"use strict";

const xtend = require("xtend");
const nanoid = require("nanoid");
const immutable = require("immutable");

module.exports = function createNotificationStore({onUpdated}) {
	let notifications = immutable.OrderedMap([]);
	let timers = new Map();

	function startTimer(notification, timeout) {
		timers.set(notification, setTimeout(() => {
			notification.expired = true;
			onUpdated();
		}, timeout));
	}

	function cancelTimer(notification) {
		if (timers.has(notification)) {
			clearTimeout(timers.get(notification));
		}
	}

	return {
		add: function (notification) {
			let id = nanoid();

			notifications = notifications.set(id, xtend(notification, {
				id: id
			}));

			this.unblockExpiry(id);
			onUpdated();

			return id;
		},
		markRead: function (id) {
			notifications.get(id).markedRead = true;
			onUpdated();
		},
		blockExpiry: function (id) {
			let notification = notifications.get(id);
			cancelTimer(notification);
		},
		unblockExpiry: function (id) {
			let notification = notifications.get(id);
			cancelTimer(notification);

			if (notification.timeout != null && notification.timeout !== false) {
				startTimer(notification, notification.timeout);
			}
		},
		getAll: function () {
			return notifications;
		},
		getVisible: function () {
			return notifications.filter((notification) => {
				return (!notification.markedRead && !notification.expired);
			});
		}
	};
};