/*
Copyright (c) 2012 Roger Light <roger@atchoo.org>
All rights reserved.

Redistribution and use in source and binary forms, with or without
modification, are permitted provided that the following conditions are met:

1. Redistributions of source code must retain the above copyright notice,
   this list of conditions and the following disclaimer.
2. Redistributions in binary form must reproduce the above copyright
   notice, this list of conditions and the following disclaimer in the
   documentation and/or other materials provided with the distribution.
3. Neither the name of mosquitto nor the names of its
   contributors may be used to endorse or promote products derived from
   this software without specific prior written permission.

THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS "AS IS"
AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT OWNER OR CONTRIBUTORS BE
LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR
CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF
SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS
INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN
CONTRACT, STRICT LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE)
ARISING IN ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE
POSSIBILITY OF SUCH DAMAGE.
*/

/* Mosquitto MQTT Javascript/Websocket client */
/* Provides complete support for QoS 0. 
 * Will not cause an error on QoS 1/2 packets.
 */

var CONNECT = 0x10;
var CONNACK = 0x20;
var PUBLISH = 0x30;
var PUBACK = 0x40;
var PUBREC = 0x50;
var PUBREL = 0x60;
var PUBCOMP = 0x70;
var SUBSCRIBE = 0x80;
var SUBACK = 0x90;
var UNSUBSCRIBE = 0xA0;
var UNSUBACK = 0xB0;
var PINGREQ = 0xC0;
var PINGRESP = 0xD0;
var DISCONNECT = 0xE0;

function AB2S(buffer) {
	var binary = '';
	var bytes = new Uint8Array(buffer);
	var len = bytes.byteLength;
	for(var i=0; i<len; i++){
		binary += String.fromCharCode(bytes[i]);
	}
	return binary;
}

function Mosquitto()
{
	this.ws = null;
	this.onconnect = null;
	this.ondisconnect = null;
	this.onmessage = null;
}

Mosquitto.prototype = {
	mqtt_ping : function()
	{
		var buffer = new ArrayBuffer(2);
		var i8V = new Int8Array(buffer);
		i8V[0] = PINGREQ;
		i8V[1] = 0;
		if(this.ws.readyState == 1){
			this.ws.send(buffer);
		}else{
			this.queue(buffer);
		}
		setTimeout(function(_this){_this.mqtt_ping();}, 60000, this);
	},

	connect : function(url, keepalive){

		this.url = url;
		this.keepalive = keepalive;
		this.mid = 1;
		this.out_queue = new Array();

		this.ws = new WebSocket(url, 'mqttv3.1');
		this.ws.binaryType = "arraybuffer";
		this.ws.onopen = this.ws_onopen;
		this.ws.onclose = this.ws_onclose;
		this.ws.onmessage = this.ws_onmessage;
		this.ws.m = this;
		this.ws.onerror = function(evt){
			alert(evt.data);
		}
	},

	disconnect : function(){
		if(this.ws.readyState == 1){
			var buffer = new ArrayBuffer(2);
			var i8V = new Int8Array(buffer);

			i8V[0] = DISCONNECT;
			i8V[1] = 0;
			this.ws.send(buffer);
			this.ws.close();
		}
	},

	ws_onopen : function(evt) {
		var buffer = new ArrayBuffer(1+1+12+2+20);
		var i8V = new Int8Array(buffer);

		i=0;
		i8V[i++] = CONNECT;
		i8V[i++] = 12+2+20;
		i8V[i++] = 0;
		i8V[i++] = 6;
		str = "MQIsdp";
		for(var j=0; j<str.length; j++){
			i8V[i++] = str.charCodeAt(j);
		}
		i8V[i++] = 3;
		i8V[i++] = 2;
		i8V[i++] = 0;
		i8V[i++] = 60;
		i8V[i++] = 0;
		i8V[i++] = 20;
		var str = "mjsws/";
		for(var j=0; j<str.length; j++){
			i8V[i++] = str.charCodeAt(j);
		}
		var chars = "0123456789ABCDEFGHIJKLMNOPQRSTUVWXYZabcdefghijklmnopqrstuvwxyz";
		for(var j=0; j<14; j++){
			i8V[i++] = chars.charCodeAt(Math.floor(Math.random()*chars.length));
		}

		this.send(buffer);
		while(this.m.out_queue.length > 0){
			this.send(this.m.out_queue.pop());
		}
		setTimeout(function(_this){_this.mqtt_ping();}, 60000, this.m);
	},

	ws_onclose : function(evt) {
		if(this.m.ondisconnect){
			this.m.ondisconnect(evt.data);
		}
	},

	ws_onmessage : function(evt) {
		var i8V = new Int8Array(evt.data);
		buffer = evt.data;
		var q=0;
		while(i8V.length > 0 && q < 1000){
			q++;
			switch(i8V[0] & 0xF0){
				case CONNACK:
					var rl = i8V[1];
					var rc = i8V[2];
					if(this.m.onconnect){
						this.m.onconnect(rc);
					}
					buffer = buffer.slice(rl+2);
					i8V = new Int8Array(buffer);
					break;
				case PUBLISH:
					var i=1;
					var mult = 1;
					var rl = 0;
					var count = 0;
					var digit;
					var qos = (i8V[0] & 0x06) >> 1;
					var retain = (i8V[0] & 0x01);
					var mid = 0;
					do{
						count++;
						digit = i8V[i++];
						rl += (digit & 127)*mult;
						mult *= 128;
					}while((digit & 128) != 0);

					var topiclen = i8V[i++]*256 + i8V[i++];
					var atopic = buffer.slice(i, i+topiclen);
					i+=topiclen;
					var topic = AB2S(atopic);
					if(qos > 0){
						mid = i8V[i++]*256 + i8V[i++];
					}
					var apayload = buffer.slice(i, rl+count+1);
					var payload = AB2S(apayload);

					buffer = buffer.slice(rl+1+count);
					i8V = new Int8Array(buffer);

					if(this.m.onmessage){
						this.m.onmessage(topic, payload, qos, retain);
					}
					break;
				case PUBREC:
				case PUBREL:
				case PUBACK:
				case PUBCOMP:
				case SUBACK:
				case UNSUBACK:
				case PINGRESP:
					var rl = i8V[1];
					buffer = buffer.slice(rl+2);
					i8V = new Int8Array(buffer);
					break;
			}
		}
	},

	get_remaining_count : function(remaining_length)
	{
		if(remaining_length >= 0 && remaining_length < 128){
			return 1;
		}else if(remaining_length >= 128 && remaining_length < 16384){
			return 2;
		}else if(remaining_length >= 16384 && remaining_length < 2097152){
			return 3;
		}else if(remaining_length >= 2097152 && remaining_length < 268435456){
			return 4;
		}else{
			return -1;
		}
	},

	generate_mid : function()
	{
		var mid = this.mid;
		this.mid++;
		if(this.mid == 256) this.mid = 0;
		return mid;
	},

	queue : function(buffer)
	{
		this.out_queue.push(buffer);
	},

	send_cmd_with_mid : function(cmd, mid)
	{
		var buffer = new ArrayBuffer(4);
		var i8V = new Int8Array(buffer);
		i8V[0] = cmd;
		i8V[1] = 2;
		i8V[2] = mid%128;
		i8V[3] = mid/128;
		if(this.ws.readyState == 1){
			this.ws.send(buffer);
		}else{
			this.queue(buffer);
		}
	},

	unsubscribe : function(topic)
	{
		var rl = 2+2+topic.length;
		var remaining_count = this.get_remaining_count(rl);
		var buffer = new ArrayBuffer(1+remaining_count+rl);
		var i8V = new Int8Array(buffer);

		var i=0;
		i8V[i++] = UNSUBSCRIBE | 0x02;
		do{
			digit = Math.floor(rl % 128);
			rl = Math.floor(rl / 128);
			if(rl > 0){
				digit = digit | 0x80;
			}
			i8V[i++] = digit;
		}while(rl > 0);
		i8V[i++] = 0;
		i8V[i++] = this.generate_mid();
		i8V[i++] = 0;
		i8V[i++] = topic.length;
		for(var j=0; j<topic.length; j++){
			i8V[i++] = topic.charCodeAt(j);
		}

		if(this.ws.readyState == 1){
			this.ws.send(buffer);
		}else{
			this.queue(buffer);
		}
	},

	subscribe : function(topic, qos)
	{
		if(qos != 0){
			return 1;
		}
		var rl = 2+2+topic.length+1;
		var remaining_count = this.get_remaining_count(rl);
		var buffer = new ArrayBuffer(1+remaining_count+rl);
		var i8V = new Int8Array(buffer);

		var i=0;
		i8V[i++] = SUBSCRIBE | 0x02;
		do{
			digit = Math.floor(rl % 128);
			rl = Math.floor(rl / 128);
			if(rl > 0){
				digit = digit | 0x80;
			}
			i8V[i++] = digit;
		}while(rl > 0);
		i8V[i++] = 0;
		i8V[i++] = this.generate_mid();
		i8V[i++] = 0;
		i8V[i++] = topic.length;
		for(var j=0; j<topic.length; j++){
			i8V[i++] = topic.charCodeAt(j);
		}
		i8V[i++] = qos;

		if(this.ws.readyState == 1){
			this.ws.send(buffer);
		}else{
			this.queue(buffer);
		}
	},

	publish : function(topic, payload, qos, retain){
		if(qos != 0) return 1;
		var rl = 2+topic.length+payload.length;
		var remaining_count = this.get_remaining_count(rl);
		var buffer = new ArrayBuffer(1+remaining_count+rl);
		var i8V = new Int8Array(buffer);

		var i=0;
		retain = retain?1:0;
		i8V[i++] = PUBLISH | (qos<<1) | retain;
		do{
			digit = Math.floor(rl % 128);
			rl = Math.floor(rl / 128);
			if(rl > 0){
				digit = digit | 0x80;
			}
			i8V[i++] = digit;
		}while(rl > 0);
		i8V[i++] = 0;
		i8V[i++] = topic.length;
		for(var j=0; j<topic.length; j++){
			i8V[i++] = topic.charCodeAt(j);
		}
		for(var j=0; j<payload.length; j++){
			i8V[i++] = payload.charCodeAt(j);
		}

		if(this.ws.readyState == 1){
			this.ws.send(buffer);
		}else{
			this.queue(buffer);
		}
	}
}