/*******************************
 * Interview Q&A Frontend JS   *
 *******************************/
const recordBtn      = document.getElementById("record-button");
const screenshotBtn  = document.getElementById("screenshot-button");
const fileInput      = document.getElementById("file-input");
const questionEl     = document.getElementById("question-output");
const answerEl       = document.getElementById("answer-output");
const editBtn        = document.getElementById("edit-btn");

/* ─────────────────── Typing effect utility ─────────────────── */
function typeEffect(el, text, speed = 30) {
  el.textContent = "";
  let idx = 0;
  const timer = setInterval(() => {
    el.textContent += text.charAt(idx);
    idx++;
    if (idx >= text.length) clearInterval(timer);
  }, speed);
}

/* ─────────────────── Abort-controller wrapper ───────────────── */
let currentController = null;
function fetchWithAbort(url, opts = {}) {
  if (currentController) currentController.abort(); // cancel previous req
  currentController = new AbortController();
  return fetch(url, { ...opts, signal: currentController.signal });
}

/* ─────────────────── Audio recording setup ─────────────────── */
let mediaRecorder, chunks = [], isRecording = false;

async function initMedia() {
  const stream = await navigator.mediaDevices.getUserMedia({ audio: true });
  mediaRecorder = new MediaRecorder(stream);
  mediaRecorder.ondataavailable = e => chunks.push(e.data);

  mediaRecorder.onstop = async () => {
    recordBtn.textContent = "🎤 Start Recording";
    isRecording = false;
    const audioBlob = new Blob(chunks, { type: "audio/wav" });
    chunks = [];

    const form = new FormData();
    form.append("file", audioBlob, "record.wav");

    questionEl.textContent = "⌛ Transcribing…";
    answerEl.innerHTML = "";

    try {
      const res  = await fetchWithAbort("/voice-transcribe", { method: "POST", body: form });
      if (!res.ok) throw new Error(`HTTP ${res.status}`);
      const data = await res.json();
      displayQa(data);
    } catch (err) {
      answerEl.textContent = "❌ " + err.message;
    }
  };
}

/* ─────────────── Click-to-record UX ─────────────── */
recordBtn.addEventListener("click", () => {
  if (!mediaRecorder) return;
  if (isRecording) {
    mediaRecorder.stop();
  } else {
    chunks = [];
    mediaRecorder.start();
    recordBtn.textContent = "🎤 Stop Recording";
    isRecording = true;
  }
});

/* ─────────────── Screenshot upload ─────────────── */
fileInput.addEventListener("change", async (e) => {
  const file = e.target.files[0];
  if (!file) return;
  const form = new FormData();
  form.append("file", file);

  questionEl.textContent = "⌛ Processing screenshot…";
  answerEl.innerHTML = "";

  try {
    const res  = await fetchWithAbort("/image-question", { method: "POST", body: form });
    if (!res.ok) throw new Error(`HTTP ${res.status}`);
    const data = await res.json();
    displayQa(data);
  } catch (err) {
    answerEl.textContent = "❌ " + err.message;
  } finally {
    fileInput.value = ""; // reset for next upload
  }
});
screenshotBtn.addEventListener("click", () => fileInput.click());

/* ─────────────── Editable question block ─────────────── */
function enableEdit() {
  questionEl.contentEditable = "true";
  questionEl.classList.add("editing");
  questionEl.focus();
}

async function sendEditedQuestion(text) {
  questionEl.contentEditable = "false";
  questionEl.classList.remove("editing");
  answerEl.textContent = "⌛ Thinking…";
  try {
    const res = await fetchWithAbort("/text-question", {
      method : "POST",
      headers: { "Content-Type": "application/json" },
      body   : JSON.stringify({ question: text })
    });
    if (!res.ok) throw new Error(`HTTP ${res.status}`);
    const data = await res.json();
    displayQa(data);
  } catch (err) {
    answerEl.textContent = "❌ " + err.message;
  }
}

editBtn.addEventListener("click", () => enableEdit());
questionEl.addEventListener("keydown", (e) => {
  if (e.key === "Enter") {
    e.preventDefault();
    const text = questionEl.innerText.trim();
    if (text) sendEditedQuestion(text);
  }
});

/* ─────────────── render helpers ─────────────── */
function displayQa(data) {
  let qHtml = "", aHtml = "";
  const qaList = Array.isArray(data) ? data : [data];
  qaList.forEach((item, idx) => {
    const q = item.question || "[no question]";
    const a = item.answer   || "[no answer]";
    qHtml += `Q${idx + 1}: ${q}\n`;
    aHtml += `<strong>Q${idx + 1}:</strong> ${DOMPurify.sanitize(marked.parseInline(q))}<br>`;
    aHtml += `<strong>A${idx + 1}:</strong> ${DOMPurify.sanitize(marked.parse(a))}<hr>`;
  });
  typeEffect(questionEl, qHtml.trim());
  setTimeout(() => { answerEl.innerHTML = aHtml.trim(); }, 400);
}

/* ─────────────── init ─────────────── */
window.addEventListener("DOMContentLoaded", async () => {
  try {
    await initMedia();
  } catch {
    alert("Microphone permission is required.");
  }
});