<?php

namespace App\Config;

use PDO;
use PDOException;

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

    private function __construct()
    {
        $configPath = dirname(__DIR__, 2) . '/config/db-config.json';

        if (!file_exists($configPath)) {
            throw new PDOException('数据库配置文件不存在');
        }

        $config = json_decode(file_get_contents($configPath), true);

        $dbname = $config['database'] ?? $config['dbname'] ?? '';
        $dsn = "mysql:host={$config['host']};port={$config['port']};dbname={$dbname};charset=utf8mb4";

        self::$instance = new PDO($dsn, $config['user'], $config['password'], [
            PDO::ATTR_ERRMODE => PDO::ERRMODE_EXCEPTION,
            PDO::ATTR_DEFAULT_FETCH_MODE => PDO::FETCH_ASSOC,
            PDO::MYSQL_ATTR_INIT_COMMAND => "SET NAMES utf8mb4",
        ]);
    }

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

        return self::$instance;
    }
}