<?php

namespace davina\sources;

require_once(DIR_LOGIC . '/helpers/string.php');
require_once(DIR_LOGIC . '/helpers/cache.php');
require_once(DIR_LOGIC . '/helpers/pit.php');
require_once(DIR_LOGIC . '/helpers/ics.php');
require_once(DIR_LOGIC . '/base.php');
require_once(DIR_LOGIC . '/sources/_interface.php');
require_once(DIR_LOGIC . '/model.php');


/**
 */
class class_source_ics_feed
	implements interface_source
{
	
	/**
	 */
	private string $url_template;
	
	
	/**
	 */
	private ?int $lifetime;
	
	
	/**
	 */
	private bool $conflate;
	
	
	/**
	 */
	public function __construct(
		string $url_template,
		?int $lifetime,
		bool $conflate
	)
	{
		$this->url_template = $url_template;
		$this->lifetime = $lifetime;
		$this->conflate = $conflate;
		$this->cache_file = \davina\helpers\call\convey(
			new \davina\helpers\cache\class_cache_file('data'),
			[
				fn($x) => new \davina\helpers\cache\class_cache_encoded(
					$x,
					fn($value) => \json_encode($value),
					fn($value_encoded) => \json_decode($value_encoded, true)
				),
			]
		);
		$this->cache_memory = \davina\helpers\call\convey(
			(new \davina\helpers\cache\class_cache_memory()),
			[
			]
		);
	}
	
	
	/**
	 */
	private function url(
		$parameters
	) : string
	{
		return \davina\helpers\string_\coin(
			$this->url_template,
			[
				'username' => ($parameters['auth_username'] ?? null),
				'password' => ($parameters['auth_password'] ?? null),
			]
		);
	}
	
	
	/**
	 */
	private function vcalendar_to_calendar(
		\davina\helpers\ics\struct_vcalendar $vcalendar,
		?string $realm_name
	) : \davina\model\struct_calendar
	{
		return (
			new \davina\model\struct_calendar(
				\array_map(
					fn($vevent) => (new \davina\model\struct_event(
						// id
						$vevent->uid,
						// title
						(
							(! $this->conflate)
							?
							$vevent->summary
							:
							\sprintf(
								'%s%s',
								$vevent->summary,
								\implode(
									'',
									\array_map(
										fn($category) => \sprintf(' (%s)', $category),
										$vevent->categories
									)
								)
							)
						),
						// begin
						\davina\helpers\ics\datetime_to_unix_timestamp($vevent->dtstart->value),
						// end
						(
							($vevent->dtend === null)
							?
							null
							:
							\davina\helpers\ics\datetime_to_unix_timestamp($vevent->dtend->value)
						),
						// location
						$vevent->location,
						// description
						$vevent->description,
						// 'tags
						(
							(! $this->conflate)
							?
							$vevent->categories
							:
							[]
						)
					)),
					$vcalendar->events
				)
			)
		);
	}
	
	
	/**
	 */
	private function retrieve(
		string $url,
		?string $realm_name
	)
	{
		$client = new \Sabre\HTTP\Client();
		$request = new \Sabre\HTTP\Request(
			'GET',
			$url,
			[],
			null
		);
		$response = $client->send($request);
		$status_code = $response->getStatus();
		switch ($status_code)
		{
			case 200:
			{
				$ics = $response->getBody();
				try
				{
					$vcalendar = \davina\helpers\ics\vcalendar_decode($ics);
				}
				catch (\Throwable $throwable)
				{
					\error_log(
						\davina\helpers\string_\coin(
							'could not parse ics: {{reason}}',
							[
								'reason' => \strval($throwable),
							]
						)
					);
					$valendar = null;
				}
				if ($vcalendar === null)
				{
					throw (new \Exception('could not parse ics'));
				}
				else
				{
					$calendar = $this->vcalendar_to_calendar($vcalendar, $realm_name);
					$calendar_raw = \davina\model\calendar_to_raw($calendar);
					return $calendar_raw;
				}
				break;
			}
			default:
			{
				throw (
					new \Exception(
						\sprintf(
							'unhandled response status code: %u',
							$status_code
						)
					)
				);
				break;
			}
		}
	}
	
	
	/**
	 * [implementation]
	 */
	public function read(
	) : \davina\model\struct_calendar
	{
		$parameters = \davina\get_parameters();
		$url = $this->url($parameters);
		$key = \sprintf(
			'%s:%u',
			$url,
			$this->conflate
		);
		$f1 = fn() => $this->retrieve(
			$url,
			$parameters['realm_name']
		);
		$f2 = fn() => \davina\helpers\cache\get(
			$this->cache_file,
			$key,
			$f1,
			[
				'ttl' => $this->lifetime,
			]
		);
		$f3 = fn() => \davina\helpers\cache\get(
			$this->cache_memory,
			$key,
			$f2,
			[
				'ttl' => null,
			]
		);
		return \davina\model\calendar_from_raw(
			($f3)()
		);
	}
	
}

 ?>