<?php

namespace davigil\overwrites;

require_once('vendor/autoload.php');
require_once('helpers/call.php');
require_once('helpers/ics.php');
require_once('sources/_interface.php');
require_once('conf.php');


/**
 */
class class_caldav_backend
	extends \Sabre\CalDAV\Backend\AbstractBackend
	implements \Sabre\CalDAV\Backend\BackendInterface
{
	
	
	/**
	 */
	private \davigil\sources\interface_source $source;
	
	
	/**
	 */
	public function __construct(
		\davigil\sources\interface_source $source
	)
	{
		// parent::__construct();
		$this->source = $source;
	}
	
	
	/**
	 */
	private function hash_tag(
		string $tag
	) : string
	{
		return \hash('sha256', $tag);
	}
	
	
	/**
	 */
	private function encode_tag(
		string $tag
	) : string
	{
		return \davigil\helpers\call\convey(
			$tag,
			[
				fn($x) => \strtolower($x),
				fn($x) => \preg_replace('/ä/', 'ae', $x),
				fn($x) => \preg_replace('/ö/', 'oe', $x),
				fn($x) => \preg_replace('/ü/', 'ue', $x),
				fn($x) => \preg_replace('/ß/', 'sz', $x),
				fn($x) => \preg_replace('/\-/', '', $x),
				fn($x) => \preg_replace('/ /', '-', $x),
				fn($x) => \preg_replace('/[^a-zA-Z0-9_\-]/s', '_', $x),
			]
		);
	}
	
	
	/**
	 */
	public function getCalendarsForUser(
		$principalUri
	)
	{
		$data = $this->source->get([]);
		$tags = [];
		foreach ($data as $entry)
		{
			foreach ($entry['tags'] as $tag)
			{
				$tags[$tag] = null;
			}
		}
		$result = \array_map(
			fn($tag) => [
				'id' => $this->hash_tag($tag),
				'uri' => $this->encode_tag($tag),
				'principaluri' => $principalUri,
				'{DAV:}displayname' => $tag,
				\sprintf('{%s}supported-calendar-component-set', \Sabre\CalDAV\Plugin::NS_CALDAV) => new \Sabre\CalDAV\Xml\Property\SupportedCalendarComponentSet(['VEVENT']),
			],
			\array_keys($tags)
		);
		// \error_log(\json_encode($result, \JSON_PRETTY_PRINT));
		return $result;
	}
	
	
	/**
	 */
	public function createCalendar(
		$principalUri,
		$calendarUri,
		array $properties
	)
	{
		throw (new \Exception('not implemented: createCalendar'));
	}
	
	
	/**
	 */
	public function deleteCalendar(
		$calendarId
	)
	{
		throw (new \Exception('not implemented: deleteCalendar'));
	}
	
	
	/**
	 */
	public function getCalendarObjects(
		$calendarId
	)
	{
		$tag = $calendarId;
		$data = $this->source->get([]);
		$result = \array_map(
			fn($entry) => [
				'calendarid' => $calendarId,
				'id' => $entry['id'],
				// 'uri' => \sprintf('%s.ics', $entry['id']),
				'uri' => $entry['id'],
				'lastmodified' => \time(),
				// 'etag' => null,
				// 'size' => null,
				'component' => 'vevent',
				'{DAV:}displayname' => $entry['title'],
			],
			\array_values(
				\array_filter(
					$data,
					fn($entry) => \in_array(
						$tag,
						\array_map(
							fn($x) => $this->hash_tag($x),
							$entry['tags']
						)
					)
				)
			)
		);
		return $result;
	}
	
	
	/**
	 * @todo outsource
	 */
	private function event_to_vevent(
		array $event
	) : \davigil\helpers\ics\struct_vevent
	{
		$vevent = new \davigil\helpers\ics\struct_vevent();
		{
			$vevent->uid = $event['id'];
			$vevent->dtstamp = \davigil\helpers\ics\datetime_from_unix_timestamp($event['begin']);
			$vevent->dtstart = new \davigil\helpers\ics\struct_dt(
				'',
				\davigil\helpers\ics\datetime_from_unix_timestamp($event['begin'])
			);
			$vevent->dtend = (
				($event['end'] === null)
				?
				null
				:
				new \davigil\helpers\ics\struct_dt(
					'',
					\davigil\helpers\ics\datetime_from_unix_timestamp($event['end'])
				)
			);
			$vevent->summary = $event['title'];
			$vevent->location = $event['location'];
			$vevent->description = $event['description'];
			$vevent->class = \davigil\helpers\ics\enum_class::public_;
		}
		return $vevent;
	}
	
	
	/**
	 * @todo outsource
	 */
	private function events_to_vcalendar(
		array $events
	) : \davigil\helpers\ics\struct_vcalendar
	{
		$vcalendar = new \davigil\helpers\ics\struct_vcalendar();
		{
			$vcalendar->version = '2.0';
			/**
			 * @todo conf
			 */
			$vcalendar->prodid = 'davigil';
			$vcalendar->method = 'PUBLISH';
			$vcalendar->events = \array_map(
				fn($event) => $this->event_to_vevent($event),
				$events
			);
		}
		return $vcalendar;
	}
	
	
	/**
	 */
	public function getCalendarObject(
		$calendarId,
		$objectUri
	)
	{
		$id = $objectUri;
		$data = $this->source->get([]);
		$entries = \array_values(
			\array_filter(
				$data,
				fn($entry) => ($entry['id'] === $id)
			)
		);
		if (\count($entries) !== 1)
		{
			throw (new \Exception(\sprintf('not found or ambiguous')));
		}
		else
		{
			$vcalendar = $this->events_to_vcalendar($entries);
			$ics = \davigil\helpers\ics\vcalendar_encode($vcalendar);
			return [
				'calendardata' => $ics,
				'uri' => $objectUri,
				/**
				 * @todo
				 */
				'lastmodified' => \time(),
				/**
				 * @todo
				 */
				// 'etag' => '""',
				/**
				 * @todo
				 */
				// 'size' => 1,
				'component' => 'vcalendar',
			];
		}
	}
	
	
	/**
	 */
	public function createCalendarObject(
		$calendarId,
		$objectUri,
		$calendarData
	)
	{
		throw (new \Exception('not implemented: createCalendarObject'));
	}
	
	
	/**
	 */
	public function updateCalendarObject(
		$calendarId,
		$objectUri,
		$calendarData
	)
	{
		throw (new \Exception('not implemented: updateCalendarObject'));
	}
	
	
	/**
	 */
	public function deleteCalendarObject(
		$calendarId,
		$objectUri
	)
	{
		throw (new \Exception('not implemented: deleteCalendarObject'));
	}
	
}

 ?>