battles/shop.php

<?php

use Battles\Shop;
use Battles\ShopItem;

require_once 'functions.php';

if (!empty($_GET['otdel'])) {
    if ($_GET['otdel'] === 'sale') {
        Shop::id(Shop::GENERAL_SHOP)->categoryType = Shop::CATEGORY_SALE_ITEMS;
    }
    elseif ($_GET['otdel'] === 'market') {
        Shop::id(Shop::GENERAL_SHOP)->categoryType = Shop::BARTER_SHOP;
    }
    else {
        Shop::id(Shop::GENERAL_SHOP)->categoryType = $_GET['otdel'];
    }
}

if (!empty($_POST['sellshop'])) {
    ShopItem::sellItem($_POST['itemId'], 1);
}

if (!empty($_POST['buyshop'])) {
    ShopItem::buyItem($_POST['itemId']);
}

if (!empty($_POST['buymarket'])) {
    ShopItem::$status = 'попытка купить с рук предмет id: ' . $_POST['itemId'];
}

require_once 'views/shop.php';