<?php
/*
 * StatusNet - the distributed open-source microblogging tool
 * Copyright (C) 2010, StatusNet, 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/>.
 */

/**
 * @package OStatusPlugin
 * @author James Walker <james@status.net>
 */

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

class SalmonAction extends Action
{
    protected $needPost = true;

    protected $oprofile = null; // Ostatus_profile of the actor
    protected $actor    = null; // Profile object of the actor

    var $xml      = null;
    var $activity = null;
    var $target   = null;

    protected function prepare(array $args=array())
    {
        GNUsocial::setApi(true); // Send smaller error pages

        parent::prepare($args);

        if (!isset($_SERVER['CONTENT_TYPE']) || $_SERVER['CONTENT_TYPE'] != 'application/magic-envelope+xml') {
            // TRANS: Client error. Do not translate "application/magic-envelope+xml".
            $this->clientError(_m('Salmon requires "application/magic-envelope+xml".'));
        }

        try {
            $envxml = file_get_contents('php://input');
            $magic_env = new MagicEnvelope($envxml);   // parse incoming XML as a MagicEnvelope

            $entry = $magic_env->getPayload();  // Not cryptographically verified yet!
            $this->activity = new Activity($entry->documentElement);
            if (empty($this->activity->actor->id)) {
                common_log(LOG_ERR, "broken actor: " . var_export($this->activity->actor->id, true));
                common_log(LOG_ERR, "activity with no actor: " . var_export($this->activity, true));
                // TRANS: Exception.
                throw new Exception(_m('Received a salmon slap from unidentified actor.'));
            }
            // ensureProfiles sets $this->actor and $this->oprofile
            $this->ensureProfiles();
        } catch (Exception $e) {
            common_debug('Salmon envelope parsing failed with: '.$e->getMessage());
            $this->clientError($e->getMessage());
        }

        // Cryptographic verification test
        if (!$magic_env->verify($this->actor)) {
            common_log(LOG_DEBUG, "Salmon signature verification failed.");
            // TRANS: Client error.
            $this->clientError(_m('Salmon signature verification failed.'));
        }

        return true;
    }

    /**
     * Check the posted activity type and break out to appropriate processing.
     */

    protected function handle()
    {
        parent::handle();

        common_log(LOG_DEBUG, "Got a " . $this->activity->verb);
        try {
            if (Event::handle('StartHandleSalmonTarget', array($this->activity, $this->target)) &&
                    Event::handle('StartHandleSalmon', array($this->activity))) {
                switch ($this->activity->verb) {
                case ActivityVerb::POST:
                    $this->handlePost();
                    break;
                case ActivityVerb::SHARE:
                    $this->handleShare();
                    break;
                case ActivityVerb::FOLLOW:
                case ActivityVerb::FRIEND:
                    $this->handleFollow();
                    break;
                case ActivityVerb::UNFOLLOW:
                    $this->handleUnfollow();
                    break;
                case ActivityVerb::JOIN:
                    $this->handleJoin();
                    break;
                case ActivityVerb::LEAVE:
                    $this->handleLeave();
                    break;
                case ActivityVerb::TAG:
                    $this->handleTag();
                    break;
                case ActivityVerb::UNTAG:
                    $this->handleUntag();
                    break;
                case ActivityVerb::UPDATE_PROFILE:
                    $this->handleUpdateProfile();
                    break;
                default:
                    // TRANS: Client exception.
                    throw new ClientException(_m('Unrecognized activity type.'));
                }
                Event::handle('EndHandleSalmon', array($this->activity));
                Event::handle('EndHandleSalmonTarget', array($this->activity, $this->target));
            }
        } catch (AlreadyFulfilledException $e) {
            // The action's results are already fulfilled. Maybe it was a
            // duplicate? Maybe someone's database is out of sync?
            // Let's just accept it and move on.
            common_log(LOG_INFO, 'Salmon slap carried an event which had already been fulfilled.');
        }
    }

    function handlePost()
    {
        // TRANS: Client exception.
        throw new ClientException(_m('This target does not understand posts.'));
    }

    function handleFollow()
    {
        // TRANS: Client exception.
        throw new ClientException(_m('This target does not understand follows.'));
    }

    function handleUnfollow()
    {
        // TRANS: Client exception.
        throw new ClientException(_m('This target does not understand unfollows.'));
    }

    function handleShare()
    {
        // TRANS: Client exception.
        throw new ClientException(_m('This target does not understand share events.'));
    }

    function handleJoin()
    {
        // TRANS: Client exception.
        throw new ClientException(_m('This target does not understand joins.'));
    }

    function handleLeave()
    {
        // TRANS: Client exception.
        throw new ClientException(_m('This target does not understand leave events.'));
    }

    function handleTag()
    {
        // TRANS: Client exception.
        throw new ClientException(_m('This target does not understand list events.'));
    }

    function handleUntag()
    {
        // TRANS: Client exception.
        throw new ClientException(_m('This target does not understand unlist events.'));
    }

    /**
     * Remote user sent us an update to their profile.
     * If we already know them, accept the updates.
     */
    function handleUpdateProfile()
    {
        $oprofile = Ostatus_profile::getActorProfile($this->activity);
        if ($oprofile instanceof Ostatus_profile) {
            common_log(LOG_INFO, "Got a profile-update ping from $oprofile->uri");
            $oprofile->updateFromActivityObject($this->activity->actor);
        } else {
            common_log(LOG_INFO, "Ignoring profile-update ping from unknown " . $this->activity->actor->id);
        }
    }

    function ensureProfiles()
    {
        try {
            $this->oprofile = Ostatus_profile::getActorProfile($this->activity);
            if (!$this->oprofile instanceof Ostatus_profile) {
                throw new UnknownUriException($this->activity->actor->id);
            }
        } catch (UnknownUriException $e) {
            // Apparently we didn't find the Profile object based on our URI,
            // so OStatus doesn't have it with this URI in ostatus_profile.
            // Try to look it up again, remote side may have changed from http to https
            // or maybe publish an acct: URI now instead of an http: URL.
            //
            // Steps:
            // 1. Check the newly received URI. Who does it say it is?
            // 2. Compare these alleged identities to our local database.
            // 3. If we found any locally stored identities, ask it about its aliases.
            // 4. Do any of the aliases from our known identity match the recently introduced one?
            //
            // Example: We have stored http://example.com/user/1 but this URI says https://example.com/user/1
            common_debug('No local Profile object found for a magicsigned activity author URI: '.$e->object_uri);
            $disco = new Discovery();
            $xrd = $disco->lookup($e->object_uri);
            // Step 1: We got a bunch of discovery data for https://example.com/user/1 which includes
            //         aliases https://example.com/user and hopefully our original http://example.com/user/1 too
            $all_ids = array_merge(array($xrd->subject), $xrd->aliases);

            if (!in_array($e->object_uri, $all_ids)) {
                common_debug('The activity author URI we got was not listed itself when doing discovery on it.');
                throw $e;
            }

            // Go through each reported alias from lookup to see if we know this already
            foreach ($all_ids as $aliased_uri) {
                $oprofile = Ostatus_profile::getKV('uri', $aliased_uri);
                if (!$oprofile instanceof Ostatus_profile) {
                    continue;   // unknown locally, check the next alias
                }
                // Step 2: We found the alleged http://example.com/user/1 URI in our local database,
                //         but this can't be trusted yet because anyone can publish any alias.
                common_debug('Found a local Ostatus_profile for "'.$e->object_uri.'" with this URI: '.$aliased_uri);

                // We found an existing OStatus profile, but is it really the same? Do a callback to the URI's origin
                // Step 3: lookup our previously known http://example.com/user/1 webfinger etc.
                $xrd = $disco->lookup($oprofile->getUri()); // getUri returns ->uri, which we filtered on earlier
                $doublecheck_aliases = array_merge(array($xrd->subject), $xrd->aliases);
                common_debug('Trying to match known "'.$aliased_uri.'" against its returned aliases: '.implode(' ', $doublecheck_aliases));
                // if we find our original URI here, it is a legitimate alias
                // Step 4: Is the newly introduced https://example.com/user/1 URI in the list of aliases
                //         presented by http://example.com/user/1 (i.e. do they both say they are the same identity?)
                if (in_array($e->object_uri, $doublecheck_aliases)) {
                    common_debug('URIFIX These identities both say they are each other: "'.$aliased_uri.'" and "'.$e->object_uri.'"');
                    $orig = clone($oprofile);
                    $oprofile->uri = $e->object_uri;
                    common_debug('URIFIX Updating Ostatus_profile URI for '.$aliased_uri.' to '.$oprofile->uri);
                    $oprofile->updateWithKeys($orig, 'uri');    // 'uri' is the primary key column
                    unset($orig);
                    $this->oprofile = $oprofile;
                    break;  // don't iterate through aliases anymore
                }
            }

            // We might end up here after $all_ids is iterated through without a $this->oprofile value,
            if (!$this->oprofile instanceof Ostatus_profile) {
                common_debug("We do not have a local profile to connect to this activity's author. Let's create one.");
                // ensureActivityObjectProfile throws exception on failure
                $this->oprofile = Ostatus_profile::ensureActivityObjectProfile($this->activity->actor);
            }
        }

        assert($this->oprofile instanceof Ostatus_profile);

        $this->actor = $this->oprofile->localProfile();
    }

    function saveNotice()
    {
        if (!$this->oprofile instanceof Ostatus_profile) {
            common_debug('Ostatus_profile missing in ' . get_class(). ' profile: '.var_export($this->profile));
        }
        return $this->oprofile->processPost($this->activity, 'salmon');
    }
}