/**
* Convert a quote/order/invoice/credit memo item to a tax details item objects
*
* This includes tax for the item as well as any additional line item tax information like Gift Wrapping
*
* @param QuoteDetailsItemInterface $item
* @param GetTaxResult $getTaxResult
* @param bool $useBaseCurrency
* @param \Magento\Framework\App\ScopeInterface $scope
* @return \Magento\Tax\Api\Data\TaxDetailsItemInterface
*/
protected function getTaxDetailsItem(QuoteDetailsItemInterface $item, GetTaxResult $getTaxResult, $useBaseCurrency, $scope)
{
$price = $item->getUnitPrice();
/* @var $taxLine \AvaTax\TaxLine */
$taxLine = $getTaxResult->getTaxLine($item->getCode());
// Items that are children of other items won't have lines in the response
if (!$taxLine instanceof \AvaTax\TaxLine) {
return false;
}
$rate = (double) ($taxLine->getRate() * Tax::RATE_MULTIPLIER);
$tax = (double) $taxLine->getTax();
/**
* Magento uses base rates for determining what to charge a customer, not the currency rate (i.e., the non-base
* rate). Because of this, the base amounts are what is being sent to AvaTax for rate calculation. When we get
* the base tax amounts back from AvaTax, we have to convert those to the current store's currency using the
* \Magento\Framework\Pricing\PriceCurrencyInterface::convert() method. However if we simply convert the AvaTax
* base tax amount * currency multiplier, we may run into issues due to rounding.
*
* For example, a $9.90 USD base price * a 6% tax rate equals a tax amount of $0.59 (.594 rounded). Assume the
* current currency has a conversion rate of 2x. The price will display to the user as $19.80. There are two
* ways we can calculate the tax amount:
* 1. Multiply the tax amount received back from AvaTax, which would be $1.18 ($0.59 * 2).
* 2. Multiply using this formula (base price * currency rate) * tax rate) ((9.99 * 2) * .06)
* which would be $1.19 (1.188 rounded)
*
* The second approach is more accurate and is what we are doing here.
*/
if (!$useBaseCurrency) {
/**
* We could recalculate the amount using the same logic found in this class:
* @see \ClassyLlama\AvaTax\Framework\Interaction\Line::convertTaxQuoteDetailsItemToData,
* but using the taxable amount returned back from AvaTax is the only way to get an accurate amount as
* some items sent to AvaTax may be tax exempt
*/
$taxableAmount = (double) $taxLine->getTaxable();
$amount = $this->priceCurrency->convert($taxableAmount, $scope);
$tax = $amount * $taxLine->getRate();
$tax = $this->calculationTool->round($tax);
}
$rowTax = $tax;
/**
* In native Magento, the "row_total_incl_tax" and "base_row_total_incl_tax" fields contain the tax before
* discount. The AvaTax 15 API doesn't have the concept of before/after discount tax, so in order to determine
* the "before discount tax amount", we need to multiply the discount by the rate returned by AvaTax.
* @see \Magento\Tax\Model\Calculation\AbstractAggregateCalculator::calculateWithTaxNotInPrice
*
* If the rate is 0, then this product doesn't have taxes applied and tax on discount shouldn't be calculated.
* If tax is 0, then item was tax-exempt for some reason and tax on discount shouldn't be calculated
*/
if ($taxLine->getRate() > 0 && $tax > 0) {
/**
* Accurately calculating what AvaTax would have charged before discount requires checking to see if any
* of the tax amount is tax exempt. If so, we need to find out what percentage of the total amount AvaTax
* deemed as taxable and then use that percentage when calculating the discount amount. This partially
* taxable scenario can arise in a situation like this:
* @see https://help.avalara.com/kb/001/Why_is_freight_taxed_partially_on_my_sale
*
* To test this functionality, you can create a "Base Override" Tax Rule in the AvaTax admin to mark certain
* jurisdictions as partially taxable.
*/
$taxableAmountPercentage = 1;
if ($taxLine->getExemption() > 0) {
// This value is the total amount sent to AvaTax for tax calculation, before AvaTax determined what
// portion of the amount is taxable
$totalAmount = $taxLine->getTaxable() + $taxLine->getExemption();
// Avoid division by 0
if ($totalAmount != 0) {
$taxableAmountPercentage = $taxLine->getTaxable() / $totalAmount;
}
}
$effectiveDiscountAmount = $taxableAmountPercentage * $item->getDiscountAmount();
$taxOnDiscountAmount = $effectiveDiscountAmount * $taxLine->getRate();
$taxOnDiscountAmount = $this->calculationTool->round($taxOnDiscountAmount);
$rowTaxBeforeDiscount = $rowTax + $taxOnDiscountAmount;
} else {
$rowTaxBeforeDiscount = 0;
}
$extensionAttributes = $item->getExtensionAttributes();
if ($extensionAttributes) {
$quantity = $extensionAttributes->getTotalQuantity() !== null ? $extensionAttributes->getTotalQuantity() : $item->getQuantity();
} else {
$quantity = $item->getQuantity();
}
$rowTotal = $price * $quantity;
$rowTotalInclTax = $rowTotal + $rowTaxBeforeDiscount;
$priceInclTax = $rowTotalInclTax / $quantity;
/**
* Since the AvaTax extension does not support merchants adding products with tax already factored into the
* price, we don't need to do any calculations for this number. The only time this value would be something
* other than 0 is when this method runs:
* @see \Magento\Tax\Model\Calculation\AbstractAggregateCalculator::calculateWithTaxInPrice
*/
$discountTaxCompensationAmount = 0;
/**
* The \Magento\Tax\Model\Calculation\AbstractAggregateCalculator::calculateWithTaxNotInPrice method that this
* method is patterned off of has $round as a variable, but any time that method is used in the context of a
* collect totals on a quote, rounding is always used.
*/
$round = true;
if ($round) {
$priceInclTax = $this->calculationTool->round($priceInclTax);
}
$appliedTax = $this->getAppliedTax($getTaxResult, $rowTax);
$appliedTaxes = [$appliedTax->getTaxRateKey() => $appliedTax];
return $this->taxDetailsItemDataObjectFactory->create()->setCode($item->getCode())->setType($item->getType())->setRowTax($rowTax)->setPrice($price)->setPriceInclTax($priceInclTax)->setRowTotal($rowTotal)->setRowTotalInclTax($rowTotalInclTax)->setDiscountTaxCompensationAmount($discountTaxCompensationAmount)->setAssociatedItemCode($item->getAssociatedItemCode())->setTaxPercent($rate)->setAppliedTaxes($appliedTaxes);
}
