var pos = 0;
var bindata = "";

var ConvertBase = function (num) {
    return {
        from : function (baseFrom) {
            return {
                to : function (baseTo) {
                    return parseInt(num, baseFrom).toString(baseTo);
                }
            };
        }
    };
};

function pad(num) {
    var s = "0000000" + num;
    return s.slice(-8);
}

ConvertBase.dec2bin = function (num) {
    return pad(ConvertBase(num).from(10).to(2));
};

ConvertBase.bin2dec = function (num) {
    return ConvertBase(num).from(2).to(10);
};

function data2bits(data) {
    var binary = "";
    for(var i=0; i<data.length; i++) {
        binary += ConvertBase.dec2bin(data[i]);
    }
    return binary;
}

function bitShift(bits) {
    var num = ConvertBase.bin2dec(bindata.substr(pos, bits));
    pos += bits;
    return Number(num);
}

function precisionRound(number, precision) {
  var factor = Math.pow(10, precision);
  return Math.round(number * factor) / factor;
}

function Decoder(fPort, bytes, variables) {
  bindata = data2bits(bytes);

  if(bytes.length != 10) return {"status": "ERROR", "description": "10 bytes are required"};

    Index = precisionRound(bitShift(8)*1, 1);
    Battery = precisionRound(bitShift(3)*0.2+3, 1);
    Wind_ave = precisionRound(bitShift(9)*0.1, 1);
    Wind_3sgust = Wind_ave + precisionRound(bitShift(9)*0.1, 1);
    Wind_3smin = Wind_ave - precisionRound(bitShift(9)*0.1, 1);
    Wind_stdev = precisionRound(bitShift(8)*0.1, 1);
    Dir_ave = precisionRound(bitShift(9)*1, 1);
    Dir_3sgust = precisionRound(bitShift(9)*1, 1);
    Dir_stdev = precisionRound(bitShift(7)*1, 1);
    Gust_time = precisionRound(bitShift(7)*5, 1);
    Vector_scalar = precisionRound(bitShift(1)*1, 1);
    Alarm_sent = precisionRound(bitShift(1)*1, 1);

    decoded = {
    "Index": Index,
    "Battery": Battery,
    "Wind_ave": Wind_ave,
    "Wind_3sgust": Wind_3sgust,
    "Wind_3smin": Wind_3smin,
    "Wind_stdev": Wind_stdev,
    "Dir_ave": Dir_ave,
    "Dir_3sgust": Dir_3sgust,
    "Dir_stdev": Dir_stdev,
    "Gust_time": Gust_time,
    "Vector_scalar": Vector_scalar,
    "Alarm_sent": Alarm_sent,
    };

return decoded;

}

function decodeUplink(input) {
        return {
            data: Decoder(input.fPort, input.bytes, input.variables)
        };
}