Drupal 7 commerce utility functionality

commerce_tools.php

<?php

/**
 * Get the node ID for a commerce product using it's product ID.
 *
 * Asumes only one. If not will return the first node referencing the product.
 * If the commerce product has no product display will return FALSE.
 */
function _get_product_referencing_nid($product_id) {
  $query = new EntityFieldQuery();
  $query->fieldCondition('field_product', 'product_id', $product_id, '=');
  $result = $query->execute();

  if (!empty($result)) {
    //return the first result
    //first product style
    $node = $result['node'];
    // first array index is the node id
    $nids = array_keys($node);
    if (!empty($nids)) {
      $nid = $nids[0];
    }
  }

  if (isset ($nid)) {
    return $nid;
  }
  else {
    return FALSE;
  }
}

/**
 * Add a product to cart using it's ID. 
 * 
 * Based on the Drupal commerce_cart_product_add_by_id() function.
 * This version supports setting of the data element. sets the context with 
 * the url in the display_path and the product_ids array.
 */
function product_add_by_id($product_id, $quantity = 1, $combine = TRUE, $uid = NULL) {
  global $user;

  // If the specified product exists...
  if ($product = commerce_product_load($product_id)) {
    // Create a new product line item for it.
    $line_item = commerce_product_line_item_new($product, $quantity);
    // Set the url.
    $url = 'node/' . _get_product_referencing_nid($product_id);
    $line_item->data['context']['display_path'] = $url;
    // Set the product_id
    $line_item->data['context']['product_ids'][] = $product_id;

    // Default to the current user if a uid was not passed in.
    if ($uid === NULL) {
      $uid = $user->uid;
    }

    return commerce_cart_product_add($uid, $line_item, $combine);
  }

  return FALSE;
}

/**
 * Get the unit price without Tax/VAT for $line_item_wrapper 
 * 
 * calls
 *  $ex_vat = hswalsh_get_ex_vat_price($line_item_wrapper);
 */
function commerce_tools_get_ex_vat_price_li($line_item_wrapper) {
  $component_types = commerce_tax_commerce_price_component_type_info();
  // Loop over the price components in the line item's unit price.
  $price = $line_item_wrapper->commerce_unit_price->value();
  $new_components = array();

  foreach ($price['data']['components'] as $key => $component) {
    // Look for components that match one of the defined tax price components.
    if (in_array($component['name'], array_keys($component_types))) {
      // Remove it from the components array.
      unset($price['data']['components'][$key]);
      // If the component was marked as "included" in the price amount, update
      // the price amount to reflect the difference.
      if (!empty($component['included'])) {
        $price['amount'] -= $component['price']['amount'];
      }

    }
  }
  return $price;
}


/**
 * Get the price without Tax/VAT for $price 
 * 
 * calls
 *  $ex_vat_unit_price = hswalsh_get_ex_vat_price($line_item_wrapper->commerce_unit_price->value())
 *  $ex_vat_line_total = hswalsh_get_ex_vat_price($line_item_wrapper->commerce_total->value())
 */
function commerce_tools_get_ex_vat_price($price) {
  $component_types = commerce_tax_commerce_price_component_type_info();
  // Loop over the price components in the line item's unit price.
  $new_components = array();
  foreach ($price['data']['components'] as $key => $component) {
    // Look for components that match one of the defined tax price components.
    if (in_array($component['name'], array_keys($component_types))) {
      // Remove it from the components array.
      unset($price['data']['components'][$key]);
      // If the component was marked as "included" in the price amount, update
      // the price amount to reflect the difference.
      if (!empty($component['included'])) {
        $price['amount'] -= $component['price']['amount'];
      }
    }
  }
  return $price;
}