function reverse(str) {
  return str
    .match(/[a-fA-F0-9]{2}/g)
    .reverse()
    .join("");
}

function parseDate(payload) {
  const bin2 = Number(`0x${reverse(payload)}`)
    .toString(2)
    .padStart(32, "0");
  const year = parseInt(bin2.substring(0, 7), 2) + 2000;
  const month = parseInt(bin2.substring(7, 11), 2) - 1;
  const day = parseInt(bin2.substring(11, 16), 2);
  const hour = parseInt(bin2.substring(16, 21), 2);
  const minute = parseInt(bin2.substring(21, 27), 2);
  const second = parseInt(bin2.substring(27, 32), 2) * 2;

  return new Date(year, month, day, hour, minute, second, 0).toISOString();
}

function parseCo2Measurement(payload) {
  const buffer = Buffer.from(payload, "hex");
  const time = parseDate(payload.substring(0, 8));
  const serie = time;
  const date = {
    variable: "date",
    value: time,
    time,
    serie,
  };
  const temp = {
    variable: "temp",
    value: buffer.readInt16LE(4) / 100,
    unit: "C",
    time,
    serie,
  };
  const hum = {
    variable: "hum",
    value: buffer.readUInt8(6) / 2,
    unit: "%",
    time,
    serie,
  };
  const pre = {
    variable: "pre",
    value: buffer.readUIntLE(7, 3) / 100,
    unit: "Pa",
    time,
    serie,
  };
  const ilum = {
    variable: "ilum",
    value: Number(`0x${reverse(payload.substring(20, 24))}`),
    unit: "lx",
    time,
    serie,
  };
  const voc = {
    variable: "voc",
    value: Number(`0x${reverse(payload.substring(24, 28))}`),
    unit: "IAQ",
    time,
    serie,
  };
  const c02 = {
    variable: "c02",
    value: Number(`0x${reverse(payload.substring(28, 32))}`),
    unit: "ppm",
    time,
    serie,
  };

  return [date, temp, hum, pre, ilum, voc, c02];
}

function parseCo2(payload, serie) {
  const m1 = parseCo2Measurement(payload.substring(2, 34));
  const m2 = parseCo2Measurement(payload.substring(34, 66));

  const batt = {
    variable: "batt",
    value: Number(`0x${payload.substring(66, 68)}`),
    unit: "%",
    serie,
  };
  const rfu = {
    variable: "rfu",
    value: payload.substring(68),
    unit: "%",
    serie,
  };

  return [...m1, ...m2, batt, rfu];
}

function parseTimeSync(payload, serie) {
  // Parse all data and format to TagoIO JSON format.
  const sync_id = {
    variable: "sync_id",
    serie,
    value: payload.substring(2, 10),
  };
  const sync_version = {
    variable: "sync_version",
    serie,
    value: payload.substring(10, 16),
  };
  const application_type = {
    variable: "application_type",
    serie,
    value: payload.substring(16, 20),
  };
  const rfu = { variable: "rfu", serie, value: payload.substring(20) };

  // Return an array with the content.
  return [sync_id, sync_version, application_type, rfu];
}

// let payload = [
//   {
//     variable: "frm_payload",
//     value:
//       "0ec025322ceb073ac38a0102002e01af012528322ceb073adb8a0109001901af014f",
//     serie: "1642488483385",
//   },
// ];

// Check if the incoming data is from TTN.
const data = payload.find(
  (x) =>
    x.variable === "payload_raw" ||
    x.variable === "payload" ||
    x.variable === "frm_payload"
);

const ignore_vars = ['timestamp', 'rssi', 'snr', 'lora_bandwidth', 'lora_spreading_factor', 'data_rate_index', 'coding_rate', 'frequency', 'time', 'gateway_eui', 'voc', 'battery', 'co2', 'humidity', 'pressure', 'rfu', 'temperature'];
//timestamp,fport,fcnt,payload,rssi,snr,'application_id','device_id','downlink_key',
payload = payload.filter(x => !ignore_vars.includes(x.variable));
if (data) {
  // Parse the data to JSON format (it comes in a String format)
  const raw_payload = data.value.toUpperCase();

  // Get a unique serie for the incoming data.
  const serie = data.serie
    ? `${new Date().getTime()}-${data.serie}`
    : new Date().getTime();

  // Get the Payload ID.
  const uplinkId = raw_payload.substring(0, 2);
  // Apply different parsers for each ID.
  let content = [];
  switch (uplinkId) {
    case "01":
      content = parseTimeSync(raw_payload, serie);
      break;
    case "0E":
      content = parseCo2(raw_payload, serie);
      console.log(content);
      break;
    default:
      break;
  }

  // Change the payload to the parsed variables.
  payload = payload.concat(content);
}
//console.log(JSON.stringify(payload));