<?php if ( ! defined('BASEPATH')) exit('No direct script access allowed'); 

/*
 * Copyright 2011-2012 Jorge López Pérez <jorge@adobo.org>
 *
 *  This file is part of AgenDAV.
 *
 *  AgenDAV is free software: you can redistribute it and/or modify
 *  it under the terms of the GNU General Public License as published by
 *  the Free Software Foundation, either version 3 of the License, or
 *  any later version.
 *
 *  AgenDAV 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 AgenDAV.  If not, see <http://www.gnu.org/licenses/>.
 */

class Shared_calendars extends CI_Model {
    function __construct() {
        parent::__construct();

    }

    /**
     * Get calendars which other users are sharing with a given user.
     *
     * @return array        Array of calendars (sid, user_from, calendar)
     */
    function get_shared_with($username) {
        $res = $this->db->get_where('shared', array(
                    'user_which' => $username));

        $tmp = $res->result_array();
        $result = array();

        foreach ($tmp as $c) {
            $index = $c['user_from'] .':'. $c['calendar'];
            $result[$index] = array(
                    'sid' => $c['sid'],
                    'user_from' => $c['user_from'],
                    'write_access' =>
                        $this->_bool_to_int($c['write_access']),
                    );
            $options = unserialize($c['options']);
            if (is_array($options)) {
                $result[$index] = array_merge($result[$index], $options);
            }
        }

        return $result;
    }

    /**
     * Get calendars which current user is sharing with other users
     *
     * @param $username     User which is sharing calendars
     * @param $cond         Additional conditions for this query (optional).
     *                      Associative array
     * @return array        Array of calendars (sid, user_from, calendar)
     */
    function get_shared_from($username, $cond = null) {
        $conditions = array('user_from' => $username);
        if (!is_null($cond) && is_array($cond)) {
            $conditions = array_merge($conditions, $cond);
        }
        $res = $this->db->get_where('shared', $conditions);

        $tmp = $res->result_array();
        $result = array();

        foreach ($tmp as $c) {
            $index = $c['user_from'] .':'. $c['calendar'];
            if (!isset($result[$index])) {
                $result[$index] = array();
            }
            $sid = $c['sid'];

            $c['write_access'] = $this->_bool_to_int($c['write_access']);

            $options = unserialize($c['options']);
            if (is_array($options)) {
                $c = array_merge($c, $options);
            }

            $result[$index][$sid] = $c;
        }

        return $result;
    }

    /**
     * Get a list of users who can access a calendar
     *
     * @param $calendar     Complete calendar name (user:calendar)
     * @return              Array of the form:
     *                       [ [ 'username' => username, 'sid' => sid, 'write_access' => write_access], 
     *                       ['username' => username2, 'sid' => sid2, 'write_access'
     *                       => write_access2], ...], 
     *
     */

    function users_with_access_to($calendar) {
        $pieces = preg_split('/:/', $calendar);
        if (count($pieces) != 2) {
            log_message('ERROR', 'Call to users_with_access_to() '
                    .'without full calendar specified (' . $calendar .')');
            return array();
        }

        $user_from = $pieces[0];
        $calendar = $pieces[1];

        $tmp = $this->get_shared_from($user_from, array(
                    'calendar' => $calendar));
        $users = array();

        if (count($tmp) > 0) {
            $tmp = array_values($tmp);
            foreach ($tmp[0] as $sid => $share) {
                $users[] = array(
                    'username' => mb_strtolower($share['user_which']),
                    'sid' => $share['sid'],
                    'write_access' => $share['write_access'],
                    );
            }
        }

        return $users;
    }

    /**
     * Store a shared calendar.
     *
     * @param $sid  Share id. Null means a new calendar sharing
     * @param $from User id who is sharing a calendar
     * @param $calendar Calendar being shared. Can be in the form
     *   'user:calendar'
     * @param $to   User id who's getting calendar rights
     * @param $options  Associative array with options for this calendar
     *   (color, displayname, ...)
     * @param $write_access (Optional) Use read+write profile on '1', read on '0'
     * @return boolean  FALSE on error, TRUE otherwise
     */
    function store($sid = null, $from = '', $calendar = '', $to = '',
            $options = array(), $write_access = null) {
        if ($sid === null && (empty($from) || empty($calendar) ||
                    empty($to))) {
            log_message('ERROR', 
                    'Call to shared_calendars->store() with no enough parameters');
            return FALSE;
        }

        $calendar = preg_replace('/^[^:]+:/', '', $calendar);
        $from = mb_strtolower($from);
        $to = mb_strtolower($to);

        $data = array(
                'user_from' => $from,
                'calendar' => $calendar,
                'user_which' => $to,
                'options' => serialize($options),
                );
        if ($write_access !== null) {
            $data['write_access'] = $write_access;
        }

        $res = false;
        if (!is_null($sid)) {
            $conditions = array('sid' => $sid);
            unset($data['user_from']);
            unset($data['user_which']);
            unset($data['calendar']);

            // Preserve options
            if (is_null($options)) {
                unset($data['options']);
            }

            $this->db->where($conditions);
            $res = $this->db->update('shared', $data);
        } else {
            $res = $this->db->insert('shared', $data);

            if ($res === TRUE) {
                log_message('INTERNALS', 'Granted access on '
                        . $data['user_from'] . ':' . $data['calendar'] . ' to '
                        . $data['user_which']);
            } else {
                log_message('ERROR', 'Error granting access on '
                        . $data['user_from'] . ':' . $data['calendar'] . ' to '
                        . $data['user_which'] . ', SQL error');
            }
        }


        return $res;
    }

    /**
     * Removes a sharing from database
     *
     * @param $sid  Sharing id
     * @return boolean  FALSE on error, TRUE otherwise
     */
    function remove($sid = null) {
        if (is_null($sid)) {
            log_message('ERROR',
                    'Call to shared_calendars->remove() without sid');
            return FALSE;
        }

        $this->db->where('sid', $sid);
        $query = $this->db->get('shared');
        $row = $query->result_array();

        if (count($row) == 0) {
            log_message('ERROR', 
                    'Tried to remove nonexistant share id [' . $sid .']');
            return FALSE;
        } else {
            $row = $row[0];
            $this->db->where('sid', $sid);
            $this->db->delete('shared');

            log_message('INTERNALS', 'Revoked access on '
                    . $row['user_from'] . ':' . $row['calendar'] . ' to '
                    . $row['user_which']);
            return TRUE;
        }
                
    }

    /**
     * Translates a boolean from PostgreSQL to 1/0
     */
    function _bool_to_int($value) {
        $ret = 0;

        switch ($value) {
            case 't':
                $ret=1;
                break;
            case 'f':
                $ret=0;
                break;
            default:
                $ret = $value;
                break;
        }

        return $ret;
    }

}