fix merge conflicts

5 files changed, 600 insertions, 56 deletions

diff --git a/apps/calendar/lib/alarm.php b/apps/calendar/lib/alarm.php
new file mode 100644
index 00000000000..a71cc086827
--- /dev/null
+++ b/apps/calendar/lib/alarm.php
@@ -0,0 +1,13 @@
+<?php
+/**
+ * Copyright (c) 2012 Georg Ehrke <ownclouddev@georgswebsite.de>
+ * This file is licensed under the Affero General Public License version 3 or
+ * later.
+ * See the COPYING-README file.
+ */
+/*
+ * This class manages reminders for calendars
+ */
+class OC_Calendar_Alarm{
+	
+}
\ No newline at end of file
diff --git a/apps/calendar/lib/app.php b/apps/calendar/lib/app.php
index 4b481a4f286..3ce0d6fa1d4 100644
--- a/apps/calendar/lib/app.php
+++ b/apps/calendar/lib/app.php
@@ -1,60 +1,121 @@
 <?php
 /**
  * Copyright (c) 2011 Bart Visscher <bartv@thisnet.nl>
+ * Copyright (c) 2012 Georg Ehrke <georg@owncloud.com>
  * This file is licensed under the Affero General Public License version 3 or
  * later.
  * See the COPYING-README file.
- */
-
-/**
+ * 
  * This class manages our app actions
  */
-OC_Calendar_App::$l10n = OC_L10N::get('calendar');
+OC_Calendar_App::$l10n = new OC_L10N('calendar');
+OC_Calendar_App::$tz = OC_Preferences::getValue(OC_USER::getUser(), 'calendar', 'timezone', date_default_timezone_get());
 class OC_Calendar_App{
+	const CALENDAR = 'calendar';
+	const EVENT = 'event';
+	/*
+	 * @brief language object for calendar app
+	 */
 	public static $l10n;
+	
+	/*
+	 * @brief categories of the user
+	 */
 	protected static $categories = null;
 
-	public static function getCalendar($id){
-		$calendar = OC_Calendar_Calendar::find( $id );
-		if( $calendar === false || $calendar['userid'] != OC_User::getUser()){
-			OC_JSON::error(array('data' => array('message' => self::$l10n->t('Wrong calendar'))));
-			exit();
+	/*
+	 * @brief timezone of the user
+	 */
+	public static $tz;
+	
+	/*
+	 * @brief returns informations about a calendar
+	 * @param int $id - id of the calendar
+	 * @param bool $security - check access rights or not
+	 * @param bool $shared - check if the user got access via sharing
+	 * @return mixed - bool / array
+	 */
+	public static function getCalendar($id, $security = true, $shared = false){
+		$calendar = OC_Calendar_Calendar::find($id);
+		if($shared === true){
+			if(OC_Calendar_Share::check_access(OC_User::getUser(), $id, OC_Calendar_Share::CALENDAR)){
+				return $calendar;
+			}
+		}
+		if($security === true){
+			if($calendar['userid'] != OC_User::getUser()){
+				return false;
+			}
 		}
-		return $calendar;
+		if($calendar === false){
+			return false;
+		}
+		return OC_Calendar_Calendar::find($id);
 	}
-
-	public static function getEventObject($id){
-		$event_object = OC_Calendar_Object::find( $id );
-		if( $event_object === false ){
-			OC_JSON::error();
-			exit();
+	
+	/*
+	 * @brief returns informations about an event
+	 * @param int $id - id of the event
+	 * @param bool $security - check access rights or not
+	 * @param bool $shared - check if the user got access via sharing
+	 * @return mixed - bool / array
+	 */
+	public static function getEventObject($id, $security = true, $shared = false){
+		$event = OC_Calendar_Object::find($id);
+		if($shared === true){
+			if(OC_Calendar_Share::check_access(OC_User::getUser(), $id, OC_Calendar_Share::EVENT)){
+				return $event;
+			}
 		}
-
-		self::getCalendar( $event_object['calendarid'] );//access check
-		return $event_object;
+		if($security === true){
+			$calendar = self::getCalendar($event['calendarid'], false);
+			if($calendar['userid'] != OC_User::getUser()){
+				return false;
+			}
+		}
+		if($event === false){
+			return false;
+		}
+		return $event;
 	}
-
-	public static function getVCalendar($id){
-		$event_object = self::getEventObject( $id );
-
-		$vcalendar = OC_VObject::parse($event_object['calendardata']);
-		// Check if the vcalendar is valid
-		if(is_null($vcalendar)){
-			OC_JSON::error();
-			exit();
+	
+	/*
+	 * @brief returns the parsed calendar data
+	 * @param int $id - id of the event
+	 * @param bool $security - check access rights or not
+	 * @return mixed - bool / object
+	 */
+	public static function getVCalendar($id, $security = true, $shared = false){
+		$event_object = self::getEventObject($id, $security, $shared);
+		if($event_object === false){
+			return false;
+		}
+		$vobject = OC_VObject::parse($event_object['calendardata']);
+		if(is_null($vobject)){
+			return false;
 		}
-		return $vcalendar;
+		return $vobject;
 	}
-
-	public static function isNotModified($vevent, $lastmodified)
-	{
+	
+	/*
+	 * @brief checks if an event was edited and dies if it was
+	 * @param (object) $vevent - vevent object of the event
+	 * @param (int) $lastmodified - time of last modification as unix timestamp
+	 * @return (bool)
+	 */
+	public static function isNotModified($vevent, $lastmodified){
 		$last_modified = $vevent->__get('LAST-MODIFIED');
 		if($last_modified && $lastmodified != $last_modified->getDateTime()->format('U')){
 			OC_JSON::error(array('modified'=>true));
 			exit;
 		}
+		return true;
 	}
-
+	
+	/*
+	 * @brief returns the default categories of ownCloud
+	 * @return (array) $categories
+	 */
 	protected static function getDefaultCategories()
 	{
 		return array(
@@ -75,14 +136,22 @@ class OC_Calendar_App{
 			self::$l10n->t('Work'),
 		);
 	}
-
+	
+	/*
+	 * @brief returns the vcategories object of the user
+	 * @return (object) $vcategories
+	 */
 	protected static function getVCategories() {
 		if (is_null(self::$categories)) {
 			self::$categories = new OC_VCategories('calendar', null, self::getDefaultCategories());
 		}
 		return self::$categories;
 	}
-
+	
+	/*
+	 * @brief returns the categories of the vcategories object
+	 * @return (array) $categories
+	 */
 	public static function getCategoryOptions()
 	{
 		$categories = self::getVCategories()->categories();
@@ -127,40 +196,226 @@ class OC_Calendar_App{
 	public static function getRepeatOptions(){
 		return OC_Calendar_Object::getRepeatOptions(self::$l10n);
 	}
-
+	
+	/*
+	 * @brief returns the options for the end of an repeating event
+	 * @return array - valid inputs for the end of an repeating events
+	 */
 	public static function getEndOptions(){
 		return OC_Calendar_Object::getEndOptions(self::$l10n);
 	}
-
+	
+	/*
+	 * @brief returns the options for an monthly repeating event
+	 * @return array - valid inputs for monthly repeating events
+	 */
 	public static function getMonthOptions(){
 		return OC_Calendar_Object::getMonthOptions(self::$l10n);
 	}
-
+	
+	/*
+	 * @brief returns the options for an weekly repeating event
+	 * @return array - valid inputs for weekly repeating events
+	 */
 	public static function getWeeklyOptions(){
 		return OC_Calendar_Object::getWeeklyOptions(self::$l10n);
 	}
-
+	
+	/*
+	 * @brief returns the options for an yearly repeating event
+	 * @return array - valid inputs for yearly repeating events
+	 */
 	public static function getYearOptions(){
 		return OC_Calendar_Object::getYearOptions(self::$l10n);
 	}
-
+	
+	/*
+	 * @brief returns the options for an yearly repeating event which occurs on specific days of the year
+	 * @return array - valid inputs for yearly repeating events
+	 */
 	public static function getByYearDayOptions(){
 		return OC_Calendar_Object::getByYearDayOptions();
 	}
-
+	
+	/*
+	 * @brief returns the options for an yearly repeating event which occurs on specific month of the year
+	 * @return array - valid inputs for yearly repeating events
+	 */
 	public static function getByMonthOptions(){
 		return OC_Calendar_Object::getByMonthOptions(self::$l10n);
 	}
 	
+	/*
+	 * @brief returns the options for an yearly repeating event which occurs on specific week numbers of the year
+	 * @return array - valid inputs for yearly repeating events
+	 */
 	public static function getByWeekNoOptions(){
 		return OC_Calendar_Object::getByWeekNoOptions();
 	}
-
+	
+	/*
+	 * @brief returns the options for an yearly or monthly repeating event which occurs on specific days of the month
+	 * @return array - valid inputs for yearly or monthly repeating events
+	 */
 	public static function getByMonthDayOptions(){
 		return OC_Calendar_Object::getByMonthDayOptions();
 	}
 	
+	/*
+	 * @brief returns the options for an monthly repeating event which occurs on specific weeks of the month
+	 * @return array - valid inputs for monthly repeating events
+	 */
 	public static function getWeekofMonth(){
 		return OC_Calendar_Object::getWeekofMonth(self::$l10n);
 	}
+	
+	/*
+	 * @brief checks the access for a calendar / an event
+	 * @param (int) $id - id of the calendar / event
+	 * @param (string) $type - type of the id (calendar/event)
+	 * @return (string) $access - level of access
+	 */
+	public static function getaccess($id, $type){
+		if($type == self::CALENDAR){
+			$calendar = self::getCalendar($id, false, false);
+			if($calendar['userid'] == OC_User::getUser()){
+				return 'owner';
+			}
+			$isshared = OC_Calendar_Share::check_access(OC_User::getUser(), $id, OC_Calendar_Share::CALENDAR);
+			if($isshared){
+				$writeaccess = OC_Calendar_Share::is_editing_allowed(OC_User::getUser(), $id, OC_Calendar_Share::CALENDAR);
+				if($writeaccess){
+					return 'rw';
+				}else{
+					return 'r';
+				}
+			}else{
+				return false;
+			}
+		}elseif($type == self::EVENT){
+			if(OC_Calendar_Object::getowner($id) == OC_User::getUser()){
+				return 'owner';
+			}
+			$isshared = OC_Calendar_Share::check_access(OC_User::getUser(), $id, OC_Calendar_Share::EVENT);
+			if($isshared){
+				$writeaccess = OC_Calendar_Share::is_editing_allowed(OC_User::getUser(), $id, OC_Calendar_Share::EVENT);
+				if($writeaccess){
+					return 'rw';
+				}else{
+					return 'r';
+				}
+			}else{
+				return false;
+			}
+		}
+	}
+	
+	/*
+	 * @brief analyses the parameter for calendar parameter and returns the objects
+	 * @param (string) $calendarid - calendarid
+	 * @param (int) $start - unixtimestamp of start
+	 * @param (int) $end - unixtimestamp of end
+	 * @return (array) $events 
+	 */
+	public static function getrequestedEvents($calendarid, $start, $end){
+		$events = array();
+		if($calendarid == 'shared_rw' || $_GET['calendar_id'] == 'shared_r'){
+			$calendars = OC_Calendar_Share::allSharedwithuser(OC_USER::getUser(), OC_Calendar_Share::CALENDAR, 1, ($_GET['calendar_id'] == 'shared_rw')?'rw':'r');
+			foreach($calendars as $calendar){
+				$calendarevents = OC_Calendar_Object::allInPeriod($calendar['calendarid'], $start, $end);
+				$events = array_merge($events, $calendarevents);
+			}
+			$singleevents = OC_Calendar_Share::allSharedwithuser(OC_USER::getUser(), OC_Calendar_Share::EVENT, 1, ($_GET['calendar_id'] == 'shared_rw')?'rw':'r');
+			foreach($singleevents as $singleevent){
+				$event = OC_Calendar_Object::find($singleevent['eventid']);
+				$events[] =  $event;
+			}
+		}else{
+			$calendar_id = $_GET['calendar_id'];
+			if (is_numeric($calendar_id)) {
+				$calendar = self::getCalendar($calendar_id);
+				OC_Response::enableCaching(0);
+				OC_Response::setETagHeader($calendar['ctag']);
+				$events = OC_Calendar_Object::allInPeriod($calendar_id, $start, $end);
+			} else {
+				OC_Hook::emit('OC_Calendar', 'getEvents', array('calendar_id' => $calendar_id, 'events' => &$events));
+			}
+		}
+		return $events;
+	}
+	
+	/*
+	 * @brief generates the output for an event which will be readable for our js
+	 * @param (mixed) $event - event object / array
+	 * @param (int) $start - unixtimestamp of start
+	 * @param (int) $end - unixtimestamp of end
+	 * @return (array) $output - readable output
+	 */
+	public static function generateEventOutput($event, $start, $end){
+		$output = array();
+		
+		if(isset($event['calendardata'])){
+			$object = OC_VObject::parse($event['calendardata']);
+			$vevent = $object->VEVENT;
+		}else{
+			$vevent = $event['vevent'];
+		}
+		
+		$last_modified = @$vevent->__get('LAST-MODIFIED');
+		$lastmodified = ($last_modified)?$last_modified->getDateTime()->format('U'):0;
+		
+		$output = array('id'=>(int)$event['id'],
+						'title' => htmlspecialchars(($event['summary']!=NULL || $event['summary'] != '')?$event['summary']: self::$l10n->t('unnamed')),
+						'description' => isset($vevent->DESCRIPTION)?htmlspecialchars($vevent->DESCRIPTION->value):'',
+						'lastmodified'=>$lastmodified);
+		
+		$dtstart = $vevent->DTSTART;
+		$start_dt = $dtstart->getDateTime();
+		$dtend = OC_Calendar_Object::getDTEndFromVEvent($vevent);
+		$end_dt = $dtend->getDateTime();
+		
+		if ($dtstart->getDateType() == Sabre_VObject_Element_DateTime::DATE){
+			$output['allDay'] = true;
+		}else{
+			$output['allDay'] = false;
+			$start_dt->setTimezone(new DateTimeZone(self::$tz));
+			$end_dt->setTimezone(new DateTimeZone(self::$tz));
+		}
+		
+		if($event['repeating'] == 1){
+			$duration = (double) $end_dt->format('U') - (double) $start_dt->format('U');
+			$r = new When();
+			$r->recur($start_dt)->rrule((string) $vevent->RRULE);
+			/*$r = new iCal_Repeat_Generator(array('RECUR'  => $start_dt,
+			 *									   'RRULE'  => (string)$vevent->RRULE
+			 *									   'RDATE'  => (string)$vevent->RDATE						
+			 *									   'EXRULE' => (string)$vevent->EXRULE
+			 *									   'EXDATE' => (string)$vevent->EXDATE));*/
+			while($result = $r->next()){
+				if($result < $start){
+					continue;
+				}
+				if($result > $end){
+					break;
+				}
+				if($output['allDay'] == true){
+					$output['start'] = $result->format('Y-m-d');
+					$output['end'] = date('Y-m-d', $result->format('U') + --$duration);
+				}else{
+					$output['start'] = $result->format('Y-m-d H:i:s');
+					$output['end'] = date('Y-m-d H:i:s', $result->format('U') + $duration);
+				}
+			}
+		}else{
+			if($output['allDay'] == true){
+				$output['start'] = $start_dt->format('Y-m-d');
+				$end_dt->modify('-1 sec');
+				$output['end'] = $end_dt->format('Y-m-d');
+			}else{
+				$output['start'] = $start_dt->format('Y-m-d H:i:s');
+				$output['end'] = $end_dt->format('Y-m-d H:i:s');
+			}
+		}
+		return $output;
+	}
 }
diff --git a/apps/calendar/lib/attendees.php b/apps/calendar/lib/attendees.php
new file mode 100644
index 00000000000..ac30e11b3be
--- /dev/null
+++ b/apps/calendar/lib/attendees.php
@@ -0,0 +1,13 @@
+<?php
+/**
+ * Copyright (c) 2012 Georg Ehrke <ownclouddev@georgswebsite.de>
+ * This file is licensed under the Affero General Public License version 3 or
+ * later.
+ * See the COPYING-README file.
+ */
+/*
+ * This class manages Attendees for calendars
+ */
+class OC_Calendar_Attendees{
+	
+}
\ No newline at end of file
diff --git a/apps/calendar/lib/object.php b/apps/calendar/lib/object.php
index 9b6554a3e25..ae6fce3c842 100644
--- a/apps/calendar/lib/object.php
+++ b/apps/calendar/lib/object.php
@@ -104,7 +104,7 @@ class OC_Calendar_Object{
 		$uri = 'owncloud-'.md5($data.rand().time()).'.ics';
 
 		$stmt = OC_DB::prepare( 'INSERT INTO *PREFIX*calendar_objects (calendarid,objecttype,startdate,enddate,repeating,summary,calendardata,uri,lastmodified) VALUES(?,?,?,?,?,?,?,?,?)' );
-		$result = $stmt->execute(array($id,$type,$startdate,$enddate,$repeating,$summary,$data,$uri,time()));
+		$stmt->execute(array($id,$type,$startdate,$enddate,$repeating,$summary,$data,$uri,time()));
 
 		OC_Calendar_Calendar::touchCalendar($id);
 
@@ -123,7 +123,7 @@ class OC_Calendar_Object{
 		list($type,$startdate,$enddate,$summary,$repeating,$uid) = self::extractData($object);
 
 		$stmt = OC_DB::prepare( 'INSERT INTO *PREFIX*calendar_objects (calendarid,objecttype,startdate,enddate,repeating,summary,calendardata,uri,lastmodified) VALUES(?,?,?,?,?,?,?,?,?)' );
-		$result = $stmt->execute(array($id,$type,$startdate,$enddate,$repeating,$summary,$data,$uri,time()));
+		$stmt->execute(array($id,$type,$startdate,$enddate,$repeating,$summary,$data,$uri,time()));
 
 		OC_Calendar_Calendar::touchCalendar($id);
 
@@ -144,7 +144,7 @@ class OC_Calendar_Object{
 		list($type,$startdate,$enddate,$summary,$repeating,$uid) = self::extractData($object);
 
 		$stmt = OC_DB::prepare( 'UPDATE *PREFIX*calendar_objects SET objecttype=?,startdate=?,enddate=?,repeating=?,summary=?,calendardata=?, lastmodified = ? WHERE id = ?' );
-		$result = $stmt->execute(array($type,$startdate,$enddate,$repeating,$summary,$data,time(),$id));
+		$stmt->execute(array($type,$startdate,$enddate,$repeating,$summary,$data,time(),$id));
 
 		OC_Calendar_Calendar::touchCalendar($oldobject['calendarid']);
 
@@ -165,7 +165,7 @@ class OC_Calendar_Object{
 		list($type,$startdate,$enddate,$summary,$repeating,$uid) = self::extractData($object);
 
 		$stmt = OC_DB::prepare( 'UPDATE *PREFIX*calendar_objects SET objecttype=?,startdate=?,enddate=?,repeating=?,summary=?,calendardata=?, lastmodified = ? WHERE id = ?' );
-		$result = $stmt->execute(array($type,$startdate,$enddate,$repeating,$summary,$data,time(),$oldobject['id']));
+		$stmt->execute(array($type,$startdate,$enddate,$repeating,$summary,$data,time(),$oldobject['id']));
 
 		OC_Calendar_Calendar::touchCalendar($oldobject['calendarid']);
 
@@ -202,7 +202,7 @@ class OC_Calendar_Object{
 
 	public static function moveToCalendar($id, $calendarid){
 		$stmt = OC_DB::prepare( 'UPDATE *PREFIX*calendar_objects SET calendarid=? WHERE id = ?' );
-		$result = $stmt->execute(array($calendarid,$id));
+		$stmt->execute(array($calendarid,$id));
 
 		OC_Calendar_Calendar::touchCalendar($id);
 
@@ -432,11 +432,6 @@ class OC_Calendar_Object{
 			$errarr['title'] = 'true';
 			$errnum++;
 		}
-		$calendar = OC_Calendar_Calendar::find($request['calendar']);
-		if($calendar['userid'] != OC_User::getUser()){
-			$errarr['cal'] = 'true';
-			$errnum++;
-		}
 
 		$fromday = substr($request['from'], 0, 2);
 		$frommonth = substr($request['from'], 3, 2);
@@ -461,11 +456,11 @@ class OC_Calendar_Object{
 		if($request['repeat'] != 'doesnotrepeat'){
 			if(is_nan($request['interval']) && $request['interval'] != ''){
 				$errarr['interval'] = 'true';
-				$ernum++;
+				$errnum++;
 			}
 			if(array_key_exists('repeat', $request) && !array_key_exists($request['repeat'], self::getRepeatOptions(OC_Calendar_App::$l10n))){
 				$errarr['repeat'] = 'true';
-				$ernum++;
+				$errnum++;
 			}
 			if(array_key_exists('advanced_month_select', $request) && !array_key_exists($request['advanced_month_select'], self::getMonthOptions(OC_Calendar_App::$l10n))){
 				$errarr['advanced_month_select'] = 'true';
@@ -760,8 +755,6 @@ class OC_Calendar_Object{
 		$vevent->setDateTime('DTSTAMP', 'now', Sabre_VObject_Property_DateTime::UTC);
 		$vevent->setString('SUMMARY', $title);
 
-		$dtstart = new Sabre_VObject_Property_DateTime('DTSTART');
-		$dtend = new Sabre_VObject_Property_DateTime('DTEND');
 		if($allday){
 			$start = new DateTime($from);
 			$end = new DateTime($to.' +1 day');
@@ -787,4 +780,15 @@ class OC_Calendar_Object{
 
 		return $vcalendar;
 	}
+
+	public static function getowner($id){
+		$event = self::find($id);
+		$cal = OC_Calendar_Calendar::find($event['calendarid']);
+		return $cal['userid'];
+	}
+	
+	public static function getCalendarid($id){
+		$event = self::find($id);
+		return $event['calendarid'];
+	}
 }
diff --git a/apps/calendar/lib/share.php b/apps/calendar/lib/share.php
new file mode 100644
index 00000000000..8f91be97474
--- /dev/null
+++ b/apps/calendar/lib/share.php
@@ -0,0 +1,259 @@
+<?php
+/**
+ * Copyright (c) 2012 Georg Ehrke <ownclouddev@georgswebsite.de>
+ * This file is licensed under the Affero General Public License version 3 or
+ * later.
+ * See the COPYING-README file.
+ */
+/*
+ * This class manages shared calendars
+ */
+class OC_Calendar_Share{
+	const CALENDAR = 'calendar';
+	const EVENT = 'event';
+	/*
+	 * @brief: returns informations about all calendar or events which users are sharing with the user - userid
+	 * @param: (string) $userid - id of the user
+	 * @param: (string) $type - use const self::CALENDAR or self::EVENT
+	 * @return: (array) $return - information about calendars
+	 */
+	public static function allSharedwithuser($userid, $type, $active=null, $permission=null){
+		$group_where = self::group_sql(OC_Group::getUserGroups($userid));
+		$permission_where = self::permission_sql($permission);
+		if($type == self::CALENDAR){
+			$active_where = self::active_sql($active);
+		}else{
+			$active_where = '';
+		}
+		$stmt = OC_DB::prepare('SELECT * FROM *PREFIX*calendar_share_' . $type . ' WHERE ((share = ? AND sharetype = "user") ' . $group_where . ') AND owner <> ? ' . $permission_where . ' ' . $active_where);
+		$result = $stmt->execute(array($userid, $userid));
+		$return = array();
+		while( $row = $result->fetchRow()){
+			$return[] = $row;
+		}
+		return $return;
+	}
+	/*
+	 * @brief: returns all users a calendar / event is shared with
+	 * @param: (int) id - id of the calendar / event
+	 * @param: (string) $type - use const self::CALENDAR or self::EVENT
+	 * @return: (array) $users - information about users a calendar / event is shared with
+	 */
+	public static function allUsersSharedwith($id, $type){
+		$stmt = OC_DB::prepare('SELECT * FROM *PREFIX*calendar_share_' . $type . ' WHERE ' . $type . 'id = ? ORDER BY share');
+		$result = $stmt->execute(array($id));
+		$users = array();
+		while( $row = $result->fetchRow()){
+			$users[] = $row;
+		}
+		return $users;
+	}
+	/*
+	 * @brief: shares a calendar / event
+	 * @param: (string) $owner - userid of the owner
+	 * @param: (string) $share - userid (if $sharetype == user) / groupid (if $sharetype == group) / token (if $sharetype == public)
+	 * @param: (string) $sharetype - type of sharing (can be: user/group/public)
+	 * @param: (string) $id - id of the calendar / event
+	 * @param: (string) $type - use const self::CALENDAR or self::EVENT
+	 * @return (mixed) - token (if $sharetype == public) / bool (if $sharetype != public)
+	 */
+	public static function share($owner, $share, $sharetype, $id, $type){
+		if(self::is_already_shared($owner, $share, $sharetype, $id, $type)){
+			return false;
+		}
+		switch($sharetype){
+			case 'user':
+			case 'group':
+			case 'public':
+				break;
+			default:
+				return false;
+		}
+		if($sharetype == 'public'){
+			$share = self::generate_token($id, $type);
+		}
+		$stmt = OC_DB::prepare('INSERT INTO *PREFIX*calendar_share_' . $type . ' (owner,share,sharetype,' . $type . 'id,permissions' . (($type == self::CALENDAR)?', active':'') . ') VALUES(?,?,?,?,0' . (($type == self::CALENDAR)?', 1':'') . ')' );
+		$result = $stmt->execute(array($owner,$share,$sharetype,$id));
+		if($sharetype == 'public'){
+			return $share;
+		}else{
+			return true;
+		}
+	}
+	/*
+	 * @brief: stops sharing a calendar / event
+	 * @param: (string) $owner - userid of the owner
+	 * @param: (string) $share - userid (if $sharetype == user) / groupid (if $sharetype == group) / token (if $sharetype == public)
+	 * @param: (string) $sharetype - type of sharing (can be: user/group/public)
+	 * @param: (string) $id - id of the calendar / event
+	 * @param: (string) $type - use const self::CALENDAR or self::EVENT
+	 * @return (bool)
+	 */
+	public static function unshare($owner, $share, $sharetype, $id, $type){
+		$stmt = OC_DB::prepare('DELETE FROM *PREFIX*calendar_share_' . $type . ' WHERE owner = ? ' . (($sharetype != 'public')?'AND share = ?':'') . ' AND sharetype = ? AND ' . $type . 'id = ?');
+		if($sharetype != 'public'){
+			$stmt->execute(array($owner,$share,$sharetype,$id));
+		}else{
+			$stmt->execute(array($owner,$sharetype,$id));
+		}
+		return true;
+	}
+	/*
+	 * @brief: changes the permission for a calendar / event
+	 * @param: (string) $share - userid (if $sharetype == user) / groupid (if $sharetype == group) / token (if $sharetype == public)
+	 * @param: (string) $sharetype - type of sharing (can be: user/group/public)
+	 * @param: (string) $id - id of the calendar / event
+	 * @param: (int) $permission - permission of user the calendar / event is shared with (if $sharetype == public then $permission = 0)
+	 * @param: (string) $type - use const self::CALENDAR or self::EVENT
+	 * @return (bool)
+	 */
+	public static function changepermission($share, $sharetype, $id, $permission, $type){
+		if($sharetype == 'public' && $permission == 1){
+			$permission = 0;
+		}
+		$stmt = OC_DB::prepare('UPDATE *PREFIX*calendar_share_' . $type . ' SET permissions = ? WHERE share = ? AND sharetype = ? AND ' . $type . 'id = ?');
+		$stmt->execute(array($permission, $share, $sharetype, $id));
+		return true;
+	}
+	/*
+	 * @brief: generates a token for public calendars / events
+	 * @return: (string) $token
+	 */
+	private static function generate_token($id, $type){
+		$uniqid = uniqid();
+		if($type == self::CALENDAR){
+			$events = OC_Calendar_Object::all($id);
+			$string = '';
+			foreach($events as $event){
+				$string .= $event['calendardata'];
+			}
+		}else{
+			$string = OC_Calendar_Object::find($id);
+		}
+		$string = sha1($string['calendardata']);
+		$id = sha1($id);
+		$array = array($uniqid,$string,$id);
+		shuffle($array);
+		$string = implode('', $array);
+		$token = md5($string);
+		return substr($token, rand(0,16), 15);
+	}
+	/*
+	 * @brief: checks if it is already shared
+	 * @param: (string) $owner - userid of the owner
+	 * @param: (string) $share - userid (if $sharetype == user) / groupid (if $sharetype == group) / token (if $sharetype == public)
+	 * @param: (string) $sharetype - type of sharing (can be: user/group/public)
+	 * @param: (string) $id - id of the calendar / event
+	 * @param: (string) $type - use const self::CALENDAR or self::EVENT
+	 * @return (bool)
+	 */
+	public static function is_already_shared($owner, $share, $sharetype, $id, $type){
+		$stmt = OC_DB::prepare('SELECT * FROM *PREFIX*calendar_share_' . $type . ' WHERE owner = ? AND share = ? AND sharetype = ? AND ' . $type . 'id = ?');
+		$result = $stmt->execute(array($owner, $share, $sharetype, $id));
+		if($result->numRows() > 0){
+			return true;
+		}
+		return false;
+	}
+	private static function group_sql($groups){
+		$group_where = '';
+		$i = 0;
+		foreach($groups as $group){
+			$group_where .= ' OR ';
+			$group_where .= ' (share = "' . $group . '" AND sharetype = "group") ';
+			$i++;
+		}
+		return $group_where;
+	}
+	private static function permission_sql($permission = null){
+		$permission_where = '';
+		if(!is_null($permission)){
+			$permission_where = ' AND permissions = ';
+			$permission_where .= ($permission=='rw')?'"1"':'"0"';
+		}
+		return $permission_where;
+	}
+	private static function active_sql($active = null){
+		$active_where = '';
+		if(!is_null($active)){
+			$active_where = 'AND active = ';
+			$active_where .= (!is_null($active) && $active)?'1':'0';
+		}
+		return $active_where;
+	}
+	/*
+	 * @brief: checks the permission for editing an event
+	 * @param: (string) $share - userid (if $sharetype == user) / groupid (if $sharetype == group) / token (if $sharetype == public)
+	 * @param: (string) $id - id of the calendar / event
+	 * @param: (string) $type - use const self::CALENDAR or self::EVENT
+	 * @return (bool)
+	 */
+	public static function is_editing_allowed($share, $id, $type){
+		$group_where = self::group_sql(OC_Group::getUserGroups($share));
+		$permission_where = self::permission_sql('rw');
+		$stmt = OC_DB::prepare('SELECT * FROM *PREFIX*calendar_share_' . $type . ' WHERE ((share = ? AND sharetype = "user") ' . $group_where . ') ' . $permission_where);
+		$result = $stmt->execute(array($share));
+		if($result->numRows() == 1){
+			return true;
+		}
+		if($type == self::EVENT){
+			$event = OC_Calendar_App::getEventObject($id, false, false);
+			return self::is_editing_allowed($share, $event['calendarid'], self::CALENDAR);
+		}
+		return false;
+	}
+	/*
+	 * @brief: checks the access of 
+	 * @param: (string) $share - userid (if $sharetype == user) / groupid (if $sharetype == group) / token (if $sharetype == public)
+	 * @param: (string) $id - id of the calendar / event
+	 * @param: (string) $type - use const self::CALENDAR or self::EVENT
+	 * @return (bool)
+	 */
+	public static function check_access($share, $id, $type){
+		$group_where = self::group_sql(OC_Group::getUserGroups($share));
+		$stmt = OC_DB::prepare('SELECT * FROM *PREFIX*calendar_share_' . $type . ' WHERE (' . $type . 'id = ? AND (share = ? AND sharetype = "user") ' . $group_where . ')');
+		$result = $stmt->execute(array($id,$share));
+		$rows =  $result->numRows();
+		if($rows > 0){
+			return true;
+		}elseif($type == self::EVENT){
+			$event = OC_Calendar_App::getEventObject($id, false, false);
+			return self::check_access($share, $event['calendarid'], self::CALENDAR);
+		}else{
+			return false;
+		}
+	}
+        /*
+         * @brief: returns the calendardata of an event or a calendar
+         * @param: (string) $token - token which should be searched
+         * @return: mixed - bool if false, array with type and id if true
+         */
+        public static function getElementByToken($token){
+            $stmt_calendar = OC_DB::prepare('SELECT * FROM *PREFIX*calendar_share_' . OC_Calendar_Share::CALENDAR . ' WHERE sharetype = "public" AND share = ?');
+            $result_calendar = $stmt_calendar->execute(array($token));
+            $stmt_event = OC_DB::prepare('SELECT * FROM *PREFIX*calendar_share_' . OC_Calendar_Share::EVENT . ' WHERE sharetype = "public" AND share = ?');
+            $result_event = $stmt_event->execute(array($token));
+            $return = array();
+            if($result_calendar->numRows() == 0 && $result_event->numRows() == 0){
+                return false;
+            }elseif($result_calendar->numRows() != 0){
+                $return ['type'] = 'calendar';
+                $calendar = $result_calendar->fetchRow();
+                $return ['id'] = $calendar['calendarid'];
+            }else{
+                $return ['type'] = 'event';
+                $event = $result_event->fetchRow();
+                $return ['id'] = $event['eventid'];
+            }
+			return $return;
+        }
+		
+		/*
+		 * @brief sets the active status of the calendar
+		 * @param (string) $
+		 */
+		public static function set_active($share, $id, $active){
+			$stmt = OC_DB::prepare('UPDATE *PREFIX*calendar_share_calendar SET active = ? WHERE share = ? AND sharetype = "user" AND calendarid = ?');
+			$stmt->execute(array($active, $share, $id));
+		}
+}
\ No newline at end of file