package database

import (
	"fmt"
	"log"

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

// Initialize creates and configures the database connection
// Uses MySQL driver with proper connection pooling and charset support
func Initialize(host, port, user, password, dbname, charset string) (*gorm.DB, error) {
	// Configure GORM logger
	gormLogger := logger.Default.LogMode(logger.Info)

	// Build MySQL DSN (Data Source Name)
	// Format: user:password@tcp(host:port)/dbname?charset=utf8mb4&parseTime=True&loc=Local
	dsn := fmt.Sprintf("%s:%s@tcp(%s:%s)/%s?charset=%s&parseTime=True&loc=Local",
		user, password, host, port, dbname, charset)

	// Open MySQL database connection
	db, err := gorm.Open(mysql.Open(dsn), &gorm.Config{
		Logger: gormLogger,
	})
	if err != nil {
		return nil, fmt.Errorf("failed to connect to database: %w", err)
	}

	// Get underlying SQL DB for connection pool configuration
	sqlDB, err := db.DB()
	if err != nil {
		return nil, fmt.Errorf("failed to get underlying database: %w", err)
	}

	// Configure connection pool for MySQL
	sqlDB.SetMaxIdleConns(10)      // Maximum number of idle connections
	sqlDB.SetMaxOpenConns(100)     // Maximum number of open connections
	sqlDB.SetConnMaxLifetime(3600) // Maximum connection lifetime (1 hour)
	sqlDB.SetConnMaxIdleTime(600)  // Maximum idle time (10 minutes)

	log.Printf("Database connected: %s@%s:%s/%s", user, host, port, dbname)

	return db, nil
}