<?php
/*
 * GNU Social - a federating social network
 * Copyright (C) 2013, Free Software Foundation, Inc.
 *
 * 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/>.
 */

/**
 * Implements WebFinger for GNU Social, as well as support for the
 * '.well-known/host-meta' resource.
 *
 * Depends on: LRDD plugin
 *
 * @package GNUsocial
 * @author  Mikael Nordfeldth <mmn@hethane.se>
 */

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

class WebFingerPlugin extends Plugin
{
    const OAUTH_ACCESS_TOKEN_REL    = 'http://apinamespace.org/oauth/access_token';
    const OAUTH_REQUEST_TOKEN_REL   = 'http://apinamespace.org/oauth/request_token';
    const OAUTH_AUTHORIZE_REL       = 'http://apinamespace.org/oauth/authorize';

    public $http_alias = false;
    public $fancyurlfix = true; // adds + interprets some extra aliases related to 'index.php/' URLs

    public function initialize()
    {
        common_config_set('webfinger', 'http_alias', $this->http_alias);
        common_config_set('webfinger', 'fancyurlfix', $this->fancyurlfix);
    }

    public function onRouterInitialized($m)
    {
        $m->connect('.well-known/host-meta', array('action' => 'hostmeta'));
        $m->connect('.well-known/host-meta.:format',
                        array('action' => 'hostmeta',
                              'format' => '(xml|json)'));
        // the resource GET parameter can be anywhere, so don't mention it here
        $m->connect('.well-known/webfinger', array('action' => 'webfinger'));
        $m->connect('.well-known/webfinger.:format',
                        array('action' => 'webfinger',
                              'format' => '(xml|json)'));
        $m->connect('main/ownerxrd', array('action' => 'ownerxrd'));
        return true;
    }

    public function onLoginAction($action, &$login)
    {
        switch ($action) {
        case 'hostmeta':
        case 'webfinger':
            $login = true;
            return false;
        }
        
        return true;
    }

    public function onStartGetProfileAcctUri(Profile $profile, &$acct)
    {
        $wfr = new WebFingerResource_Profile($profile);
        try {
            $acct = $wfr->reconstructAcct();
        } catch (Exception $e) {
            return true;
        }

        return false;
    }

    public function onEndGetWebFingerResource($resource, WebFingerResource &$target=null, array $args=array())
    {
        $profile = null;
        if (Discovery::isAcct($resource)) {
            $parts = explode('@', substr(urldecode($resource), 5)); // 5 is strlen of 'acct:'
            if (count($parts) == 2) {
                list($nick, $domain) = $parts;
                if ($domain === common_config('site', 'server')) {
                    $nick = common_canonical_nickname($nick);
                    $user = User::getKV('nickname', $nick);
                    if (!($user instanceof User)) {
                        throw new NoSuchUserException(array('nickname'=>$nick));
                    }
                    $profile = $user->getProfile();
                } else {
                    throw new Exception(_('Remote profiles not supported via WebFinger yet.'));
                }
            }
        } else {
            try {
                $user = User::getByUri($resource);
                $profile = $user->getProfile();
            } catch (NoResultException $e) {
                if (common_config('webfinger', 'fancyurlfix')) {
                    try {
                        try {   // if it's a /index.php/ url
                            // common_fake_local_fancy_url can throw an exception
                            $alt_url = common_fake_local_fancy_url($resource);
                        } catch (Exception $e) {    // let's try to create a fake local /index.php/ url
                            // this too if it can't do anything about the URL
                            $alt_url = common_fake_local_nonfancy_url($resource);
                        }

                        // and this will throw a NoResultException if not found
                        $user = User::getByUri($alt_url);
                        $profile = $user->getProfile();
                    } catch (Exception $e) {
                        // apparently we didn't get any matches with that, so continue...
                    }
                }
            }
        }

        // if we still haven't found a match...
        if (!$profile instanceof Profile) {
            // if our rewrite hack didn't work, try to get something by profile URL
            $profile = Profile::getKV('profileurl', $resource);
        }

        if ($profile instanceof Profile) {
            $target = new WebFingerResource_Profile($profile);
            return false;   // We got our target, stop handler execution
        }

        $notice = Notice::getKV('uri', $resource);
        if ($notice instanceof Notice) {
            $target = new WebFingerResource_Notice($notice);
            return false;
        }

        return true;
    }

    public function onStartHostMetaLinks(array &$links)
    {
        foreach (Discovery::supportedMimeTypes() as $type) {
            $links[] = new XML_XRD_Element_Link(Discovery::LRDD_REL,
                            common_local_url('webfinger') . '?resource={uri}',
                            $type,
                            true);    // isTemplate
        }

        // OAuth connections
        $links[] = new XML_XRD_Element_link(self::OAUTH_ACCESS_TOKEN_REL,  common_local_url('ApiOAuthAccessToken'));
        $links[] = new XML_XRD_Element_link(self::OAUTH_REQUEST_TOKEN_REL, common_local_url('ApiOAuthRequestToken'));
        $links[] = new XML_XRD_Element_link(self::OAUTH_AUTHORIZE_REL,     common_local_url('ApiOAuthAuthorize'));
    }

    /**
     * Add a link header for LRDD Discovery
     */
    public function onStartShowHTML($action)
    {
        if ($action instanceof ShowstreamAction) {
            $resource = $action->getTarget()->getUri();
            $url = common_local_url('webfinger') . '?resource='.urlencode($resource);

            foreach (array(Discovery::JRD_MIMETYPE, Discovery::XRD_MIMETYPE) as $type) {
                header('Link: <'.$url.'>; rel="'. Discovery::LRDD_REL.'"; type="'.$type.'"', false);
            }
        }
    }

    public function onPluginVersion(array &$versions)
    {
        $versions[] = array('name' => 'WebFinger',
                            'version' => GNUSOCIAL_VERSION,
                            'author' => 'Mikael Nordfeldth',
                            'homepage' => 'http://www.gnu.org/software/social/',
                            // TRANS: Plugin description.
                            'rawdescription' => _m('Adds WebFinger lookup to GNU Social'));

        return true;
    }
}