package service

import (
	"errors"
	"sync"
	"testing"

	"github.com/stretchr/testify/assert"
	"github.com/stretchr/testify/require"
	"go.uber.org/zap"

	"nex/backend/internal/domain"
)

type mockModelRepo struct {
	models map[string]*domain.Model
}

func (m *mockModelRepo) Create(model *domain.Model) error {
	return nil
}

func (m *mockModelRepo) GetByID(id string) (*domain.Model, error) {
	return nil, nil
}

func (m *mockModelRepo) FindByProviderAndModelName(providerID, modelName string) (*domain.Model, error) {
	key := providerID + "/" + modelName
	if model, ok := m.models[key]; ok {
		return model, nil
	}
	return nil, errors.New("not found")
}

func (m *mockModelRepo) List(providerID string) ([]domain.Model, error) {
	var result []domain.Model
	for _, model := range m.models {
		if providerID == "" || model.ProviderID == providerID {
			result = append(result, *model)
		}
	}
	return result, nil
}

func (m *mockModelRepo) ListEnabled() ([]domain.Model, error) {
	return nil, nil
}

func (m *mockModelRepo) Update(id string, updates map[string]interface{}) error {
	return nil
}

func (m *mockModelRepo) Delete(id string) error {
	return nil
}

type mockProviderRepo struct {
	providers map[string]*domain.Provider
}

func (m *mockProviderRepo) Create(provider *domain.Provider) error {
	return nil
}

func (m *mockProviderRepo) GetByID(id string) (*domain.Provider, error) {
	if provider, ok := m.providers[id]; ok {
		return provider, nil
	}
	return nil, errors.New("not found")
}

func (m *mockProviderRepo) List() ([]domain.Provider, error) {
	var result []domain.Provider
	for _, provider := range m.providers {
		result = append(result, *provider)
	}
	return result, nil
}

func (m *mockProviderRepo) Update(id string, updates map[string]interface{}) error {
	return nil
}

func (m *mockProviderRepo) Delete(id string) error {
	return nil
}

func TestRoutingCache_GetProvider_CacheHit(t *testing.T) {
	logger := zap.NewNop()
	modelRepo := &mockModelRepo{models: make(map[string]*domain.Model)}
	providerRepo := &mockProviderRepo{providers: map[string]*domain.Provider{
		"openai": {ID: "openai", Name: "OpenAI", Enabled: true},
	}}

	cache := NewRoutingCache(modelRepo, providerRepo, logger)

	provider, err := cache.GetProvider("openai")
	require.NoError(t, err)
	assert.Equal(t, "openai", provider.ID)

	provider2, err := cache.GetProvider("openai")
	require.NoError(t, err)
	assert.Equal(t, provider, provider2)
}

func TestRoutingCache_GetProvider_CacheMiss(t *testing.T) {
	logger := zap.NewNop()
	modelRepo := &mockModelRepo{models: make(map[string]*domain.Model)}
	providerRepo := &mockProviderRepo{providers: make(map[string]*domain.Provider)}

	cache := NewRoutingCache(modelRepo, providerRepo, logger)

	_, err := cache.GetProvider("notexist")
	assert.Error(t, err)
}

func TestRoutingCache_GetModel_CacheHit(t *testing.T) {
	logger := zap.NewNop()
	modelRepo := &mockModelRepo{models: map[string]*domain.Model{
		"openai/gpt-4": {ID: "1", ProviderID: "openai", ModelName: "gpt-4", Enabled: true},
	}}
	providerRepo := &mockProviderRepo{providers: make(map[string]*domain.Provider)}

	cache := NewRoutingCache(modelRepo, providerRepo, logger)

	model, err := cache.GetModel("openai", "gpt-4")
	require.NoError(t, err)
	assert.Equal(t, "gpt-4", model.ModelName)

	model2, err := cache.GetModel("openai", "gpt-4")
	require.NoError(t, err)
	assert.Equal(t, model, model2)
}

func TestRoutingCache_GetModel_CacheMiss(t *testing.T) {
	logger := zap.NewNop()
	modelRepo := &mockModelRepo{models: make(map[string]*domain.Model)}
	providerRepo := &mockProviderRepo{providers: make(map[string]*domain.Provider)}

	cache := NewRoutingCache(modelRepo, providerRepo, logger)

	_, err := cache.GetModel("openai", "notexist")
	assert.Error(t, err)
}

func TestRoutingCache_DoubleCheck(t *testing.T) {
	logger := zap.NewNop()
	modelRepo := &mockModelRepo{models: make(map[string]*domain.Model)}
	providerRepo := &mockProviderRepo{providers: map[string]*domain.Provider{
		"openai": {ID: "openai", Name: "OpenAI", Enabled: true},
	}}

	cache := NewRoutingCache(modelRepo, providerRepo, logger)

	var wg sync.WaitGroup
	for i := 0; i < 10; i++ {
		wg.Add(1)
		go func() {
			defer wg.Done()
			_, err := cache.GetProvider("openai")
			assert.NoError(t, err)
		}()
	}
	wg.Wait()
}

func TestRoutingCache_InvalidateProvider_CascadingModels(t *testing.T) {
	logger := zap.NewNop()
	modelRepo := &mockModelRepo{models: map[string]*domain.Model{
		"openai/gpt-4":     {ID: "1", ProviderID: "openai", ModelName: "gpt-4", Enabled: true},
		"openai/gpt-3.5":   {ID: "2", ProviderID: "openai", ModelName: "gpt-3.5", Enabled: true},
		"anthropic/claude": {ID: "3", ProviderID: "anthropic", ModelName: "claude", Enabled: true},
	}}
	providerRepo := &mockProviderRepo{providers: map[string]*domain.Provider{
		"openai":    {ID: "openai", Name: "OpenAI", Enabled: true},
		"anthropic": {ID: "anthropic", Name: "Anthropic", Enabled: true},
	}}

	cache := NewRoutingCache(modelRepo, providerRepo, logger)

	_, err := cache.GetModel("openai", "gpt-4")
	require.NoError(t, err)
	_, err = cache.GetModel("openai", "gpt-3.5")
	require.NoError(t, err)
	_, err = cache.GetModel("anthropic", "claude")
	require.NoError(t, err)

	cache.InvalidateProvider("openai")

	var openaiCount, anthropicCount int
	cache.models.Range(func(key, value interface{}) bool {
		if key.(string) == "anthropic/claude" {
			anthropicCount++
		}
		return true
	})
	assert.Equal(t, 0, openaiCount)
	assert.Equal(t, 1, anthropicCount)
}

func TestRoutingCache_InvalidateModel(t *testing.T) {
	logger := zap.NewNop()
	modelRepo := &mockModelRepo{models: map[string]*domain.Model{
		"openai/gpt-4": {ID: "1", ProviderID: "openai", ModelName: "gpt-4", Enabled: true},
	}}
	providerRepo := &mockProviderRepo{providers: make(map[string]*domain.Provider)}

	cache := NewRoutingCache(modelRepo, providerRepo, logger)

	_, err := cache.GetModel("openai", "gpt-4")
	require.NoError(t, err)

	cache.InvalidateModel("openai", "gpt-4")

	var count int
	cache.models.Range(func(key, value interface{}) bool {
		count++
		return true
	})
	assert.Equal(t, 0, count)
}

func TestRoutingCache_Preload_Success(t *testing.T) {
	logger := zap.NewNop()
	modelRepo := &mockModelRepo{models: map[string]*domain.Model{
		"openai/gpt-4": {ID: "1", ProviderID: "openai", ModelName: "gpt-4", Enabled: true},
	}}
	providerRepo := &mockProviderRepo{providers: map[string]*domain.Provider{
		"openai": {ID: "openai", Name: "OpenAI", Enabled: true},
	}}

	cache := NewRoutingCache(modelRepo, providerRepo, logger)

	err := cache.Preload()
	require.NoError(t, err)

	var providerCount, modelCount int
	cache.providers.Range(func(key, value interface{}) bool {
		providerCount++
		return true
	})
	cache.models.Range(func(key, value interface{}) bool {
		modelCount++
		return true
	})
	assert.Equal(t, 1, providerCount)
	assert.Equal(t, 1, modelCount)
}

func TestRoutingCache_ConcurrentAccess(t *testing.T) {
	logger := zap.NewNop()
	modelRepo := &mockModelRepo{models: map[string]*domain.Model{
		"openai/gpt-4": {ID: "1", ProviderID: "openai", ModelName: "gpt-4", Enabled: true},
	}}
	providerRepo := &mockProviderRepo{providers: map[string]*domain.Provider{
		"openai": {ID: "openai", Name: "OpenAI", Enabled: true},
	}}

	cache := NewRoutingCache(modelRepo, providerRepo, logger)

	var wg sync.WaitGroup
	for i := 0; i < 100; i++ {
		wg.Add(1)
		go func() {
			defer wg.Done()
			_, _ = cache.GetProvider("openai")
			_, _ = cache.GetModel("openai", "gpt-4")
			cache.InvalidateProvider("openai")
			cache.InvalidateModel("openai", "gpt-4")
		}()
	}
	wg.Wait()
}