package config

import (
	"context"
	"fmt"
	"net/http"
	"os"
	"path/filepath"
	"time"

	"engimind/internal/models"
	"engimind/internal/vector"

	"gorm.io/driver/sqlite"
	"gorm.io/gorm"
	"gorm.io/gorm/logger"
)

// ConfigService manages global LLM and VectorDB configuration.
// Bound to Wails as a service.
type ConfigService struct {
	db *gorm.DB
}

// NewConfigService initializes the global config database.
func NewConfigService() *ConfigService {
	return &ConfigService{}
}

// OnStartup is called by Wails on app start.
func (s *ConfigService) Init() error {
	homeDir, err := os.UserHomeDir()
	if err != nil {
		return fmt.Errorf("get home dir: %w", err)
	}
	dbDir := filepath.Join(homeDir, ".engimind")
	if err := os.MkdirAll(dbDir, 0755); err != nil {
		return fmt.Errorf("create config dir: %w", err)
	}

	db, err := gorm.Open(sqlite.Open(filepath.Join(dbDir, "global.db")), &gorm.Config{
		Logger: logger.Default.LogMode(logger.Silent),
	})
	if err != nil {
		return fmt.Errorf("open global db: %w", err)
	}
	s.db = db

	if err := db.AutoMigrate(
		&models.LLMProvider{},
		&models.VectorDBConfig{},
		&models.Project{},
	); err != nil {
		return fmt.Errorf("auto migrate: %w", err)
	}

	// Seed defaults if empty
	var count int64
	db.Model(&models.LLMProvider{}).Count(&count)
	if count == 0 {
		s.seedDefaults()
	}
	return nil
}

func (s *ConfigService) seedDefaults() {
	providers := []models.LLMProvider{
		{ID: "cfg1", Name: "DeepSeek Cloud", Provider: "DeepSeek", BaseURL: "https://api.deepseek.com", APIKey: "", ModelID: "deepseek-reasoner", Enabled: true},
		{ID: "cfg2", Name: "Ollama: Local", Provider: "Ollama", BaseURL: "http://localhost:11434", APIKey: "", ModelID: "qwen2.5:32b", Enabled: true},
	}
	for _, p := range providers {
		s.db.Create(&p)
	}
	s.db.Create(&models.VectorDBConfig{
		ID: 1, Endpoint: "http://localhost:6333", APIKey: "", Status: "disconnected",
	})
}

// --- LLM Provider CRUD ---

func (s *ConfigService) GetAllProviders() ([]models.LLMProvider, error) {
	var providers []models.LLMProvider
	err := s.db.Find(&providers).Error
	return providers, err
}

func (s *ConfigService) SaveProvider(p models.LLMProvider) error {
	return s.db.Save(&p).Error
}

func (s *ConfigService) DeleteProvider(id string) error {
	return s.db.Delete(&models.LLMProvider{}, "id = ?", id).Error
}

// --- VectorDB Config ---

func (s *ConfigService) GetVectorDBConfig() (models.VectorDBConfig, error) {
	var cfg models.VectorDBConfig
	err := s.db.First(&cfg).Error
	return cfg, err
}

func (s *ConfigService) SaveVectorDBConfig(c models.VectorDBConfig) error {
	c.ID = 1 // singleton
	return s.db.Save(&c).Error
}

func (s *ConfigService) GetDB() *gorm.DB {
	return s.db
}

// --- Connection Testing ---

// TestVectorDBConnection verifies the Qdrant server is reachable.
func (s *ConfigService) TestVectorDBConnection(endpoint string) (bool, error) {
	ctx, cancel := context.WithTimeout(context.Background(), 5*time.Second)
	defer cancel()

	// Normalize endpoint for gRPC (Qdrant default gRPC is 6334, HTTP is 6333)
	// Strip http:// or https:// prefix
	if len(endpoint) > 7 && endpoint[:7] == "http://" {
		endpoint = endpoint[7:]
	} else if len(endpoint) > 8 && endpoint[:8] == "https://" {
		endpoint = endpoint[8:]
	}

	// If user inputs 6333 (HTTP port), we auto-correct to 6334 for gRPC for ease of use
	if len(endpoint) > 5 && endpoint[len(endpoint)-5:] == ":6333" {
		endpoint = endpoint[:len(endpoint)-5] + ":6334"
	}

	store, err := vector.NewQdrantStore(endpoint, 1) // dimension is mostly ignored for list operation
	if err != nil {
		return false, fmt.Errorf("建立到 Qdrant 的连接失败 (尝试连接 %s): %w", endpoint, err)
	}
	defer store.Close()

	ok, err := store.TestConnection(ctx)
	if err != nil {
		return false, fmt.Errorf("Qdrant 测试请求错误 (请确保使用的是 gRPC 端口, 默认 6334): %w", err)
	}
	return ok, nil
}

// TestLLMConnection tests connectivity and auth configuration for a provider.
func (s *ConfigService) TestLLMConnection(provider, baseURL, apiKey string) (bool, error) {
	var reqURL string
	if provider == "Ollama" {
		reqURL = baseURL + "/api/tags"
	} else {
		// DeepSeek/OpenAI compatible models endpoint
		// Often requires /v1/models. If user provides baseURL with /v1, we just append /models
		// Or we can just let it try the URL directly if we assume user's base URL is the completions one?
		// Usually standard is "https://api.deepseek.com" or "https://api.deepseek.com/v1"
		// Wait, some BaseURLs don't have /v1. Let's do a basic normalization.
		if baseURL[len(baseURL)-1] == '/' {
			baseURL = baseURL[:len(baseURL)-1]
		}
		if provider == "DeepSeek" || provider == "OpenAI" {
			reqURL = baseURL + "/models"
		} else {
			reqURL = baseURL + "/v1/models"
		}
	}

	req, err := http.NewRequestWithContext(context.Background(), "GET", reqURL, nil)
	if err != nil {
		return false, err
	}
	if apiKey != "" && provider != "Ollama" {
		req.Header.Set("Authorization", "Bearer "+apiKey)
	}

	client := &http.Client{Timeout: 8 * time.Second}
	resp, err := client.Do(req)
	if err != nil {
		return false, fmt.Errorf("网络连通性异常: %w", err)
	}
	defer resp.Body.Close()

	if resp.StatusCode >= 200 && resp.StatusCode < 400 {
		return true, nil
	}
	if resp.StatusCode == 401 {
		return false, fmt.Errorf("API Key 无效 (HTTP 无授权 %d)", resp.StatusCode)
	}
	return false, fmt.Errorf("返回非健康状态码: HTTP %d", resp.StatusCode)
}