ID:         "high",
		Attributes: map[string]string{"priority": "10"},
		ModelStates: map[string]*ModelState{
			baseModel: {
				Status:         StatusActive,
				Unavailable:    true,
				NextRetryAfter: now.Add(30 * time.Minute),
				Quota: QuotaState{
					Exceeded: true,
				},
			},
		},
	}
	low := &Auth{
		ID:         "low",
		Attributes: map[string]string{"priority": "0"},
	}

	got, err := selector.Pick(context.Background(), "mixed", requestedModel, cliproxyexecutor.Options{}, []*Auth{high, low})
	if err != nil {
		t.Fatalf("Pick() error = %v", err)
	}
	if got == nil {
		t.Fatalf("Pick() auth = nil")
	}
	if got.ID != "low" {
		t.Fatalf("Pick() auth.ID = %q, want %q", got.ID, "low")
	}
}

func TestRoundRobinSelectorPick_ThinkingSuffixSharesCursor(t *testing.T) {
	t.Parallel()

	selector := &RoundRobinSelector{}
	auths := []*Auth{
		{ID: "b"},
		{ID: "a"},
	}

	first, err := selector.Pick(context.Background(), "gemini", "test-model(high)", cliproxyexecutor.Options{}, auths)
	if err != nil {
		t.Fatalf("Pick() first error = %v", err)
	}
	second, err := selector.Pick(context.Background(), "gemini", "test-model(low)", cliproxyexecutor.Options{}, auths)
	if err != nil {
		t.Fatalf("Pick() second error = %v", err)
	}
	if first == nil || second == nil {
		t.Fatalf("Pick() returned nil auth")
	}
	if first.ID != "a" {
		t.Fatalf("Pick() first auth.ID = %q, want %q", first.ID, "a")
	}
	if second.ID != "b" {
		t.Fatalf("Pick() second auth.ID = %q, want %q", second.ID, "b")
	}
}

func TestRoundRobinSelectorPick_CursorKeyCap(t *testing.T) {
	t.Parallel()

	selector := &RoundRobinSelector{maxKeys: 2}
	auths := []*Auth{{ID: "a"}}

	_, _ = selector.Pick(context.Background(), "gemini", "m1", cliproxyexecutor.Options{}, auths)
	_, _ = selector.Pick(context.Background(), "gemini", "m2", cliproxyexecutor.Options{}, auths)
	_, _ = selector.Pick(context.Background(), "gemini", "m3", cliproxyexecutor.Options{}, auths)

	selector.mu.Lock()
	defer selector.mu.Unlock()

	if selector.cursors == nil {
		t.Fatalf("selector.cursors = nil")
	}
	if len(selector.cursors) != 1 {
		t.Fatalf("len(selector.cursors) = %d, want %d", len(selector.cursors), 1)
	}
	if _, ok := selector.cursors["gemini:m3"]; !ok {
		t.Fatalf("selector.cursors missing key %q", "gemini:m3")
	}
}

func TestRoundRobinSelectorPick_GeminiCLICredentialGrouping(t *testing.T) {
	t.Parallel()

	selector := &RoundRobinSelector{}

	// Simulate two gemini-cli credentials, each with multiple projects:
	// Credential A (parent = "cred-a.json") has 3 projects
	// Credential B (parent = "cred-b.json") has 2 projects
	auths := []*Auth{
		{ID: "cred-a.json::proj-a1", Attributes: map[string]string{"gemini_virtual_parent": "cred-a.json"}},
		{ID: "cred-a.json::proj-a2", Attributes: map[string]string{"gemini_virtual_parent": "cred-a.json"}},
		{ID: "cred-a.json::proj-a3", Attributes: map[string]string{"gemini_virtual_parent": "cred-a.json"}},
		{ID: "cred-b.json::proj-b1", Attributes: map[string]string{"gemini_virtual_parent": "cred-b.json"}},
		{ID: "cred-b.json::proj-b2", Attributes: map[string]string{"gemini_virtual_parent": "cred-b.json"}},
	}

	// Two-level round-robin: consecutive picks must alternate between credentials.
	// Credential group order is randomized, but within each call the group cursor
	// advances by 1, so consecutive picks should cycle through different parents.
	picks := make([]string, 6)
	parents := make([]string, 6)
	for i := 0; i < 6; i++ {
		got, err := selector.Pick(context.Background(), "gemini-cli", "gemini-2.5-pro", cliproxyexecutor.Options{}, auths)
		if err != nil {
			t.Fatalf("Pick() #%d error = %v", i, err)
		}
		if got == nil {
			t.Fatalf("Pick() #%d auth = nil", i)
		}
		picks[i] = got.ID
		parents[i] = got.Attributes["gemini_virtual_parent"]
	}

	// Verify property: consecutive picks must alternate between credential groups.
	for i := 1; i < len(parents); i++ {
		if parents[i] == parents[i-1] {
			t.Fatalf("Pick() #%d and #%d both from same parent %q (IDs: %q, %q); expected alternating credentials",
				i-1, i, parents[i], picks[i-1], picks[i])
		}
	}

	// Verify property: each credential's projects are picked in sequence (round-robin within group).
	credPicks := map[string][]string{}
	for i, id := range picks {
		credPicks[parents[i]] = append(credPicks[parents[i]], id)
	}
	for parent, ids := range credPicks {
		for i := 1; i < len(ids); i++ {
			if ids[i] == ids[i-1] {
				t.Fatalf("Credential %q picked same project %q twice in a row", parent, ids[i])
			}
		}
	}
}

func TestExtractSessionID(t *testing.T) {
	t.Parallel()

	tests := []struct {
		name    string
		payload string
		want    string
	}{
		{
			name:    "valid_claude_code_format",
			payload: `{"metadata":{"user_id":"user_3f221fe75652cf9a89a31647f16274bb8036a9b85ac4dc226a4df0efec8dc04d_account__session_ac980658-63bd-4fb3-97ba-8da64cb1e344"}}`,
			want:    "claude:ac980658-63bd-4fb3-97ba-8da64cb1e344",
		},
		{
			name:    "json_user_id_with_session_id",
			payload: `{"metadata":{"user_id":"{\"device_id\":\"be82c3aee1e0c2d74535bacc85f9f559228f02dd8a17298cf522b71e6c375714\",\"account_uuid\":\"\",\"session_id\":\"e26d4046-0f88-4b09-bb5b-f863ab5fb24e\"}"}}`,
			want:    "claude:e26d4046-0f88-4b09-bb5b-f863ab5fb24e",
		},
		{
			name:    "json_user_id_without_session_id",
			payload: `{"metadata":{"user_id":"{\"device_id\":\"abc123\"}"}}`,
			want:    `user:{"device_id":"abc123"}`,
		},
		{
			name:    "no_session_but_user_id",
			payload: `{"metadata":{"user_id":"user_abc123"}}`,
			want:    "user:user_abc123",
		},
		{
			name:    "conversation_id",
			payload: `{"conversation_id":"conv-12345"}`,
			want:    "conv:conv-12345",
		},
		{
			name:    "no_metadata",
			payload: `{"model":"claude-3"}`,
			want:    "",
		},
		{
			name:    "empty_payload",
			payload: ``,
			want:    "",
		},
	}

	for _, tt := range tests {
		t.Run(tt.name, func(t *testing.T) {
			got := extractSessionID([]byte(tt.payload))
			if got != tt.want {
				t.Errorf("extractSessionID() = %q, want %q", got, tt.want)
			}
		})
	}
}

func TestSessionAffinitySelector_SameSessionSameAuth(t *testing.T) {
	t.Parallel()

	fallback := &RoundRobinSelector{}
	selector := NewSessionAffinitySelector(fallback)

	auths := []*Auth{
		{ID: "auth-a"},
		{ID: "auth-b"},
		{ID: "auth-c"},
	}

	// Use valid UUID format for session ID
	payload := []byte(`{"metadata":{"user_id":"user_xxx_account__session_ac980658-63bd-4fb3-97ba-8da64cb1e344"}}`)
	opts := cliproxyexecutor.Options{OriginalRequest: payload}

	// Same session should always pick the same auth
	first, err := selector.Pick(context.Background(), "claude", "claude-3", opts, auths)
	if err != nil {
		t.Fatalf("Pick() error = %v", err)
	}
	if first == nil {
		t.Fatalf("Pick() returned nil")
	}

	// Verify consistency: same session, same auths -> same result
	for i := 0; i < 10; i++ {
		got, err := selector.Pick(context.Background(), "claude", "claude-3", opts, auths)
		if err != nil {
			t.Fatalf("Pick() #%d error = %v", i, err)
		}
		if got.ID != first.ID {
			t.Fatalf("Pick() #%d auth.ID = %q, want %q (same session should pick same auth)", i, got.ID, first.ID)
		}
	}
}

func TestSessionAffinitySelector_NoSessionFallback(t *testing.T) {
	t.Parallel()

	fallback := &FillFirstSelector{}
	selector := NewSessionAffinitySelector(fallback)

	auths := []*Auth{
		{ID: "auth-b"},
		{ID: "auth-a"},
		{ID: "auth-c"},
	}

	// No session in payload, should fallback to FillFirstSelector (picks "auth-a" after sorting)
	payload := []byte(`{"model":"claude-3"}`)
	opts := cliproxyexecutor.Options{OriginalRequest: payload}

	got, err := selector.Pick(context.Background(), "claude", "claude-3", opts, auths)
	if err != nil {
		t.Fatalf("Pick() error = %v", err)
	}
	if got.ID != "auth-a" {
		t.Fatalf("Pick() auth.ID = %q, want %q (should fallback to FillFirst)", got.ID, "auth-a")
	}
}

func TestSessionAffinitySelector_DifferentSessionsDifferentAuths(t *testing.T) {
	t.Parallel()

	fallback := &RoundRobinSelector{}
	selector := NewSessionAffinitySelector(fallback)

	auths := []*Auth{
		{ID: "auth-a"},
		{ID: "auth-b"},
		{ID: "auth-c"},
	}

	// Use valid UUID format for session IDs
	session1 := []byte(`{"metadata":{"user_id":"user_xxx_account__session_11111111-1111-1111-1111-111111111111"}}`)
	session2 := []byte(`{"metadata":{"user_id":"user_xxx_account__session_22222222-2222-2222-2222-222222222222"}}`)

	opts1 := cliproxyexecutor.Options{OriginalRequest: session1}
	opts2 := cliproxyexecutor.Options{OriginalRequest: session2}

	auth1, _ := selector.Pick(context.Background(), "claude", "claude-3", opts1, auths)
	auth2, _ := selector.Pick(context.Background(), "claude", "claude-3", opts2, auths)

	// Different sessions may or may not pick different auths (depends on hash collision)
	// But each session should be consistent
	for i := 0; i < 5; i++ {
		got1, _ := selector.Pick(context.Background(), "claude", "claude-3", opts1, auths)
		got2, _ := selector.Pick(context.Background(), "claude", "claude-3", opts2, auths)
		if got1.ID != auth1.ID {
			t.Fatalf("session1 Pick() #%d inconsistent: got %q, want %q", i, got1.ID, auth1.ID)
		}
		if got2.ID != auth2.ID {
			t.Fatalf("session2 Pick() #%d inconsistent: got %q, want %q", i, got2.ID, auth2.ID)
		}
	}
}

func TestRoundRobinSelectorPick_SingleParentFallsBackToFlat(t *testing.T) {
	t.Parallel()

	selector := &RoundRobinSelector{}

	// All auths from the same parent - should fall back to flat round-robin
	// because there's only one credential group (no benefit from two-level).
	auths := []*Auth{
		{ID: "cred-a.json::proj-a1", Attributes: map[string]string{"gemini_virtual_parent": "cred-a.json"}},
		{ID: "cred-a.json::proj-a2", Attributes: map[string]string{"gemini_virtual_parent": "cred-a.json"}},
		{ID: "cred-a.json::proj-a3", Attributes: map[string]string{"gemini_virtual_parent": "cred-a.json"}},
	}

	// With single parent group, parentOrder has length 1, so it uses flat round-robin.
	// Sorted by ID: proj-a1, proj-a2, proj-a3
	want := []string{
		"cred-a.json::proj-a1",
		"cred-a.json::proj-a2",
		"cred-a.json::proj-a3",
		"cred-a.json::proj-a1",
	}

	for i, expectedID := range want {
		got, err := selector.Pick(context.Background(), "gemini-cli", "gemini-2.5-pro", cliproxyexecutor.Options{}, auths)
		if err != nil {
			t.Fatalf("Pick() #%d error = %v", i, err)
		}
		if got == nil {
			t.Fatalf("Pick() #%d auth = nil", i)
		}
		if got.ID != expectedID {
			t.Fatalf("Pick() #%d auth.ID = %q, want %q", i, got.ID, expectedID)
		}
	}
}

func TestSessionAffinitySelector_FailoverWhenAuthUnavailable(t *testing.T) {
	t.Parallel()

	fallback := &RoundRobinSelector{}
	selector := NewSessionAffinitySelectorWithConfig(SessionAffinityConfig{
		Fallback: fallback,
		TTL:      time.Minute,
	})
	defer selector.Stop()

	auths := []*Auth{
		{ID: "auth-a"},
		{ID: "auth-b"},
		{ID: "auth-c"},
	}

	payload := []byte(`{"metadata":{"user_id":"user_xxx_account__session_failover-test-uuid"}}`)
	opts := cliproxyexecutor.Options{OriginalRequest: payload}

	// First pick establishes binding
	first, err := selector.Pick(context.Background(), "claude", "claude-3", opts, auths)
	if err != nil {
		t.Fatalf("Pick() error = %v", err)
	}

	// Remove the bound auth from available list (simulating rate limit)
	availableWithoutFirst := make([]*Auth, 0, len(auths)-1)
	for _, a := range auths {
		if a.ID != first.ID {
			availableWithoutFirst = append(availableWithoutFirst, a)
		}
	}

	// With failover enabled, should pick a new auth
	second, err := selector.Pick(context.Background(), "claude", "claude-3", opts, availableWithoutFirst)
	if err != nil {
		t.Fatalf("Pick() after failover error = %v", err)
	}
	if second.ID == first.ID {
		t.Fatalf("Pick() after failover returned same auth %q, expected different", first.ID)
	}

	// Subsequent picks should consistently return the new binding
	for i := 0; i < 5; i++ {
		got, _ := selector.Pick(context.Background(), "claude", "claude-3", opts, availableWithoutFirst)
		if got.ID != second.ID {
			t.Fatalf("Pick() #%d after failover inconsistent: got %q, want %q", i, got.ID, second.ID)
		}
	}
}

func TestRoundRobinSelectorPick_MixedVirtualAndNonVirtualFallsBackToFlat(t *testing.T) {
	t.Parallel()

	selector := &RoundRobinSelector{}

	// Mix of virtual and non-virtual auths (e.g., a regular gemini-cli auth without projects
	// alongside virtual ones). Should fall back to flat round-robin.
	auths := []*Auth{
		{ID: "cred-a.json::proj-a1", Attributes: map[string]string{"gemini_virtual_parent": "cred-a.json"}},
		{ID: "cred-regular.json"}, // no gemini_virtual_parent
	}

	// groupByVirtualParent returns nil when any auth lacks the attribute,
	// so flat round-robin is used. Sorted by ID: cred-a.json::proj-a1, cred-regular.json
	want := []string{
		"cred-a.json::proj-a1",
		"cred-regular.json",
		"cred-a.json::proj-a1",
	}

	for i, expectedID := range want {
		got, err := selector.Pick(context.Background(), "gemini-cli", "", cliproxyexecutor.Options{}, auths)
		if err != nil {
			t.Fatalf("Pick() #%d error = %v", i, err)
		}
		if got == nil {
			t.Fatalf("Pick() #%d auth = nil", i)
		}
		if got.ID != expectedID {
			t.Fatalf("Pick() #%d auth.ID = %q, want %q", i, got.ID, expectedID)
		}
	}
}
func TestExtractSessionID_ClaudeCodePriorityOverHeader(t *testing.T) {
	t.Parallel()

	// Claude Code metadata.user_id should have highest priority, even when X-Session-ID header is present
	headers := make(http.Header)
	headers.Set("X-Session-ID", "header-session-id")

	payload := []byte(`{"metadata":{"user_id":"user_xxx_account__session_ac980658-63bd-4fb3-97ba-8da64cb1e344"}}`)

	got := ExtractSessionID(headers, payload, nil)
	want := "claude:ac980658-63bd-4fb3-97ba-8da64cb1e344"
	if got != want {
		t.Errorf("ExtractSessionID() = %q, want %q (Claude Code should have highest priority over header)", got, want)
	}
}

func TestExtractSessionID_ClaudeCodePriorityOverIdempotencyKey(t *testing.T) {
	t.Parallel()

	// Claude Code metadata.user_id should have highest priority, even when idempotency_key is present
	metadata := map[string]any{"idempotency_key": "idem-12345"}
	payload := []byte(`{"metadata":{"user_id":"user_xxx_account__session_ac980658-63bd-4fb3-97ba-8da64cb1e344"}}`)

	got := ExtractSessionID(nil, payload, metadata)
	want := "claude:ac980658-63bd-4fb3-97ba-8da64cb1e344"
	if got != want {
		t.Errorf("ExtractSessionID() = %q, want %q (Claude Code should have highest priority over idempotency_key)", got, want)
	}
}

func TestExtractSessionID_Headers(t *testing.T) {
	t.Parallel()

	headers := make(http.Header)
	headers.Set("X-Session-ID", "my-explicit-session")

	got := ExtractSessionID(headers, nil, nil)
	want := "header:my-explicit-session"
	if got != want {
		t.Errorf("ExtractSessionID() with header = %q, want %q", got, want)
	}
}

func TestExtractSessionID_CodexSessionIDHeader(t *testing.T) {
	t.Parallel()

	headers := make(http.Header)
	headers.Set("Session_id", "codex-session-123")

	got := ExtractSessionID(headers, nil, nil)
	want := "codex:codex-session-123"
	if got != want {
		t.Errorf("ExtractSessionID() with Session_id = %q, want %q", got, want)
	}
}

func TestExtractSessionID_ClientRequestIDHeader(t *testing.T) {
	t.Parallel()

	headers := make(http.Header)
	headers.Set("X-Client-Request-Id", "pi-session-123")

	got := ExtractSessionID(headers, nil, nil)
	want := "clientreq:pi-session-123"
	if got != want {
		t.Errorf("ExtractSessionID() with X-Client-Request-Id = %q, want %q", got, want)
	}
}

func TestExtractSessionID_CodexSessionIDPriorityOverClientRequestID(t *testing.T) {
	t.Parallel()

	headers := make(http.Header)
	headers.Set("X-Client-Request-Id", "pi-session-123")
	headers.Set("Session_id", "codex-session-456")

	got := ExtractSessionID(headers, nil, nil)
	want := "codex:codex-session-456"
	if got != want {
		t.Errorf("ExtractSessionID() = %q, want %q (Session_id should take priority over X-Client-Request-Id)", got, want)
	}
}

func TestExtractSessionID_AmpThreadId(t *testing.T) {
	t.Parallel()

	headers := make(http.Header)
	headers.Set("X-Amp-Thread-Id", "T-7873e6bd-6354-4a9a-be2c-c7702c6e1b64")

	got := ExtractSessionID(headers, nil, nil)
	want := "amp:T-7873e6bd-6354-4a9a-be2c-c7702c6e1b64"
	if got != want {
		t.Errorf("ExtractSessionID() with X-Amp-Thread-Id = %q, want %q", got, want)
	}
}

func TestExtractSessionID_AmpThreadIdPriorityOverClientRequestID(t *testing.T) {
	t.Parallel()

	headers := make(http.Header)
	headers.Set("X-Amp-Thread-Id", "T-priority-test")
	headers.Set("X-Client-Request-Id", "pi-session-123")

	got := ExtractSessionID(headers, nil, nil)
	want := "amp:T-priority-test"
	if got != want {
		t.Errorf("ExtractSessionID() = %q, want %q (X-Amp-Thread-Id should take priority over X-Client-Request-Id)", got, want)
	}
}

// TestExtractSessionID_AmpThreadIdLowerPriority verifies X-Amp-Thread-Id is lower
// priority than Claude Code metadata.user_id but higher than conversation_id.
func TestExtractSessionID_AmpThreadIdPriority(t *testing.T) {
	t.Parallel()

	// X-Amp-Thread-Id should be used when no Claude Code user_id is present
	headers := make(http.Header)
	headers.Set("X-Amp-Thread-Id", "T-priority-test")

	payload := []byte(`{"conversation_id":"conv-12345"}`)
	got := ExtractSessionID(headers, payload, nil)
	want := "amp:T-priority-test"
	if got != want {
		t.Errorf("ExtractSessionID() = %q, want %q (Amp thread ID should take priority over conversation_id)", got, want)
	}

	// Claude Code user_id should take priority over X-Amp-Thread-Id
	headers2 := make(http.Header)
	headers2.Set("X-Amp-Thread-Id", "T-priority-test")
	payload2 := []byte(`{"metadata":{"user_id":"user_xxx_account__session_ac980658-63bd-4fb3-97ba-8da64cb1e344"}}`)
	got2 := ExtractSessionID(headers2, payload2, nil)
	want2 := "claude:ac980658-63bd-4fb3-97ba-8da64cb1e344"
	if got2 != want2 {
		t.Errorf("ExtractSessionID() = %q, want %q (Claude Code should take priority over Amp thread ID)", got2, want2)
	}
}

// TestExtractSessionID_IdempotencyKey verifies that idempotency_key is intentionally
// ignored for session affinity (it's auto-generated per-request, causing cache misses).
func TestExtractSessionID_IdempotencyKey(t *testing.T) {
	t.Parallel()

	metadata := map[string]any{"idempotency_key": "idem-12345"}

	got := ExtractSessionID(nil, nil, metadata)
	// idempotency_key is disabled - should return empty (no payload to hash)
	if got != "" {
		t.Errorf("ExtractSessionID() with idempotency_key = %q, want empty (idempotency_key is disabled)", got)
	}
}

func TestExtractSessionID_MessageHashFallback(t *testing.T) {
	t.Parallel()

	// First request (user only) generates short hash
	firstRequestPayload := []byte(`{"messages":[{"role":"user","content":"Hello world"}]}`)
	shortHash := ExtractSessionID(nil, firstRequestPayload, nil)
	if shortHash == "" {
		t.Error("ExtractSessionID() first request should return short hash")
	}
	if !strings.HasPrefix(shortHash, "msg:") {
		t.Errorf("ExtractSessionID() = %q, want prefix 'msg:'", shortHash)
	}

	// Multi-turn with assistant generates full hash (different from short hash)
	multiTurnPayload := []byte(`{"messages":[
		{"role":"user","content":"Hello world"},
		{"role":"assistant","content":"Hi! How can I help?"},
		{"role":"user","content":"Tell me a joke"}
	]}`)
	fullHash := ExtractSessionID(nil, multiTurnPayload, nil)
	if fullHash == "" {
		t.Error("ExtractSessionID() multi-turn should return full hash")
	}
	if fullHash == shortHash {
		t.Error("Full hash should differ from short hash (includes assistant)")
	}

	// Same multi-turn payload should produce same hash
	fullHash2 := ExtractSessionID(nil, multiTurnPayload, nil)
	if fullHash != fullHash2 {
		t.Errorf("ExtractSessionID() not stable: got %q then %q", fullHash, fullHash2)
	}
}

func TestExtractSessionID_ClaudeAPITopLevelSystem(t *testing.T) {
	t.Parallel()

	// Claude API: system prompt in top-level "system" field (array format)
	arraySystem := []byte(`{
		"messages": [{"role": "user", "content": [{"type": "text", "text": "Hello"}]}],
		"system": [{"type": "text", "text": "You are Claude Code"}]
	}`)
	got1 := ExtractSessionID(nil, arraySystem, nil)
	if got1 == "" || !strings.HasPrefix(got1, "msg:") {
		t.Errorf("ExtractSessionID() with array system = %q, want msg:* prefix", got1)
	}

	// Claude API: system prompt in top-level "system" field (string format)
	stringSystem := []byte(`{
		"messages": [{"role": "user", "content": "Hello"}],
		"system": "You are Claude Code"
	}`)
	got2 := ExtractSessionID(nil, stringSystem, nil)
	if got2 == "" || !strings.HasPrefix(got2, "msg:") {
		t.Errorf("ExtractSessionID() with string system = %q, want msg:* prefix", got2)
	}

	// Multi-turn with top-level system should produce stable hash
	multiTurn := []byte(`{
		"messages": [
			{"role": "user", "content": "Hello"},
			{"role": "assistant", "content": "Hi!"},
			{"role": "user", "content": "Help me"}
		],
		"system": "You are Claude Code"
	}`)
	got3 := ExtractSessionID(nil, multiTurn, nil)
	if got3 == "" {
		t.Error("ExtractSessionID() multi-turn with top-level system should return hash")
	}
	if got3 == got2 {
		t.Error("Multi-turn hash should differ from first-turn hash (includes assistant)")
	}
}

func TestExtractSessionID_GeminiFormat(t *testing.T) {
	t.Parallel()

	// Gemini format with systemInstruction and contents
	payload := []byte(`{
		"systemInstruction": {"parts": [{"text": "You are a helpful assistant."}]},
		"contents": [
			{"role": "user", "parts": [{"text": "Hello Gemini"}]},
			{"role": "model", "parts": [{"text": "Hi there!"}]}
		]
	}`)

	got := ExtractSessionID(nil, payload, nil)
	if got == "" {
		t.Error("ExtractSessionID() with Gemini format should return hash-based session ID")
	}
	if !strings.HasPrefix(got, "msg:") {
		t.Errorf("ExtractSessionID() = %q, want prefix 'msg:'", got)
	}

	// Same payload should produce same hash
	got2 := ExtractSessionID(nil, payload, nil)
	if got != got2 {
		t.Errorf("ExtractSessionID() not stable: got %q then %q", got, got2)
	}

	// Different user message should produce different hash
	differentPayload := []byte(`{
		"systemInstruction": {"parts": [{"text": "You are a helpful assistant."}]},
		"contents": [
			{"role": "user", "parts": [{"text": "Hello different"}]},
			{"role": "model", "parts": [{"text": "Hi there!"}]}
		]
	}`)
	got3 := ExtractSessionID(nil, differentPayload, nil)
	if got == got3 {
		t.Errorf("ExtractSessionID() should produce different hash for different user message")
	}
}

func TestExtractSessionID_OpenAIResponsesAPI(t *testing.T) {
	t.Parallel()

	firstTurn := []byte(`{
		"instructions": "You are Codex, based on GPT-5.",
		"input": [
			{"type": "message", "role": "developer", "content": [{"type": "input_text", "text": "system instructions"}]},
			{"type": "message", "role": "user", "content": [{"type": "input_text", "text": "hi"}]}
		]
	}`)

	got1 := ExtractSessionID(nil, firstTurn, nil)
	if got1 == "" {
		t.Error("ExtractSessionID() should return hash for OpenAI Responses API format")
	}
	if !strings.HasPrefix(got1, "msg:") {
		t.Errorf("ExtractSessionID() = %q, want prefix 'msg:'", got1)
	}

	secondTurn := []byte(`{
		"instructions": "You are Codex, based on GPT-5.",
		"input": [
			{"type": "message", "role": "developer", "content": [{"type": "input_text", "text": "system instructions"}]},
			{"type": "message", "role": "user", "content": [{"type": "input_text", "text": "hi"}]},
			{"type": "reasoning", "summary": [{"type": "summary_text", "text": "thinking..."}], "encrypted_content": "xxx"},
			{"type": "message", "role": "assistant", "content": [{"type": "output_text", "text": "Hello!"}]},
			{"type": "message", "role": "user", "content": [{"type": "input_text", "text": "what can you do"}]}
		]
	}`)

	got2 := ExtractSessionID(nil, secondTurn, nil)
	if got2 == "" {
		t.Error("ExtractSessionID() should return hash for second turn")
	}

	if got1 == got2 {
		t.Log("First turn and second turn have different hashes (expected: second includes assistant)")
	}

	thirdTurn := []byte(`{
		"instructions": "You are Codex, based on GPT-5.",
		"input": [
			{"type": "message", "role": "developer", "content": [{"type": "input_text", "text": "system instructions"}]},
			{"type": "message", "role": "user", "content": [{"type": "input_text", "text": "hi"}]},
			{"type": "reasoning", "summary": [{"type": "summary_text", "text": "thinking..."}], "encrypted_content": "xxx"},
			{"type": "message", "role": "assistant", "content": [{"type": "output_text", "text": "Hello!"}]},
			{"type": "message", "role": "user", "content": [{"type": "input_text", "text": "what can you do"}]},
			{"type": "message", "role": "assistant", "content": [{"type": "output_text", "text": "I can help with..."}]},
			{"type": "message", "role": "user", "content": [{"type": "input_text", "text": "thanks"}]}
		]
	}`)

	got3 := ExtractSessionID(nil, thirdTurn, nil)
	if got2 != got3 {
		t.Errorf("Second and third turn should have same hash (same first assistant): got %q vs %q", got2, got3)
	}
}

func TestSessionAffinitySelector_ThreeScenarios(t *testing.T) {
	t.Parallel()

	fallback := &RoundRobinSelector{}
	selector := NewSessionAffinitySelectorWithConfig(SessionAffinityConfig{
		Fallback: fallback,
		TTL:      time.Minute,
	})
	defer selector.Stop()

	auths := []*Auth{{ID: "auth-a"}, {ID: "auth-b"}, {ID: "auth-c"}}

	testCases := []struct {
		name     string
		scenario string
		payload  []byte
	}{
		{
			name:     "OpenAI_Scenario1_NewRequest",
			scenario: "new",
			payload:  []byte(`{"messages":[{"role":"system","content":"You are helpful"},{"role":"user","content":"Hello"}]}`),
		},
		{
			name:     "OpenAI_Scenario2_SecondTurn",
			scenario: "second",
			payload:  []byte(`{"messages":[{"role":"system","content":"You are helpful"},{"role":"user","content":"Hello"},{"role":"assistant","content":"Hi there!"},{"role":"user","content":"Help me"}]}`),
		},
		{
			name:     "OpenAI_Scenario3_ManyTurns",
			scenario: "many",
			payload:  []byte(`{"messages":[{"role":"system","content":"You are helpful"},{"role":"user","content":"Hello"},{"role":"assistant","content":"Hi there!"},{"role":"user","content":"Help me"},{"role":"assistant","content":"Sure!"},{"role":"user","content":"Thanks"}]}`),
		},
		{
			name:     "Gemini_Scenario1_NewRequest",
			scenario: "new",
			payload:  []byte(`{"systemInstruction":{"parts":[{"text":"You are helpful"}]},"contents":[{"role":"user","parts":[{"text":"Hello Gemini"}]}]}`),
		},
		{
			name:     "Gemini_Scenario2_SecondTurn",
			scenario: "second",
			payload:  []byte(`{"systemInstruction":{"parts":[{"text":"You are helpful"}]},"contents":[{"role":"user","parts":[{"text":"Hello Gemini"}]},{"role":"model","parts":[{"text":"Hi!"}]},{"role":"user","parts":[{"text":"Help"}]}]}`),
		},
		{
			name:     "Gemini_Scenario3_ManyTurns",
			scenario: "many",
			payload:  []byte(`{"systemInstruction":{"parts":[{"text":"You are helpful"}]},"contents":[{"role":"user","parts":[{"text":"Hello Gemini"}]},{"role":"model","parts":[{"text":"Hi!"}]},{"role":"user","parts":[{"text":"Help"}]},{"role":"model","parts":[{"text":"Sure!"}]},{"role":"user","parts":[{"text":"Thanks"}]}]}`),
		},
		{
			name:     "Claude_Scenario1_NewRequest",
			scenario: "new",
			payload:  []byte(`{"messages":[{"role":"user","content":"Hello Claude"}]}`),
		},
		{
			name:     "Claude_Scenario2_SecondTurn",
			scenario: "second",
			payload:  []byte(`{"messages":[{"role":"user","content":"Hello Claude"},{"role":"assistant","content":"Hello!"},{"role":"user","content":"Help me"}]}`),
		},
		{
			name:     "Claude_Scenario3_ManyTurns",
			scenario: "many",
			payload:  []byte(`{"messages":[{"role":"user","content":"Hello Claude"},{"role":"assistant","content":"Hello!"},{"role":"user","content":"Help"},{"role":"assistant","content":"Sure!"},{"role":"user","content":"Thanks"}]}`),
		},
	}

	for _, tc := range testCases {
		tc := tc
		t.Run(tc.name, func(t *testing.T) {
			opts := cliproxyexecutor.Options{OriginalRequest: tc.payload}
			picked, err := selector.Pick(context.Background(), "provider", "model", opts, auths)
			if err != nil {
				t.Fatalf("Pick() error = %v", err)
			}
			if picked == nil {
				t.Fatal("Pick() returned nil")
			}
			t.Logf("%s: picked %s", tc.name, picked.ID)
		})
	}

	t.Run("Scenario2And3_SameAuth", func(t *testing.T) {
		openaiS2 := []byte(`{"messages":[{"role":"system","content":"Stable test"},{"role":"user","content":"First msg"},{"role":"assistant","content":"Response"},{"role":"user","content":"Second"}]}`)
		openaiS3 := []byte(`{"messages":[{"role":"system","content":"Stable test"},{"role":"user","content":"First msg"},{"role":"assistant","content":"Response"},{"role":"user","content":"Second"},{"role":"assistant","content":"More"},{"role":"user","content":"Third"}]}`)

		opts2 := cliproxyexecutor.Options{OriginalRequest: openaiS2}
		opts3 := cliproxyexecutor.Options{OriginalRequest: openaiS3}

		picked2, _ := selector.Pick(context.Background(), "test", "model", opts2, auths)
		picked3, _ := selector.Pick(context.Background(), "test", "model", opts3, auths)

		if picked2.ID != picked3.ID {
			t.Errorf("Scenario2 and Scenario3 should pick same auth: got %s vs %s", picked2.ID, picked3.ID)
		}
	})

	t.Run("Scenario1To2_InheritBinding", func(t *testing.T) {
		s1 := []byte(`{"messages":[{"role":"system","content":"Inherit test"},{"role":"user","content":"Initial"}]}`)
		s2 := []byte(`{"messages":[{"role":"system","content":"Inherit test"},{"role":"user","content":"Initial"},{"role":"assistant","content":"Reply"},{"role":"user","content":"Continue"}]}`)

		opts1 := cliproxyexecutor.Options{OriginalRequest: s1}
		opts2 := cliproxyexecutor.Options{OriginalRequest: s2}

		picked1, _ := selector.Pick(context.Background(), "inherit", "model", opts1, auths)
		picked2, _ := selector.Pick(context.Background(), "inherit", "model", opts2, auths)

		if picked1.ID != picked2.ID {
			t.Errorf("Scenario2 should inherit Scenario1 binding: got %s vs %s", picked1.ID, picked2.ID)
		}
	})
}

func TestSessionAffinitySelector_MultiModelSession(t *testing.T) {
	t.Parallel()

	fallback := &RoundRobinSelector{}
	selector := NewSessionAffinitySelectorWithConfig(SessionAffinityConfig{
		Fallback: fallback,
		TTL:      time.Minute,
	})
	defer selector.Stop()

	// auth-a supports only model-a, auth-b supports only model-b
	authA := &Auth{ID: "auth-a"}
	authB := &Auth{ID: "auth-b"}

	// Same session ID for all requests
	payload := []byte(`{"metadata":{"user_id":"user_xxx_account__session_multi-model-test"}}`)
	opts := cliproxyexecutor.Options{OriginalRequest: payload}

	// Request model-a with only auth-a available for that model
	authsForModelA := []*Auth{authA}
	pickedA, err := selector.Pick(context.Background(), "provider", "model-a", opts, authsForModelA)
	if err != nil {
		t.Fatalf("Pick() for model-a error = %v", err)
	}
	if pickedA.ID != "auth-a" {
		t.Fatalf("Pick() for model-a = %q, want auth-a", pickedA.ID)
	}

	// Request model-b with only auth-b available for that model
	authsForModelB := []*Auth{authB}
	pickedB, err := selector.Pick(context.Background(), "provider", "model-b", opts, authsForModelB)
	if err != nil {
		t.Fatalf("Pick() for model-b error = %v", err)
	}
	if pickedB.ID != "auth-b" {
		t.Fatalf("Pick() for model-b = %q, want auth-b", pickedB.ID)
	}

	// Switch back to model-a - should still get auth-a (separate binding per model)
	pickedA2, err := selector.Pick(context.Background(), "provider", "model-a", opts, authsForModelA)
	if err != nil {
		t.Fatalf("Pick() for model-a (2nd) error = %v", err)
	}
	if pickedA2.ID != "auth-a" {
		t.Fatalf("Pick() for model-a (2nd) = %q, want auth-a", pickedA2.ID)
	}

	// Verify bindings are stable for multiple calls
	for i := 0; i < 5; i++ {
		gotA, _ := selector.Pick(context.Background(), "provider", "model-a", opts, authsForModelA)
		gotB, _ := selector.Pick(context.Background(), "provider", "model-b", opts, authsForModelB)
		if gotA.ID != "auth-a" {
			t.Fatalf("Pick() #%d for model-a = %q, want auth-a", i, gotA.ID)
		}
		if gotB.ID != "auth-b" {
			t.Fatalf("Pick() #%d for model-b = %q, want auth-b", i, gotB.ID)
		}
	}
}

func TestExtractSessionID_MultimodalContent(t *testing.T) {
	t.Parallel()

	// First request generates short hash
	firstRequestPayload := []byte(`{"messages":[{"role":"user","content":[{"type":"text","text":"Hello world"},{"type":"image","source":{"data":"..."}}]}]}`)
	shortHash := ExtractSessionID(nil, firstRequestPayload, nil)
	if shortHash == "" {
		t.Error("ExtractSessionID() first request should return short hash")
	}
	if !strings.HasPrefix(shortHash, "msg:") {
		t.Errorf("ExtractSessionID() = %q, want prefix 'msg:'", shortHash)
	}

	// Multi-turn generates full hash
	multiTurnPayload := []byte(`{"messages":[
		{"role":"user","content":[{"type":"text","text":"Hello world"},{"type":"image","source":{"data":"..."}}]},
		{"role":"assistant","content":"I see an image!"},
		{"role":"user","content":"What is it?"}
	]}`)
	fullHash := ExtractSessionID(nil, multiTurnPayload, nil)
	if fullHash == "" {
		t.Error("ExtractSessionID() multimodal multi-turn should return full hash")
	}
	if fullHash == shortHash {
		t.Error("Full hash should differ from short hash")
	}

	// Different user content produces different hash
	differentPayload := []byte(`{"messages":[
		{"role":"user","content":[{"type":"text","text":"Different content"}]},
		{"role":"assistant","content":"I see something different!"}
	]}`)
	differentHash := ExtractSessionID(nil, differentPayload, nil)
	if fullHash == differentHash {
		t.Errorf("ExtractSessionID() should produce different hash for different content")
	}
}

func TestSessionAffinitySelector_CrossProviderIsolation(t *testing.T) {
	t.Parallel()

	fallback := &RoundRobinSelector{}
	selector := NewSessionAffinitySelectorWithConfig(SessionAffinityConfig{
		Fallback: fallback,
		TTL:      time.Minute,
	})
	defer selector.Stop()

	authClaude := &Auth{ID: "auth-claude"}
	authGemini := &Auth{ID: "auth-gemini"}

	// Same session ID for both providers
	payload := []byte(`{"metadata":{"user_id":"user_xxx_account__session_cross-provider-test"}}`)
	opts := cliproxyexecutor.Options{OriginalRequest: payload}

	// Request via claude provider
	pickedClaude, err := selector.Pick(context.Background(), "claude", "claude-3", opts, []*Auth{authClaude})
	if err != nil {
		t.Fatalf("Pick() for claude error = %v", err)
	}
	if pickedClaude.ID != "auth-claude" {
		t.Fatalf("Pick() for claude = %q, want auth-claude", pickedClaude.ID)
	}

	// Same session but via gemini provider should get different auth
	pickedGemini, err := selector.Pick(context.Background(), "gemini", "gemini-2.5-pro", opts, []*Auth{authGemini})
	if err != nil {
		t.Fatalf("Pick() for gemini error = %v", err)
	}
	if pickedGemini.ID != "auth-gemini" {
		t.Fatalf("Pick() for gemini = %q, want auth-gemini", pickedGemini.ID)
	}

	// Verify both bindings remain stable
	for i := 0; i < 5; i++ {
		gotC, _ := selector.Pick(context.Background(), "claude", "claude-3", opts, []*Auth{authClaude})
		gotG, _ := selector.Pick(context.Background(), "gemini", "gemini-2.5-pro", opts, []*Auth{authGemini})
		if gotC.ID != "auth-claude" {
			t.Fatalf("Pick() #%d for claude = %q, want auth-claude", i, gotC.ID)
		}
		if gotG.ID != "auth-gemini" {
			t.Fatalf("Pick() #%d for gemini = %q, want auth-gemini", i, gotG.ID)
		}
	}
}

func TestSessionCache_GetAndRefresh(t *testing.T) {
	t.Parallel()

	cache := NewSessionCache(100 * time.Millisecond)
	defer cache.Stop()

	cache.Set("session1", "auth1")

	// Verify initial value
	got, ok := cache.GetAndRefresh("session1")
	if !ok || got != "auth1" {
		t.Fatalf("GetAndRefresh() = %q, %v, want auth1, true", got, ok)
	}

	// Wait half TTL and access again (should refresh)
	time.Sleep(60 * time.Millisecond)
	got, ok = cache.GetAndRefresh("session1")
	if !ok || got != "auth1" {
		t.Fatalf("GetAndRefresh() after 60ms = %q, %v, want auth1, true", got, ok)
	}

	// Wait another 60ms (total 120ms from original, but TTL refreshed at 60ms)
	// Entry should still be valid because TTL was refreshed
	time.Sleep(60 * time.Millisecond)
	got, ok = cache.GetAndRefresh("session1")
	if !ok || got != "auth1" {
		t.Fatalf("GetAndRefresh() after refresh = %q, %v, want auth1, true (TTL should have been refreshed)", got, ok)
	}

	// Now wait full TTL without access
	time.Sleep(110 * time.Millisecond)
	got, ok = cache.GetAndRefresh("session1")
	if ok {
		t.Fatalf("GetAndRefresh() after expiry = %q, %v, want '', false", got, ok)
	}
}

func TestSessionAffinitySelector_RoundRobinDistribution(t *testing.T) {
	t.Parallel()

	fallback := &RoundRobinSelector{}
	selector := NewSessionAffinitySelectorWithConfig(SessionAffinityConfig{
		Fallback: fallback,
		TTL:      time.Minute,
	})
	defer selector.Stop()

	auths := []*Auth{
		{ID: "auth-a"},
		{ID: "auth-b"},
		{ID: "auth-c"},
	}

	sessionCount := 12
	counts := make(map[string]int)
	for i := 0; i < sessionCount; i++ {
		payload := []byte(fmt.Sprintf(`{"metadata":{"user_id":"user_xxx_account__session_%08d-0000-0000-0000-000000000000"}}`, i))
		opts := cliproxyexecutor.Options{OriginalRequest: payload}
		got, err := selector.Pick(context.Background(), "provider", "model", opts, auths)
		if err != nil {
			t.Fatalf("Pick() session %d error = %v", i, err)
		}
		counts[got.ID]++
	}

	expected := sessionCount / len(auths)
	for _, auth := range auths {
		got := counts[auth.ID]
		if got != expected {
			t.Errorf("auth %s got %d sessions, want %d (round-robin should distribute evenly)", auth.ID, got, expected)
		}
	}
}

func TestSessionAffinitySelector_Concurrent(t *testing.T) {
	t.Parallel()

	fallback := &RoundRobinSelector{}
	selector := NewSessionAffinitySelectorWithConfig(SessionAffinityConfig{
		Fallback: fallback,
		TTL:      time.Minute,
	})
	defer selector.Stop()

	auths := []*Auth{
		{ID: "auth-a"},
		{ID: "auth-b"},
		{ID: "auth-c"},
	}

	payload := []byte(`{"metadata":{"user_id":"user_xxx_account__session_concurrent-test"}}`)
	opts := cliproxyexecutor.Options{OriginalRequest: payload}

	// First pick to establish binding
	first, err := selector.Pick(context.Background(), "claude", "claude-3", opts, auths)
	if err != nil {
		t.Fatalf("Initial Pick() error = %v", err)
	}
	expectedID := first.ID

	start := make(chan struct{})
	var wg sync.WaitGroup
	errCh := make(chan error, 1)

	goroutines := 32
	iterations := 50
	for i := 0; i < goroutines; i++ {
		wg.Add(1)
		go func() {
			defer wg.Done()
			<-start
			for j := 0; j < iterations; j++ {
				got, err := selector.Pick(context.Background(), "claude", "claude-3", opts, auths)
				if err != nil {
					select {
					case errCh <- err:
					default:
					}
					return
				}
				if got.ID != expectedID {
					select {
					case errCh <- fmt.Errorf("concurrent Pick() returned %q, want %q", got.ID, expectedID):
					default:
					}
					return
				}
			}
		}()
	}

	close(start)
	wg.Wait()

	select {
	case err := <-errCh:
		t.Fatalf("concurrent Pick() error = %v", err)
	default:
	}
}