<?php
function getDbConnection(): PDO
{
    static $pdo = null;

    if ($pdo === null) {
        $dbPath = __DIR__ . '/../app.sqlite';
        $pdo = new PDO('sqlite:' . $dbPath);
        $pdo->setAttribute(PDO::ATTR_ERRMODE, PDO::ERRMODE_EXCEPTION);
        $pdo->exec('PRAGMA foreign_keys = ON');
        $pdo->exec('CREATE TABLE IF NOT EXISTS users (
            id INTEGER PRIMARY KEY AUTOINCREMENT,
            username TEXT NOT NULL UNIQUE,
            email TEXT NOT NULL UNIQUE,
            password TEXT NOT NULL
        )');
    }

    return $pdo;
}