/*
This file is part of »munin«.

Copyright 2025 'Fenris Wolf' <fenris@folksprak.org>

»munin« is free software: you can redistribute it and/or modify
it under the terms of the GNU Lesser General Public License as published by
the Free Software Foundation, either version 3 of the License, or
(at your option) any later version.

»munin« 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 Lesser General Public License for more details.

You should have received a copy of the GNU Lesser General Public License
along with »munin«. If not, see <http://www.gnu.org/licenses/>.
 */


namespace _munin.sources.ical_feed
{

	/**
	 */
	export type type_parameters = {
		url : string;
		filtration : {
			category_whitelist : (null | Array<string>);
			category_blacklist : (null | Array<string>);
			title_whitelist : (null | Array<string>);
			title_blacklist : (null | Array<string>);
		};
	};
	
	
	/**
	 */
	async function fetch(
		parameters : type_parameters
	) : Promise<Array<_munin.type_event>>
	{
		const url : lib_plankton.url.type_url = lib_plankton.url.decode(parameters.url);
		const http_request : lib_plankton.http.type_request = {
			"scheme": (url.scheme as ("http" | "https")),
			"host": url.host,
			"path": url.path,
			"version": "HTTP/2",
			"method": lib_plankton.http.enum_method.get,
			"query": ("?" + url.query),
			"headers": {},
			"body": null,
		};
		const http_response : lib_plankton.http.type_response = await lib_plankton.http.call(http_request);
		const ics : string = http_response.body.toString();
		const vcalendar : lib_plankton.ical.type_vcalendar = lib_plankton.ical.ics_decode(ics);
		const events : Array<_munin.type_event> = (
			vcalendar.vevents
			.filter(
				vevent => (
					// category whitelist
					(
						(parameters.filtration.category_whitelist === null)
						||
						vevent.categories.some(
							category => (
								parameters.filtration.category_whitelist
								.map(category_ => category_.toLowerCase())
								.includes(category.toLowerCase())
							)
						)
					)
					&&
					// category blacklist
					(
						(parameters.filtration.category_blacklist === null)
						||
						vevent.categories.every (
							category => ! (
								parameters.filtration.category_blacklist
								.map(category_ => category_.toLowerCase())
								.includes(category.toLowerCase())
							)
						)
					)
					&&
					// title whitelist
					(
						(parameters.filtration.title_whitelist === null)
						||
						parameters.filtration.title_whitelist.some(
							title => (
								vevent.summary.toLowerCase()
								.includes(title.toLowerCase())
							)
						)
					)
					&&
					// title blacklist
					(
						(parameters.filtration.title_blacklist === null)
						||
						parameters.filtration.title_blacklist.every(
							title => ! (
								vevent.summary.toLowerCase()
								.includes(title.toLowerCase())
							)
						)
					)
				)
			)
			.map(
				vevent => {
					const begin : lib_plankton.pit.type_datetime = {
						"timezone_shift": 0,
						"date": vevent.dtstart.value.date,
						"time": vevent.dtstart.value.time,
					};
					const end : lib_plankton.pit.type_datetime = {
						"timezone_shift": 0,
						"date": vevent.dtend.value.date,
						"time": vevent.dtend.value.time,
					};
					const event : _munin.type_event = {
						"title": vevent.summary,
						"begin": begin,
						"end": end,
						"description": (vevent.description ?? null),
						"location": (vevent.location ?? null),
						"tags": vevent.categories,
					};
					return event;
				}
			)
		);
		return events;
	}
	
	
	/**
	 */
	export function implementation_source(
		parameters : type_parameters
	) : _munin.type_source
	{
		return {
			"fetch": () => fetch(parameters),
		};
	}
	
}