buy.php

<?php

session_start();

require_once "storage/UserStorage.php";
require_once "storage/CardStorage.php";
require_once "auth.php";

$userStorage = new UserStorage();
$cardStorage = new CardStorage();

if (!$auth->is_authenticated()) {
    header('Location: index.php');
    exit();
}

$id = isset($_GET["id"]) ? $_GET["id"] : '';

if (empty($id)) {
    header("Location: index.php");
    exit();
}

//Id of card to buy
$id = $_GET["id"];

//Find card by card id
$card = $cardStorage->findById($id);

//Handle if not found
if (empty($id)) {
    header('Location: index.php');
    exit();
}

//Get current user
$uid = $auth->authenticated_user()["id"];
$user = $userStorage->findById($uid);

if(!($user["credits"] >= $card["price"]) || !(count($cardStorage->findAll(["owner" => $user["username"]])) < 5))
{
    header('Location: index.php');
    exit();
}

//Update credits
$user["credits"] -= $card["price"];

$userStorage->update($uid, $user);

//Give card to user
$card["owner"] = $user["username"];

//Update card
$cardStorage->update($id, $card);

header('Location: index.php');
exit();

?>