hiqdev / php-billing

src/charge/modifiers/FixedDiscount.php

<?php
/**
 * PHP Billing Library
 *
 * @link      https://github.com/hiqdev/php-billing
 * @package   php-billing
 * @license   BSD-3-Clause
 * @copyright Copyright (c) 2017-2018, HiQDev (http://hiqdev.com/)
 */

namespace hiqdev\php\billing\charge\modifiers;

use hiqdev\php\billing\action\ActionInterface;
use hiqdev\php\billing\charge\Charge;
use hiqdev\php\billing\charge\ChargeInterface;
use hiqdev\php\billing\charge\modifiers\addons\Discount;

This use statement conflicts with another class in this namespace, hiqdev\php\billing\charge\modifiers\Discount. Consider defining an alias.

use hiqdev\php\billing\price\SinglePrice;
use hiqdev\php\billing\target\Target;
use hiqdev\php\billing\target\TargetInterface;
use hiqdev\php\billing\type\Type;
use hiqdev\php\units\Quantity;
use Money\Money;

/**
 * Fixed discount.
 *
 * @author Andrii Vasyliev <sol@hiqdev.com>
 */
class FixedDiscount extends Modifier
{
    const VALUE = 'value';

    public function __construct($value, array $addons = [])
    {
        parent::__construct($addons);
        $this->addAddon(self::VALUE, new Discount($value));
    }

    public function getNext()
    {
        return $this;
    }

    public function getValue(ChargeInterface $charge = null): Discount
    {
        return $this->getAddon(self::VALUE);

The expression return $this->getAddon(self::VALUE) returns the type null which is incompatible with the type-hinted return hiqdev\php\billing\charge\modifiers\addons\Discount.

    }

    public function isAbsolute()
    {
        return $this->getAddon(self::VALUE)->isAbsolute();

The method isAbsolute() does not exist on hiqdev\php\billing\charge\modifiers\AddonInterface. It seems like you code against a sub-type of hiqdev\php\billing\charge\modifiers\AddonInterface such as hiqdev\php\billing\charge\modifiers\addons\Discount.

    }

    public function isRelative()
    {
        return !$this->isAbsolute();
    }

    public function calculateSum(ChargeInterface $charge = null): Money
    {
        return $this->getValue($charge)->calculateSum($charge);

It seems like $charge can also be of type null; however, parameter $charge of hiqdev\php\billing\charge\modifiers\addons\Discount::calculateSum() does only seem to accept hiqdev\php\billing\charge\ChargeInterface, maybe add an additional type check?

    }

    private function getType()
    {
        return new Type(Type::ANY, 'discount,discount');
    }

    public function modifyCharge(?ChargeInterface $charge, ActionInterface $action): array
    {
        if ($charge === null) {
            return [];
        }

        $month = $action->getTime()->modify('first day of this month midnight');
        if (!$this->checkPeriod($month)) {
            return [$charge];
        }

        $sum    = $this->calculateSum($charge)->multiply(-1);
        $usage  = Quantity::create('items', 1);
        $type   = $this->getType();
        $price  = $charge->getPrice();
        $target = $price->getTarget();

        $discount = new Charge(null, $type, $target, $action, $price, $usage, $sum);
        $discount->setParent($charge);

        $reason = $this->getReason();
        if ($reason) {

$reason is of type hiqdev\php\billing\charge\modifiers\addons\Reason, thus it always evaluated to true.

            $discount->setComment($reason->getValue());
        }

        return [$charge, $discount];
    }
}