<?php
/**
 * @copyright 2017, Georg Ehrke <oc.list@georgehrke.com>
 *
 * @author Georg Ehrke <oc.list@georgehrke.com>
 *
 * @license GNU AGPL version 3 or any later version
 *
 * This program 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.
 *
 * 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 Affero General Public License for more details.
 *
 * You should have received a copy of the GNU Affero General Public License
 * along with this program. If not, see <http://www.gnu.org/licenses/>.
 *
 */

namespace OC\Calendar;

use OCP\Calendar\ICalendar;

class Manager implements \OCP\Calendar\IManager {

	/**
	 * @var ICalendar[] holds all registered calendars
	 */
	private $calendars=[];

	/**
	 * @var \Closure[] to call to load/register calendar providers
	 */
	private $calendarLoaders=[];

	/**
	 * This function is used to search and find objects within the user's calendars.
	 * In case $pattern is empty all events/journals/todos will be returned.
	 *
	 * @param string $pattern which should match within the $searchProperties
	 * @param array $searchProperties defines the properties within the query pattern should match
	 * @param array $options - optional parameters:
	 * 	['timerange' => ['start' => new DateTime(...), 'end' => new DateTime(...)]]
	 * @param integer|null $limit - limit number of search results
	 * @param integer|null $offset - offset for paging of search results
	 * @return array an array of events/journals/todos which are arrays of arrays of key-value-pairs
	 * @since 13.0.0
	 */
	public function search($pattern, array $searchProperties=[], array $options=[], $limit=null, $offset=null) {
		$this->loadCalendars();
		$result = [];
		foreach ($this->calendars as $calendar) {
			$r = $calendar->search($pattern, $searchProperties, $options, $limit, $offset);
			foreach ($r as $o) {
				$o['calendar-key'] = $calendar->getKey();
				$result[] = $o;
			}
		}

		return $result;
	}

	/**
	 * Check if calendars are available
	 *
	 * @return bool true if enabled, false if not
	 * @since 13.0.0
	 */
	public function isEnabled() {
		return !empty($this->calendars) || !empty($this->calendarLoaders);
	}

	/**
	 * Registers a calendar
	 *
	 * @param ICalendar $calendar
	 * @return void
	 * @since 13.0.0
	 */
	public function registerCalendar(ICalendar $calendar) {
		$this->calendars[$calendar->getKey()] = $calendar;
	}

	/**
	 * Unregisters a calendar
	 *
	 * @param ICalendar $calendar
	 * @return void
	 * @since 13.0.0
	 */
	public function unregisterCalendar(ICalendar $calendar) {
		unset($this->calendars[$calendar->getKey()]);
	}

	/**
	 * In order to improve lazy loading a closure can be registered which will be called in case
	 * calendars are actually requested
	 *
	 * @param \Closure $callable
	 * @return void
	 * @since 13.0.0
	 */
	public function register(\Closure $callable) {
		$this->calendarLoaders[] = $callable;
	}

	/**
	 * @return ICalendar[]
	 * @since 13.0.0
	 */
	public function getCalendars() {
		$this->loadCalendars();

		return array_values($this->calendars);
	}

	/**
	 * removes all registered calendar instances
	 * @return void
	 * @since 13.0.0
	 */
	public function clear() {
		$this->calendars = [];
		$this->calendarLoaders = [];
	}

	/**
	 * loads all calendars
	 */
	private function loadCalendars() {
		foreach ($this->calendarLoaders as $callable) {
			$callable($this);
		}
		$this->calendarLoaders = [];
	}
}