package db

import (
	"fmt"
	"log"
	"server/internal/models"

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

func ConnectDB(host, port, user, password, dbName string) (*gorm.DB, error) {
	// Kết nối ban đầu không chọn database để tạo database nếu chưa tồn tại
	dsnWithoutDB := fmt.Sprintf("%s:%s@tcp(%s:%s)/?charset=utf8mb4&parseTime=True&loc=Local", user, password, host, port)
	tmpDB, err := gorm.Open(mysql.Open(dsnWithoutDB), &gorm.Config{})
	if err != nil {
		return nil, fmt.Errorf("failed to connect to MySQL server: %w", err)
	}

	createDBQuery := fmt.Sprintf("CREATE DATABASE IF NOT EXISTS `%s` CHARACTER SET utf8mb4 COLLATE utf8mb4_unicode_ci;", dbName)
	if err := tmpDB.Exec(createDBQuery).Error; err != nil {
		return nil, fmt.Errorf("failed to create database: %w", err)
	}

	// Kết nối chính thức vào database chỉ định
	dsnWithDB := fmt.Sprintf("%s:%s@tcp(%s:%s)/%s?charset=utf8mb4&parseTime=True&loc=Local", user, password, host, port, dbName)
	gormDB, err := gorm.Open(mysql.Open(dsnWithDB), &gorm.Config{})
	if err != nil {
		return nil, fmt.Errorf("failed to connect to database %s: %w", dbName, err)
	}

	log.Printf("Successfully connected to MySQL database: %s", dbName)
	return gormDB, nil
}

func AutoMigrate(db *gorm.DB) error {
	log.Println("Running AutoMigrate...")
	return db.AutoMigrate(
		&models.Class{},
		&models.ClassCourseLink{},
		&models.Student{},
		&models.ClassStudent{},
	)
}