package storage

import (
	"context"
	"encoding/json"
	"fmt"
	"u-desk/internal/crypto"
	"u-desk/internal/dbclient"
	"u-desk/internal/storage/models"

	"gorm.io/gorm"
)

// ConnectionService 连接管理服务
type ConnectionService struct {
	db *gorm.DB
}

// NewConnectionService 创建连接服务
func NewConnectionService() (*ConnectionService, error) {
	db := GetDB()
	if db == nil {
		// 尝试重新初始化
		var err error
		db, err = Init()
		if err != nil {
			return nil, fmt.Errorf("数据库初始化失败: %v", err)
		}
	}
	return &ConnectionService{db: db}, nil
}

// SaveConnection 保存连接配置
func (s *ConnectionService) SaveConnection(conn *models.DbConnection) error {
	if conn.Name == "" {
		return fmt.Errorf("连接名称不能为空")
	}
	if conn.Type == "" {
		return fmt.Errorf("数据库类型不能为空")
	}
	if conn.Host == "" {
		return fmt.Errorf("主机地址不能为空")
	}

	// 检查名称是否重复（排除当前记录）
	var count int64
	query := s.db.Model(&models.DbConnection{}).Where("name = ?", conn.Name)
	if conn.ID > 0 {
		query = query.Where("id != ?", conn.ID)
	}
	query.Count(&count)
	if count > 0 {
		return fmt.Errorf("连接名称已存在")
	}

	if conn.ID > 0 {
		// 更新模式
		updateData := map[string]interface{}{
			"name":              conn.Name,
			"type":              conn.Type,
			"host":              conn.Host,
			"port":              conn.Port,
			"username":          conn.Username,
			"database":          conn.Database,
			"options":           conn.Options,
			"visible_databases": conn.VisibleDatabases,
		}

		// 如果提供了新密码，加密后更新
		if conn.Password != "" {
			encrypted, err := crypto.EncryptPassword(conn.Password)
			if err != nil {
				return fmt.Errorf("密码加密失败: %v", err)
			}
			updateData["password"] = encrypted
		}
		// 如果密码为空，不更新密码字段（保留原密码）

		return s.db.Model(&models.DbConnection{}).Where("id = ?", conn.ID).Updates(updateData).Error
	}

	// 新增模式 - 必须提供密码
	if conn.Password == "" {
		return fmt.Errorf("新增连接时密码不能为空")
	}

	// 加密密码
	encrypted, err := crypto.EncryptPassword(conn.Password)
	if err != nil {
		return fmt.Errorf("密码加密失败: %v", err)
	}
	conn.Password = encrypted

	return s.db.Create(conn).Error
}

// ListConnections 获取连接列表
func (s *ConnectionService) ListConnections() ([]models.DbConnection, error) {
	var connections []models.DbConnection
	err := s.db.Order("created_at DESC").Find(&connections).Error
	return connections, err
}

// GetConnection 获取连接详情
func (s *ConnectionService) GetConnection(id uint) (*models.DbConnection, error) {
	var conn models.DbConnection
	err := s.db.First(&conn, id).Error
	if err != nil {
		return nil, err
	}
	return &conn, nil
}

// DeleteConnection 删除连接配置
func (s *ConnectionService) DeleteConnection(id uint) error {
	var conn models.DbConnection
	if err := s.db.First(&conn, id).Error; err != nil {
		return nil // 连接不存在视为成功
	}

	// 使用事务删除
	return s.db.Transaction(func(tx *gorm.DB) error {
		// 清理关联数据
		tx.Where("connection_id = ?", id).Delete(&models.SqlResultHistory{})
		tx.Where("connection_id = ?", id).Delete(&models.SqlTab{})

		// 删除连接
		if err := tx.Delete(&conn).Error; err != nil {
			return err
		}

		// 关闭连接池
		dbclient.GetPool().CloseConnection(id, conn.Type)
		return nil
	})
}

// TestConnection 测试连接（需要根据类型调用不同的测试方法）
func (s *ConnectionService) TestConnection(conn *models.DbConnection) error {
	// 解密密码用于测试
	password, err := crypto.DecryptPassword(conn.Password)
	if err != nil {
		return fmt.Errorf("密码解密失败: %v", err)
	}

	// 根据类型测试连接
	switch conn.Type {
	case "mysql":
		return testMySQLConnection(conn.Host, conn.Port, conn.Username, password, conn.Database)
	case "redis":
		return testRedisConnection(conn.Host, conn.Port, password)
	case "mongo":
		// 解析 Options 获取 MongoDB 连接参数
		authSource := ""
		authMechanism := ""
		if conn.Options != "" {
			var opts map[string]interface{}
			if err := json.Unmarshal([]byte(conn.Options), &opts); err == nil {
				if as, ok := opts["authSource"].(string); ok && as != "" {
					authSource = as
				}
				if am, ok := opts["authMechanism"].(string); ok && am != "" {
					authMechanism = am
				}
			}
		}
		return testMongoConnection(conn.Host, conn.Port, conn.Username, password, conn.Database, authSource, authMechanism)
	default:
		return fmt.Errorf("不支持的数据库类型: %s", conn.Type)
	}
}

// testMySQLConnection 测试 MySQL 连接
func testMySQLConnection(host string, port int, username, password, database string) error {
	return dbclient.TestMySQLConnection(host, port, username, password, database)
}

// testRedisConnection 测试 Redis 连接
func testRedisConnection(host string, port int, password string) error {
	return dbclient.TestRedisConnection(host, port, password)
}

// testMongoConnection 测试 MongoDB 连接
func testMongoConnection(host string, port int, username, password, database, authSource, authMechanism string) error {
	return dbclient.TestMongoConnectionWithOptions(host, port, username, password, database, authSource, authMechanism)
}

// TestConnectionWithParams 使用参数测试连接（不保存数据）
func (s *ConnectionService) TestConnectionWithParams(dbType, host string, port int, username, password, database, options string, id uint) error {
	// 如果是编辑模式且有ID，获取已保存的密码
	if id > 0 && password == "" {
		conn, err := s.GetConnection(id)
		if err != nil {
			return fmt.Errorf("获取连接信息失败: %v", err)
		}
		decryptPassword, err := crypto.DecryptPassword(conn.Password)
		if err != nil {
			return fmt.Errorf("密码解密失败: %v", err)
		}
		password = decryptPassword
	}

	// 根据类型测试连接
	switch dbType {
	case "mysql":
		return testMySQLConnection(host, port, username, password, database)
	case "redis":
		return testRedisConnection(host, port, password)
	case "mongo":
		// 解析 Options 获取 MongoDB 连接参数
		authSource := ""
		authMechanism := ""
		if options != "" {
			var opts map[string]interface{}
			if err := json.Unmarshal([]byte(options), &opts); err == nil {
				if as, ok := opts["authSource"].(string); ok && as != "" {
					authSource = as
				}
				if am, ok := opts["authMechanism"].(string); ok && am != "" {
					authMechanism = am
				}
			}
		}
		return testMongoConnection(host, port, username, password, database, authSource, authMechanism)
	default:
		return fmt.Errorf("不支持的数据库类型: %s", dbType)
	}
}

// LoadAllDatabases 加载全部数据库列表
func (s *ConnectionService) LoadAllDatabases(dbType, host string, port int, username, password, database, options string, id uint) ([]string, error) {
	// 如果是编辑模式且有ID，获取已保存的密码
	if id > 0 && password == "" {
		conn, err := s.GetConnection(id)
		if err != nil {
			return nil, fmt.Errorf("获取连接信息失败: %v", err)
		}
		decryptPassword, err := crypto.DecryptPassword(conn.Password)
		if err != nil {
			return nil, fmt.Errorf("密码解密失败: %v", err)
		}
		password = decryptPassword
	}

	// 根据类型加载数据库列表
	switch dbType {
	case "mysql":
		return loadMySQLDatabases(host, port, username, password, database)
	case "mongo":
		return loadMongoDatabases(host, port, username, password, database, options)
	case "redis":
		// Redis 没有数据库概念，返回空列表
		return []string{}, nil
	default:
		return nil, fmt.Errorf("不支持的数据库类型: %s", dbType)
	}
}

// loadMySQLDatabases 加载 MySQL 数据库列表
func loadMySQLDatabases(host string, port int, username, password, defaultDatabase string) ([]string, error) {
	config := &dbclient.MySQLConfig{
		Host:     host,
		Port:     port,
		Username: username,
		Password: password,
		Database: defaultDatabase,
	}
	client, err := dbclient.NewMySQLClient(config)
	if err != nil {
		return nil, err
	}
	defer client.Close()

	return client.ListDatabases(context.Background())
}

// loadMongoDatabases 加载 MongoDB 数据库列表
func loadMongoDatabases(host string, port int, username, password, defaultDatabase, options string) ([]string, error) {
	// 解析 Options 获取 MongoDB 连接参数
	authSource := ""
	authMechanism := ""
	if options != "" {
		var opts map[string]interface{}
		if err := json.Unmarshal([]byte(options), &opts); err == nil {
			if as, ok := opts["authSource"].(string); ok && as != "" {
				authSource = as
			}
			if am, ok := opts["authMechanism"].(string); ok && am != "" {
				authMechanism = am
			}
		}
	}

	mongoConfig := &dbclient.MongoConfig{
		Host:          host,
		Port:          port,
		Username:      username,
		Password:      password,
		Database:      defaultDatabase,
		AuthSource:    authSource,
		AuthMechanism: authMechanism,
	}
	client, err := dbclient.NewMongoClient(mongoConfig)
	if err != nil {
		return nil, err
	}
	defer client.Close()

	return client.ListDatabases(context.Background())
}