aoc16

hex = document.getElementsByTagName("pre")[0].innerText.split("\n").filter(function(n){return n;})[0];
arr = hex.split("").map(function(i){str='000' + parseInt(i, 16).toString(2);return str.substring(str.length-4)}).join("");

var currentPosition = 0;
var versionSum = 0;

function read(start, len) {
	str = '';
	for (i=start;i<start+len;i++) {
		str+=arr[i];
	}
	return parseInt(str, 2);
}

function readPacket() {
	var packet = {}
	packet.version = read(currentPosition, 3);
	versionSum+=packet.version;
	packet.type = read(currentPosition + 3, 3);
	if (packet.type == 4) {
		currentPosition += 6;
		packet.val = 0;
		//literal
		while (true) {
			packet.val = packet.val * 16 + read(currentPosition+1, 4);
			currentPosition += 5;
			if (arr[currentPosition-5] == '0') {
				break;
			}
		}
	} else {
		//operator
		if (arr[currentPosition + 6] == '0') {
			currentPosition += 7;
			var len = read(currentPosition, 15);
			currentPosition += 15;
			var endOfPacket = currentPosition + len;
			packet.subpackets = [];
			while (currentPosition < endOfPacket) {
				packet.subpackets.push(readPacket());
			}
		} else {
			currentPosition += 7;
			var subPacketNumber = read(currentPosition, 11);
			currentPosition += 11;
			packet.subpackets = [];
			while (packet.subpackets.length < subPacketNumber) {
				packet.subpackets.push(readPacket());
			}
		}
	}
	return packet;
}

x=readPacket();

function calculate(packet) {
	console.log(packet);
	switch (packet.type) {
		case 0: return packet.subpackets.map(calculate).reduce(function(a,b){return a+b});
		case 1: return packet.subpackets.map(calculate).reduce(function(a,b){return a*b});
		case 2: return packet.subpackets.map(calculate).reduce(function(a,b){return Math.min(a,b)});
		case 3: return packet.subpackets.map(calculate).reduce(function(a,b){return Math.max(a,b)});
		case 4: return packet.val;
		case 5: return (calculate(packet.subpackets[0]) > calculate(packet.subpackets[1])) ? 1 : 0;
		case 6: return (calculate(packet.subpackets[0]) < calculate(packet.subpackets[1])) ? 1 : 0;
		case 7: return (calculate(packet.subpackets[0]) ==calculate(packet.subpackets[1])) ? 1 : 0;
	}
}

result=calculate(x);