<?php

/**
 * @file
 * Page callback for Authorize.Net's Silent POST feature.
 */

/**
 * Receives a payment notification and handles it appropriately.
 */
function uc_authorizenet_silent_post() {
  // Determine if this is an ARB notification or not.
  $arb = (isset($_POST['x_subscription_id']) and isset($_POST['x_subscription_paynum']));

  // Log ARB payment notification, if enabled.
  if (variable_get('uc_authnet_report_arb_post', FALSE)) {
    $args = array(
      '!arb' => $arb ? 'ARB ' : '',
      '@order_id' => $_POST['x_invoice_num'],
      '@post' => print_r($_POST, TRUE),
    );
    watchdog('uc_authorizenet', '!arbSilent POST received for order @order_id: <pre>@post</pre>', $args);
  }

  // Decrypt the Auth.Net API login data.
  $login_data = _uc_authorizenet_login_data();

  // TODO: Modify the MD5 hash to accommodate differences from AIM to ARB.

  // This is an ARB notification.
  if ($arb) {

    // Compare our expected MD5 Hash against what was received.
    $md5 = strtoupper(md5($login_data['md5_hash'] . $_POST['x_trans_id'] . $_POST['x_amount']));

    // Post an error message if the MD5 hash does not validate.
    if ($_POST['x_MD5_Hash'] != $md5) {
      watchdog('uc_authorizenet', 'Invalid ARB payment notification received.', array(), WATCHDOG_ERROR);
    }
    // Otherwise, let other modules act on the data.
    else {
      module_invoke_all('uc_auth_arb_payment', $_POST);
    }
  }

  exit();
}
