<?php
/**
 * StatusNet, the distributed open-source microblogging tool
 *
 * Base API action
 *
 * PHP version 5
 *
 * LICENCE: This program is free software: you can redistribute it and/or modify
 * it under the terms of the GNU Affero General Public License as published by
 * the Free Software Foundation, either version 3 of the License, or
 * (at your option) any later version.
 *
 * This program is distributed in the hope that it will be useful,
 * but WITHOUT ANY WARRANTY; without even the implied warranty of
 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
 * GNU Affero General Public License for more details.
 *
 * You should have received a copy of the GNU Affero General Public License
 * along with this program.  If not, see <http://www.gnu.org/licenses/>.
 *
 * @category  API
 * @package   StatusNet
 * @author    Craig Andrews <candrews@integralblue.com>
 * @author    Dan Moore <dan@moore.cx>
 * @author    Evan Prodromou <evan@status.net>
 * @author    Jeffery To <jeffery.to@gmail.com>
 * @author    Toby Inkster <mail@tobyinkster.co.uk>
 * @author    Zach Copley <zach@status.net>
 * @copyright 2009 StatusNet, Inc.
 * @license   http://www.fsf.org/licensing/licenses/agpl-3.0.html GNU Affero General Public License version 3.0
 * @link      http://status.net/
 */

/* External API usage documentation. Please update when you change how the API works. */

/*! @mainpage StatusNet REST API

    @section Introduction

    Some explanatory text about the API would be nice.

    @section API Methods

    @subsection timelinesmethods_sec Timeline Methods

    @li @ref publictimeline
    @li @ref friendstimeline

    @subsection statusmethods_sec Status Methods

    @li @ref statusesupdate

    @subsection usermethods_sec User Methods

    @subsection directmessagemethods_sec Direct Message Methods

    @subsection friendshipmethods_sec Friendship Methods

    @subsection socialgraphmethods_sec Social Graph Methods

    @subsection accountmethods_sec Account Methods

    @subsection favoritesmethods_sec Favorites Methods

    @subsection blockmethods_sec Block Methods

    @subsection oauthmethods_sec OAuth Methods

    @subsection helpmethods_sec Help Methods

    @subsection groupmethods_sec Group Methods

    @page apiroot API Root

    The URLs for methods referred to in this API documentation are
    relative to the StatusNet API root. The API root is determined by the
    site's @b server and @b path variables, which are generally specified
    in config.php. For example:

    @code
    $config['site']['server'] = 'example.org';
    $config['site']['path'] = 'statusnet'
    @endcode

    The pattern for a site's API root is: @c protocol://server/path/api E.g:

    @c http://example.org/statusnet/api

    The @b path can be empty.  In that case the API root would simply be:

    @c http://example.org/api

*/

if (!defined('STATUSNET')) {
    exit(1);
}

class ApiValidationException extends Exception { }

/**
 * Contains most of the Twitter-compatible API output functions.
 *
 * @category API
 * @package  StatusNet
 * @author   Craig Andrews <candrews@integralblue.com>
 * @author   Dan Moore <dan@moore.cx>
 * @author   Evan Prodromou <evan@status.net>
 * @author   Jeffery To <jeffery.to@gmail.com>
 * @author   Toby Inkster <mail@tobyinkster.co.uk>
 * @author   Zach Copley <zach@status.net>
 * @license  http://www.fsf.org/licensing/licenses/agpl-3.0.html GNU Affero General Public License version 3.0
 * @link     http://status.net/
 */

class ApiAction extends Action
{
    const READ_ONLY  = 1;
    const READ_WRITE = 2;

    var $format    = null;
    var $user      = null;
    var $auth_user = null;
    var $page      = null;
    var $count     = null;
    var $max_id    = null;
    var $since_id  = null;

    var $access    = self::READ_ONLY;  // read (default) or read-write

    /**
     * Initialization.
     *
     * @param array $args Web and URL arguments
     *
     * @return boolean false if user doesn't exist
     */

    function prepare($args)
    {
        StatusNet::setApi(true); // reduce exception reports to aid in debugging
        parent::prepare($args);

        $this->format   = $this->arg('format');
        $this->page     = (int)$this->arg('page', 1);
        $this->count    = (int)$this->arg('count', 20);
        $this->max_id   = (int)$this->arg('max_id', 0);
        $this->since_id = (int)$this->arg('since_id', 0);

        if ($this->arg('since')) {
            header('X-StatusNet-Warning: since parameter is disabled; use since_id');
        }

        return true;
    }

    /**
     * Handle a request
     *
     * @param array $args Arguments from $_REQUEST
     *
     * @return void
     */

    function handle($args)
    {
        header('Access-Control-Allow-Origin: *');
        parent::handle($args);
    }

    /**
     * Overrides XMLOutputter::element to write booleans as strings (true|false).
     * See that method's documentation for more info.
     *
     * @param string $tag     Element type or tagname
     * @param array  $attrs   Array of element attributes, as
     *                        key-value pairs
     * @param string $content string content of the element
     *
     * @return void
     */
    function element($tag, $attrs=null, $content=null)
    {
        if (is_bool($content)) {
            $content = ($content ? 'true' : 'false');
        }

        return parent::element($tag, $attrs, $content);
    }

    function twitterUserArray($profile, $get_notice=false)
    {
        $twitter_user = array();

        $twitter_user['id'] = intval($profile->id);
        $twitter_user['name'] = $profile->getBestName();
        $twitter_user['screen_name'] = $profile->nickname;
        $twitter_user['location'] = ($profile->location) ? $profile->location : null;
        $twitter_user['description'] = ($profile->bio) ? $profile->bio : null;

        $avatar = $profile->getAvatar(AVATAR_STREAM_SIZE);
        $twitter_user['profile_image_url'] = ($avatar) ? $avatar->displayUrl() :
            Avatar::defaultImage(AVATAR_STREAM_SIZE);

        $twitter_user['url'] = ($profile->homepage) ? $profile->homepage : null;
        $twitter_user['protected'] = false; # not supported by StatusNet yet
        $twitter_user['followers_count'] = $profile->subscriberCount();

        $design        = null;
        $user          = $profile->getUser();

        // Note: some profiles don't have an associated user

        $defaultDesign = Design::siteDesign();

        if (!empty($user)) {
            $design = $user->getDesign();
        }

        if (empty($design)) {
            $design = $defaultDesign;
        }

        $color = Design::toWebColor(empty($design->backgroundcolor) ? $defaultDesign->backgroundcolor : $design->backgroundcolor);
        $twitter_user['profile_background_color'] = ($color == null) ? '' : '#'.$color->hexValue();
        $color = Design::toWebColor(empty($design->textcolor) ? $defaultDesign->textcolor : $design->textcolor);
        $twitter_user['profile_text_color'] = ($color == null) ? '' : '#'.$color->hexValue();
        $color = Design::toWebColor(empty($design->linkcolor) ? $defaultDesign->linkcolor : $design->linkcolor);
        $twitter_user['profile_link_color'] = ($color == null) ? '' : '#'.$color->hexValue();
        $color = Design::toWebColor(empty($design->sidebarcolor) ? $defaultDesign->sidebarcolor : $design->sidebarcolor);
        $twitter_user['profile_sidebar_fill_color'] = ($color == null) ? '' : '#'.$color->hexValue();
        $twitter_user['profile_sidebar_border_color'] = '';

        $twitter_user['friends_count'] = $profile->subscriptionCount();

        $twitter_user['created_at'] = $this->dateTwitter($profile->created);

        $twitter_user['favourites_count'] = $profile->faveCount(); // British spelling!

        $timezone = 'UTC';

        if (!empty($user) && $user->timezone) {
            $timezone = $user->timezone;
        }

        $t = new DateTime;
        $t->setTimezone(new DateTimeZone($timezone));

        $twitter_user['utc_offset'] = $t->format('Z');
        $twitter_user['time_zone'] = $timezone;

        $twitter_user['profile_background_image_url']
            = empty($design->backgroundimage)
            ? '' : ($design->disposition & BACKGROUND_ON)
            ? Design::url($design->backgroundimage) : '';

        $twitter_user['profile_background_tile']
            = empty($design->disposition)
            ? '' : ($design->disposition & BACKGROUND_TILE) ? 'true' : 'false';

        $twitter_user['statuses_count'] = $profile->noticeCount();

        // Is the requesting user following this user?
        $twitter_user['following'] = false;
        $twitter_user['notifications'] = false;

        if (isset($this->auth_user)) {

            $twitter_user['following'] = $this->auth_user->isSubscribed($profile);

            // Notifications on?
            $sub = Subscription::pkeyGet(array('subscriber' =>
                                               $this->auth_user->id,
                                               'subscribed' => $profile->id));

            if ($sub) {
                $twitter_user['notifications'] = ($sub->jabber || $sub->sms);
            }
        }

        if ($get_notice) {
            $notice = $profile->getCurrentNotice();
            if ($notice) {
                # don't get user!
                $twitter_user['status'] = $this->twitterStatusArray($notice, false);
            }
        }

        return $twitter_user;
    }

    function twitterStatusArray($notice, $include_user=true)
    {
        $base = $this->twitterSimpleStatusArray($notice, $include_user);

        if (!empty($notice->repeat_of)) {
            $original = Notice::staticGet('id', $notice->repeat_of);
            if (!empty($original)) {
                $original_array = $this->twitterSimpleStatusArray($original, $include_user);
                $base['retweeted_status'] = $original_array;
            }
        }

        return $base;
    }

    function twitterSimpleStatusArray($notice, $include_user=true)
    {
        $profile = $notice->getProfile();

        $twitter_status = array();
        $twitter_status['text'] = $notice->content;
        $twitter_status['truncated'] = false; # Not possible on StatusNet
        $twitter_status['created_at'] = $this->dateTwitter($notice->created);
        $twitter_status['in_reply_to_status_id'] = ($notice->reply_to) ?
            intval($notice->reply_to) : null;

        $source = null;

        $ns = $notice->getSource();
        if ($ns) {
            if (!empty($ns->name) && !empty($ns->url)) {
                $source = '<a href="'
		    . htmlspecialchars($ns->url)
		    . '" rel="nofollow">'
		    . htmlspecialchars($ns->name)
		    . '</a>';
            } else {
                $source = $ns->code;
            }
        }

        $twitter_status['source'] = $source;
        $twitter_status['id'] = intval($notice->id);

        $replier_profile = null;

        if ($notice->reply_to) {
            $reply = Notice::staticGet(intval($notice->reply_to));
            if ($reply) {
                $replier_profile = $reply->getProfile();
            }
        }

        $twitter_status['in_reply_to_user_id'] =
            ($replier_profile) ? intval($replier_profile->id) : null;
        $twitter_status['in_reply_to_screen_name'] =
            ($replier_profile) ? $replier_profile->nickname : null;

        if (isset($notice->lat) && isset($notice->lon)) {
            // This is the format that GeoJSON expects stuff to be in
            $twitter_status['geo'] = array('type' => 'Point',
                                           'coordinates' => array((float) $notice->lat,
                                                                  (float) $notice->lon));
        } else {
            $twitter_status['geo'] = null;
        }

        if (isset($this->auth_user)) {
            $twitter_status['favorited'] = $this->auth_user->hasFave($notice);
        } else {
            $twitter_status['favorited'] = false;
        }

        // Enclosures
        $attachments = $notice->attachments();

        if (!empty($attachments)) {

            $twitter_status['attachments'] = array();

            foreach ($attachments as $attachment) {
                $enclosure_o=$attachment->getEnclosure();
                if ($enclosure_o) {
                    $enclosure = array();
                    $enclosure['url'] = $enclosure_o->url;
                    $enclosure['mimetype'] = $enclosure_o->mimetype;
                    $enclosure['size'] = $enclosure_o->size;
                    $twitter_status['attachments'][] = $enclosure;
                }
            }
        }

        if ($include_user && $profile) {
            # Don't get notice (recursive!)
            $twitter_user = $this->twitterUserArray($profile, false);
            $twitter_status['user'] = $twitter_user;
        }

        return $twitter_status;
    }

    function twitterGroupArray($group)
    {
        $twitter_group=array();
        $twitter_group['id']=$group->id;
        $twitter_group['url']=$group->permalink();
        $twitter_group['nickname']=$group->nickname;
        $twitter_group['fullname']=$group->fullname;
        $twitter_group['original_logo']=$group->original_logo;
        $twitter_group['homepage_logo']=$group->homepage_logo;
        $twitter_group['stream_logo']=$group->stream_logo;
        $twitter_group['mini_logo']=$group->mini_logo;
        $twitter_group['homepage']=$group->homepage;
        $twitter_group['description']=$group->description;
        $twitter_group['location']=$group->location;
        $twitter_group['created']=$this->dateTwitter($group->created);
        $twitter_group['modified']=$this->dateTwitter($group->modified);
        return $twitter_group;
    }

    function twitterRssGroupArray($group)
    {
        $entry = array();
        $entry['content']=$group->description;
        $entry['title']=$group->nickname;
        $entry['link']=$group->permalink();
        $entry['published']=common_date_iso8601($group->created);
        $entry['updated']==common_date_iso8601($group->modified);
        $taguribase = common_config('integration', 'groupuri');
        $entry['id'] = "group:$groupuribase:$entry[link]";

        $entry['description'] = $entry['content'];
        $entry['pubDate'] = common_date_rfc2822($group->created);
        $entry['guid'] = $entry['link'];

        return $entry;
    }

    function twitterRssEntryArray($notice)
    {
        $profile = $notice->getProfile();
        $entry = array();

        // We trim() to avoid extraneous whitespace in the output

        $entry['content'] = common_xml_safe_str(trim($notice->rendered));
        $entry['title'] = $profile->nickname . ': ' . common_xml_safe_str(trim($notice->content));
        $entry['link'] = common_local_url('shownotice', array('notice' => $notice->id));
        $entry['published'] = common_date_iso8601($notice->created);

        $taguribase = TagURI::base();
        $entry['id'] = "tag:$taguribase:$entry[link]";

        $entry['updated'] = $entry['published'];
        $entry['author'] = $profile->getBestName();

        // Enclosures
        $attachments = $notice->attachments();
        $enclosures = array();

        foreach ($attachments as $attachment) {
            $enclosure_o=$attachment->getEnclosure();
            if ($enclosure_o) {
                 $enclosure = array();
                 $enclosure['url'] = $enclosure_o->url;
                 $enclosure['mimetype'] = $enclosure_o->mimetype;
                 $enclosure['size'] = $enclosure_o->size;
                 $enclosures[] = $enclosure;
            }
        }

        if (!empty($enclosures)) {
            $entry['enclosures'] = $enclosures;
        }

        // Tags/Categories
        $tag = new Notice_tag();
        $tag->notice_id = $notice->id;
        if ($tag->find()) {
            $entry['tags']=array();
            while ($tag->fetch()) {
                $entry['tags'][]=$tag->tag;
            }
        }
        $tag->free();

        // RSS Item specific
        $entry['description'] = $entry['content'];
        $entry['pubDate'] = common_date_rfc2822($notice->created);
        $entry['guid'] = $entry['link'];

        if (isset($notice->lat) && isset($notice->lon)) {
            // This is the format that GeoJSON expects stuff to be in.
            // showGeoRSS() below uses it for XML output, so we reuse it
            $entry['geo'] = array('type' => 'Point',
                                  'coordinates' => array((float) $notice->lat,
                                                         (float) $notice->lon));
        } else {
            $entry['geo'] = null;
        }

        return $entry;
    }

    function twitterRelationshipArray($source, $target)
    {
        $relationship = array();

        $relationship['source'] =
            $this->relationshipDetailsArray($source, $target);
        $relationship['target'] =
            $this->relationshipDetailsArray($target, $source);

        return array('relationship' => $relationship);
    }

    function relationshipDetailsArray($source, $target)
    {
        $details = array();

        $details['screen_name'] = $source->nickname;
        $details['followed_by'] = $target->isSubscribed($source);
        $details['following'] = $source->isSubscribed($target);

        $notifications = false;

        if ($source->isSubscribed($target)) {

            $sub = Subscription::pkeyGet(array('subscriber' =>
                $source->id, 'subscribed' => $target->id));

            if (!empty($sub)) {
                $notifications = ($sub->jabber || $sub->sms);
            }
        }

        $details['notifications_enabled'] = $notifications;
        $details['blocking'] = $source->hasBlocked($target);
        $details['id'] = $source->id;

        return $details;
    }

    function showTwitterXmlRelationship($relationship)
    {
        $this->elementStart('relationship');

        foreach($relationship as $element => $value) {
            if ($element == 'source' || $element == 'target') {
                $this->elementStart($element);
                $this->showXmlRelationshipDetails($value);
                $this->elementEnd($element);
            }
        }

        $this->elementEnd('relationship');
    }

    function showXmlRelationshipDetails($details)
    {
        foreach($details as $element => $value) {
            $this->element($element, null, $value);
        }
    }

    function showTwitterXmlStatus($twitter_status, $tag='status')
    {
        $this->elementStart($tag);
        foreach($twitter_status as $element => $value) {
            switch ($element) {
            case 'user':
                $this->showTwitterXmlUser($twitter_status['user']);
                break;
            case 'text':
                $this->element($element, null, common_xml_safe_str($value));
                break;
            case 'attachments':
                $this->showXmlAttachments($twitter_status['attachments']);
                break;
            case 'geo':
                $this->showGeoXML($value);
                break;
            case 'retweeted_status':
                $this->showTwitterXmlStatus($value, 'retweeted_status');
                break;
            default:
                $this->element($element, null, $value);
            }
        }
        $this->elementEnd($tag);
    }

    function showTwitterXmlGroup($twitter_group)
    {
        $this->elementStart('group');
        foreach($twitter_group as $element => $value) {
            $this->element($element, null, $value);
        }
        $this->elementEnd('group');
    }

    function showTwitterXmlUser($twitter_user, $role='user')
    {
        $this->elementStart($role);
        foreach($twitter_user as $element => $value) {
            if ($element == 'status') {
                $this->showTwitterXmlStatus($twitter_user['status']);
            } else {
                $this->element($element, null, $value);
            }
        }
        $this->elementEnd($role);
    }

    function showXmlAttachments($attachments) {
        if (!empty($attachments)) {
            $this->elementStart('attachments', array('type' => 'array'));
            foreach ($attachments as $attachment) {
                $attrs = array();
                $attrs['url'] = $attachment['url'];
                $attrs['mimetype'] = $attachment['mimetype'];
                $attrs['size'] = $attachment['size'];
                $this->element('enclosure', $attrs, '');
            }
            $this->elementEnd('attachments');
        }
    }

    function showGeoXML($geo)
    {
        if (empty($geo)) {
            // empty geo element
            $this->element('geo');
        } else {
            $this->elementStart('geo', array('xmlns:georss' => 'http://www.georss.org/georss'));
            $this->element('georss:point', null, $geo['coordinates'][0] . ' ' . $geo['coordinates'][1]);
            $this->elementEnd('geo');
        }
    }

    function showGeoRSS($geo)
    {
        if (!empty($geo)) {
            $this->element(
                'georss:point',
                null,
                $geo['coordinates'][0] . ' ' . $geo['coordinates'][1]
            );
        }
    }

    function showTwitterRssItem($entry)
    {
        $this->elementStart('item');
        $this->element('title', null, $entry['title']);
        $this->element('description', null, $entry['description']);
        $this->element('pubDate', null, $entry['pubDate']);
        $this->element('guid', null, $entry['guid']);
        $this->element('link', null, $entry['link']);

        # RSS only supports 1 enclosure per item
        if(array_key_exists('enclosures', $entry) and !empty($entry['enclosures'])){
            $enclosure = $entry['enclosures'][0];
            $this->element('enclosure', array('url'=>$enclosure['url'],'type'=>$enclosure['mimetype'],'length'=>$enclosure['size']), null);
        }

        if(array_key_exists('tags', $entry)){
            foreach($entry['tags'] as $tag){
                $this->element('category', null,$tag);
            }
        }

        $this->showGeoRSS($entry['geo']);
        $this->elementEnd('item');
    }

    function showJsonObjects($objects)
    {
        print(json_encode($objects));
    }

    function showSingleXmlStatus($notice)
    {
        $this->initDocument('xml');
        $twitter_status = $this->twitterStatusArray($notice);
        $this->showTwitterXmlStatus($twitter_status);
        $this->endDocument('xml');
    }

    function show_single_json_status($notice)
    {
        $this->initDocument('json');
        $status = $this->twitterStatusArray($notice);
        $this->showJsonObjects($status);
        $this->endDocument('json');
    }

    function showXmlTimeline($notice)
    {

        $this->initDocument('xml');
        $this->elementStart('statuses', array('type' => 'array'));

        if (is_array($notice)) {
            foreach ($notice as $n) {
                $twitter_status = $this->twitterStatusArray($n);
                $this->showTwitterXmlStatus($twitter_status);
            }
        } else {
            while ($notice->fetch()) {
                $twitter_status = $this->twitterStatusArray($notice);
                $this->showTwitterXmlStatus($twitter_status);
            }
        }

        $this->elementEnd('statuses');
        $this->endDocument('xml');
    }

    function showRssTimeline($notice, $title, $link, $subtitle, $suplink = null, $logo = null, $self = null)
    {

        $this->initDocument('rss');

        $this->element('title', null, $title);
        $this->element('link', null, $link);

        if (!is_null($self)) {
            $this->element(
                'atom:link',
                array(
                    'type' => 'application/rss+xml',
                    'href' => $self,
                    'rel'  => 'self'
                )
           );
        }

        if (!is_null($suplink)) {
            // For FriendFeed's SUP protocol
            $this->element('link', array('xmlns' => 'http://www.w3.org/2005/Atom',
                                         'rel' => 'http://api.friendfeed.com/2008/03#sup',
                                         'href' => $suplink,
                                         'type' => 'application/json'));
        }

        if (!is_null($logo)) {
            $this->elementStart('image');
            $this->element('link', null, $link);
            $this->element('title', null, $title);
            $this->element('url', null, $logo);
            $this->elementEnd('image');
        }

        $this->element('description', null, $subtitle);
        $this->element('language', null, 'en-us');
        $this->element('ttl', null, '40');

        if (is_array($notice)) {
            foreach ($notice as $n) {
                $entry = $this->twitterRssEntryArray($n);
                $this->showTwitterRssItem($entry);
            }
        } else {
            while ($notice->fetch()) {
                $entry = $this->twitterRssEntryArray($notice);
                $this->showTwitterRssItem($entry);
            }
        }

        $this->endTwitterRss();
    }

    function showAtomTimeline($notice, $title, $id, $link, $subtitle=null, $suplink=null, $selfuri=null, $logo=null)
    {

        $this->initDocument('atom');

        $this->element('title', null, $title);
        $this->element('id', null, $id);
        $this->element('link', array('href' => $link, 'rel' => 'alternate', 'type' => 'text/html'), null);

        if (!is_null($logo)) {
            $this->element('logo',null,$logo);
        }

        if (!is_null($suplink)) {
            # For FriendFeed's SUP protocol
            $this->element('link', array('rel' => 'http://api.friendfeed.com/2008/03#sup',
                                         'href' => $suplink,
                                         'type' => 'application/json'));
        }

        if (!is_null($selfuri)) {
            $this->element('link', array('href' => $selfuri,
                'rel' => 'self', 'type' => 'application/atom+xml'), null);
        }

        $this->element('updated', null, common_date_iso8601('now'));
        $this->element('subtitle', null, $subtitle);

        if (is_array($notice)) {
            foreach ($notice as $n) {
                $this->raw($n->asAtomEntry());
            }
        } else {
            while ($notice->fetch()) {
                $this->raw($notice->asAtomEntry());
            }
        }

        $this->endDocument('atom');

    }

    function showRssGroups($group, $title, $link, $subtitle)
    {

        $this->initDocument('rss');

        $this->element('title', null, $title);
        $this->element('link', null, $link);
        $this->element('description', null, $subtitle);
        $this->element('language', null, 'en-us');
        $this->element('ttl', null, '40');

        if (is_array($group)) {
            foreach ($group as $g) {
                $twitter_group = $this->twitterRssGroupArray($g);
                $this->showTwitterRssItem($twitter_group);
            }
        } else {
            while ($group->fetch()) {
                $twitter_group = $this->twitterRssGroupArray($group);
                $this->showTwitterRssItem($twitter_group);
            }
        }

        $this->endTwitterRss();
    }

    function showTwitterAtomEntry($entry)
    {
        $this->elementStart('entry');
        $this->element('title', null, common_xml_safe_str($entry['title']));
        $this->element(
            'content',
            array('type' => 'html'),
            common_xml_safe_str($entry['content'])
        );
        $this->element('id', null, $entry['id']);
        $this->element('published', null, $entry['published']);
        $this->element('updated', null, $entry['updated']);
        $this->element('link', array('type' => 'text/html',
                                     'href' => $entry['link'],
                                     'rel' => 'alternate'));
        $this->element('link', array('type' => $entry['avatar-type'],
                                     'href' => $entry['avatar'],
                                     'rel' => 'image'));
        $this->elementStart('author');

        $this->element('name', null, $entry['author-name']);
        $this->element('uri', null, $entry['author-uri']);

        $this->elementEnd('author');
        $this->elementEnd('entry');
    }

    function showXmlDirectMessage($dm)
    {
        $this->elementStart('direct_message');
        foreach($dm as $element => $value) {
            switch ($element) {
            case 'sender':
            case 'recipient':
                $this->showTwitterXmlUser($value, $element);
                break;
            case 'text':
                $this->element($element, null, common_xml_safe_str($value));
                break;
            default:
                $this->element($element, null, $value);
                break;
            }
        }
        $this->elementEnd('direct_message');
    }

    function directMessageArray($message)
    {
        $dmsg = array();

        $from_profile = $message->getFrom();
        $to_profile = $message->getTo();

        $dmsg['id'] = $message->id;
        $dmsg['sender_id'] = $message->from_profile;
        $dmsg['text'] = trim($message->content);
        $dmsg['recipient_id'] = $message->to_profile;
        $dmsg['created_at'] = $this->dateTwitter($message->created);
        $dmsg['sender_screen_name'] = $from_profile->nickname;
        $dmsg['recipient_screen_name'] = $to_profile->nickname;
        $dmsg['sender'] = $this->twitterUserArray($from_profile, false);
        $dmsg['recipient'] = $this->twitterUserArray($to_profile, false);

        return $dmsg;
    }

    function rssDirectMessageArray($message)
    {
        $entry = array();

        $from = $message->getFrom();

        $entry['title'] = sprintf('Message from %1$s to %2$s',
            $from->nickname, $message->getTo()->nickname);

        $entry['content'] = common_xml_safe_str($message->rendered);
        $entry['link'] = common_local_url('showmessage', array('message' => $message->id));
        $entry['published'] = common_date_iso8601($message->created);

        $taguribase = TagURI::base();

        $entry['id'] = "tag:$taguribase:$entry[link]";
        $entry['updated'] = $entry['published'];

        $entry['author-name'] = $from->getBestName();
        $entry['author-uri'] = $from->homepage;

        $avatar = $from->getAvatar(AVATAR_STREAM_SIZE);

        $entry['avatar']      = (!empty($avatar)) ? $avatar->url : Avatar::defaultImage(AVATAR_STREAM_SIZE);
        $entry['avatar-type'] = (!empty($avatar)) ? $avatar->mediatype : 'image/png';

        // RSS item specific

        $entry['description'] = $entry['content'];
        $entry['pubDate'] = common_date_rfc2822($message->created);
        $entry['guid'] = $entry['link'];

        return $entry;
    }

    function showSingleXmlDirectMessage($message)
    {
        $this->initDocument('xml');
        $dmsg = $this->directMessageArray($message);
        $this->showXmlDirectMessage($dmsg);
        $this->endDocument('xml');
    }

    function showSingleJsonDirectMessage($message)
    {
        $this->initDocument('json');
        $dmsg = $this->directMessageArray($message);
        $this->showJsonObjects($dmsg);
        $this->endDocument('json');
    }

    function showAtomGroups($group, $title, $id, $link, $subtitle=null, $selfuri=null)
    {

        $this->initDocument('atom');

        $this->element('title', null, common_xml_safe_str($title));
        $this->element('id', null, $id);
        $this->element('link', array('href' => $link, 'rel' => 'alternate', 'type' => 'text/html'), null);

        if (!is_null($selfuri)) {
            $this->element('link', array('href' => $selfuri,
                'rel' => 'self', 'type' => 'application/atom+xml'), null);
        }

        $this->element('updated', null, common_date_iso8601('now'));
        $this->element('subtitle', null, common_xml_safe_str($subtitle));

        if (is_array($group)) {
            foreach ($group as $g) {
                $this->raw($g->asAtomEntry());
            }
        } else {
            while ($group->fetch()) {
                $this->raw($group->asAtomEntry());
            }
        }

        $this->endDocument('atom');

    }

    function showJsonTimeline($notice)
    {

        $this->initDocument('json');

        $statuses = array();

        if (is_array($notice)) {
            foreach ($notice as $n) {
                $twitter_status = $this->twitterStatusArray($n);
                array_push($statuses, $twitter_status);
            }
        } else {
            while ($notice->fetch()) {
                $twitter_status = $this->twitterStatusArray($notice);
                array_push($statuses, $twitter_status);
            }
        }

        $this->showJsonObjects($statuses);

        $this->endDocument('json');
    }

    function showJsonGroups($group)
    {

        $this->initDocument('json');

        $groups = array();

        if (is_array($group)) {
            foreach ($group as $g) {
                $twitter_group = $this->twitterGroupArray($g);
                array_push($groups, $twitter_group);
            }
        } else {
            while ($group->fetch()) {
                $twitter_group = $this->twitterGroupArray($group);
                array_push($groups, $twitter_group);
            }
        }

        $this->showJsonObjects($groups);

        $this->endDocument('json');
    }

    function showXmlGroups($group)
    {

        $this->initDocument('xml');
        $this->elementStart('groups', array('type' => 'array'));

        if (is_array($group)) {
            foreach ($group as $g) {
                $twitter_group = $this->twitterGroupArray($g);
                $this->showTwitterXmlGroup($twitter_group);
            }
        } else {
            while ($group->fetch()) {
                $twitter_group = $this->twitterGroupArray($group);
                $this->showTwitterXmlGroup($twitter_group);
            }
        }

        $this->elementEnd('groups');
        $this->endDocument('xml');
    }

    function showTwitterXmlUsers($user)
    {

        $this->initDocument('xml');
        $this->elementStart('users', array('type' => 'array'));

        if (is_array($user)) {
            foreach ($user as $u) {
                $twitter_user = $this->twitterUserArray($u);
                $this->showTwitterXmlUser($twitter_user);
            }
        } else {
            while ($user->fetch()) {
                $twitter_user = $this->twitterUserArray($user);
                $this->showTwitterXmlUser($twitter_user);
            }
        }

        $this->elementEnd('users');
        $this->endDocument('xml');
    }

    function showJsonUsers($user)
    {

        $this->initDocument('json');

        $users = array();

        if (is_array($user)) {
            foreach ($user as $u) {
                $twitter_user = $this->twitterUserArray($u);
                array_push($users, $twitter_user);
            }
        } else {
            while ($user->fetch()) {
                $twitter_user = $this->twitterUserArray($user);
                array_push($users, $twitter_user);
            }
        }

        $this->showJsonObjects($users);

        $this->endDocument('json');
    }

    function showSingleJsonGroup($group)
    {
        $this->initDocument('json');
        $twitter_group = $this->twitterGroupArray($group);
        $this->showJsonObjects($twitter_group);
        $this->endDocument('json');
    }

    function showSingleXmlGroup($group)
    {
        $this->initDocument('xml');
        $twitter_group = $this->twitterGroupArray($group);
        $this->showTwitterXmlGroup($twitter_group);
        $this->endDocument('xml');
    }

    function dateTwitter($dt)
    {
        $dateStr = date('d F Y H:i:s', strtotime($dt));
        $d = new DateTime($dateStr, new DateTimeZone('UTC'));
        $d->setTimezone(new DateTimeZone(common_timezone()));
        return $d->format('D M d H:i:s O Y');
    }

    function initDocument($type='xml')
    {
        switch ($type) {
        case 'xml':
            header('Content-Type: application/xml; charset=utf-8');
            $this->startXML();
            break;
        case 'json':
            header('Content-Type: application/json; charset=utf-8');

            // Check for JSONP callback
            $callback = $this->arg('callback');
            if ($callback) {
                print $callback . '(';
            }
            break;
        case 'rss':
            header("Content-Type: application/rss+xml; charset=utf-8");
            $this->initTwitterRss();
            break;
        case 'atom':
            header('Content-Type: application/atom+xml; charset=utf-8');
            $this->initTwitterAtom();
            break;
        default:
            // TRANS: Client error on an API request with an unsupported data format.
            $this->clientError(_('Not a supported data format.'));
            break;
        }

        return;
    }

    function endDocument($type='xml')
    {
        switch ($type) {
        case 'xml':
            $this->endXML();
            break;
        case 'json':

            // Check for JSONP callback
            $callback = $this->arg('callback');
            if ($callback) {
                print ')';
            }
            break;
        case 'rss':
            $this->endTwitterRss();
            break;
        case 'atom':
            $this->endTwitterRss();
            break;
        default:
            // TRANS: Client error on an API request with an unsupported data format.
            $this->clientError(_('Not a supported data format.'));
            break;
        }
        return;
    }

    function clientError($msg, $code = 400, $format = 'xml')
    {
        $action = $this->trimmed('action');

        common_debug("User error '$code' on '$action': $msg", __FILE__);

        if (!array_key_exists($code, ClientErrorAction::$status)) {
            $code = 400;
        }

        $status_string = ClientErrorAction::$status[$code];

        header('HTTP/1.1 '.$code.' '.$status_string);

        if ($format == 'xml') {
            $this->initDocument('xml');
            $this->elementStart('hash');
            $this->element('error', null, $msg);
            $this->element('request', null, $_SERVER['REQUEST_URI']);
            $this->elementEnd('hash');
            $this->endDocument('xml');
        } elseif ($format == 'json'){
            $this->initDocument('json');
            $error_array = array('error' => $msg, 'request' => $_SERVER['REQUEST_URI']);
            print(json_encode($error_array));
            $this->endDocument('json');
        } else {

            // If user didn't request a useful format, throw a regular client error
            throw new ClientException($msg, $code);
        }
    }

    function serverError($msg, $code = 500, $content_type = 'xml')
    {
        $action = $this->trimmed('action');

        common_debug("Server error '$code' on '$action': $msg", __FILE__);

        if (!array_key_exists($code, ServerErrorAction::$status)) {
            $code = 400;
        }

        $status_string = ServerErrorAction::$status[$code];

        header('HTTP/1.1 '.$code.' '.$status_string);

        if ($content_type == 'xml') {
            $this->initDocument('xml');
            $this->elementStart('hash');
            $this->element('error', null, $msg);
            $this->element('request', null, $_SERVER['REQUEST_URI']);
            $this->elementEnd('hash');
            $this->endDocument('xml');
        } else {
            $this->initDocument('json');
            $error_array = array('error' => $msg, 'request' => $_SERVER['REQUEST_URI']);
            print(json_encode($error_array));
            $this->endDocument('json');
        }
    }

    function initTwitterRss()
    {
        $this->startXML();
        $this->elementStart(
            'rss',
            array(
                'version'      => '2.0',
                'xmlns:atom'   => 'http://www.w3.org/2005/Atom',
                'xmlns:georss' => 'http://www.georss.org/georss'
            )
        );
        $this->elementStart('channel');
        Event::handle('StartApiRss', array($this));
    }

    function endTwitterRss()
    {
        $this->elementEnd('channel');
        $this->elementEnd('rss');
        $this->endXML();
    }

    function initTwitterAtom()
    {
        $this->startXML();
        // FIXME: don't hardcode the language here!
        $this->elementStart('feed', array('xmlns' => 'http://www.w3.org/2005/Atom',
                                          'xml:lang' => 'en-US',
                                          'xmlns:thr' => 'http://purl.org/syndication/thread/1.0'));
    }

    function endTwitterAtom()
    {
        $this->elementEnd('feed');
        $this->endXML();
    }

    function showProfile($profile, $content_type='xml', $notice=null, $includeStatuses=true)
    {
        $profile_array = $this->twitterUserArray($profile, $includeStatuses);
        switch ($content_type) {
        case 'xml':
            $this->showTwitterXmlUser($profile_array);
            break;
        case 'json':
            $this->showJsonObjects($profile_array);
            break;
        default:
            // TRANS: Client error on an API request with an unsupported data format.
            $this->clientError(_('Not a supported data format.'));
            return;
        }
        return;
    }

    function getTargetUser($id)
    {
        if (empty($id)) {

            // Twitter supports these other ways of passing the user ID
            if (is_numeric($this->arg('id'))) {
                return User::staticGet($this->arg('id'));
            } else if ($this->arg('id')) {
                $nickname = common_canonical_nickname($this->arg('id'));
                return User::staticGet('nickname', $nickname);
            } else if ($this->arg('user_id')) {
                // This is to ensure that a non-numeric user_id still
                // overrides screen_name even if it doesn't get used
                if (is_numeric($this->arg('user_id'))) {
                    return User::staticGet('id', $this->arg('user_id'));
                }
            } else if ($this->arg('screen_name')) {
                $nickname = common_canonical_nickname($this->arg('screen_name'));
                return User::staticGet('nickname', $nickname);
            } else {
                // Fall back to trying the currently authenticated user
                return $this->auth_user;
            }

        } else if (is_numeric($id)) {
            return User::staticGet($id);
        } else {
            $nickname = common_canonical_nickname($id);
            return User::staticGet('nickname', $nickname);
        }
    }

    function getTargetGroup($id)
    {
        if (empty($id)) {
            if (is_numeric($this->arg('id'))) {
                return User_group::staticGet($this->arg('id'));
            } else if ($this->arg('id')) {
                $nickname = common_canonical_nickname($this->arg('id'));
                $local = Local_group::staticGet('nickname', $nickname);
                if (empty($local)) {
                    return null;
                } else {
                    return User_group::staticGet('id', $local->id);
                }
            } else if ($this->arg('group_id')) {
                // This is to ensure that a non-numeric user_id still
                // overrides screen_name even if it doesn't get used
                if (is_numeric($this->arg('group_id'))) {
                    return User_group::staticGet('id', $this->arg('group_id'));
                }
            } else if ($this->arg('group_name')) {
                $nickname = common_canonical_nickname($this->arg('group_name'));
                $local = Local_group::staticGet('nickname', $nickname);
                if (empty($local)) {
                    return null;
                } else {
                    return User_group::staticGet('id', $local->group_id);
                }
            }

        } else if (is_numeric($id)) {
            return User_group::staticGet($id);
        } else {
            $nickname = common_canonical_nickname($id);
            $local = Local_group::staticGet('nickname', $nickname);
            if (empty($local)) {
                return null;
            } else {
                return User_group::staticGet('id', $local->group_id);
            }
        }
    }

    /**
     * Returns query argument or default value if not found. Certain
     * parameters used throughout the API are lightly scrubbed and
     * bounds checked.  This overrides Action::arg().
     *
     * @param string $key requested argument
     * @param string $def default value to return if $key is not provided
     *
     * @return var $var
     */
    function arg($key, $def=null)
    {

        // XXX: Do even more input validation/scrubbing?

        if (array_key_exists($key, $this->args)) {
            switch($key) {
            case 'page':
                $page = (int)$this->args['page'];
                return ($page < 1) ? 1 : $page;
            case 'count':
                $count = (int)$this->args['count'];
                if ($count < 1) {
                    return 20;
                } elseif ($count > 200) {
                    return 200;
                } else {
                    return $count;
                }
            case 'since_id':
                $since_id = (int)$this->args['since_id'];
                return ($since_id < 1) ? 0 : $since_id;
            case 'max_id':
                $max_id = (int)$this->args['max_id'];
                return ($max_id < 1) ? 0 : $max_id;
            default:
                return parent::arg($key, $def);
            }
        } else {
            return $def;
        }
    }

    /**
     * Calculate the complete URI that called up this action.  Used for
     * Atom rel="self" links.  Warning: this is funky.
     *
     * @return string URL    a URL suitable for rel="self" Atom links
     */
    function getSelfUri()
    {
        $action = mb_substr(get_class($this), 0, -6); // remove 'Action'

        $id = $this->arg('id');
        $aargs = array('format' => $this->format);
        if (!empty($id)) {
            $aargs['id'] = $id;
        }

        $tag = $this->arg('tag');
        if (!empty($tag)) {
            $aargs['tag'] = $tag;
        }

        parse_str($_SERVER['QUERY_STRING'], $params);
        $pstring = '';
        if (!empty($params)) {
            unset($params['p']);
            $pstring = http_build_query($params);
        }

        $uri = common_local_url($action, $aargs);

        if (!empty($pstring)) {
            $uri .= '?' . $pstring;
        }

        return $uri;
    }

}