code.js

var list = [];
var current = -1;
var preloaders = [];

var max_preload = 10;

// we load list.json which lists all images so far

function updateCurrent(preload_forward) {
	$.History.setHash(""+current);
	var im = document.getElementById("image");
	if (current >= 0) {
		var element = document.getElementById("current_id");
		if (element.textContent != undefined)
			element.textContent = current+" ("+list[current]+")";
		else
			element.innerText = current+" ("+list[current]+")";
		im.src = "img/"+list[current];
	}

	var new_preloaders = [];
	var i;

	for (i = 1 ; i <= max_preload ; i++) {
		var preload_idx = preload_forward ? (current + i) : (current - i);
		var preload = list[preload_idx];

		if (!preload) {
			break;
		}

		var image = new Image();
		image.src = "img/" + preload;
		new_preloaders.push(image);
	}
	preloaders = new_preloaders;
}

function update_list(play_sound,first_run) {
	$.getJSON( "list.json?r="+Math.random(), function(data) {
		var do_go_last = false;
		if (current == list.length - 1) do_go_last = true;
		list = data;
		if (first_run) {
			var pos = $.History.getHash();
			var pos_int = pos || 0;
			if ((pos_int) || (pos == '0')) {
				go_to(pos_int);
				return;
			}
		}
		if ((do_go_last) && (current != list.length - 1)) {
			go_last();
			if ((document.hasFocus) && (!document.hasFocus())) {
				document.title = "[!] xkcd 1446";
			}
			if (play_sound)
				$.playSound('sound');
		}
	});
	// Disable auto loading since it's over now
//	setTimeout(function() { update_list(true,false); }, 60000);
}

function go_to(frame) {
	frame = frame || 0;
	if (frame == current) return;
	if (frame < 0) return;
	if (frame > (list.length-1)) return;
	current = frame;
	updateCurrent(true); // assume direction will be forward
}

function go_prev() {
	if (current <= 0) return;
	current--;
	updateCurrent(false);
}

function go_next() {
	if (current >= (list.length-1)) return;
	current++;
	updateCurrent(true);
}

function go_first() {
	current = 0;
	updateCurrent(true);
}

function go_last() {
	current = list.length-1;
	updateCurrent(false);
}

$(document).keydown(function(e) {
	switch(e.which) {
		case 37: // left
			go_prev();
			break;
		case 38: // up
			go_first();
			break;
		case 39: // right
			go_next();
			break;
		case 40: // down
			go_last();
			break;
		default: return;
	}
	e.preventDefault();
});

update_list(false,true);
$.History.bind(go_to);
$(window).focus(function(){document.title = "xkcd 1446";});