/**
 * Captures audio from the active tab in Google Chrome.
 * @returns {Promise<MediaStream>} A promise that resolves with the captured audio stream.
 */
function captureTabAudio() {
  return new Promise((resolve) => {
    chrome.tabCapture.capture(
      {
        audio: true,
        video: false,
      },
      (stream) => {
        resolve(stream);
      }
    );
  });
}


/**
 * Sends a message to a specific tab in Google Chrome.
 * @param {number} tabId - The ID of the tab to send the message to.
 * @param {any} data - The data to be sent as the message.
 * @returns {Promise<any>} A promise that resolves with the response from the tab.
 */
function sendMessageToTab(tabId, data) {
  return new Promise((resolve) => {
    chrome.tabs.sendMessage(tabId, data, (response) => {
      resolve(response);
    });
  });
}


/**
 * Starts recording audio from the captured tab.
 * @param {Object} option - The options object containing the currentTabId.
 */
async function startRecord(option) {
  const stream = await captureTabAudio();
  if (stream) {
    // call when the stream inactive
    stream.oninactive = () => {
      window.close();
    };

    const socket = new WebSocket("ws://localhost:9090/");
    socket.onopen = function(e) { 
      socket.send("handshake");
    };

    socket.onmessage = async (event) => {
      // console.log(event.data);
      await sendMessageToTab(option.currentTabId, {
        data: event.data,
      });
    };

    const audioDataCache = [];
    const context = new AudioContext({sampleRate: 16000});
    const mediaStream = context.createMediaStreamSource(stream);
    const recorder = context.createScriptProcessor(4096, 1, 1);

    recorder.onaudioprocess = async (event) => {
      if (!context) return;

      const inputData = event.inputBuffer.getChannelData(0);

      audioDataCache.push(inputData);
      socket.send(inputData);
    };

    // Prevent page mute
    mediaStream.connect(recorder);
    recorder.connect(context.destination);
    mediaStream.connect(context.destination);
  } else {
    window.close();
  }
}

/**
 * Listener for incoming messages from the extension's background script.
 * @param {Object} request - The message request object.
 * @param {Object} sender - The sender object containing information about the message sender.
 * @param {Function} sendResponse - The function to send a response back to the message sender.
 */
chrome.runtime.onMessage.addListener(async (request, sender, sendResponse) => {
  const { type, data } = request;

  switch (type) {
    case "start_capture":
      await startRecord(data);
      break;
    default:
      break;
  }

  sendResponse({});
});