How is «discount_tax_compensation_amount» calculated by Magento\Tax\Model\Calculation\UnitBaseCalculator::calculateWithTaxInPrice()?

dmitry_fedyuk · October 1, 2017, 12:34am

The base article: How is discount_tax_compensation_amount calculated?

Step 1

magento/magento2/blob/2.2.0/app/code/Magento/Tax/Model/Calculation/UnitBaseCalculator.php#L45-L45


$applyTaxAfterDiscount = $this->config->applyTaxAfterDiscount($this->storeId);

Details:

How is \Magento\Tax\Model\Config::applyTaxAfterDiscount() implemented and used?
How is the «Apply Customer Tax» («Before Discount» / «After Discount») option handled?

Step 2

Step 3

github.com

magento/magento2/blob/2.2.0/app/code/Magento/Tax/Model/Calculation/UnitBaseCalculator.php#L61-L84


if ($applyTaxAfterDiscount) {
    //TODO: handle originalDiscountAmount
    $unitDiscountAmount = $discountAmount / $quantity;
    $taxableAmount = max($priceInclTax - $unitDiscountAmount, 0);
    $unitTaxAfterDiscount = $this->calculationTool->calcTaxAmount(
        $taxableAmount,
        $rate,
        true,
        false
    );
    $unitTaxAfterDiscount = $this->roundAmount(
        $unitTaxAfterDiscount,
        $rate,
        true,
        self::KEY_REGULAR_DELTA_ROUNDING,
        $round,
        $item
    );


    // Set discount tax compensation
    $unitDiscountTaxCompensationAmount = $uniTax - $unitTaxAfterDiscount;
    $discountTaxCompensationAmount = $unitDiscountTaxCompensationAmount * $quantity;
    $uniTax = $unitTaxAfterDiscount;
}

Step 4

github.com

magento/magento2/blob/2.2.0/app/code/Magento/Tax/Model/Calculation/UnitBaseCalculator.php#L100-L100


->setDiscountTaxCompensationAmount($discountTaxCompensationAmount)