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);
}

function windify(num) {
    if (num > 0) {
        return num * 0.6335 + 0.3582;
    } else {
        return 0;
    }

}

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 != 12) return {
        "status": "ERROR",
        "description": "12 bytes are required"
    }

    Index = bitShift(8) * 1;

    Battery_t = bitShift(1);

    if ((Index % 10) <= 4) {
        Battery_voltage = (Index % 10) * 0.2 + 3.3;
        if (Battery_t) {
            Battery = "> " + Battery_voltage;
        } else {
            Battery = "< " + Battery_voltage;
        }
    } else {
        Battery_voltage = (Index % 10) * 0.2 + 3.3 - 1;
        if (Battery_t) {
            Battery = "> " + Battery_voltage;
        } else {
            Battery = "< " + Battery_voltage;
        }
    }

    Hz_avg = bitShift(12) * 0.02;
    Wind_10m_avg = precisionRound(windify(Hz_avg), 2);

    Hz_3s_gust = bitShift(9) * 0.1 + Hz_avg;
    Wind_3s_gust = precisionRound(windify(Hz_3s_gust), 1);

    Hz_1s_gust = bitShift(8) * 0.1 + Hz_3s_gust;
    Wind_1s_gust = precisionRound(windify(Hz_1s_gust), 1);

    Hz_3s_min = bitShift(9) * 0.1;
    Wind_3s_min = precisionRound(windify(Hz_3s_min), 1);

    Wind_stdev = precisionRound(bitShift(8) * 0.1, 1);

    Dir_10m_avg = bitShift(9);

    Dir_1s_gust = bitShift(9);

    Dir_stdev = bitShift(8);

    Duration_gust = bitShift(7) * 5;

    Alarm_sent = bitShift(1);

    Debug_flags = bitShift(1);

    decoded = {
        "Index": Index,
        "Battery": Battery,
        "Wind_10m_avg": Wind_10m_avg,
        "Wind_3s_gust": Wind_3s_gust,
        "Wind_1s_gust": Wind_1s_gust,
        "Wind_3s_min": Wind_3s_min,
        "Wind_stdev": Wind_stdev,
        "Dir_10m_avg": Dir_10m_avg,
        "Dir_1s_gust": Dir_1s_gust,
        "Dir_stdev": Dir_stdev,
        "Duration_gust": Duration_gust,
        "Alarm_sent": Alarm_sent,
        "Debug_flags": Debug_flags,
    }

    return decoded;

}

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

// function hexToBytes(hex) {
//     let bytes = [];
//     for (let c = 0; c < hex.length; c += 2)
//         bytes.push(parseInt(hex.substr(c, 2), 16));
//     return bytes;
// }

// console.log("Testing decoder with sample data 0x0B80520C1C001F399C852001: ")
// console.table(Decoder(1,hexToBytes("0B80520C1C001F399C852001"),1))