<?php
/**
 * @file
 * Defines a class that parses iCalcreator vcalendar objects into
 * Feeds-compatible data arrays.
 */

class ParserVcalendar {
  /**
   * Variables used for parsing.
   */
  protected $calendar;
  protected $source;
  protected $fetcherResult;
  protected $config;
  protected $timezones = array();
  protected $xtimezone;

  /**
   * The parsed data for the component that's currently being processed.
   *
   * ParserVcalendar parses one component at a time. This array is stored as a
   * property so that each handler can tell what work the previous handlers
   * have already completed on the current component.
   *
   * @var array
   */
  protected $parsed_data = array();

  /**
   * Variables used for batch processing.
   */
  protected $totalComponents = 0;
  protected $lastComponentParsed = 0;

  /**
   * This is the list of iCal properties which are allowed to have more than
   * one entry in a single VEVENT. If we ever support parsing more than just
   * the first one, this listing will be useful.
   */
  protected $multi_entry_properties = array(
    'ATTACH', 'ATTENDEE', 'CATEGORIES', 'COMMENT', 'CONTACT', 'DESCRIPTION',
    'EXDATE', 'EXRULE', 'FREEBUSY', 'RDATE', 'RELATED-TO', 'RESOURCES',
    'RRULE', 'REQUEST-STATUS', 'TZNAME', 'X-PROP'
  );

  /**
   * Constructor.
   */
  public function __construct($calendar, $source, $fetcher_result, $config) {
    $this->calendar = $calendar;
    $this->source = $source;
    $this->mapping_sources = feeds_importer($source->id)->parser->getMappingSources();
    $this->fetcherResult = $fetcher_result;
    $this->config = $config;
  }

  /**
   * Parses the vcalendar object into an array of event data arrays.
   *
   * @param int $offset
   *   Specifies which section of the feed to start parsing at.
   *
   * @param int $limit
   *   Specifies how many components to parse on this run.
   *
   * @return array
   *   An array of parsed event data keyed by our mapping source property keys.
   */
  public function parse($offset, $limit) {
    // Sometimes, the feed will set a timezone for every event in the calendar
    // using the non-standard X-WR-TIMEZONE property. Date iCal uses this
    // timezone only if the date property is not in UTC and has no TZID.
    $xtimezone = $this->calendar->getProperty('X-WR-TIMEZONE');
    if (!empty($xtimezone[1])) {
      // Allow modules to alter the timezone string before it gets converted
      // into a DateTimeZone.
      $context = array(
        'property_key' => NULL,
        'calendar_component' => NULL,
        'calendar' => $this->calendar,
        'feeeds_source' => $this->source,
        'feeds_fetcher_result' => $this->fetcherResult,
      );
      drupal_alter('date_ical_import_timezone', $xtimezone[1], $context);
      $this->xtimezone = $this->_tzid_to_datetimezone($xtimezone[1]);
    }

    // Collect the timezones into an array, for easier access.
    while ($component = $this->calendar->getComponent('VTIMEZONE')) {
      $this->timezones[] = $component;
    }

    // This context array is used by date_ical_import_component_alter() and
    // date_ical_import_parsed_data_alter().
    $context2 = array(
      'calendar' => $this->calendar,
      'source' => $this->source,
      'fetcher_result' => $this->fetcherResult,
    );

    // Collect each component, so we can batch them properly in the next loop.
    $raw_components = array();
    $types = array('VEVENT', 'VTODO', 'VJOURNAL', 'VFREEBUSY', 'VALARM');
    foreach ($types as $type) {
      while ($vcalendar_component = $this->calendar->getComponent($type)) {
        // Allow modules to alter the vcalendar component before we parse it
        // into a Feeds-compatible data array.
        drupal_alter('date_ical_import_component', $vcalendar_component, $context2);
        $raw_components[] = $vcalendar_component;
      }
    }

    // Store this for use by DateiCalFeedsParser's batch processing code.
    $this->totalComponents = count($raw_components);

    // Parse each raw component in the current batch into a Feeds-compatible
    // event data array.
    $events = array();
    $batch = array_slice($raw_components, $offset, $limit, TRUE);
    foreach ($batch as $ndx => $raw_component) {
      $this->parsed_data = array();
      foreach ($this->mapping_sources as $property_key => $data) {
        $handler = NULL;
        if (isset($data['date_ical_parse_handler'])) {
          $handler = $data['date_ical_parse_handler'];
        }
        else {
          // This is not one of our sources, so if we don't recognize and
          // support it, we'll have to pass a warning to the user.
          if ($property_key == 'geofield') {
            $handler = 'parseGeofield';
          }
          else {
            // We can safely ignore certain sources.
            $known_unknowns = array(
              'Blank source 1', // "Black Source 1" is from Feeds Tamper.
              'parent:nid', // Defined in FeedsParser
              'parent:uid', // Defined in FeedsParser
            );
            if (!in_array($property_key, $known_unknowns)) {
              // Only warn the user if this mapping source is in use.
              foreach ($this->source->importer->processor->config['mappings'] as $mapping) {
                if ($mapping['source'] == $property_key) {
                  drupal_set_message(t('Date iCal does not recognize the "@name" Mapping Source, and must skip it.', array('@name' => $data['name'])), 'warning', FALSE);
                  break;
                }
              }
            }
          }
        }
        if ($handler) {
          $this->parsed_data[$property_key] = $this->$handler($property_key, $raw_component);
        }

        if ($property_key == 'geofield' && !empty($this->parsed_data['geofield'])) {
          // To make our data readable by geofield_feeds_combined_source(), we
          // need to put it into the format output by Simplepie 1.3.
          $this->parsed_data['location_latitude'] = array($this->parsed_data['geofield']['lat']);
          $this->parsed_data['location_longitude'] = array($this->parsed_data['geofield']['lon']);
        }
      }

      // Allow modules to alter the final parsed data before we send it to the
      // Feeds processor.
      drupal_alter('date_ical_import_post_parse', $this->parsed_data, $context2);

      // Skip this event if it's earlier than the user's specified skip time.
      if (!$this->_skip_current_event()) {
        $events[] = $this->parsed_data;
      }
      // The indices of the original $raw_components array are preserved in
      // $batch, so using the $ndx value here lets us communicate our progress
      // through the full collection of components.
      $this->lastComponentParsed = $ndx;
    }

    return $events;
  }

  /**
   * Getter for the protected totalComponents property.
   */
  public function getTotalComponents() {
    return $this->totalComponents;
  }

  /**
   * Getter for the protected lastComponentParsed property.
   */
  public function getLastComponentParsed() {
    return $this->lastComponentParsed;
  }

  /**
   * Handler that parses GEO fields.
   *
   * @return array
   *   The latitude and longitude values, keyed by 'lat' and 'lon'.
   */
  public function parseGeofield($property_key, $vcalendar_component) {
    $geo = array();
    if (!empty($vcalendar_component->geo['value'])) {
      $geo['lat'] = $vcalendar_component->geo['value']['latitude'];
      $geo['lon'] = $vcalendar_component->geo['value']['longitude'];
    }
    return $geo;
  }

  /**
   * Handler that parses text fields.
   *
   * @return string
   *   The parsed text property.
   */
  public function parseTextProperty($property_key, $vcalendar_component) {
    $text = $vcalendar_component->getProperty($property_key);
    // In case someone writes a hook that adds a source for a multi-entry
    // property and a parameter of that same property, we need to force
    // iCalcreator to assume it has not accessed that property, yet.
    // TODO: This is really just a hack. If/when multi-entry properties
    // become supported, this will need to be redesigned.
    if (in_array($property_key, $this->multi_entry_properties)) {
      unset($vcalendar_component->propix[$property_key]);
    }

    if ($text === FALSE) {
      if ($property_key != 'SUMMARY') {
        return NULL;
      }
      else {
        $uid = $vcalendar_component->getProperty('UID');
        if ($vcalendar_component->objName == 'vfreebusy') {
          // FREEBUSY elements can't have SUMMARY, but they can have COMMENT.
          // So if the feed has been configured to ask for SUMMARY, use COMMENT
          // instead. If COMMENT is also missing, we can't import.
          $text = $vcalendar_component->getProperty('COMMENT');
          if ($text === FALSE) {
            throw new DateIcalParseException(t('The VFREEBUSY component with UID %uid is invalid because it has no COMMENT.
              Nodes require a title, and since VFREEBUSY components can\'t have SUMMARY, Date iCal pulls that title from the COMMENT.',
              array('%uid' => $uid))
            );
          }
        }
        else {
          // Non-VFREEBUSY components must have a SUMMARY.
          throw new DateIcalParseException(t('The component with UID %uid is invalid because it has no SUMMARY (nodes require a title).',
            array('%uid' => $uid))
          );
        }
      }
    }
    // Convert literal \n and \N into newline characters.
    $text = str_replace(array('\n', '\N'), "\n", $text);
    return $text;
  }

  /**
   * Handler that parses field parameters.
   *
   * @return string
   *   The parsed field parameter.
   */
  public function parsePropertyParameter($property_key, $vcalendar_component) {
    list($key, $attr) = explode(':', $property_key);
    $property = $vcalendar_component->getProperty($key, FALSE, TRUE);
    // See parseTextProperty() for why this is here.
    if (in_array($property_key, $this->multi_entry_properties)) {
      unset($vcalendar_component->propix[$property_key]);
    }

    if ($property === FALSE) {
      // If the component doesn't have this property, return NULL.
      return NULL;
    }
    $param = isset($property['params'][$attr]) ? $property['params'][$attr] : '';
    return $param;
  }

  /**
   * Handler that parses DATE-TIME and DATE fields.
   *
   * @return FeedsDateTime
   *   The parsed datetime object.
   */
  public function parseDateTimeProperty($property_key, $vcalendar_component) {
    $property = $vcalendar_component->getProperty($property_key, FALSE, TRUE);
    // Gather all the other date properties, so we can work with them later.
    $duration = $vcalendar_component->getProperty('DURATION', FALSE, TRUE);
    $dtstart = $vcalendar_component->getProperty('DTSTART', FALSE, TRUE);
    $uid = $vcalendar_component->getProperty('UID');

    // DATE-type properties are treated as All Day events which can span over
    // multiple days.
    // The Date module's All Day event handling was never finalized
    // (http://drupal.org/node/874322), which requires us to do some some
    // special coddling later.
    $is_all_day = (isset($property['params']['VALUE']) && $property['params']['VALUE'] == 'DATE');

    // Cover various conditions in which either DTSTART or DTEND are not set.
    if ($property === FALSE) {
      // When DTEND isn't defined, we may need to emulate it.
      if ($property_key == 'DTEND') {
        // Unset DTENDs need to emulate the DATE type from DTSTART.
        $is_all_day = (isset($dtstart['params']['VALUE']) && $dtstart['params']['VALUE'] == 'DATE');

        if ($duration !== FALSE) {
          // If a DURATION is defined, emulate DTEND as DTSTART + DURATION.
          $property = array(
            'value' => iCalUtilityFunctions::_duration2date($dtstart['value'], $duration['value']),
            'params' => $dtstart['params'],
          );
        }
        elseif ($is_all_day) {
          // If this is an all-day event with no end or duration, treat this
          // as a single-day event by emulating DTEND as 1 day after DTSTART.
          $property = $dtstart;
          $property['value'] = iCalUtilityFunctions::_duration2date($property['value'], array('day' => 1));
        }
        else {
          // This event has no end date.
          return NULL;
        }
      }
      elseif ($property_key == 'DTSTART') {
        // DTSTART can only be legally unset in non-VEVENT components.
        if ($vcalendar_component->objName == 'vevent') {
          throw new DateIcalParseException(t('Feed import failed! The VEVENT with UID %uid is invalid: it has no DTSTART.', array('%uid' => $uid)));
        }
        else {
          return NULL;
        }
      }
    }

    // When iCalcreator parses a UTC date (one that ends with Z) from an iCal
    // feed, it stores that 'Z' into the $property['value']['tz'] value.
    if (isset($property['value']['tz'])) {
      $property['params']['TZID'] = 'UTC';
    }

    if ($is_all_day) {
      if ($property_key == 'DTEND') {
        if ($dtstart === FALSE) {
          // This will almost certainly never happen, but the error message
          // would be incomprehensible without this check.
          throw new DateIcalParseException(t('Feed import failed! The event with UID %uid is invalid: it has a DTEND but no DTSTART!', array('%uid' => $uid)));
        }

        if (module_exists('date_all_day')) {
          // If the Date All Day module is installed, we need to rewind the
          // DTEND by one day, because of the problem with FeedsDateTime
          // mentioned below.
          $prev_day = iCalUtilityFunctions::_duration2date($property['value'], array('day' => -1));
          $property['value'] = $prev_day;
        }
      }

      // FeedsDateTime->setTimezone() ignores timezone changes made to dates
      // with no time element, which means we can't compensate for the Date
      // module's automatic timezone conversion when it writes to the DB. To
      // get around that, we must add 00:00:00 explicitly, even though this
      // causes other problems (see above and below).
      $date_string = sprintf('%d-%d-%d 00:00:00', $property['value']['year'], $property['value']['month'], $property['value']['day']);
      // Use the server's timezone rather than letting it default to UTC.
      // This will help ensure that the date value doesn't get messed up when
      // Date converts its timezone as the value is read from the database.
      // This is *essential* for All Day events, because Date stores them as
      // '2013-10-03 00:00:00' in the database, rather than doing the sensible
      // thing and storing them as '2013-10-03'.
      // NOTE TO MAINTAINERS:
      // This will not work properly if the site is configured to allow users
      // to set their own timezone. Unfortunately, there isn't anything that
      // Date iCal can do about that, as far as I can tell.
      $datetimezone = new DateTimeZone(date_default_timezone_get());
    }
    else {
      // This is a DATE-TIME property.
      $date_string = iCalUtilityFunctions::_format_date_time($property['value']);

      // Allow modules to alter the timezone string. This also allows for
      // setting a TZID when one was not originally set for this property.
      $tzid = isset($property['params']['TZID']) ? $property['params']['TZID'] : NULL;
      $context = array(
        'property_key' => $property_key,
        'calendar_component' => $vcalendar_component,
        'calendar' => $this->calendar,
        'feeeds_source' => $this->source,
        'feeds_fetcher_result' => $this->fetcherResult,
      );
      drupal_alter('date_ical_import_timezone', $tzid, $context);

      if (isset($tzid)) {
        $datetimezone = $this->_tzid_to_datetimezone($tzid);
      }
      elseif (isset($this->xtimezone)) {
        // No timezone was set on the parsed date property, so if a timezone
        // was detected for the entire iCal feed, use it.
        $datetimezone = $this->xtimezone;
      }
      else {
        $msg = t("No timezone was detected for one or more of the events in this feed, forcing Date iCal to use this server's timezone as a fallback.<br>
            To make timezone-less events use a different timezone, implement hook_date_ical_import_timezone_alter() in a custom module.");
        drupal_set_message($msg, 'status', FALSE);
        $this->source->log('parse', $msg, array(), WATCHDOG_NOTICE);
        $datetimezone = new DateTimeZone(date_default_timezone_get());
      }
    }

    $datetime = new FeedsDateTime($date_string, $datetimezone);
    return $datetime;
  }

  /**
   * Handler that parses multi-value fields, like the CATEGORIES component.
   *
   * @return array
   *   An array of strings contaning the individual values.
   */
  public function parseMultivalueProperty($property_key, $vcalendar_component) {
    // Since we're not telling it to give us the params data, $property will
    // be either FALSE, a string, or an array of strings.
    $property = $vcalendar_component->getProperty($property_key);
    if (empty($property)) {
      // If this multi-value property is being mapped to a Taxonomy field,
      // Feeds will interpret anything besides empty array as an array of
      // empty values (e.g. array('')). This will create a term for that
      // empty value, rather than leaving the field blank.
      return array();
    }
    if (!is_array($property)) {
      $property = array($property);
    }
    return $property;
  }

  /**
   * Handler that parses RRULE, RDATE, EXRULE, and EXDATE together.
   *
   * @return string
   *   The RRULE, RDATE, EXRULE, and EXDATE values concatinated with |.
   */
  public function parseRepeatProperty($property_key, $vcalendar_component) {
    if ($vcalendar_component->getProperty($property_key) === FALSE) {
      return NULL;
    }

    $uid = $vcalendar_component->getProperty('UID');
    $count = $this->config['indefinite_count'];
    // Due to a few bugs and limitations with Date Repeat, we need to massage
    // the RRULE a bit.
    if (count($vcalendar_component->rrule) > 1) {
      // TODO: Is Date Repeat still limited to 1 RRULE with Feeds 2.0-beta1?
      $msg = 'The event with UID %uid has multiple RRULEs, but the Date Repeat module only supports one. Only the first RRULE in the event will be used.
        If your events need to have a complex repeat pattern, using RDATEs should help.';
      watchdog('date_ical', $msg, array('%uid' => $uid), 'warning');
      drupal_set_message('At least one of the events in this iCal feed has multiple RRULEs, but the Date Repeat module only supports one.
        Only the first RRULE in an event will be used.', 'warning', FALSE);

      // Date Repeat will get extremely confused if it's sent multiple RRULE
      // values, so we need to manually pare it down to only the first one.
      $vcalendar_component->rrule = array($vcalendar_component->rrule[0]);
    }
    foreach ($vcalendar_component->rrule as &$rrule_data) {
      // RRULEs must have an INTERVAL, or Date Repeat will throw errors.
      // TODO: Is this still true with Feeds 2.0-beta1?
      if (!isset($rrule_data['value']['INTERVAL'])) {
        $rrule_data['value']['INTERVAL'] = '1';
      }

      if ((!isset($rrule_data['value']['COUNT']) && !isset($rrule_data['value']['UNTIL']))) {
        $msg = "The event with UID %uid has an indefinitely repeating RRULE, which the Date Repeat module doesn't support.
          As a workaround, Date iCal set the repeat count to @count. This value can be customized in the iCal parser settings.";
        watchdog('date_ical', $msg, array('%uid' => $uid, '@count' => $count), WATCHDOG_WARNING);
        if ($this->config['indefinite_message_display']) {
          drupal_set_message(
            t("At least one of the events in this iCal feed has an indefinitely repeating RRULE, which the Date Repeat module doesn't support.<br>
              As a workaround, Date iCal set the repeat count to @count. This value can be customized in the iCal parser settings.",
            array('@count' => $count)),
            'warning',
            FALSE
          );
        }
        $rrule_data['value']['COUNT'] = $this->config['indefinite_count'];
      }
    }

    $rrule = trim($vcalendar_component->createRrule());
    $rdate = trim($vcalendar_component->createRdate());
    $exrule = trim($vcalendar_component->createExrule());
    $exdate = trim($vcalendar_component->createExdate());
    return "$rrule|$rdate|$exrule|$exdate";
  }

  /**
   * Internal helper function for creating DateTimeZone objects.
   */
  protected function _tzid_to_datetimezone($tzid) {
    try {
      $datetimezone = new DateTimeZone($tzid);
    }
    catch (Exception $e) {
      // In case this is a Windows TZID, read the mapping file to try and
      // convert it to a real TZID.
      $zones = file_get_contents(drupal_get_path('module', 'date_ical') . '/libraries/windowsZones.json');
      $zones_assoc = json_decode($zones, TRUE);
      $windows_to_olson_map = array();
      foreach ($zones_assoc['supplemental']['windowsZones']['mapTimezones'] as $mapTimezone) {
        if ($mapTimezone['mapZone']['_other'] == $tzid) {
          // Parse out the space-separated TZIDs from $mapTimezone['mapZone']['_type'].
          $tzids = preg_split('/\s/', $mapTimezone['mapZone']['_type']);
          try {
            // They all have the same UTC offset, so for our purposes we can
            // just take the first one.
            return new DateTimeZone($tzids[0]);
          }
          catch (Exception $e) {
            // If this one also fails, we're out of luck, so just fall through
            // to the regular error report code.
            break;
          }
        }
      }

      $tz_wiki = l(t('here'), 'http://en.wikipedia.org/wiki/List_of_tz_database_time_zones#List');
      $help = l(t('README'), 'admin/help/date_ical', array('absolute' => TRUE));
      $msg = t(
          '"@tz" is not a valid timezone (see the TZ column !here), so Date iCal had to fall back to UTC (which is probably wrong!).<br>
          Please read the Date iCal !readme for instructions on how to fix this.',
          array('@tz' => $tzid, '!here' => $tz_wiki, '!readme' => $help)
      );
      $this->source->log('parse', $msg, array(), WATCHDOG_WARNING);
      drupal_set_message($msg, 'warning', FALSE);
      $datetimezone = new DateTimeZone('UTC');
    }
    return $datetimezone;
  }

  /**
   * Internal helper function for skipping old events.
   */
  protected function _skip_current_event() {
    // Must use !isset() here, because 0 and NULL mean different things.
    if (!isset($this->config['skip_days'])) {
      return FALSE;
    }
    $compare_date = isset($this->parsed_data['DTEND']) ? $this->parsed_data['DTEND'] : $this->parsed_data['DTSTART'];
    $skip_date = new FeedsDateTime("today -{$this->config['skip_days']} days", $compare_date->getTimezone());
    $skip = ($skip_date > $compare_date);
    return $skip;
  }
}
