<?php
class Database {
    private static $instance = null;
    private $pdo;

    private function __construct() {
        $config = require __DIR__ . '/../config.php';
        
        // 如果配置了 socket，使用 socket 连接
        if (isset($config['socket'])) {
            $dsn = "mysql:unix_socket={$config['socket']};dbname={$config['dbname']};charset={$config['charset']}";
        } else {
            $dsn = "mysql:host={$config['host']};port={$config['port']};dbname={$config['dbname']};charset={$config['charset']}";
        }
        
        $this->pdo = new PDO($dsn, $config['username'], $config['password'], [
            PDO::ATTR_ERRMODE => PDO::ERRMODE_EXCEPTION,
            PDO::ATTR_DEFAULT_FETCH_MODE => PDO::FETCH_ASSOC,
            PDO::ATTR_EMULATE_PREPARES => false,
        ]);
    }

    public static function getInstance() {
        if (self::$instance === null) {
            self::$instance = new self();
        }
        return self::$instance;
    }

    public function query($sql, $params = []) {
        $stmt = $this->pdo->prepare($sql);
        $stmt->execute($params);
        return $stmt;
    }

    public function fetchAll($sql, $params = []) {
        return $this->query($sql, $params)->fetchAll();
    }

    public function fetchOne($sql, $params = []) {
        return $this->query($sql, $params)->fetch();
    }

    public function lastInsertId() {
        return $this->pdo->lastInsertId();
    }
}