<?php
// This file is part of GNU social - https://www.gnu.org/software/social
//
// GNU social 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.
//
// GNU social 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 GNU social.  If not, see <http://www.gnu.org/licenses/>.

/**
 * Plugin to do "real time" updates using Meteor
 *
 * @category  Plugin
 * @package   GNUsocial
 * @author    Evan Prodromou <evan@status.net>
 * @copyright 2010-2019 Free Software Foundation, Inc http://www.fsf.org
 * @license   https://www.gnu.org/licenses/agpl.html GNU AGPL v3 or later
 */

defined('GNUSOCIAL') || die();

require_once INSTALLDIR . DIRECTORY_SEPARATOR . 'lib/modules/Realtime/RealtimePlugin.php';

/**
 * Plugin to do realtime updates using Meteor
 *
 * @category  Plugin
 * @package   GNUsocial
 * @author    Evan Prodromou <evan@status.net>
 * @license   https://www.gnu.org/licenses/agpl.html GNU AGPL v3 or later
 */
class MeteorPlugin extends RealtimePlugin
{
    const PLUGIN_VERSION = '2.0.0';

    public $webserver     = null;
    public $webport       = null;
    public $controlport   = null;
    public $controlserver = null;
    public $channelbase   = null;
    public $protocol      = null;
    public $persistent    = true;
    protected $_socket    = null;

    public function __construct(
        ?string $webserver = null,
        int $webport = 4670,
        int $controlport = 4671,
        ?string $controlserver = null,
        string $channelbase = '',
        string $protocol = 'http'
    ) {
        global $config;

        $this->webserver     = (empty($webserver)) ? $config['site']['server'] : $webserver;
        $this->webport       = $webport;
        $this->controlport   = $controlport;
        $this->controlserver = (empty($controlserver)) ? $webserver : $controlserver;
        $this->channelbase   = $channelbase;
        $this->protocol      = $protocol;

        parent::__construct();
    }

    /**
     * Pull settings from config file/database if set.
     */
    public function initialize()
    {
        $settings = [
            'webserver',
            'webport',
            'controlport',
            'controlserver',
            'channelbase',
            'protocol',
        ];
        foreach ($settings as $name) {
            $val = common_config('meteor', $name);
            if ($val !== false) {
                $this->$name = $val;
            }
        }

        return parent::initialize();
    }

    public function _getScripts()
    {
        $scripts = parent::_getScripts();
        if ($this->protocol == 'https') {
            $scripts[] = 'https://' . $this->webserver . (($this->webport == 443) ? '' : ':' . $this->webport) . '/meteor.js';
        } else {
            $scripts[] = 'http://' . $this->webserver . (($this->webport == 80) ? '' : ':' . $this->webport) . '/meteor.js';
        }
        $scripts[] = $this->path('js/meteorupdater.js');
        return $scripts;
    }

    public function _updateInitialize($timeline, int $user_id)
    {
        $script = parent::_updateInitialize($timeline, $user_id);
        $ours = sprintf(
            "MeteorUpdater.init(%s, %s, %s, %s);",
            json_encode($this->webserver),
            json_encode($this->webport),
            json_encode($this->protocol),
            json_encode($timeline)
        );
        return $script." ".$ours;
    }

    public function _connect()
    {
        $controlserver = (empty($this->controlserver)) ? $this->webserver : $this->controlserver;

        $errno = $errstr = null;
        $timeout = 5;
        $flags = STREAM_CLIENT_CONNECT;
        if ($this->persistent) {
            $flags |= STREAM_CLIENT_PERSISTENT;
        }

        // May throw an exception.
        $this->_socket = stream_socket_client(
            "tcp://{$controlserver}:{$this->controlport}",
            $errno,
            $errstr,
            $timeout,
            $flags
        );
        if (!$this->_socket) {
            // TRANS: Exception. %1$s is the control server, %2$s is the control port.
            throw new Exception(sprintf(_m('Could not connect to %1$s on %2$s.'), $controlserver, $this->controlport));
        }
    }

    public function _publish($channel, $message)
    {
        $message = json_encode($message);
        $message = addslashes($message);
        $cmd = "ADDMESSAGE $channel $message\n";
        $cnt = fwrite($this->_socket, $cmd);
        $result = fgets($this->_socket);
        if (preg_match('/^ERR (.*)$/', $result, $matches)) {
            // TRANS: Exception. %s is the Meteor message that could not be added.
            throw new Exception(sprintf(_m('Error adding meteor message "%s".'), $matches[1]));
        }
        // TODO: parse and deal with result
    }

    public function _disconnect()
    {
        if (!$this->persistent) {
            $cnt = fwrite($this->_socket, "QUIT\n");
            @fclose($this->_socket);
        }
    }

    // Meteord flips out with default '/' separator

    public function _pathToChannel(array $path): string
    {
        if (!empty($this->channelbase)) {
            array_unshift($path, $this->channelbase);
        }
        return implode('-', $path);
    }

    public function onPluginVersion(array &$versions): bool
    {
        $versions[] = [
            'name' => 'Meteor',
            'version' => self::PLUGIN_VERSION,
            'author' => 'Evan Prodromou',
            'homepage' => GNUSOCIAL_ENGINE_REPO_URL . 'tree/master/plugins/Meteor',
            'rawdescription' =>
            // TRANS: Plugin description.
                _m('Plugin to do "real time" updates using Meteor.')
        ];
        return true;
    }
}