function Screen(dom) {
	var root = document.getElementById('screen');

	return {
		appendText: appendText,
		clear: clear,
		frame: frame,
		input: input,
		markAsRead: markAsRead,
		menu: menu,
		select: select,
		show: show,
		text: text
	};

	function appendText(message) {
		getTextZone().children[0].textContent += message;
	}

	function clear(elem) {
		if(elem == 'text') {
			var textElem = findTextZone();
			if(textElem != undefined) {
				root.removeChild(textElem);
			}
		} else if(elem != undefined) {
			root.removeChild(elem);
		} else {
			dom.clear(root);
		}
	}

	function frame(n) {
		root.className = "frame" + n;
	}

	function findTextZone() {
		return root.getElementsByClassName('text')[0];
	}

	function getTextZone() {
		var textZone = findTextZone();
		if(textZone == undefined) {
			textZone = dom.make('div', {class: ['text', 'framed']}, [
				dom.make('p')
			]);
			root.appendChild(textZone);
		}
		return textZone
	}

	function input(size) {
		var elem = dom.make('input', {
			type: 'text',
			class: 'framed',
			maxlength: size,
			size: size
		});
		show(elem);
		return elem;
	}

	function markAsRead(yes) {
		if(yes == undefined) {
			yes = true;
		}
		getTextZone().classList[yes ? 'add' : 'remove']('read');
	}

	function menu(name, entries) {
		var domEntries = [];
		for(var i = 0; i < entries.length; i++) {
			domEntries.push(dom.make('li', {
				class: [entries].concat(i == 0 ? ['selected'] : []),
				textContent: entries[i].label
			}, []));
		}
		var ul = dom.make('ul', {class: ['menu', 'framed'], id: name}, domEntries);
		root.appendChild(ul);
		return ul;
	}

	function select(cursor) {
		var ul = root.getElementsByClassName('menu')[0];
		ul.getElementsByClassName('selected')[0].className = '';
		ul.children[cursor].className = 'selected';
	}

	function show(elem) {
		root.appendChild(elem);
	}

	function text(message) {
		getTextZone().children[0].textContent = message;
		markAsRead(message.length > 0);
	}
}