/** Decoder **/
var payloadStr = decodeToString(payload);
var data = JSON.parse(payloadStr);

var KOEF_PULSE = 0.01;

var deviceName = data.deviceName;
var deviceType = 'Water Pulse';
var res = _base64ToArrayBuffer(data.data);
var dateTime = GetCurrentDateTime();

var waterPulseValue1 = GetPulseMeterValue(res[3], res[4], res[5], res[6]);
var waterPulseValue2 = GetPulseMeterValue(res[7], res[8], res[9], res[10]);

var fraud1 = GetFraud(res[2], 1);
var fraud2 = GetFraud(res[2], 2);

var flg_err_pulse1 = GetErrPulse(res[2], 1);
var flg_err_pulse2 = GetErrPulse(res[2], 2);

var low_bat = GetFlagError(res[0], 1);
var motion_detect = GetFlagError(res[0], 2);
var magnet_detect = GetFlagError(res[0], 3);
var tamper_detect = GetFlagError(res[0], 4);
var power_on = GetFlagError(res[0], 5);
var power_bat = GetFlagError(res[0], 6);
var err_time = GetFlagError(res[0], 7);
var cfg_done = GetFlagError(res[0], 8);

var result = {
   deviceName: deviceName,
   deviceType: deviceType,
   attributes: {
       integrationName: metadata['integrationName'],
   },
   telemetry: {
       NAME_DEV: "Water meter Pulse Sensor LoRaWAN 'Smartico P22-LR'",
       SN: data.deviceName,
       REAL_TIME: dateTime,
       WATER_PULSE_VALUE_1: waterPulseValue1,
       WATER_PULSE_VALUE_2: waterPulseValue2,
       FRAUD_1: fraud1,
       FRAUD_2: fraud2,
       FLG_ERR_PULSE_1: flg_err_pulse1,
       FLG_ERR_PULSE_2: flg_err_pulse2,
       FLG_LOW_BAT: low_bat,
       FLG_MOTION_DETECT: motion_detect,
       FLG_MAGNET_DETECT: magnet_detect,
       FLG_TAMPER_DETECT: tamper_detect,
       FLG_POWER_ON: power_on,
       FLG_POWER_BAT: power_bat,
       FLG_ERR_TIME: err_time,
       FLG_CFG_DONE: cfg_done
   }
};

/** Helper functions **/

function decodeToString(payload) {
   return String.fromCharCode.apply(String, payload);
}

function decodeToJson(payload) {
   var str = decodeToString(payload);
   return JSON.parse(str);
}

function _base64ToArrayBuffer(base64) {
    var binary_string = atob(base64);
    var len = binary_string.length;
    var bytes = new Uint8Array(len);
    for (var i = 0; i < len; i++) {
        bytes[i] = binary_string.charCodeAt(i);
    }
    return bytes;
}

function GetCurrentDateTime(){
    var a = new Date();
    var year = a.getFullYear().toString();
    var month = (a.getMonth()+1).toString();
    if(month.length==1) month="0"+month;
    var date = a.getDate().toString();
    if(date.length==1) date="0"+date;
    var hour = a.getHours().toString();
    if(hour.length==1) hour="0"+hour;
    var min = a.getMinutes().toString();
    if(min.length==1) min="0"+min;
    var sec = a.getSeconds().toString();
    if(sec.length==1) sec="0"+sec;
    return date + '.' + month + '.' + year + ' ' + hour + ':' + min + ':' + sec;
}

function GetPulseMeterValue(byte1, byte2, byte3, byte4) {
    var value1 = parseInt(byte1, 10).toString(16);
    while(value1.length<2){value1='0'+value1;}
    var value2 = parseInt(byte2, 10).toString(16);
    while(value2.length<2){value2='0'+value2;}
    var value3 = parseInt(byte3, 10).toString(16);
    while(value3.length<2){value3='0'+value3;}
    var value4 = parseInt(byte4, 10).toString(16);
    while(value4.length<2){value4='0'+value4;}

    var value = value1 + value2 + value3 + value4;
    var res = parseInt(value, 16);

    return res * KOEF_PULSE;
}

function GetFraud(byte1, num) {
    var value1 = parseInt(byte1, 10).toString(2);
    while(value1.length<8){value1='0'+value1;}

    if(num==1){
        var res = value1[5]+value1[6]+value1[7];
        return parseInt(res,2);
    }
    if(num==2){
        var res1 = value1[2]+value1[3]+value1[4];
        return parseInt(res1,2);
    }
    return null;
}

function GetErrPulse(byte1, num) {
    var value1 = parseInt(byte1, 10).toString(2);
    while(value1.length<8){value1='0'+value1;}

    if(num==1) return parseInt(value1[1],2);
    if(num==2) return parseInt(value1[0],2);

    return null;
}

function GetFlagError(byte1, num) {
    var value = parseInt(byte1, 10).toString(2);
    while(value.length<8){value='0'+value;}

    if(num==1) return Number(value[7]);
    if(num==2) return Number(value[6]);
    if(num==3) return Number(value[5]);
    if(num==4) return Number(value[4]);
    if(num==5) return Number(value[3]);
    if(num==6) return Number(value[2]);
    if(num==7) return Number(value[1]);
    if(num==8) return Number(value[0]);

    return null;
}

return result;