WooCommerce Prices by Country - Export single product prices

/**
 * WooCommerce Prices by Country - Export prices by country in separate columns.
 * This example shows how to "explode" the prices by country assigned to each
 * product into separate columns (one column for each combination of region ID,
 * price type and currency).
 *
 * Note
 * This code will export the raw prices by country stored in the database. Prices
 * left as "Auto" won't be calculated on the fly, as calculated data is outside
 * the scope of the export function.
 *
 * HOW TO USE THIS CODE
 * Simply add the code to the bottom of your theme's functions.php file, and it
 * will run automatically. For more information: https://www.skyverge.com/blog/add-custom-code-to-wordpress/
 *
 * GPL DISCLAIMER
 * Because this code program is free of charge, there is no warranty for it, to the extent permitted by applicable law.
 * Except when otherwise stated in writing the copyright holders and/or other parties provide the program "as is"
 * without warranty of any kind, either expressed or implied, including, but not limited to, the implied warranties of
 * merchantability and fitness for a particular purpose. The entire risk as to the quality and performance of the program
 * is with you. should the program prove defective, you assume the cost of all necessary servicing, repair or correction.
 *
 * Need a consultation, or assistance to customise this code? Find us on Codeable: https://aelia.co/hire_us
 */

/**
 * Adds one new column to the exported file, for each combination of the following elements:
 * - Region ID
 * - Region Name
 * - Price type (regular price, sale price)
 * - Currency
 *
 * @param array columns
 * @param object exporter
 * @return array
 */
add_filter('woocommerce_product_export_column_names', function($columns, $exporter) {
  // @var An array of price keys (region ID, currency, price type)
  global $price_keys;
  $price_keys = array();

  // Safety check. We can skip the logic if the Prices by Country plugin has not
  // been initialised
  if(empty($GLOBALS['wc-aelia-prices-by-country'])) {
    return $columns;
  }

  $price_regions = \Aelia\WC\PricesByCountry\WC_Aelia_Prices_By_Country::settings()->get_regions();
  $currencies = apply_filters('wc_aelia_cs_enabled_currencies', get_woocommerce_currency());
  $price_types = array('regular_price', 'sale_price');

  foreach($price_regions as $region_id => $region) {
    foreach($currencies as $currency) {
      foreach($price_types as $price_type) {
        $meta_key = "_price_by_region_{$region_id}_{$region['region_name']}_{$price_type}_{$currency}";
        $columns['meta:' . $meta_key] = 'Meta: ' . $meta_key;

        $price_keys[] = array(
          'region_id' => $region_id,
          'region_name' => $region['region_name'],
          'price_type' => $price_type,
          'currency' => $currency,
        );
      }
    }
  }

  return $columns;
}, 99, 2);

/**
 * Given a combination of region ID, currency and price type, it returns the
 * matching price from the array of Prices by Country data.
 *
 * @param string price_key
 * @param array pbc_prices An array of prices stored by the Prices by Country
 * plugin.
 * @return float|string The price stored in the database for the key, or an empty
 * string if that price is not set.
 */
function aelia_get_pbc_price_by_key($price_key, $pbc_prices) {
  if(!empty($pbc_prices[$price_key['region_id']][$price_key['currency']][$price_key['price_type']])) {
    return $pbc_prices[$price_key['region_id']][$price_key['currency']][$price_key['price_type']];
  }
  return '';
}

/**
 * Adds data from the Prices by Country plugin to the rows generated by the
 * product exported in WooCommerce 3.1 and later.
 *
 * @param array row
 * @param WC_Product product
 * @return array
 */
add_filter('woocommerce_product_export_row_data', function($row, $product) {
  // @var An array of price keys (region ID, currency, price type)
  // This variable is populated within woocommerce_product_export_column_names
  // filter
  global $price_keys;

  $pbc_prices = $product->get_meta('_prices_by_country');

  if(is_array($pbc_prices)) {
    foreach($price_keys as $price_key) {
      // Generate the price key
      $meta_key = "meta:_price_by_region_{$price_key['region_id']}_{$price_key['region_name']}_{$price_key['price_type']}_{$price_key['currency']}";
      // Get the price for the product, based on the key
      $row[$meta_key] = aelia_get_pbc_price_by_key($price_key, $pbc_prices);
    }
  }

  return $row;
}, 10, 2);