package dao

import (
	"exam_registration/internal/model"
	"fmt"
	"github.com/spf13/viper"
	"gorm.io/driver/mysql"
	"gorm.io/gorm"
	"gorm.io/gorm/logger"
	"time"
)

var DB *gorm.DB

func InitMySQL(config *viper.Viper) error {
	host := config.GetString("database.host")
	port := config.GetString("database.port")
	user := config.GetString("database.user")
	password := config.GetString("database.password")
	dbname := config.GetString("database.dbname")
	charset := config.GetString("database.charset")
	maxIdleConns := config.GetInt("database.max_idle_conns")
	maxOpenConns := config.GetInt("database.max_open_conns")
	connMaxLifetime := config.GetInt("database.conn_max_lifetime")

	dsn := fmt.Sprintf("%s:%s@tcp(%s:%s)/%s?charset=%s&parseTime=True&loc=Local",
		user, password, host, port, dbname, charset)

	var err error
	DB, err = gorm.Open(mysql.Open(dsn), &gorm.Config{
		Logger: logger.Default.LogMode(logger.Info),
	})

	if err != nil {
		return fmt.Errorf("failed to connect database: %w", err)
	}

	// 配置连接池
	sqlDB, err := DB.DB()
	if err != nil {
		return fmt.Errorf("failed to get sql.DB: %w", err)
	}

	sqlDB.SetMaxIdleConns(maxIdleConns)
	sqlDB.SetMaxOpenConns(maxOpenConns)
	sqlDB.SetConnMaxLifetime(time.Duration(connMaxLifetime) * time.Second)

	// 自动迁移表结构
	err = DB.AutoMigrate(
		&model.User{},
		&model.Exam{},
		&model.ExamRegistration{},
		&model.ExamNotice{},
		&model.ExamScore{},
	)

	if err != nil {
		return fmt.Errorf("failed to auto migrate: %w", err)
	}

	return nil
}