<?php
declare(strict_types=1);

namespace Src\PackItems;

final class Item
{
    /**
     * @var int
     */
    private $price;
    /**
     * @var int
     */
    private $quantity;
    /**
     * @var array
     */
    private $packPrice;
    /**
     * @var string
     */
    private $code;

    private function __construct(string $code, int $price, int $quantity, array $packPrice)
    {
        $this->code = $code;
        $this->price = $price;
        $this->quantity = $quantity;
        $this->packPrice = $packPrice;
    }

    /**
     * @param string $code
     * @param int $price
     *
     * @return Item
     */
    public static function fromBasic(string $code, int $price)
    {
        return new static($code, $price, 1, []);
    }

    /**
     * @return int
     */
    public function getQuantity(): int
    {
        return $this->quantity;
    }

    /**
     * @param Item $item
     *
     * @return bool
     */
    public function equals(Item $item): bool
    {
        return $this->code === $item->getCode();
    }

    /**
     * @return float
     */
    public function getTotal(): float
    {
        if (!count($this->packPrice)) {
            return $this->quantity * $this->price;
        }
        $packs = array_keys($this->packPrice);
        $minPack = min($packs);
        if ($this->quantity < $minPack) {
            return $this->quantity * $this->price;
        }
        $totalPrice = 0;
        $quantity = $this->quantity;
        foreach ($this->packPrice as $packQuantity => $packPrice) {
            if ($quantity < $packQuantity) {
                break;
            }
            $totalPrice += $packQuantity * $packPrice;
            $quantity -= $packQuantity;
        }
        $totalPrice += $quantity * $this->price;

        return $totalPrice;
    }

    /**
     * @return string
     */
    public function getCode(): string
    {
        return $this->code;
    }

    /**
     * @param int $quantity
     */
    public function setQuantity(int $quantity): void
    {
        $this->quantity = $quantity;
    }

    /**
     * @param array $packPrice
     *
     * @return Item
     */
    public function withPackPrice(array $packPrice): Item
    {
        $this->packPrice = $packPrice;

        return $this;
    }
}