function asAtom($app_root)
{
$item = $this->getItem();
$tag = $this->getTag();
$feed = new Dase_Atom_Feed();
if (is_numeric($item->updated)) {
$updated = date(DATE_ATOM, $item->updated);
} else {
$updated = $item->updated;
}
$feed->setUpdated($updated);
$feed->setTitle($item->getTitle());
$feed->setId($app_root . '/tag/item/' . $tag->id . '/' . $this->id);
$feed->setGenerator('DASe', 'http://daseproject.org', '1.0');
$feed->addAuthor($tag->eid);
//$feed->addCategory($tag->type,"http://daseproject.org/category/tag_type",$tag->type);
$feed->addCategory('set', "http://daseproject.org/category/tag_type");
//$feed->addLink($tag->getUrl($app_root),"http://daseproject.org/relation/feed-link");
$feed->addLink($tag->getUrl($app_root), "up");
$tag_item_id_array = $tag->getTagItemIds();
$position = array_search($this->id, $tag_item_id_array) + 1;
$feed->addCategory($position, "http://daseproject.org/category/position");
if (1 == $position) {
$prev_id = array_pop($tag_item_id_array);
array_push($tag_item_id_array, $prev_id);
//because array_pop shortened array
} else {
$prev_id = $tag_item_id_array[$position - 2];
}
if (isset($tag_item_id_array[$position])) {
$next_id = $tag_item_id_array[$position];
} else {
$next_id = $tag_item_id_array[0];
}
//overloading opensearch elements here
$feed->setOpensearchTotalResults($tag->item_count);
$feed->setOpensearchQuery($tag->name);
//$feed->addLink($tag->getLink().'/'.$prev_id,"previous");
//$feed->addLink($tag->getLink().'/'.$next_id,"next");
$feed->addLink($app_root . '/tag/item/' . $tag->id . '/' . $this->id . '.atom', "self");
$feed->addLink($app_root . '/tag/item/' . $tag->id . '/' . $prev_id, "previous");
$feed->addLink($app_root . '/tag/item/' . $tag->id . '/' . $next_id, "next");
$feed->setFeedType('tagitem');
//tag name goes in subtitle, so doesn't need to be in category
$feed->setSubtitle($tag->name . ' ' . $position . ' of ' . count($tag_item_id_array));
//regenerated!!! (should cache)
$entry = $item->injectAtomEntryData($feed->addEntry(), $app_root);
//very strange to use summary for annotation (?)
$entry->setSummary($this->annotation);
return $feed->asXml();
}