package db

import (
	"apiServer_service/utils/logger"
	"fmt"
	"os"
	"sync"
	"time"

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

var (
	DB   *gorm.DB
	once sync.Once
)

func ConnectDatabase() {
	once.Do(func() {
		dbType := os.Getenv("DB_TYPE")
		dbUser := os.Getenv("DB_USER")
		dbPassword := os.Getenv("DB_PASSWORD")
		dbName := os.Getenv("DB_NAME")
		dbHost := os.Getenv("DB_HOST")
		dbPort := os.Getenv("DB_PORT")

		if dbType == "" {
			logger.Warn("Database", "DB_TYPE 未配置，跳过数据库连接")
			return
		}

		var dialector gorm.Dialector

		switch dbType {
		case "mysql":
			dsn := fmt.Sprintf("%s:%s@tcp(%s:%s)/%s?charset=utf8mb4&parseTime=True&loc=Local",
				dbUser, dbPassword, dbHost, dbPort, dbName)
			dialector = mysql.Open(dsn)
		case "postgres":
			dbSchema := os.Getenv("DB_SCHEMA")
			if dbSchema == "" {
				dbSchema = "public"
			}
			dsn := fmt.Sprintf("host=%s user=%s password=%s dbname=%s port=%s sslmode=disable TimeZone=Asia/Shanghai search_path=%s",
				dbHost, dbUser, dbPassword, dbName, dbPort, dbSchema)
			dialector = postgres.Open(dsn)
		default:
			logger.Fatal("Database", fmt.Sprintf("不支持的 DB_TYPE: %s（仅支持 mysql / postgres）", dbType))
			return
		}

		conn, err := gorm.Open(dialector, &gorm.Config{})
		if err != nil {
			logger.Fatal("Database", "连接失败: ", err)
			return
		}

		sqlDB, err := conn.DB()
		if err != nil {
			logger.Fatal("Database", "获取底层连接池失败: ", err)
			return
		}
		sqlDB.SetMaxOpenConns(50)
		sqlDB.SetMaxIdleConns(10)
		sqlDB.SetConnMaxLifetime(30 * time.Minute)
		sqlDB.SetConnMaxIdleTime(10 * time.Minute)

		DB = conn
		logger.Info("Database", fmt.Sprintf("连接成功 (%s)", dbType))
	})
}

func GetDB() *gorm.DB {
	if DB == nil {
		ConnectDatabase()
	}
	return DB
}

// Migrate 自动迁移所有模型，新增模型在此注册
func Migrate() {
	if DB == nil {
		logger.Warn("Database", "数据库未连接，跳过迁移")
		return
	}

	models := []interface{}{
		&HostGroup{},
	}

	for _, model := range models {
		if err := DB.AutoMigrate(model); err != nil {
			logger.Error("Database", fmt.Sprintf("迁移 %T 失败: %v", model, err))
		} else {
			logger.Info("Database", fmt.Sprintf("迁移 %T 完成", model))
		}
	}
}