/**
 * Payload Decoder for The Things Network
 *
 * Copyright 2023 Milesight IoT
 *
 * @product WS50x v2
 */
function Decoder(bytes, port) {
    return milesight(bytes);
}

function milesight(bytes) {
    var decoded = {};

    for (var i = 0; i < bytes.length; ) {
        var channel_id = bytes[i++];
        var channel_type = bytes[i++];

        // SWITCH STATE
        if (channel_id === 0x08 && channel_type === 0x29) {
            // payload (0 0 0 0 0 0 0 0)
            //  Switch    3 2 1   3 2 1
            //          ------- -------
            // bit mask  change   state
            decoded.switch_1 = (bytes[i] & 1) == 1 ? "on" : "off";
            decoded.switch_1_change = ((bytes[i] >> 4) & 1) == 1 ? "yes" : "no";

            decoded.switch_2 = ((bytes[i] >> 1) & 1) == 1 ? "on" : "off";
            decoded.switch_2_change = ((bytes[i] >> 5) & 1) == 1 ? "yes" : "no";

            decoded.switch_3 = ((bytes[i] >> 2) & 1) == 1 ? "on" : "off";
            decoded.switch_3_change = ((bytes[i] >> 6) & 1) == 1 ? "yes" : "no";
            i += 1;
        }
        // VOLTAGE
        else 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.power = readUInt32LE(bytes.slice(i, i + 4));
            i += 4;
        }
        // POWER FACTOR
        else if (channel_id === 0x05 && channel_type === 0x81) {
            decoded.factor = bytes[i];
            i += 1;
        }
        // POWER CONSUMPTION
        else if (channel_id === 0x06 && channel_type == 0x83) {
            decoded.power_sum = readUInt32LE(bytes.slice(i, i + 4));
            i += 4;
        }
        // CURRENT
        else if (channel_id === 0x07 && channel_type == 0xc9) {
            decoded.current = readUInt16LE(bytes.slice(i, i + 2));
            i += 2;
        } else {
            break;
        }
    }

    return decoded;
}

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) >>> 0;
}

function readInt32LE(bytes) {
    var ref = readUInt32LE(bytes);
    return ref > 0x7fffffff ? ref - 0x100000000 : ref;
}