package database

import (
	"log"
	"os"
	"strings"
	"time"

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

func OpenMySQL(dsn string, logLevel string) (*gorm.DB, error) {
	db, err := gorm.Open(mysql.Open(dsn), &gorm.Config{
		Logger: newGormLogger(logLevel),
	})
	if err != nil {
		return nil, err
	}

	sqlDB, err := db.DB()
	if err != nil {
		return nil, err
	}
	// 限制连接池，避免本地压测瞬间打满 MySQL max_connections。
	sqlDB.SetMaxOpenConns(50)
	sqlDB.SetMaxIdleConns(10)
	sqlDB.SetConnMaxLifetime(30 * time.Minute)
	sqlDB.SetConnMaxIdleTime(5 * time.Minute)

	return db, nil
}

func newGormLogger(logLevel string) logger.Interface {
	level := logger.Warn
	if strings.EqualFold(strings.TrimSpace(logLevel), "debug") {
		level = logger.Info
	}
	return logger.New(
		log.New(os.Stdout, "\r\n", log.LstdFlags),
		logger.Config{
			SlowThreshold:             500 * time.Millisecond,
			LogLevel:                  level,
			IgnoreRecordNotFoundError: true,
			Colorful:                  false,
		},
	)
}