package db

import (
	"context"
	"fmt"
	"log"
	"time"

	"github.com/timetracker/backend/internal/config"
	"gorm.io/driver/postgres"
	"gorm.io/gorm"
	"gorm.io/gorm/logger"
)

// Global variable for the DB connection
var db *gorm.DB

// InitDB initializes the database connection (once at startup)
// with the provided configuration
func InitDB(config config.DatabaseConfig) error {
	// Create DSN (Data Source Name)
	dsn := fmt.Sprintf("host=%s port=%d user=%s password=%s dbname=%s sslmode=%s",
		config.Host, config.Port, config.User, config.Password, config.DBName, config.SSLMode)

	// Configure GORM logger
	gormLogger := logger.New(
		log.New(log.Writer(), "\r\n", log.LstdFlags), // io writer
		logger.Config{
			SlowThreshold:             200 * time.Millisecond, // Slow SQL threshold
			LogLevel:                  config.LogLevel,        // Log level
			IgnoreRecordNotFoundError: true,                   // Ignore ErrRecordNotFound error for logger
			Colorful:                  true,                   // Enable color
		},
	)

	// Establish database connection with custom logger
	var err error
	db, err = gorm.Open(postgres.Open(dsn), &gorm.Config{
		Logger: gormLogger,
	})
	if err != nil {
		return fmt.Errorf("error connecting to the database: %w", err)
	}

	// Configure connection pool
	sqlDB, err := db.DB()
	if err != nil {
		return fmt.Errorf("error getting database connection: %w", err)
	}

	// Set connection pool parameters
	sqlDB.SetMaxIdleConns(config.MaxIdleConns)
	sqlDB.SetMaxOpenConns(config.MaxOpenConns)
	sqlDB.SetConnMaxLifetime(config.MaxLifetime)

	return nil
}

// GetEngine returns the DB instance, possibly with context
func GetEngine(ctx context.Context) *gorm.DB {
	if db == nil {
		panic("database not initialized")
	}
	// If a special transaction is in ctx, you could check it here
	return db.WithContext(ctx)
}

// CloseDB closes the database connection
func CloseDB() error {
	if db == nil {
		return nil
	}

	sqlDB, err := db.DB()
	if err != nil {
		return fmt.Errorf("error getting database connection: %w", err)
	}

	if err := sqlDB.Close(); err != nil {
		return fmt.Errorf("error closing database connection: %w", err)
	}

	return nil
}