var packet_type = ["heart","fix_success","fix_false","sys_close_info","shake_info","idle_info","demolish_alarm","event","battery_consume","config","store_data","limit_gps_data"];
var dev_mode = ["standby mode","period mode","timing mode","motion mode"];
var dev_fix_type = ["work_mode_fix","down_request_fix"];
function substringBytes(bytes, start, len)
{
	var char = [];
	for(var i = 0; i < len; i++)
	{
		char.push("0x"+ bytes[start+i].toString(16) < 0X10 ? ("0"+bytes[start+i].toString(16)) : bytes[start+i].toString(16) );
	}
	return char.join("");
}
function BytestoInt(bytes,start) {
    var value = ((bytes[start] << 24) | (bytes[start+1] << 16) | (bytes[start+2] << 8) | (bytes[start+3]));
    return value;
}
function Decoder(bytes, port)
{
	var dev_info = {};
	dev_info.pack_type = packet_type[port-1];
	//common frame head
	if(port<=10)
	{
		dev_info.work_mode = dev_mode[bytes[0]&0x03];
		dev_info.low_power_state = (bytes[0]>>2)&0x01;
		dev_info.demolish_state = (bytes[0]>>3)&0x01;
		dev_info.idle_state = (bytes[0]>>4)&0x01;
		dev_info.motion_state = (bytes[0]>>5)&0x01;
		if(port==2 || port ==3)
		{
			dev_info.fix_type = dev_fix_type[(bytes[0]>>6)&0x01];
		}
		
		if(bytes[1]>0x80)
		{
			dev_info.ic_temperature = bytes[1] - 0x100 + "°C";
		}
		else
		{
			dev_info.ic_temperature = bytes[1] + "°C";
		}

		dev_info.lorawan_downlink_count = bytes[2]&0x0f;
		dev_info.battery_voltage = (22+((bytes[2]>>4)&0x0f))/10 + "V";
	}
	if(port == 1)
	{
		var restart_reason = ["power_restart","ble_cmd_restart","lorawan_cmd_restart","switch_off_mode_restart"];
		dev_info.last_restart_reason = restart_reason[bytes[3]];

		
		ver_major = (bytes[4]>>6)&0x03;
		ver_mijor = (bytes[4]>>4)&0x03;
		ver_patch = bytes[4]&0x0f;
		dev_info.firmware_ver = "V" + ver_major+"."+ver_mijor+"."+ver_patch;

		dev_info.motion_count = BytestoInt(bytes,5);
	}
	else if(port == 2)
	{
		var  fix_tech = ["wifi","ble","gps"];
		var parse_len = 3; // common head is 3 byte
		var datas = [];
		tech = bytes[parse_len++];
		dev_info.fix_tech = fix_tech[tech];

		year = bytes[parse_len]*256 + bytes[parse_len+1];
		parse_len += 2;
		mon = bytes[parse_len++];
		days = bytes[parse_len++];
		hour = bytes[parse_len++];
		minute = bytes[parse_len++];
		sec = bytes[parse_len++];
		timezone = bytes[parse_len++];

		if(timezone>0x80)
		{
			dev_info.utc_time =  year + "-" + mon + "-" + days + " " + hour + ":" + minute + ":" + sec + "  TZ:" +  (timezone-0x100);
		}
		else
		{
			dev_info.utc_time =  year + "-" + mon + "-" + days + " " + hour + ":" + minute + ":" + sec + "  TZ:" + timezone;
		}
		datalen =  bytes[parse_len++];

		if(tech==0 || tech ==1)
		{
			for(var i=0 ; i<(datalen/7) ; i++)
			{
			  var data = {};
				data.mac = substringBytes(bytes, parse_len, 6);
				parse_len += 6;
				data.rssi = bytes[parse_len++]-256 +"dBm";
				datas.push(data);
			}
			dev_info.mac_data = datas;
		}
		else
		{
			lat =BytestoInt(bytes,parse_len);
			parse_len += 4;
			lon =BytestoInt(bytes,parse_len);
			parse_len += 4;

			if(lat>0x80000000)
				lat = lat-0x100000000;
			if(lon>0x80000000)
				lon = lon-0x100000000;

			dev_info.lat = lat/10000000;
			dev_info.lon = lon/10000000;
			dev_info.pdop = bytes[parse_len] /10;
		}
	}
	else if(port == 3)
	{

		var fix_false_reason = ["wifi_fix_time_timeout","wifi_fix_tech_timeout","wifi_module_nofind","ble_fix_time_timeout","ble_fix_tech_timeout","ble_adv","gps_no_budget","gps_coarse_acc_timeout","gps_fine_acc_timeout","gps_fix_timeout","gps_assistnow_timeout","gps_cold_start_timeout","down_request_fix_interrupt","motion_start_fix_false_by_motion_end","motion_end_fix_false_by_motion_start"];
		var parse_len = 3; 
		var datas = [];
		reason = bytes[parse_len++];
		dev_info.fix_false_reason = fix_false_reason[reason];
		datalen =  bytes[parse_len++];
		if(reason<=5) //wifi and ble reason
		{
		  if(datalen)
		  {
  			for(var i=0 ; i<(datalen/7) ; i++)
  			{
  			  var data = {};
  				data.mac = substringBytes(bytes, parse_len, 6);
  				parse_len += 6;
  				data.rssi = bytes[parse_len++]-256 +"dBm";
  				datas.push(data);
  			}
  			dev_info.mac_data = datas;
		  }
		}
		else if(reason<=11) //gps reason
		{	
			pdop = bytes[parse_len++];
			if(pdop!=0xff)
				dev_info.pdop = pdop/10
			else
				dev_info.pdop = "unknow";
			dev_info.gps_satellite_cn = bytes[parse_len] +"-" + bytes[parse_len+1] +"-" + bytes[parse_len+2] +"-" + bytes[parse_len+3] ;
		}
	}
	else if(port == 4)
	{
		var sys_close_reason = ["ble_cmd_close","lorawan_cmd_close","reed_switch_close"];
		dev_info.sys_close_reason = sys_close_reason[bytes[3]];
	}
	else if(port == 5)
	{
		dev_info.shake_num = bytes[3]*256+ bytes[4];
	}
	else if(port == 6)
	{
		dev_info.idle_time = bytes[3]*256+ bytes[4];
	}
	else if(port == 7)
	{
		var parse_len = 3; // common head is 3 byte
		year = bytes[parse_len]*256 + bytes[parse_len+1];
		parse_len += 2;
		mon = bytes[parse_len++];
		days = bytes[parse_len++];
		hour = bytes[parse_len++];
		minute = bytes[parse_len++];
		sec = bytes[parse_len++];
		timezone = bytes[parse_len++];

		if(timezone>0x80)
		{
			dev_info.alarm_time =  year + "-" + mon + "-" + days + " " + hour + ":" + minute + ":" + sec + "  TZ:" +  (timezone-0x100);
		}
		else
		{
			dev_info.alarm_time =  year + "-" + mon + "-" + days + " " + hour + ":" + minute + ":" + sec + "  TZ:" + timezone;
		}
	}
	else if(port == 8)
	{
		var event = ["motion start","moving fix start","motion end","lorawan downlink trigger uplink"];
		dev_info.event_info = event[bytes[3]];
	}
	else if(port == 9)
	{
		var parse_len = 3;
		dev_info.gps_work_time = BytestoInt(bytes,parse_len);
		parse_len += 4;
		dev_info.wifi_work_time = BytestoInt(bytes,parse_len);
		parse_len += 4;
		dev_info.ble_scan_work_time = BytestoInt(bytes,parse_len);
		parse_len += 4;
		dev_info.ble_adv_work_time = BytestoInt(bytes,parse_len);
		parse_len += 4;
		dev_info.lorawan_work_time = BytestoInt(bytes,parse_len);
		parse_len += 4;
	}
	else if(port == 10)
	{
		//
	}
	else if(port == 11)
	{
		//
	}
	else if(port == 12)
	{

		dev_info.work_mode = dev_mode[bytes[0]&0x03];
		dev_info.low_power_state = bytes[0]&0x04;
		dev_info.demolish_state = bytes[0]&0x08;
		dev_info.idle_state = bytes[0]&0x10;
		dev_info.motion_state = bytes[0]&0x20;
		dev_info.fix_type = dev_fix_type[(bytes[0]>>6)&0x01];

		dev_info.lorawan_downlink_count = bytes[1]&0x0f;
		dev_info.battery_voltage = (22+((bytes[2]>>4)&0x0f))/10 + "V";

		var parse_len = 2;
		lat =BytestoInt(bytes,parse_len);
		parse_len += 4;
		lon =BytestoInt(bytes,parse_len);
		parse_len += 4;

		if(lat>0x80000000)
			lat = lat-0x100000000;
		if(lon>0x80000000)
			lon = lon-0x100000000;

		dev_info.lat = lat/10000000 ;
		dev_info.lon = lon/10000000;
		dev_info.pdop = bytes[parse_len]/10;
	}
	return dev_info;
}