function commerce_tax_commerce_line_item_rebase_unit_price in Commerce Core 7

Implements hook_commerce_line_item_rebase_unit_price().

File

modules/tax/commerce_tax.module, line 507

Defines tax rates and Rules integration for configuring tax rules for applicability and display.

Code

function commerce_tax_commerce_line_item_rebase_unit_price(&$price, $old_components, $line_item) {
  $inclusive_taxes = array();

  // Loop over the old components looking for taxes that were applied.
  foreach ($old_components as $key => $component) {

    // Find tax components based on the tax_rate property the Tax modules adds
    // to tax rate component types.
    if ($component_type = commerce_price_component_type_load($component['name'])) {

      // Ensure the tax rate still exists.
      if (!empty($component_type['tax_rate']) && ($tax_rate = commerce_tax_rate_load($component_type['tax_rate']))) {

        // If this tax is displayed inclusively with product prices, add it to an
        // array that we'll calculate in reverse order later.
        if ($component['included']) {
          $inclusive_taxes[] = $tax_rate;
        }
        else {

          // Otherwise assume we'll just have sales taxes and add this one now.
          // Note that this means component arrays that mix display inclusive
          // and non-display inclusive tax types will not be supported; however,
          // this shouldn't be possible in real world scenarios.
          $tax_price = $tax_rate['calculation_callback']($tax_rate, entity_metadata_wrapper('commerce_line_item', $line_item));

          // If we received a valid price array, add it as a component.
          if (!empty($tax_price)) {
            $price['data'] = commerce_price_component_add($price, $tax_rate['price_component'], $tax_price, FALSE);
          }
        }
      }
    }
  }

  // If this unit price had inclusive taxes...
  if (!empty($inclusive_taxes)) {

    // We assume the first price component is the base price component that we
    // will deduct the included tax amount from. If it isn't, exit without
    // applying taxes because we would not be able to update the base price.
    if ($price['data']['components'][0]['name'] != 'base_price') {
      return;
    }

    // Prepare an array of tax price components.
    $tax_components = array();

    // Calculate these taxes in reverse order to accommodate cumulative display
    // inclusive tax rates.
    foreach (array_reverse($inclusive_taxes) as $tax_rate) {

      // The amount of this tax is determined by dividing the current base price
      // by 1 + the tax rate expressed as a decimal (i.e. 1.1 for a 10% tax).
      // The result is the base price against which the tax would have been
      // applied, so the difference becomes our tax amount.
      $tax_amount = $price['data']['components'][0]['price']['amount'] - $price['data']['components'][0]['price']['amount'] / (1 + $tax_rate['rate']);
      $tax_amount = commerce_tax_rate_round_amount($tax_rate, $tax_amount);
      $pretax_base = $price['data']['components'][0]['price']['amount'] - $tax_amount;

      // Update the base price component.
      $price['data']['components'][0]['price']['amount'] = $pretax_base;

      // Prepare a tax component that will be added to the price after every tax
      // has been calculated.
      $tax_components[$tax_rate['price_component']] = array(
        'amount' => $tax_amount,
        'currency_code' => $price['currency_code'],
        'data' => array(
          'tax_rate' => $tax_rate,
        ),
      );
    }

    // Add their components to the price in their order of appearance, though.
    foreach (array_reverse($tax_components, TRUE) as $name => $tax_component) {
      $price['data'] = commerce_price_component_add($price, $name, $tax_component, TRUE);
    }
  }
}