<?php

/**
 * Database Attachments
 *
 * This plugin which provides database backed storage for temporary
 * attachment file handling. The primary advantage of this plugin
 * is its compatibility with round-robin dns multi-server roundcube
 * installations.
 *
 * This plugin relies on the core filesystem_attachments plugin
 *
 * @author Ziba Scott <ziba@umich.edu>
 * @author Aleksander Machniak <alec@alec.pl>
 *
 * This program is free software; you can redistribute it and/or modify
 * it under the terms of the GNU General Public License version 2
 * as published by the Free Software Foundation.
 *
 * 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 General Public License for more details.
 *
 * You should have received a copy of the GNU General Public License along
 * with this program; if not, write to the Free Software Foundation, Inc.,
 * 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301 USA.
 */

if (class_exists('filesystem_attachments', false) && !defined('TESTS_DIR')) {
    die("Configuration issue. There can be only one enabled plugin for attachments handling");
}

require_once INSTALL_PATH . 'plugins/filesystem_attachments/filesystem_attachments.php';

class database_attachments extends filesystem_attachments
{
    // Cache object
    protected $cache;

    // A prefix for the cache key used in the session and in the key field of the cache table
    const PREFIX = "ATTACH";

    /**
     * Save a newly uploaded attachment
     */
    function upload($args)
    {
        $args['status'] = false;

        $cache = $this->get_cache();
        $key   = $this->_key($args);
        $data  = file_get_contents($args['path']);

        if ($data === false) {
            return $args;
        }

        $data   = base64_encode($data);
        $status = $cache->write($key, $data);

        if ($status) {
            $args['id']     = $key;
            $args['status'] = true;
            $args['path']   = null;
        }

        return $args;
    }

    /**
     * Save an attachment from a non-upload source (draft or forward)
     */
    function save($args)
    {
        $args['status'] = false;

        $cache = $this->get_cache();
        $key   = $this->_key($args);

        if ($args['path']) {
            $args['data'] = file_get_contents($args['path']);

            if ($args['data'] === false) {
                return $args;
            }

            $args['path'] = null;
        }

        $data   = base64_encode($args['data']);
        $status = $cache->write($key, $data);

        if ($status) {
            $args['id'] = $key;
            $args['status'] = true;
        }

        return $args;
    }

    /**
     * Remove an attachment from storage
     * This is triggered by the remove attachment button on the compose screen
     */
    function remove($args)
    {
        $cache  = $this->get_cache();
        $status = $cache->remove($args['id']);

        $args['status'] = true;

        return $args;
    }

    /**
     * When composing an html message, image attachments may be shown
     * For this plugin, $this->get() will check the file and
     * return it's contents
     */
    function display($args)
    {
        return $this->get($args);
    }

    /**
     * When displaying or sending the attachment the file contents are fetched
     * using this method. This is also called by the attachment_display hook.
     */
    function get($args)
    {
        $cache = $this->get_cache();
        $data  = $cache->read($args['id']);

        if ($data !== null && $data !== false) {
            $args['data'] = base64_decode($data);
            $args['status'] = true;
        }
        else {
            $args['status'] = false;
        }

        return $args;
    }

    /**
     * Delete all temp files associated with this user
     */
    function cleanup($args)
    {
        // check if cache object exist, it may be empty on session_destroy (#1489726)
        if ($cache = $this->get_cache()) {
            $cache->remove($args['group'], true);
        }
    }

    /**
     * Helper method to generate a unique key for the given attachment file
     */
    protected function _key($args)
    {
        $uname = $args['path'] ?: $args['name'];
        return $args['group'] . md5(time() . $uname . $_SESSION['user_id']);
    }

    /**
     * Initialize and return cache object
     */
    protected function get_cache()
    {
        if (!$this->cache) {
            $this->load_config();

            $rcmail = rcube::get_instance();
            $ttl    = 12 * 60 * 60; // default: 12 hours
            $ttl    = $rcmail->config->get('database_attachments_cache_ttl', $ttl);
            $type   = $rcmail->config->get('database_attachments_cache', 'db');
            $prefix = self::PREFIX;

            // Add session identifier to the prefix to prevent from removing attachments
            // in other sessions of the same user (#1490542)
            if ($id = session_id()) {
                $prefix .= $id;
            }

            // Init SQL cache (disable cache data serialization)
            $this->cache = $rcmail->get_cache($prefix, $type, $ttl, false);
        }

        return $this->cache;
    }
}