<?php
/**
 * Database Singleton
 * PDO Connection Handler
 */

class Database {
    private static ?PDO $instance = null;

    private function __construct() {}
    private function __clone() {}

    public static function getInstance(): PDO {
        if (self::$instance === null) {
            $config = require __DIR__ . '/../config/database.php';
            
            $dsn = sprintf(
                "mysql:host=%s;port=%d;dbname=%s;charset=%s",
                $config['host'],
                $config['port'],
                $config['dbname'],
                $config['charset']
            );

            try {
                self::$instance = new PDO(
                    $dsn,
                    $config['username'],
                    $config['password'],
                    $config['options']
                );
            } catch (PDOException $e) {
                // In production, log error without revealing DB credentials
                error_log("Database Connection Error: " . $e->getMessage());
                http_response_code(500);
                require_once __DIR__ . '/../views/errors/500.php';
                exit;
            }
        }

        return self::$instance;
    }
}