const hideClass = "hide";
let isSending = false;
let workers = [];

const textInput = document.getElementById("textInput");
const startSendingButton = document.getElementById("start-sending-button");
const stopSendingButton = document.getElementById("stop-sending-button");
const startCalibrationButton = document.getElementById("start-calibration-button");
const stopCalibrationButton = document.getElementById("stop-calibration-button");
startCalibrationButton.addEventListener("click", startCalibration);
stopCalibrationButton.addEventListener("click", stopCalibration);
startSendingButton.addEventListener("click", startSending);
stopSendingButton.addEventListener("click", stopSending);

function getWebWorker() {
  return new Worker("./scripts/Worker.js");
}

function startWorkers() {
  for (let i = 0; i < 8; i++) {
    workers.push(getWebWorker());
  }
}

function stopWorkers() {
  for (const worker of workers) {
    worker.terminate();
  }

  workers = [];
}

function startCalibration() {
  console.log("Starting calibration");

  startCalibrationButton.classList.add(hideClass);
  stopCalibrationButton.classList.remove(hideClass);
  Utility.setMessage("Calibration currently ongoing.");

  startWorkers();
}

function stopCalibration() {
  console.log("Stopping calibration");

  stopCalibrationButton.classList.add(hideClass);
  startCalibrationButton.classList.remove(hideClass);
  Utility.setMessage("");

  stopWorkers();
}

function startSending() {
  startSendingButton.classList.add(hideClass);
  stopSendingButton.classList.remove(hideClass);
  Utility.setMessage(`Sending message: ${textInput.value}`);
  console.log(`Start sending message: ${textInput.value}`);

  const packet = new Packet(textInput.value);
  const signal = Utility.manchesterEncode(packet.getData());

  isSending = true;
  transmitSignal(signal);
}

function stopSending() {
  console.log("Stop Sending");
  Utility.setMessage("");

  stopSendingButton.classList.add(hideClass);
  startSendingButton.classList.remove(hideClass);
  isSending = false;
}

/**
 * Transmit the given bit array until the sending is stopped.
 *
 * @param {Number[]} signal
 */
async function transmitSignal(signal) {
  while (isSending) {
    // Send the preamble
    for (const bit of PREAMBLE) {
      if (!isSending) {
        stopWorkers();
        return;
      }

      console.log(`Sending preamble: ${bit}`);
      await transmitBit(bit);
    }

    for (let i = 0; i < signal.length; i++) {
      if (!isSending) {
        stopWorkers();
        return;
      }

      console.log(`Sending bit ${i + 1} of ${signal.length} of packet: ${signal[i]}`);
      await transmitBit(signal[i]);
    }
  }
}

/**
 * This either starts or stops the web workers depending on the bit value
 * and then waits for a duration of CLOCK_TIME.
 *
 * @param {Number} bit
 */
function transmitBit(bit) {
  if (bit === 1) {
    startWorkers();
    return new Promise((resolve) => setTimeout(resolve, CLOCK_TIME));
  }

  stopWorkers();
  return new Promise((resolve) => setTimeout(resolve, CLOCK_TIME));
}