package db

import (
	"admin/internal/errcode"
	"admin/internal/global"
	"admin/lib/xlog"
	"fmt"
	mysqlDriver "github.com/go-sql-driver/mysql"
	"gorm.io/driver/mysql"
	"gorm.io/driver/sqlite"
	"gorm.io/gorm"
	"strings"
	"sync"
	"time"
)

var (
	globalTables []any
	locker       sync.Mutex
)

func RegisterTableModels(models ...any) {
	locker.Lock()
	defer locker.Unlock()
	globalTables = append(globalTables, models...)
}

func NewDB(dbType, dbAddr, dbName, dbUser, dbPass string) (db *gorm.DB, err error) {
	dsn := fmt.Sprintf("%v:%v@tcp(%v)/%v?charset=utf8mb4&parseTime=True&loc=Local", dbUser, dbPass, dbAddr, dbName)
	dsnWithoutDB := fmt.Sprintf("%v:%v@tcp(%v)/?charset=utf8mb4&parseTime=True&loc=Local", dbUser, dbPass, dbAddr)
	db, err = createDBAndGuaranteeMigrate(dbType, dsnWithoutDB, dsn, globalTables)
	if err != nil {
		return nil, err
	}
	global.GLOB_DB = db
	return db, nil
}

func createDBAndGuaranteeMigrate(dbType string, dsnWithoutDb, dsn string, tables []any) (*gorm.DB, error) {
	mysqlDriverConf, err := mysqlDriver.ParseDSN(dsn)
	if err != nil {
		return nil, fmt.Errorf("parse dsn:%v error:%v", dsn, err)
	}
	dbName := mysqlDriverConf.DBName

	var dialector gorm.Dialector
	switch dbType {
	case "sqlite":
		dialector = sqlite.Open(dbName)
	case "mysql":
		dialector = mysql.Open(dsnWithoutDb)
	default:
		panic(fmt.Errorf("unsupported db type: %v", dbType))
	}

	_, err = tryCreateDB(dbType, dialector, dbName)
	if err != nil {
		xlog.Fatalf(err)
		return nil, err
	}

	switch dbType {
	case "sqlite":
		dialector = sqlite.Open(dbName)
	case "mysql":
		dialector = mysql.Open(dsn)
	default:
		panic(fmt.Errorf("unsupported db type: %v", dbType))
	}

	//driverConf := mysql.Config{
	//	DSN:                     dsn,
	//	DontSupportRenameColumn: true,
	//	//SkipInitializeWithVersion: false, // 根据数据库版本自动配置
	//}
	//dialector = mysql.New(driverConf)

	//slowLogger := logger.New(
	//	syslog.New(xlog.GetGlobalWriter(), "\n", syslog.LstdFlags),
	//	logger.Config{
	//		// 设定慢查询时间阈值为 默认值：200 * time.Millisecond
	//		SlowThreshold: 200 * time.Millisecond,
	//		// 设置日志级别
	//		LogLevel: logger.Warn,
	//		Colorful: true,
	//	},
	//)

	db, err := gorm.Open(dialector, &gorm.Config{
		Logger:      &gormLogger{},
		PrepareStmt: false, // 关闭缓存sql语句功能，因为后续use db会报错，这个缓存会无限存储可能导致内存泄露
		//SkipDefaultTransaction: true, // 跳过默认事务
	})
	if err != nil {
		return nil, fmt.Errorf("failed to connect to mysql:%v", err)
	}

	sqlDB, _ := db.DB()
	sqlDB.SetMaxIdleConns(10)
	sqlDB.SetMaxOpenConns(50)
	sqlDB.SetConnMaxIdleTime(time.Minute * 5)
	sqlDB.SetConnMaxLifetime(time.Minute * 10)

	if len(tables) > 0 {
		err = autoMigrate(db, tables...)
		if err != nil {
			xlog.Fatalf(err)
			return nil, fmt.Errorf("automigrate error:%v", err)
		}
	}

	//addMetricsCollection(db, strconv.Itoa(int(serverId)), dbName)
	return db, nil
}

func tryCreateDB(dbType string, dialector gorm.Dialector, dbName string) (string, error) {

	db, err := gorm.Open(dialector, &gorm.Config{
		PrepareStmt: false, // 关闭缓存sql语句功能，因为后续use db会报错，这个缓存会无限存储可能导致内存泄露
		//SkipDefaultTransaction: true, // 跳过默认事务
	})
	if err != nil {
		return "", fmt.Errorf("failed to connect to mysql:%v", err)
	}

	// 检查数据库是否存在
	if dbType != "sqlite" {
		var count int
		db.Raw("SELECT COUNT(*) FROM information_schema.schemata WHERE schema_name = ?", dbName).Scan(&count)
		if count == 0 {
			// 数据库不存在，创建它
			sql := fmt.Sprintf("create database if not exists `%s` default charset utf8mb4 collate utf8mb4_unicode_ci",
				dbName)
			if e := db.Exec(sql).Error; e != nil {
				return "", fmt.Errorf("failed to create database:%v", e)
			}
		}
	}

	sqlDb, _ := db.DB()
	sqlDb.Close()

	return dbName, nil
}

func autoMigrate(db *gorm.DB, tables ...interface{}) error {
	// 这个函数是在InitConn之后调用的

	// 初始化表
	for _, table := range tables {
		if err := db.AutoMigrate(table); err != nil {
			if strings.Contains(err.Error(), "there is already a table named") {
				continue
			}
			if strings.Contains(err.Error(), "already exists") {
				continue
			}
			return errcode.New(errcode.DBError, "failed to init tables:%v", err)
		}
	}

	return nil
}