<?php

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

    public static function connection(): PDO
    {
        if (self::$connection !== null) {
            return self::$connection;
        }

        $db = config('database');
        $dsn = sprintf(
            'mysql:host=%s;dbname=%s;charset=%s',
            $db['host'],
            $db['dbname'],
            $db['charset']
        );

        try {
            self::$connection = new PDO($dsn, $db['user'], $db['password'], [
                PDO::ATTR_ERRMODE => PDO::ERRMODE_EXCEPTION,
                PDO::ATTR_DEFAULT_FETCH_MODE => PDO::FETCH_ASSOC,
            ]);
        } catch (PDOException $exception) {
            throw new PDOException('Datenbankverbindung fehlgeschlagen.');
        }

        return self::$connection;
    }
}