<?php

if (!is_callable('http_build_url')) {
    define('HTTP_URL_REPLACE', 1);          // Replace every part of the first URL when there's one of the second URL
    define('HTTP_URL_JOIN_PATH', 2);        // Join relative paths
    define('HTTP_URL_JOIN_QUERY', 4);       // Join query strings
    define('HTTP_URL_STRIP_USER', 8);       // Strip any user authentication information
    define('HTTP_URL_STRIP_PASS', 16);      // Strip any password authentication information
    define('HTTP_URL_STRIP_AUTH', 32);      // Strip any authentication information
    define('HTTP_URL_STRIP_PORT', 64);      // Strip explicit port numbers
    define('HTTP_URL_STRIP_PATH', 128);     // Strip complete path
    define('HTTP_URL_STRIP_QUERY', 256);    // Strip query string
    define('HTTP_URL_STRIP_FRAGMENT', 512); // Strip any fragments (#identifier)
    define('HTTP_URL_STRIP_ALL', 1024);     // Strip anything but scheme and host

    // Build an URL
    // The parts of the second URL will be merged into the first according to the flags argument.
    //
    // @param mixed     (Part(s) of) an URL in form of a string or associative array like parse_url() returns
    // @param mixed     Same as the first argument
    // @param int       A bitmask of binary or'ed HTTP_URL constants (Optional)HTTP_URL_REPLACE is the default
    // @param array     If set, it will be filled with the parts of the composed url like parse_url() would return
    function http_build_url($url, $parts = array(), $flags = HTTP_URL_REPLACE, &$new_url = false)
    {
        $keys = array(
        'user',
        'pass',
        'port',
        'path',
        'query',
        'fragment',
      );

      // HTTP_URL_STRIP_ALL becomes all the HTTP_URL_STRIP_Xs
      if ($flags & HTTP_URL_STRIP_ALL) {
          $flags |= HTTP_URL_STRIP_USER;
          $flags |= HTTP_URL_STRIP_PASS;
          $flags |= HTTP_URL_STRIP_PORT;
          $flags |= HTTP_URL_STRIP_PATH;
          $flags |= HTTP_URL_STRIP_QUERY;
          $flags |= HTTP_URL_STRIP_FRAGMENT;
      }
      // HTTP_URL_STRIP_AUTH becomes HTTP_URL_STRIP_USER and HTTP_URL_STRIP_PASS
      elseif ($flags & HTTP_URL_STRIP_AUTH) {
          $flags |= HTTP_URL_STRIP_USER;
          $flags |= HTTP_URL_STRIP_PASS;
      }

      // Parse the original URL
      $parse_url = parse_url($url);

      // Scheme and Host are always replaced
      if (isset($parts['scheme'])) {
          $parse_url['scheme'] = $parts['scheme'];
      }

        if (isset($parts['host'])) {
            $parse_url['host'] = $parts['host'];
        }

      // (If applicable) Replace the original URL with it's new parts
      if ($flags & HTTP_URL_REPLACE) {
          foreach ($keys as $key) {
              if (isset($parts[$key])) {
                  $parse_url[$key] = $parts[$key];
              }
          }
      } else {
          // Join the original URL path with the new path
        if (isset($parts['path']) && ($flags & HTTP_URL_JOIN_PATH)) {
            if (isset($parse_url['path'])) {
                $parse_url['path'] = rtrim(str_replace(basename($parse_url['path']), '', $parse_url['path']), '/').'/'.ltrim($parts['path'], '/');
            } else {
                $parse_url['path'] = $parts['path'];
            }
        }

        // Join the original query string with the new query string
        if (isset($parts['query']) && ($flags & HTTP_URL_JOIN_QUERY)) {
            if (isset($parse_url['query'])) {
                $parse_url['query'] .= '&'.$parts['query'];
            } else {
                $parse_url['query'] = $parts['query'];
            }
        }
      }

      // Strips all the applicable sections of the URL
      // Note: Scheme and Host are never stripped
      foreach ($keys as $key) {
          if ($flags & (int) constant('HTTP_URL_STRIP_'.strtoupper($key))) {
              unset($parse_url[$key]);
          }
      }

        $new_url = $parse_url;

        return ((isset($parse_url['scheme'])) ? $parse_url['scheme'].'://' : '').((isset($parse_url['user'])) ? $parse_url['user'].((isset($parse_url['pass'])) ? ':'.$parse_url['pass'] : '').'@' : '')
        .((isset($parse_url['host'])) ? $parse_url['host'] : '').((isset($parse_url['port'])) ? ':'.$parse_url['port'] : '').((isset($parse_url['path'])) ? $parse_url['path'] : '')
        .((isset($parse_url['query'])) ? '?'.$parse_url['query'] : '').((isset($parse_url['fragment'])) ? '#'.$parse_url['fragment'] : '');
    }
}
