function IP() {
	var crypto = require('crypto');

	this.cloak = function(ip, parts) {
		ip = ip.split('.');

		while(ip.length < 4) {
			ip.push('*');
		}

		if(parts === undefined) {
			parts = 0;
		}
		else {
			parts = ip.length - parts;
		}

		var accumulator = '';

		return ip
			.map(function (segment, i) {
				if(i < parts || segment === '*') {
					return segment;
				}

				var part = iphash(accumulator + segment + i, 3);
				accumulator += segment;
				return part;
			})
			.join('.');
	}

	this.uncloak = function(ip, parts)
	{
		ip = ip.split('.');

		if(parts === undefined) {
			for(parts = 0; parts < ip.length && !isCloaked(ip[parts]); ++parts);
		}
		else {
			parts = Math.max(ip.length - parts, 0);
		}

		return doUncloak(ip, ip.slice(), '', parts, []);

		/*
		var parts = ip.split('.');
		var ret = [];
		parts[0] = parseInt(parts[0]);
		parts[1] = parseInt(parts[1]);
		for(parts[2] = 0; parts[2] < 256; ++parts[2])
		{
			for(parts[3] = 0; parts[3] < 256; ++parts[3])
			{
				var test = parts.join('.');
				if(this.cloakIP(test) === ip)
				{
					ret.push(test);
				}
			}
			process.stdout.write('*');
		}
		process.stdout.write('\n');
		return ret;
		*/
	}

	function iphash(data, len) {
		var md5 = crypto.createHash('md5');
		md5.update(data);
		return md5.digest('base64').substring(0, len);
	}

	function isCloaked(part) {
		return /[^0-9]/.test(part) || parseInt(part) >= 256;
	}

	function doUncloak(ip, parts, accumulator, i, ret) {
		if(i >= ip.length) {
			ret.push(parts.join('.'));
			return ret;
		}
		var tmp;
		for(var j = 0; j < 256; ++j) {
			tmp = iphash(accumulator.concat(j, i), 3);
			if(tmp === ip[i]) {
				parts[i] = j;
				doUncloak(ip, parts, accumulator.concat(j), i + 1, ret);
			}
		}
		return ret;
	}

	return this;
}

module.exports = new IP();