<?php
// $Id: parser_ical.module,v 1.1.4.2 2008-12-10 12:24:41 ekes Exp $

/**
 * @file
 * Parse the incoming URL with date_api_ical 
 * 
 * TODO Figure out how to incorporate VVENUE information into the parser.  
 */

/**
 * Implementation of hook_help().
 */
function parser_ical_help($path) {
  switch ($path) {
    case 'admin/modules#description':
      return t('Provide a common iCal parser for FeedAPI-compatible modules.');
    case 'feedapi/full_name':
      return t('iCal Parser');
  }
}

/**
 * Implementation of hook_feedapi_feed().
 */
function parser_ical_feedapi_feed($op) {
  $args = func_get_args();
  switch ($op) {
    case 'type':
      return array('iCal feed');

    case 'compatible':
      $url = is_object($args[1]) ? $args[1] : FALSE;      
      $ical_array = _parser_ical_feedapi_parse($url, FALSE);
      if ($ical_array !== FALSE) {
        return 'iCal feed';
      }
      else {
        return FALSE;
      }
    
    case 'parse':
      $feed = is_object($args[1]) ? $args[1] : FALSE;
      $cache = isset($args[2]) ? $args[2] : FALSE;
      return _parser_ical_feedapi_parse($feed, $cache);
  }
}

/**
 * Parse the feed into a data structure
 *
 * @param $url
 *  The feed's url
 * @param $cache
 *  If the results can be cached or not
 * @return stdClass
 *  The structured datas extracted from the feed
 */
function _parser_ical_feedapi_parse($feed, $cache = FALSE) {
  $url = $feed->url;
  // Substitute webcal with http.
  if (stripos($url, 'webcal') === 0) {
    $url = 'http'. substr($url, 6);
  }
  $downloaded_string = _parser_ical_download($url);

  if ($downloaded_string === FALSE || empty($downloaded_string)) {
    return $downloaded_string;
  }
  
  return _parser_ical_parse($downloaded_string);
}

/**
 * Parse iCal feeds.
 *
 * Uses patched ical_upload.
 */
function _parser_ical_parse($feed_content) {
  include_once(drupal_get_path('module', 'date_api') .'/date_api_ical.inc');
  $feed_folded = explode("\n", $feed_content);
  $ical_parsed = date_ical_parse($feed_folded);
  
  // TODO, should we change this to a foreach() instead of just picking 
  // out the first one in case there is more than one CALENDAR grouping 
  // in a feed? Not sure that ever actually happens. 
  
  $ical = $ical_parsed[0]; // Pick out the first CALENDAR group.
  
  // Any or all of these items could be missing, so always use isset() to test.
  $parsed_source = new stdClass();
  // Detect the title
  $parsed_source->title = isset($ical['X-WR-CALNAME']) ? $ical['X-WR-CALNAME'] : ''; 
  // Detect the description
  $parsed_source->description = isset($ical['X-WR-CALDESC']) ? $ical['X-WR-CALDESC'] : '';
  $parsed_source->options = new stdClass();
  $parsed_source->options->calscale = isset($ical['CALSCALE']) ? $ical['CALSCALE'] : '';
  $parsed_source->options->timezone = isset($ical['X-WR-TIMEZONE']) ? $ical['X-WR-TIMEZONE'] : '';
  $parsed_source->items = array();
  
  foreach ($ical['VEVENT'] as $event) {
    $item = new stdClass();
    $item->title = $event['SUMMARY'];
    $item->description = isset($event['DESCRIPTION']) ? $event['DESCRIPTION'] : '';
    
    $item->options = new stdClass();
    $item->options->original_author = '';
    $item->options->location = isset($event['URL']) ? $event['URL'] : '';
    $item->options->original_url = $item->options->location;
    
    // Make sure a valid timestamp is created.
    $item->options->timestamp = time();
    if (isset($event['DTSTAMP'])) {
      $date = date_ical_date($event['DTSTAMP']);
      if (date_is_valid($date, DATE_OBJECT)) {
        $item->options->timestamp = date_format($date, 'U');
      }
    }

    $item->options->guid = isset($event['UID']) ? $event['UID'] : ''; // intention
    $item->options->tags = isset($event['CATEGORIES']) ? explode(',', $event['CATEGORIES']) : array();

    // Keep iCal timezone information in the feed item so we can create the right date value.
    $date_info = array('DTSTART', 'DTEND', 'RDATE', 'EXDATE', 'DURATION', 'RRULE');
    foreach ($date_info as $key) {
      if (isset($event[$key])) {
        $item->options->VEVENT['DATE'][$key] = $event[$key];
        unset($event[$key]);
      }
    }
    foreach ($event as $key => $value) {
      $item->options->VEVENT[$key] = $value;
    }

  
    $parsed_source->items[] = $item;
  }
  
  return $parsed_source;
}

/**
 * Copied from _parser_common_syndication_download().
 * 
 * Changed to allow passing of $allowed_mine array().
 */
function _parser_ical_download($url) {
  $method = 'GET';
  $follow = 3;
  $data = NULL;
  $headers = array();
  if (!empty($username)) {
    $headers['Authorization'] = 'Basic '. base64_encode("$username:$password");
  }
  $result = drupal_http_request($url, $headers, $method, $data, $follow);
  return $result->data;
}