// Décodeur LoRaWAN officiel : Milesight WS558 Smart Light Controller (Milesight)
// Source : https://github.com/TheThingsNetwork/lorawan-devices/blob/master/vendor/milesight-iot/ws558.js
// The Things Network Device Repository, fichier publié par le constructeur, distribué sans modification.
// Format : decodeUplink(input) (TTN v3 / ChirpStack v4). Hébergé par smartbuildings.fr.

function decodeUplink(input) {
    var res = Decoder(input.bytes, input.fPort);
    if (res.error) {
        return {
            errors: [res.error],
        };
    }
    return {
        data: res,
    };
}

/**
 * Payload Decoder for The Things Network
 *
 * Copyright 2021 Milesight IoT
 *
 * @product WS558
 */
function Decoder(bytes, port) {
    var decoded = {};

    for (var i = 0; i < bytes.length;) {
        var channel_id = bytes[i++];
        var channel_type = bytes[i++];
        // VOLTAGE
        if (channel_id === 0x03 && channel_type === 0x74) {
            decoded.voltage = readUInt16LE(bytes.slice(i, i + 2)) / 10;
            i += 2;
        }
        // ACTIVE POWER
        else if (channel_id === 0x04 && channel_type === 0x80) {
            decoded.active_power = readUInt32LE(bytes.slice(i, i + 4));
            i += 4;
        }
        // POWER FACTOR
        else if (channel_id === 0x05 && channel_type === 0x81) {
            decoded.power_factor = bytes[i];
            i += 1;
        }
        // POWER CONSUMPTION
        else if (channel_id === 0x06 && channel_type === 0x83) {
            decoded.power_consumption = readUInt32LE(bytes.slice(i, i + 4));
            i += 4;
        }
        // TOTAL CURRENT
        else if (channel_id === 0x07 && channel_type === 0xC9) {
            decoded.total_current = readUInt16LE(bytes.slice(i, i + 2));
            i += 2;
        }
        // SWITCH STATUS
        else if (channel_id === 0x08 && channel_type === 0x31) {
            var switchFlags = bytes[i + 1];

            // output all switch status
            for (var idx = 0; idx < 8; idx++) {
                var switchTag = "switch_" + (idx + 1);
                decoded[switchTag] = (switchFlags >> idx) & 1 === 1 ? "on" : "off";
            }

            i += 2;
        } else {
            break;
        }
    }

    return decoded;
}

/* ******************************************
 * bytes to number
 ********************************************/
function readUInt8LE(bytes) {
    return (bytes & 0xFF);
}

function readInt8LE(bytes) {
    var ref = readUInt8LE(bytes);
    return (ref > 0x7F) ? ref - 0x100 : ref;
}

function readUInt16LE(bytes) {
    var value = (bytes[1] << 8) + bytes[0];
    return (value & 0xFFFF);
}

function readInt16LE(bytes) {
    var ref = readUInt16LE(bytes);
    return (ref > 0x7FFF) ? ref - 0x10000 : ref;
}


function readUInt32LE(bytes) {
    var value = (bytes[3] << 24) + (bytes[2] << 16) + (bytes[1] << 8) + bytes[0];
    return (value & 0xFFFFFFFF);
}

function readInt32LE(bytes) {
    var ref = readUInt32LE(bytes);
    return (ref > 0x7FFFFFFF) ? ref - 0x100000000 : ref;
}