/**
 */
type type_role = (
	"editor"
	|
	"viewer"
);


/**
 */
type type_user_id = int;


/**
 */
type type_user_object = {
	name : string;
};


/**
 */
type type_event = {
	name : string;
	begin : type_datetime;
	end : (
		null
		|
		type_datetime
	);
	description : (
		null
		|
		string
	);
};


/**
 */
type type_calendar_id = int;


/**
 */
type type_calendar_object = (
	{
		kind : "concrete";
		data : {
			name : string;
			users : Array<
				{
					id : type_user_id;
					role : type_role;
				}
			>;
			events : Array<type_event>;
		};
	}
	|
	{
		kind : "collection";
		data : {
			name : string;
			sources : Array<
				type_calendar_id
			>;
		}
	}
);


/**
 */
type type_datamodel = {
	users : Array<
		{
			id : type_user_id;
			object : type_user_object;
		}
	>;
	calendars : Array<
		{
			id : type_calendar_id;
			object : type_calendar_object;
		}
	>;
};


/**
 */
function calendar_list(
	data : type_datamodel
) : Array<
	{
		key : type_calendar_id;
		preview : {
			name : string;
		}
	}
>
{
	return (
		data.calendars
		.map(
			(calendar_entry) => ({
				"key": calendar_entry.id,
				"preview": {
					"name": calendar_entry.object.data.name,
				}
			})
		)
	);
}


/**
 */
function calendar_read(
	data : type_datamodel,
	calendar_id : type_calendar_id
) : type_calendar_object
{
	const hits = (
		data.calendars
		.filter(
			(calendar_entry) => (calendar_entry.id === calendar_id)
		)
	);
	if (hits.length <= 0) {
		throw (new Error("not found"));
	}
	else {
		return hits[0].object;
	}
}


/**
 */
function calendar_gather_events(
	data : type_datamodel,
	calendar_id : type_calendar_id,
	from_pit : type_pit,
	to_pit : type_pit
) : Array<
	{
		calendar_id : type_calendar_id;
		event : type_event;
	}
>
{
	const calendar_object : type_calendar_object = calendar_read(
		data,
		calendar_id
	);
	switch (calendar_object.kind) {
		case "concrete": {
			return (
				calendar_object.data.events
				.filter(
					(event) => pit_is_between(
						pit_from_datetime(event.begin),
						from_pit,
						to_pit
					)
				)
				.map(
					(event) => ({"calendar_id": calendar_id, "event": event})
				)
			);
			break;
		}
		case "collection": {
			return (
				calendar_object.data.sources
				.map(
					(source_calendar_id) => calendar_gather_events(
						data,
						source_calendar_id,
						from_pit,
						to_pit
					)
				)
				.reduce(
					(x, y) => x.concat(y),
					[]
				)
			);
			break;
		}
	}
}


/**
 */
function calendar_view_table(
	data : type_datamodel,
	calendar_id : type_calendar_id,
	from : {
		year : int;
		week : int;
	},
	to : {
		year : int;
		week : int;
	},
	options : {
		timezone_shift ?: int;
	} = {}
) : Array<
	Array<
		{
			pit : type_pit;
			entries : Array<
				{
					calendar_id : type_calendar_id;
					event : type_event;
				}
			>;
		}
	>
>
{
	options = Object.assign(
		{
			"timezone_shift": 0,
		},
		options
	);
	/*
	const calendar_object : type_calendar_object = calendar_read(
		data,
		calendar_id
	);
	 */
	const from_pit : type_pit = pit_from_year_and_week(
		from.year,
		from.week,
		{
			"timezone_shift": (options.timezone_shift as int),
		}
	);
	const to_pit : type_pit = pit_from_year_and_week(
		to.year,
		to.week,
		{
			"timezone_shift": (options.timezone_shift as int),
		}
	);
	
	// prepare
	const entries : Array<
		{
			calendar_id : type_calendar_id;
			event : type_event;
		}
	> = calendar_gather_events(
		data,
		calendar_id,
		from_pit,
		to_pit
	);
	let result : Array<
		Array<
			{
				pit : type_pit;
				entries : Array<
					{
						calendar_id : type_calendar_id;
						event : type_event;
					}
				>;
			}
		>
	> = [];
	let row : Array<
		{
			pit : type_pit;
			entries : Array<
				{
					calendar_id : type_calendar_id;
					event : type_event;
				}
			>;
		}
	> = [];
	let day : int = 0;
	while (true) {
		const pit_current : type_pit = pit_shift_day(from_pit, day);
		if (pit_is_before(pit_current, to_pit)) {
			day += 1;
			row.push(
				{
					"pit": pit_current,
					"entries": [],
				}
			);
			if (day % 7 === 0) {
				result.push(row);
				row = [];
			}
			else {
				// do nothing
			}
		}
		else {
			break;
		}
	}
	
	// fill
	(
		entries
		.forEach(
			(entry) => {
				const distance_seconds : int = (pit_from_datetime(entry.event.begin) - from_pit);
// process.stderr.write(JSON.stringify({"begin": entry.event.begin, "begin_pit": pit_from_datetime(entry.event.begin), "from": from_pit, "diff": distance_seconds}) + "\n");
				const distance_days : int = (distance_seconds / (60 * 60 * 24));
				
				const week : int = Math.floor(Math.floor(distance_days) / 7);
				const day : int = (Math.floor(distance_days) % 7);
				
				process.stderr.write(JSON.stringify({entry, distance_days, week, day}, undefined, "\t") + "\n");
				
				result[week][day].entries.push(entry);
			}
		)
	);
	
	return result;
}


/**
 */
function calendar_view_table_html(
	data : type_datamodel,
	calendar_id : type_calendar_id,
	from : {
		year : int;
		week : int;
	},
	to : {
		year : int;
		week : int;
	},
	options : {
		timezone_shift ?: int;
	} = {}
) : string
{
	options = Object.assign(
		{
			"timezone_shift": 0,
		},
		options
	);
	const rows = calendar_view_table(
		data,
		calendar_id,
		from,
		to,
		{
			"timezone_shift": options.timezone_shift,
		}
	);
	return (
		(
			"<style>\n"
			+
			"table {border-collapse: collapse;}\n"
			+
			"td {border: 1px solid black; padding: 8px; margin: 8px; width: 14%;}\n"
			+
			"</style>\n"
		)
		+
		"<table>\n"
		+
		(
			"\t<thead>\n"
			+
			"\t</thead>\n"
		)
		+
		(
			"\t<tbody>\n"
			+
			(
				rows
				.map(
					(row) => (
						"\t\t<tr>\n"
						+
						(
							row
							.map(
								(cell) => (
									"\t\t\t<td>\n"
									+
									(
										"\t\t\t\t<ul>\n"
										+
										(
											cell.entries
											.map(
												entry => (
													"\t\t\t\t\t<li>\n"
													+
													entry.event.name
													+
													"\t\t\t\t\t</li>\n"
												)
											)
											.join("")
										)
										+
										"\t\t\t\t</ul>\n"
									)
									// JSON.stringify(cell) + "\n"
									+
									"\t\t\t</td>\n"
								)
							)
							.join("")
						)
						+
						"\t\t</tr>\n"
					)
				)
				.join("")
			)
			+
			"\t</tbody>\n"
		)
		+
		"</table>\n"
	);
}