<?php

namespace Sabre\CalDAV\Backend;

/**
 * Every CalDAV backend must at least implement this interface.
 *
 * @copyright Copyright (C) 2007-2013 fruux GmbH (https://fruux.com/).
 * @author Evert Pot (http://evertpot.com/)
 * @license http://code.google.com/p/sabredav/wiki/License Modified BSD License
 */
interface BackendInterface {

    /**
     * Returns a list of calendars for a principal.
     *
     * Every project is an array with the following keys:
     *  * id, a unique id that will be used by other functions to modify the
     *    calendar. This can be the same as the uri or a database key.
     *  * uri, which the basename of the uri with which the calendar is
     *    accessed.
     *  * principaluri. The owner of the calendar. Almost always the same as
     *    principalUri passed to this method.
     *
     * Furthermore it can contain webdav properties in clark notation. A very
     * common one is '{DAV:}displayname'.
     *
     * @param string $principalUri
     * @return array
     */
    public function getCalendarsForUser($principalUri);

    /**
     * Creates a new calendar for a principal.
     *
     * If the creation was a success, an id must be returned that can be used to reference
     * this calendar in other methods, such as updateCalendar.
     *
     * @param string $principalUri
     * @param string $calendarUri
     * @param array $properties
     * @return void
     */
    public function createCalendar($principalUri,$calendarUri,array $properties);

    /**
     * Updates properties for a calendar.
     *
     * The mutations array uses the propertyName in clark-notation as key,
     * and the array value for the property value. In the case a property
     * should be deleted, the property value will be null.
     *
     * This method must be atomic. If one property cannot be changed, the
     * entire operation must fail.
     *
     * If the operation was successful, true can be returned.
     * If the operation failed, false can be returned.
     *
     * Deletion of a non-existent property is always successful.
     *
     * Lastly, it is optional to return detailed information about any
     * failures. In this case an array should be returned with the following
     * structure:
     *
     * array(
     *   403 => array(
     *      '{DAV:}displayname' => null,
     *   ),
     *   424 => array(
     *      '{DAV:}owner' => null,
     *   )
     * )
     *
     * In this example it was forbidden to update {DAV:}displayname.
     * (403 Forbidden), which in turn also caused {DAV:}owner to fail
     * (424 Failed Dependency) because the request needs to be atomic.
     *
     * @param mixed $calendarId
     * @param array $mutations
     * @return bool|array
     */
    public function updateCalendar($calendarId, array $mutations);

    /**
     * Delete a calendar and all it's objects
     *
     * @param mixed $calendarId
     * @return void
     */
    public function deleteCalendar($calendarId);

    /**
     * Returns all calendar objects within a calendar.
     *
     * Every item contains an array with the following keys:
     *   * id - unique identifier which will be used for subsequent updates
     *   * calendardata - The iCalendar-compatible calendar data
     *   * uri - a unique key which will be used to construct the uri. This can be any arbitrary string.
     *   * lastmodified - a timestamp of the last modification time
     *   * etag - An arbitrary string, surrounded by double-quotes. (e.g.:
     *   '  "abcdef"')
     *   * calendarid - The calendarid as it was passed to this function.
     *   * size - The size of the calendar objects, in bytes.
     *
     * Note that the etag is optional, but it's highly encouraged to return for
     * speed reasons.
     *
     * The calendardata is also optional. If it's not returned
     * 'getCalendarObject' will be called later, which *is* expected to return
     * calendardata.
     *
     * If neither etag or size are specified, the calendardata will be
     * used/fetched to determine these numbers. If both are specified the
     * amount of times this is needed is reduced by a great degree.
     *
     * @param mixed $calendarId
     * @return array
     */
    public function getCalendarObjects($calendarId);

    /**
     * Returns information from a single calendar object, based on it's object
     * uri.
     *
     * The returned array must have the same keys as getCalendarObjects. The
     * 'calendardata' object is required here though, while it's not required
     * for getCalendarObjects.
     *
     * This method must return null if the object did not exist.
     *
     * @param mixed $calendarId
     * @param string $objectUri
     * @return array|null
     */
    public function getCalendarObject($calendarId,$objectUri);

    /**
     * Creates a new calendar object.
     *
     * It is possible return an etag from this function, which will be used in
     * the response to this PUT request. Note that the ETag must be surrounded
     * by double-quotes.
     *
     * However, you should only really return this ETag if you don't mangle the
     * calendar-data. If the result of a subsequent GET to this object is not
     * the exact same as this request body, you should omit the ETag.
     *
     * @param mixed $calendarId
     * @param string $objectUri
     * @param string $calendarData
     * @return string|null
     */
    public function createCalendarObject($calendarId,$objectUri,$calendarData);

    /**
     * Updates an existing calendarobject, based on it's uri.
     *
     * It is possible return an etag from this function, which will be used in
     * the response to this PUT request. Note that the ETag must be surrounded
     * by double-quotes.
     *
     * However, you should only really return this ETag if you don't mangle the
     * calendar-data. If the result of a subsequent GET to this object is not
     * the exact same as this request body, you should omit the ETag.
     *
     * @param mixed $calendarId
     * @param string $objectUri
     * @param string $calendarData
     * @return string|null
     */
    public function updateCalendarObject($calendarId,$objectUri,$calendarData);

    /**
     * Deletes an existing calendar object.
     *
     * @param mixed $calendarId
     * @param string $objectUri
     * @return void
     */
    public function deleteCalendarObject($calendarId,$objectUri);

    /**
     * Performs a calendar-query on the contents of this calendar.
     *
     * The calendar-query is defined in RFC4791 : CalDAV. Using the
     * calendar-query it is possible for a client to request a specific set of
     * object, based on contents of iCalendar properties, date-ranges and
     * iCalendar component types (VTODO, VEVENT).
     *
     * This method should just return a list of (relative) urls that match this
     * query.
     *
     * The list of filters are specified as an array. The exact array is
     * documented by Sabre\CalDAV\CalendarQueryParser.
     *
     * Note that it is extremely likely that getCalendarObject for every path
     * returned from this method will be called almost immediately after. You
     * may want to anticipate this to speed up these requests.
     *
     * This method provides a default implementation, which parses *all* the
     * iCalendar objects in the specified calendar.
     *
     * This default may well be good enough for personal use, and calendars
     * that aren't very large. But if you anticipate high usage, big calendars
     * or high loads, you are strongly adviced to optimize certain paths.
     *
     * The best way to do so is override this method and to optimize
     * specifically for 'common filters'.
     *
     * Requests that are extremely common are:
     *   * requests for just VEVENTS
     *   * requests for just VTODO
     *   * requests with a time-range-filter on either VEVENT or VTODO.
     *
     * ..and combinations of these requests. It may not be worth it to try to
     * handle every possible situation and just rely on the (relatively
     * easy to use) CalendarQueryValidator to handle the rest.
     *
     * Note that especially time-range-filters may be difficult to parse. A
     * time-range filter specified on a VEVENT must for instance also handle
     * recurrence rules correctly.
     * A good example of how to interprete all these filters can also simply
     * be found in Sabre\CalDAV\CalendarQueryFilter. This class is as correct
     * as possible, so it gives you a good idea on what type of stuff you need
     * to think of.
     *
     * @param mixed $calendarId
     * @param array $filters
     * @return array
     */
    public function calendarQuery($calendarId, array $filters);

}
