/*
Usage

	// Send an notification
	mediator.emit('notification:send',{
		title: 'Woop',
		body: 'Woop woop',
		icon: 'gfx/icon.png'
	});

	// Turn notifications on
	mediator.emit('notification:on');

	// Turn notifications off
	mediator.emit('notification:off');

*/


export default function(mediator, settings, win) {

	var enabled = true,

		native_supported = false,

		new_title,
		original_title,
		blink_timer,
		interval,

		last,

		now = function () {
			return performance.now() || Date.now();
		},

		on = function () {
			enabled = true;
		},

		off = function () {
			enabled = false;
		},

		resetState = function() {
			clearTimeout(blink_timer);
			if (original_title !== undefined) win.setTitle(original_title);
			original_title = undefined;
			new_title = undefined;
		},

		doBlink = function() {
			if(enabled) {
				if( win.getTitle() === original_title )
					win.setTitle( new_title );
				else
					win.setTitle( original_title);

				blink_timer = setTimeout(doBlink,interval);
			} else {
				resetState();
			}
		},

		enableNative = function() {
			if( native_supported && Notification.permission !== 'denied' ) {
				Notification.requestPermission();
			}
		},

		blinkTitleUntilFocus = function(t,i) {
			interval = (i === undefined) ? 1000 : i;
			if ( enabled && original_title === undefined ) {
				new_title = t;
				original_title = win.getTitle();
				doBlink();
			}
		},

		notify = function(title,body,icon,fallback) {

			// Only notify while in background, and if sufficient time has passed
			if( enabled && (now() - last) > settings.notifications.maxOnePerMs ) {

				// Set default value for fallback parameter
				if ( fallback === undefined) fallback = false;

				if ( native_supported && Notification.permission === 'granted') {

					// Create notification
					var n = new Notification(title, {body: body, icon:icon});

					// Handle on show event
					n.onshow = function () { 
						// Automatically close the notification after 5000ms
						setTimeout(function(){n.close();},3000);
					};

					last = now();

				} else if ( fallback ) {
					blinkTitleUntilFocus('Attention', 1000);

				}
			}
		};

	native_supported = (window.Notification !== undefined);

	mediator.on('notification:send',function(data) { notify(data.title,data.body,data.icon,true); });
	mediator.on('notification:on',function() { on(); });
	mediator.on('notification:off',function() { off(); });

	// Always enable native notifications
	enableNative();

	// Start with notifications disabled
	off();

	// If this is undefined, notifications will fail to show
	last = now();

	// Make sure we are at square one
	resetState();
}