<?php
// classes/DB.php
class DB {
    private static $instance = null;
    private $pdo;
    
    private function __construct() {
        require_once __DIR__ . '/../config/database.php';
        global $pdo;
        $this->pdo = $pdo;
    }
    
    public static function getInstance() {
        if (self::$instance === null) {
            self::$instance = new DB();
        }
        return self::$instance;
    }
    
    public function getConnection() {
        return $this->pdo;
    }
    
    public function query($sql, $params = []) {
        $stmt = $this->pdo->prepare($sql);
        $stmt->execute($params);
        return $stmt;
    }
    
    public function lastInsertId() {
        return $this->pdo->lastInsertId();
    }
}
?>