package database

import (
	"fmt"
	"log"
	"smart-customer-service/config"
	"smart-customer-service/internal/models"

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

var DB *gorm.DB

// Init 初始化数据库连接
func Init(cfg *config.Config) error {
	dsn := cfg.GetDSN()
	
	// 设置日志级别
	var logLevel logger.LogLevel
	if cfg.Server.Mode == "debug" {
		logLevel = logger.Info
	} else {
		logLevel = logger.Warn
	}

	var err error
	// 连接 MySQL 数据库
	DB, err = gorm.Open(mysql.Open(dsn), &gorm.Config{
		Logger: logger.Default.LogMode(logLevel),
		DisableForeignKeyConstraintWhenMigrating: true,
	})
	
	if err != nil {
		return fmt.Errorf("failed to connect to database: %w", err)
	}

	log.Println("✅ Database connection established")
	
	// 自动迁移模型
	if err := Migrate(cfg); err != nil {
		return fmt.Errorf("failed to migrate database: %w", err)
	}

	log.Println("✅ Database migration completed")
	return nil
}

// Migrate 执行数据库迁移
func Migrate(cfg *config.Config) error {
	// 全局模型
	if err := DB.AutoMigrate(
		// 租户体系
		&models.Tenant{},
		&models.User{},
		&models.Role{},
		&models.Resource{},
		&models.RoleResource{},
		&models.UserRole{},
		
		// 业务模型
		&models.Conversation{},
		&models.Message{},
		&models.Ticket{},
		&models.KnowledgeBase{},
		&models.KnowledgeItem{},
	); err != nil {
		return err
	}
	
	return nil
}

// Close 关闭数据库连接
func Close() {
	if DB != nil {
		db, _ := DB.DB()
		db.Close()
		log.Println("✅ Database connection closed")
	}
}