Goods

gistfile1.txt

interface IGood {
  public $title;
  public $price;
  
  public GetPrice();
}

class OriginalGood implements IGood {
  public $title;
  public $price;
  
  function __construct() { ... }
  public GetPrice(){
    return $this->price;
  }
}
class SaleGood implements IGood {
  public $title;
  public $price;
  
  function __construct() { ... };
  public GetPrice(){
    $discount = $this->calculateDiscount();
    return $this->price * $this->discount;
  }
  public calculateDiscount() {
    ...
  }
}
class Cart {
  public $goods = [];
  
  private SetReserved($good) {
    //Резервация заказа на  какое-то время.
    App::DB->Goods->setReserved($good->id, "10000");
  }
  public AddGoodsToShowCase($good) {
    $this->goods[] = $good;
    $this->SetReserved($good);
  }
  
  public GetTotalPrice() {
    $price = 0;
    if (count($this->goods) > 3) {
      foreach($this->goods as $good) {
        $price += $good->GetPrice();
      }
    }
    return $price * $this->_discount;
  }
}


$cart = new Cart;
$sGood = new SaleGood;
$oGood = new OriginalGood;
$cart->AddGoodsToShowCase($sGood);
$cart->AddGoodsToShowCase($oGood);