package service

import (
	"errors"
	"testing"
	"time"

	"github.com/google/uuid"
	"github.com/stretchr/testify/assert"
	"github.com/stretchr/testify/require"
	"gorm.io/gorm"

	testHelpers "nex/backend/tests"

	"nex/backend/internal/domain"
	"nex/backend/internal/repository"
	appErrors "nex/backend/pkg/errors"
)

func setupServiceTestDB(t *testing.T) *gorm.DB {
	t.Helper()
	return testHelpers.SetupTestDB(t)
}

// ============ RoutingService - RouteByModelName 测试 ============

func TestRoutingService_RouteByModelName_Success(t *testing.T) {
	db := setupServiceTestDB(t)
	providerRepo := repository.NewProviderRepository(db)
	modelRepo := repository.NewModelRepository(db)
	svc := NewRoutingService(modelRepo, providerRepo)

	require.NoError(t, providerRepo.Create(&domain.Provider{ID: "openai", Name: "OpenAI", APIKey: "key", BaseURL: "https://api.openai.com", Enabled: true}))
	require.NoError(t, modelRepo.Create(&domain.Model{ID: "m1", ProviderID: "openai", ModelName: "gpt-4", Enabled: true}))

	result, err := svc.RouteByModelName("openai", "gpt-4")
	require.NoError(t, err)
	assert.Equal(t, "openai", result.Provider.ID)
	assert.Equal(t, "gpt-4", result.Model.ModelName)
}

func TestRoutingService_RouteByModelName_NotFound(t *testing.T) {
	db := setupServiceTestDB(t)
	providerRepo := repository.NewProviderRepository(db)
	modelRepo := repository.NewModelRepository(db)
	svc := NewRoutingService(modelRepo, providerRepo)

	_, err := svc.RouteByModelName("openai", "nonexistent-model")
	assert.True(t, errors.Is(err, appErrors.ErrModelNotFound))
}

func TestRoutingService_RouteByModelName_DisabledModel(t *testing.T) {
	db := setupServiceTestDB(t)
	providerRepo := repository.NewProviderRepository(db)
	modelRepo := repository.NewModelRepository(db)
	svc := NewRoutingService(modelRepo, providerRepo)

	require.NoError(t, providerRepo.Create(&domain.Provider{ID: "openai", Name: "OpenAI", APIKey: "key", BaseURL: "https://api.openai.com", Enabled: true}))
	require.NoError(t, modelRepo.Create(&domain.Model{ID: "m1", ProviderID: "openai", ModelName: "gpt-4", Enabled: true}))
	require.NoError(t, modelRepo.Update("m1", map[string]interface{}{"enabled": false}))

	_, err := svc.RouteByModelName("openai", "gpt-4")
	assert.True(t, errors.Is(err, appErrors.ErrModelDisabled))
}

func TestRoutingService_RouteByModelName_DisabledProvider(t *testing.T) {
	db := setupServiceTestDB(t)
	providerRepo := repository.NewProviderRepository(db)
	modelRepo := repository.NewModelRepository(db)
	svc := NewRoutingService(modelRepo, providerRepo)

	require.NoError(t, providerRepo.Create(&domain.Provider{ID: "openai", Name: "OpenAI", APIKey: "key", BaseURL: "https://api.openai.com", Enabled: true}))
	require.NoError(t, modelRepo.Create(&domain.Model{ID: "m1", ProviderID: "openai", ModelName: "gpt-4", Enabled: true}))
	require.NoError(t, providerRepo.Update("openai", map[string]interface{}{"enabled": false}))

	_, err := svc.RouteByModelName("openai", "gpt-4")
	assert.True(t, errors.Is(err, appErrors.ErrProviderDisabled))
}

// ============ ModelService - Create with UUID 测试 ============

func TestModelService_Create_GeneratesUUID(t *testing.T) {
	db := setupServiceTestDB(t)
	providerRepo := repository.NewProviderRepository(db)
	modelRepo := repository.NewModelRepository(db)
	svc := NewModelService(modelRepo, providerRepo)

	require.NoError(t, providerRepo.Create(&domain.Provider{ID: "openai", Name: "OpenAI", APIKey: "key", BaseURL: "https://api.openai.com"}))

	model := &domain.Model{ProviderID: "openai", ModelName: "gpt-4"}
	err := svc.Create(model)
	require.NoError(t, err)

	// 验证返回的 model 拥有有效的 UUID
	assert.NotEmpty(t, model.ID)
	_, err = uuid.Parse(model.ID)
	assert.NoError(t, err, "model.ID should be a valid UUID")

	// 通过 Get 验证持久化
	stored, err := svc.Get(model.ID)
	require.NoError(t, err)
	assert.Equal(t, model.ID, stored.ID)
	assert.Equal(t, "gpt-4", stored.ModelName)
}

func TestModelService_Create_DuplicateModelName(t *testing.T) {
	db := setupServiceTestDB(t)
	providerRepo := repository.NewProviderRepository(db)
	modelRepo := repository.NewModelRepository(db)
	svc := NewModelService(modelRepo, providerRepo)

	require.NoError(t, providerRepo.Create(&domain.Provider{ID: "openai", Name: "OpenAI", APIKey: "key", BaseURL: "https://api.openai.com"}))

	model1 := &domain.Model{ProviderID: "openai", ModelName: "gpt-4"}
	err := svc.Create(model1)
	require.NoError(t, err)

	// 使用相同的 (providerID, modelName) 创建第二个模型应失败
	model2 := &domain.Model{ProviderID: "openai", ModelName: "gpt-4"}
	err = svc.Create(model2)
	assert.True(t, errors.Is(err, appErrors.ErrDuplicateModel))
}

func TestModelService_Create_ProviderNotFound(t *testing.T) {
	db := setupServiceTestDB(t)
	providerRepo := repository.NewProviderRepository(db)
	modelRepo := repository.NewModelRepository(db)
	svc := NewModelService(modelRepo, providerRepo)

	model := &domain.Model{ProviderID: "nonexistent", ModelName: "gpt-4"}
	err := svc.Create(model)
	assert.True(t, errors.Is(err, appErrors.ErrProviderNotFound))
}

// ============ ProviderService - Create with validation 测试 ============

func TestProviderService_Create_InvalidID(t *testing.T) {
	db := setupServiceTestDB(t)
	repo := repository.NewProviderRepository(db)
	modelRepo := repository.NewModelRepository(db)
	svc := NewProviderService(repo, modelRepo)

	provider := &domain.Provider{ID: "open-ai", Name: "OpenAI", APIKey: "key", BaseURL: "https://api.openai.com"}
	err := svc.Create(provider)
	assert.True(t, errors.Is(err, appErrors.ErrInvalidProviderID))
}

func TestProviderService_Create_ValidID(t *testing.T) {
	db := setupServiceTestDB(t)
	repo := repository.NewProviderRepository(db)
	modelRepo := repository.NewModelRepository(db)
	svc := NewProviderService(repo, modelRepo)

	provider := &domain.Provider{ID: "openai", Name: "OpenAI", APIKey: "key", BaseURL: "https://api.openai.com"}
	err := svc.Create(provider)
	require.NoError(t, err)
	assert.Equal(t, "openai", provider.ID)
	assert.True(t, provider.Enabled)
}

// ============ ModelService - Update with duplicate check 测试 ============

func TestModelService_Update_DuplicateModelName(t *testing.T) {
	db := setupServiceTestDB(t)
	providerRepo := repository.NewProviderRepository(db)
	modelRepo := repository.NewModelRepository(db)
	svc := NewModelService(modelRepo, providerRepo)

	require.NoError(t, providerRepo.Create(&domain.Provider{ID: "openai", Name: "OpenAI", APIKey: "key", BaseURL: "https://api.openai.com"}))
	require.NoError(t, providerRepo.Create(&domain.Provider{ID: "anthropic", Name: "Anthropic", APIKey: "key", BaseURL: "https://api.anthropic.com"}))

	model1 := &domain.Model{ProviderID: "openai", ModelName: "gpt-4"}
	err := svc.Create(model1)
	require.NoError(t, err)

	model2 := &domain.Model{ProviderID: "anthropic", ModelName: "claude-3"}
	err = svc.Create(model2)
	require.NoError(t, err)

	// 将 model2 的 model_name 改为 "gpt-4" 且 provider_id 改为 "openai"，与 model1 冲突
	err = svc.Update(model2.ID, map[string]interface{}{
		"provider_id": "openai",
		"model_name":  "gpt-4",
	})
	assert.True(t, errors.Is(err, appErrors.ErrDuplicateModel))
}

func TestModelService_Update_ModelNotFound(t *testing.T) {
	db := setupServiceTestDB(t)
	providerRepo := repository.NewProviderRepository(db)
	modelRepo := repository.NewModelRepository(db)
	svc := NewModelService(modelRepo, providerRepo)

	err := svc.Update("nonexistent-id", map[string]interface{}{
		"model_name": "gpt-4",
	})
	assert.True(t, errors.Is(err, appErrors.ErrModelNotFound))
}

func TestModelService_Update_Success(t *testing.T) {
	db := setupServiceTestDB(t)
	providerRepo := repository.NewProviderRepository(db)
	modelRepo := repository.NewModelRepository(db)
	svc := NewModelService(modelRepo, providerRepo)

	require.NoError(t, providerRepo.Create(&domain.Provider{ID: "openai", Name: "OpenAI", APIKey: "key", BaseURL: "https://api.openai.com"}))

	model := &domain.Model{ProviderID: "openai", ModelName: "gpt-4"}
	err := svc.Create(model)
	require.NoError(t, err)

	// 更新 model_name 为不冲突的值
	err = svc.Update(model.ID, map[string]interface{}{
		"model_name": "gpt-4-turbo",
	})
	require.NoError(t, err)

	updated, err := svc.Get(model.ID)
	require.NoError(t, err)
	assert.Equal(t, "gpt-4-turbo", updated.ModelName)
}

// ============ ProviderService - Update immutable ID 测试 ============

func TestProviderService_Update_ImmutableID(t *testing.T) {
	db := setupServiceTestDB(t)
	repo := repository.NewProviderRepository(db)
	modelRepo := repository.NewModelRepository(db)
	svc := NewProviderService(repo, modelRepo)

	provider := &domain.Provider{ID: "openai", Name: "OpenAI", APIKey: "key", BaseURL: "https://api.openai.com"}
	err := svc.Create(provider)
	require.NoError(t, err)

	// 尝试更新 id 字段
	err = svc.Update("openai", map[string]interface{}{
		"id": "new-id",
	})
	assert.True(t, errors.Is(err, appErrors.ErrImmutableField))
}

func TestProviderService_Update_Success(t *testing.T) {
	db := setupServiceTestDB(t)
	repo := repository.NewProviderRepository(db)
	modelRepo := repository.NewModelRepository(db)
	svc := NewProviderService(repo, modelRepo)

	provider := &domain.Provider{ID: "openai", Name: "OpenAI", APIKey: "key", BaseURL: "https://api.openai.com"}
	err := svc.Create(provider)
	require.NoError(t, err)

	// 更新 name
	err = svc.Update("openai", map[string]interface{}{
		"name": "OpenAI Updated",
	})
	require.NoError(t, err)

	updated, err := svc.Get("openai", false)
	require.NoError(t, err)
	assert.Equal(t, "OpenAI Updated", updated.Name)
}

// ============ StatsService - Aggregate ByModel 测试 ============

func TestStatsService_Aggregate_ByModel(t *testing.T) {
	tests := []struct {
		name     string
		stats    []domain.UsageStats
		expected []map[string]interface{}
	}{
		{
			name: "multiple providers with same model name",
			stats: []domain.UsageStats{
				{ProviderID: "openai", ModelName: "gpt-4", RequestCount: 10},
				{ProviderID: "azure", ModelName: "gpt-4", RequestCount: 20},
				{ProviderID: "openai", ModelName: "gpt-4", RequestCount: 5},
			},
			expected: []map[string]interface{}{
				{"provider_id": "openai", "model_name": "gpt-4", "request_count": 15},
				{"provider_id": "azure", "model_name": "gpt-4", "request_count": 20},
			},
		},
		{
			name: "empty providerID",
			stats: []domain.UsageStats{
				{ProviderID: "", ModelName: "gpt-4", RequestCount: 10},
				{ProviderID: "", ModelName: "gpt-4", RequestCount: 5},
			},
			expected: []map[string]interface{}{
				{"provider_id": "", "model_name": "gpt-4", "request_count": 15},
			},
		},
		{
			name:     "empty result set",
			stats:    []domain.UsageStats{},
			expected: []map[string]interface{}{},
		},
	}

	for _, tt := range tests {
		t.Run(tt.name, func(t *testing.T) {
			db := setupServiceTestDB(t)
			statsRepo := repository.NewStatsRepository(db)
			svc := NewStatsService(statsRepo)

			result := svc.Aggregate(tt.stats, "model")

			assert.Len(t, result, len(tt.expected))
			for _, exp := range tt.expected {
				found := false
				for _, r := range result {
					if r["provider_id"] == exp["provider_id"] && r["model_name"] == exp["model_name"] {
						assert.Equal(t, exp["request_count"], r["request_count"])
						found = true
						break
					}
				}
				assert.True(t, found, "expected result not found: %v", exp)
			}
		})
	}
}

// ============ StatsService - Aggregate ByDate 测试 ============

func TestStatsService_Aggregate_ByDate(t *testing.T) {
	tests := []struct {
		name     string
		stats    []domain.UsageStats
		expected []map[string]interface{}
	}{
		{
			name: "normal date grouping",
			stats: []domain.UsageStats{
				{Date: time.Date(2024, 1, 1, 0, 0, 0, 0, time.UTC), RequestCount: 10},
				{Date: time.Date(2024, 1, 1, 12, 0, 0, 0, time.UTC), RequestCount: 5},
				{Date: time.Date(2024, 1, 2, 0, 0, 0, 0, time.UTC), RequestCount: 20},
			},
			expected: []map[string]interface{}{
				{"date": "2024-01-01", "request_count": 15},
				{"date": "2024-01-02", "request_count": 20},
			},
		},
		{
			name: "zero-value time",
			stats: []domain.UsageStats{
				{Date: time.Time{}, RequestCount: 10},
				{Date: time.Time{}, RequestCount: 5},
			},
			expected: []map[string]interface{}{
				{"date": "0001-01-01", "request_count": 15},
			},
		},
		{
			name:     "empty result set",
			stats:    []domain.UsageStats{},
			expected: []map[string]interface{}{},
		},
	}

	for _, tt := range tests {
		t.Run(tt.name, func(t *testing.T) {
			db := setupServiceTestDB(t)
			statsRepo := repository.NewStatsRepository(db)
			svc := NewStatsService(statsRepo)

			result := svc.Aggregate(tt.stats, "date")

			assert.Len(t, result, len(tt.expected))
			for _, exp := range tt.expected {
				found := false
				for _, r := range result {
					if r["date"] == exp["date"] {
						assert.Equal(t, exp["request_count"], r["request_count"])
						found = true
						break
					}
				}
				assert.True(t, found, "expected result not found: %v", exp)
			}
		})
	}
}

// ============ ProviderService - isUniqueConstraintError 测试 ============

func TestProviderService_isUniqueConstraintError(t *testing.T) {
	tests := []struct {
		name     string
		err      error
		expected bool
	}{
		{
			name:     "nil error",
			err:      nil,
			expected: false,
		},
		{
			name:     "UNIQUE constraint failed",
			err:      errors.New("UNIQUE constraint failed"),
			expected: true,
		},
		{
			name:     "duplicate key value",
			err:      errors.New("duplicate key value"),
			expected: true,
		},
		{
			name:     "UNIQUE constraint case insensitive",
			err:      errors.New("unique constraint violation"),
			expected: true,
		},
		{
			name:     "other error",
			err:      errors.New("some other error"),
			expected: false,
		},
	}

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

// ============ ProviderService - List MaskAPIKey 测试 ============

func TestProviderService_List_MaskAPIKey(t *testing.T) {
	db := setupServiceTestDB(t)
	repo := repository.NewProviderRepository(db)
	modelRepo := repository.NewModelRepository(db)
	svc := NewProviderService(repo, modelRepo)

	provider1 := &domain.Provider{ID: "openai", Name: "OpenAI", APIKey: "sk-1234567890", BaseURL: "https://api.openai.com"}
	provider2 := &domain.Provider{ID: "anthropic", Name: "Anthropic", APIKey: "sk-anthropic1234", BaseURL: "https://api.anthropic.com"}
	require.NoError(t, svc.Create(provider1))
	require.NoError(t, svc.Create(provider2))

	providers, err := svc.List()
	require.NoError(t, err)
	require.Len(t, providers, 2)

	for _, p := range providers {
		assert.Contains(t, p.APIKey, "***")
		assert.Len(t, p.APIKey, 7)
	}
}

func TestModelService_ConcurrentCreate(t *testing.T) {
	db := setupServiceTestDB(t)
	providerRepo := repository.NewProviderRepository(db)
	modelRepo := repository.NewModelRepository(db)
	svc := NewModelService(modelRepo, providerRepo)

	require.NoError(t, providerRepo.Create(&domain.Provider{ID: "openai", Name: "OpenAI", APIKey: "key", BaseURL: "https://api.openai.com"}))

	results := make(chan error, 2)
	for i := 0; i < 2; i++ {
		go func() {
			model := &domain.Model{ProviderID: "openai", ModelName: "gpt-4"}
			results <- svc.Create(model)
		}()
	}

	err1 := <-results
	err2 := <-results

	successCount := 0
	errorCount := 0
	for _, err := range []error{err1, err2} {
		if err == nil {
			successCount++
		} else {
			errorCount++
		}
	}
	assert.Equal(t, 1, successCount)
	assert.Equal(t, 1, errorCount)
}