static/app.js

/* ============================================================
   Viet AutoSub Editor – Dashboard JavaScript
   Tương thích cả offline (file://) và online (HF Spaces)
   Hỗ trợ 2 chế độ: Lời bài hát (music) + Giọng nói (speech)
   ============================================================ */

const state = {
  jobId: null,
  file: null,
  segments: [],
  isOnline: false,
  mode: "music", // "music" | "speech"
  karaokeStyle: {
    font: "Bangers",
    color: "#FFFFFF",
    highlight: "#FFD700",
    outline: "#000000",
    outlineWidth: 2,
    sizePct: 100,
    positionPct: 90,
    karaokeMode: false,
  },
};

/* --- Detect environment ------------------------------------ */
const IS_FILE_PROTOCOL = window.location.protocol === "file:";

function getApiBase() {
  if (IS_FILE_PROTOCOL) return null;
  return "";
}

/* --- DOM refs ---------------------------------------------- */
const $ = (id) => document.getElementById(id);

const els = {
  fileInput:       $("videoFile"),
  preview:         $("preview"),
  videoPlaceholder:$("videoPlaceholder"),
  status:          $("status"),
  statusText:      $("statusText"),
  btnTranscribe:   $("btnTranscribe"),
  btnAddRow:       $("btnAddRow"),
  btnExportSrt:    $("btnExportSrt"),
  btnExportMp4:    $("btnExportMp4"),
  btnClearFile:    $("btnClearFile"),
  subtitleBody:    $("subtitleBody"),
  segmentCount:    $("segmentCount"),
  downloadSrt:     $("downloadSrt"),
  downloadMp4:     $("downloadMp4"),
  downloadGroup:   $("downloadGroup"),
  dropZone:        $("dropZone"),
  uploadPanel:     $("uploadPanel"),
  fileInfo:        $("fileInfo"),
  fileName:        $("fileName"),
  fileSize:        $("fileSize"),
  progressWrap:    $("progressWrap"),
  progressFill:    $("progressFill"),
  progressText:    $("progressText"),
  // Offline banner + badge
  offlineBanner:     $("offlineBanner"),
  offlineBannerText: $("offlineBannerText"),
  offlineBannerClose:$("offlineBannerClose"),
  badgeEnv:          $("badgeEnv"),
  badgeEnvText:      $("badgeEnvText"),
  pulseDot:          $("pulseDot"),
  // Mode selector
  modeToggle:      $("modeToggle"),
  modeMusic:       $("modeMusic"),
  modeSpeech:      $("modeSpeech"),
  modeHint:        $("modeHint"),
  // Coverage
  coverageBar:     $("coverageBar"),
  coveragePct:     $("coveragePct"),
  coverageFill:    $("coverageFill"),
  // Karaoke Style
  ksFont:          $("ksFont"),
  ksColor:         $("ksColor"),
  ksColorHex:      $("ksColorHex"),
  ksHighlight:     $("ksHighlight"),
  ksHighlightHex:  $("ksHighlightHex"),
  ksOutline:       $("ksOutline"),
  ksOutlineHex:    $("ksOutlineHex"),
  ksOutlineWidth:  $("ksOutlineWidth"),
  ksOutlineWidthVal: $("ksOutlineWidthVal"),
  ksSize:          $("ksSize"),
  ksSizeVal:       $("ksSizeVal"),
  ksPosition:      $("ksPosition"),
  ksPositionVal:   $("ksPositionVal"),
  ksKaraokeMode:   $("ksKaraokeMode"),
  ksKaraokeHint:   $("ksKaraokeHint"),
  btnPreviewStyle: $("btnPreviewStyle"),
  videoWrap:       $("videoWrap"),
  subPreviewOverlay: $("subPreviewOverlay"),
  subPreviewText:  $("subPreviewText"),
};

/* --- Mode selector ----------------------------------------- */
const MODE_HINTS = {
  music: "Tối ưu cho Vietsub lời bài hát, nhận diện toàn bộ lyrics khớp timeline.",
  speech: "Tối ưu cho giọng nói, thuyết trình, podcast. Lọc tiếng ồn nền.",
};

function setMode(mode) {
  state.mode = mode;
  // Update toggle buttons
  if (els.modeMusic) els.modeMusic.classList.toggle("active", mode === "music");
  if (els.modeSpeech) els.modeSpeech.classList.toggle("active", mode === "speech");
  if (els.modeHint) els.modeHint.textContent = MODE_HINTS[mode] || "";
}

// Mode toggle event listeners
if (els.modeToggle) {
  els.modeToggle.addEventListener("click", (e) => {
    const btn = e.target.closest(".mode-btn");
    if (!btn) return;
    const mode = btn.dataset.mode;
    if (mode) setMode(mode);
  });
}

/* --- Coverage display -------------------------------------- */
function showCoverage(pct) {
  if (!els.coverageBar) return;
  els.coverageBar.hidden = false;
  const val = Math.min(100, Math.max(0, pct));
  if (els.coveragePct) els.coveragePct.textContent = val + "%";
  if (els.coverageFill) els.coverageFill.style.width = val + "%";

  // Color coding
  if (els.coverageFill) {
    els.coverageFill.classList.remove("cov-low", "cov-mid", "cov-high");
    if (val >= 80) els.coverageFill.classList.add("cov-high");
    else if (val >= 50) els.coverageFill.classList.add("cov-mid");
    else els.coverageFill.classList.add("cov-low");
  }
}

function hideCoverage() {
  if (els.coverageBar) els.coverageBar.hidden = true;
}

/* --- Health check ------------------------------------------ */
let healthRetryTimer = null;

async function checkHealth() {
  if (IS_FILE_PROTOCOL) {
    setOnlineState(false, "Offline (file://)");
    return;
  }

  try {
    const res = await fetch("/health", { method: "GET", cache: "no-store" });
    if (res.ok) {
      const data = await res.json();
      setOnlineState(true, "HF Space");
      if (healthRetryTimer) { clearInterval(healthRetryTimer); healthRetryTimer = null; }
    } else {
      setOnlineState(false, "Server lỗi");
    }
  } catch (_) {
    setOnlineState(false, "Không kết nối");
  }
}

function setOnlineState(online, label) {
  state.isOnline = online;

  if (els.badgeEnv) {
    els.badgeEnv.classList.toggle("badge-online", online);
    els.badgeEnv.classList.toggle("badge-offline", !online);
  }
  if (els.badgeEnvText) {
    els.badgeEnvText.textContent = label || (online ? "Online" : "Offline");
  }
  if (els.pulseDot) {
    els.pulseDot.className = online ? "pulse-dot pulse-online" : "pulse-dot pulse-offline";
  }

  if (!online) {
    if (els.offlineBanner) els.offlineBanner.hidden = false;
    if (els.offlineBannerText) {
      els.offlineBannerText.textContent = IS_FILE_PROTOCOL
        ? "Đang chạy offline (file://) — Bạn có thể sửa subtitle và xuất SRT. Auto sub & xuất MP4 cần deploy lên HF Space."
        : "Không kết nối được server — Đang thử lại mỗi 30 giây...";
    }
    if (!IS_FILE_PROTOCOL && !healthRetryTimer) {
      healthRetryTimer = setInterval(checkHealth, 30000);
    }
  } else {
    if (els.offlineBanner) els.offlineBanner.hidden = true;
    if (healthRetryTimer) { clearInterval(healthRetryTimer); healthRetryTimer = null; }
  }
}

if (els.offlineBannerClose) {
  els.offlineBannerClose.addEventListener("click", () => {
    if (els.offlineBanner) els.offlineBanner.hidden = true;
  });
}

/* --- Steps ------------------------------------------------- */
function setStep(num) {
  document.querySelectorAll(".step").forEach((el) => {
    const s = parseInt(el.dataset.step, 10);
    el.classList.toggle("active", s === num);
    el.classList.toggle("done", s < num);
  });
}

/* --- Status ------------------------------------------------ */
function setStatus(message, type = "idle") {
  els.status.className = `status-box status-${type}`;
  els.statusText.textContent = message;
}

/* --- Buttons state ----------------------------------------- */
function setEditButtons(enabled) {
  els.btnAddRow.disabled = !enabled;
  els.btnExportSrt.disabled = !enabled;
  els.btnExportMp4.disabled = !enabled;
}

/* --- Download link helpers --------------------------------- */
function showDownload(el, url, visible) {
  el.href = visible ? url : "#";
  el.classList.toggle("disabled", !visible);
}
function showDownloadGroup(show) {
  els.downloadGroup.hidden = !show;
}

/* --- Progress simulation ----------------------------------- */
let progressTimer = null;
function startProgress(label) {
  els.progressWrap.hidden = false;
  els.progressFill.style.width = "0%";
  els.progressText.textContent = label || "Đang xử lý...";

  let pct = 0;
  clearInterval(progressTimer);
  progressTimer = setInterval(() => {
    const remaining = 90 - pct;
    const step = Math.max(0.3, remaining * 0.04);
    pct = Math.min(90, pct + step);
    els.progressFill.style.width = pct + "%";
  }, 300);
}
function finishProgress() {
  clearInterval(progressTimer);
  els.progressFill.style.width = "100%";
  setTimeout(() => {
    els.progressWrap.hidden = true;
    els.progressFill.style.width = "0%";
  }, 600);
}
function cancelProgress() {
  clearInterval(progressTimer);
  els.progressWrap.hidden = true;
  els.progressFill.style.width = "0%";
}

/* --- File size formatter ----------------------------------- */
function formatSize(bytes) {
  if (bytes < 1024 * 1024) return (bytes / 1024).toFixed(1) + " KB";
  return (bytes / (1024 * 1024)).toFixed(1) + " MB";
}

/* --- Create table cell inputs ------------------------------ */
function createInput(value, className) {
  const input = document.createElement("input");
  input.type = "text";
  input.value = value || "";
  input.className = className;
  input.spellcheck = false;
  return input;
}

function createTextArea(value) {
  const textarea = document.createElement("textarea");
  textarea.value = value || "";
  textarea.rows = 2;
  textarea.className = "text-input";
  return textarea;
}

/* --- Collect segments from table --------------------------- */
function collectSegmentsFromTable() {
  const rows = Array.from(els.subtitleBody.querySelectorAll("tr[data-row='1']"));
  return rows.map((row, index) => ({
    id: index + 1,
    start: row.querySelector(".start-input").value.trim(),
    end:   row.querySelector(".end-input").value.trim(),
    text:  row.querySelector(".text-input").value.trim(),
  }));
}

/* --- Render table ------------------------------------------ */
function renderTable() {
  els.subtitleBody.innerHTML = "";

  if (!state.segments.length) {
    els.subtitleBody.innerHTML = `
      <tr class="empty-row">
        <td colspan="5">
          <div class="empty-state">
            <svg viewBox="0 0 48 48" fill="none" class="empty-icon">
              <rect x="6" y="10" width="36" height="28" rx="4" stroke="currentColor" stroke-width="1.5"/>
              <line x1="12" y1="20" x2="36" y2="20" stroke="currentColor" stroke-width="1.5" opacity="0.3"/>
              <line x1="12" y1="26" x2="30" y2="26" stroke="currentColor" stroke-width="1.5" opacity="0.3"/>
              <line x1="12" y1="32" x2="24" y2="32" stroke="currentColor" stroke-width="1.5" opacity="0.3"/>
            </svg>
            <p>Chưa có subtitle. Upload video rồi bấm <strong>Auto sub tiếng Việt</strong> để bắt đầu.</p>
          </div>
        </td>
      </tr>`;
    els.segmentCount.textContent = "0 dòng";
    setEditButtons(false);
    return;
  }

  state.segments.forEach((seg, index) => {
    const tr = document.createElement("tr");
    tr.dataset.row = "1";

    const tdIdx = document.createElement("td");
    tdIdx.className = "idx-cell";
    tdIdx.textContent = String(index + 1);

    const tdStart = document.createElement("td");
    tdStart.appendChild(createInput(seg.start, "start-input time-input"));

    const tdEnd = document.createElement("td");
    tdEnd.appendChild(createInput(seg.end, "end-input time-input"));

    const tdText = document.createElement("td");
    tdText.appendChild(createTextArea(seg.text));

    const tdAct = document.createElement("td");
    tdAct.style.textAlign = "center";
    const delBtn = document.createElement("button");
    delBtn.className = "btn btn-danger-sm";
    delBtn.innerHTML = `<svg viewBox="0 0 20 20" fill="currentColor" style="width:14px;height:14px"><path fill-rule="evenodd" d="M9 2a1 1 0 00-.894.553L7.382 4H4a1 1 0 000 2v10a2 2 0 002 2h8a2 2 0 002-2V6a1 1 0 100-2h-3.382l-.724-1.447A1 1 0 0011 2H9zM7 8a1 1 0 012 0v6a1 1 0 11-2 0V8zm5-1a1 1 0 00-1 1v6a1 1 0 102 0V8a1 1 0 00-1-1z" clip-rule="evenodd"/></svg>`;
    delBtn.title = "Xóa dòng";
    delBtn.addEventListener("click", () => {
      state.segments = collectSegmentsFromTable();
      state.segments.splice(index, 1);
      renderTable();
    });
    tdAct.appendChild(delBtn);

    tr.append(tdIdx, tdStart, tdEnd, tdText, tdAct);
    els.subtitleBody.appendChild(tr);
  });

  els.segmentCount.textContent = `${state.segments.length} dòng`;
  setEditButtons(true);
}

/* --- Transcribe -------------------------------------------- */
async function transcribeVideo() {
  if (!state.file) {
    setStatus("Hãy chọn video trước.", "error");
    return;
  }

  if (!state.isOnline) {
    setStatus(
      IS_FILE_PROTOCOL
        ? "Đang offline — Auto sub cần chạy trên HF Space (server). Hãy upload ứng dụng lên HF Space trước."
        : "Server không phản hồi. Đang thử kết nối lại...",
      "error"
    );
    if (!IS_FILE_PROTOCOL) checkHealth();
    return;
  }

  const fd = new FormData();
  fd.append("file", state.file);
  fd.append("mode", state.mode);

  els.btnTranscribe.disabled = true;
  els.btnTranscribe.classList.add("btn-loading");
  const modeLabel = state.mode === "music" ? "lời bài hát" : "giọng nói";
  setStatus(`Đang nhận diện ${modeLabel} tiếng Việt...`, "loading");
  setStep(2);
  startProgress(`Đang upload và nhận diện ${modeLabel}...`);
  showDownload(els.downloadSrt, "#", false);
  showDownload(els.downloadMp4, "#", false);
  showDownloadGroup(false);
  hideCoverage();

  try {
    const res = await fetch("/api/transcribe", {
      method: "POST",
      body: fd,
    });
    const data = await res.json();
    if (!res.ok) throw new Error(data.detail || "Không thể nhận diện subtitle.");

    state.jobId = data.job_id;
    state.segments = data.segments || [];
    renderTable();
    finishProgress();

    // Show coverage
    if (data.coverage_pct !== undefined) {
      showCoverage(data.coverage_pct);
    }

    const coverageInfo = data.coverage_pct ? ` (phủ ${data.coverage_pct}% timeline)` : "";
    setStatus(`Hoàn tất. Đã tạo ${state.segments.length} dòng Vietsub${coverageInfo}.`, "success");
    setStep(3);
  } catch (err) {
    cancelProgress();
    const msg = err.message.includes("Failed to fetch")
      ? "Mất kết nối server. Kiểm tra lại mạng hoặc server HF Space."
      : (err.message || "Có lỗi khi auto sub.");
    setStatus(msg, "error");
    setStep(1);
    checkHealth();
  } finally {
    els.btnTranscribe.disabled = false;
    els.btnTranscribe.classList.remove("btn-loading");
  }
}

/* --- Client-side SRT generation (offline-capable) ---------- */
function generateSrtString(segments) {
  let lines = [];
  segments.forEach((seg, idx) => {
    const start = seg.start || "00:00:00,000";
    const end = seg.end || "00:00:02,000";
    const text = (seg.text || "").trim();
    if (!text) return;
    lines.push(String(idx + 1));
    lines.push(`${start} --> ${end}`);
    lines.push(text);
    lines.push("");
  });
  return lines.join("\n");
}

function downloadSrtOffline() {
  const segments = collectSegmentsFromTable();
  if (!segments.length) {
    setStatus("Chưa có subtitle để xuất.", "error");
    return;
  }
  const srtContent = generateSrtString(segments);
  const blob = new Blob([srtContent], { type: "text/plain;charset=utf-8" });
  const url = URL.createObjectURL(blob);
  const a = document.createElement("a");
  a.href = url;
  a.download = "subtitle.srt";
  document.body.appendChild(a);
  a.click();
  document.body.removeChild(a);
  URL.revokeObjectURL(url);
  setStatus("Đã xuất file SRT thành công (offline).", "success");
  setStep(4);
}

/* --- Export ------------------------------------------------- */
async function exportResult(burnIn) {
  if (!burnIn && (!state.isOnline || !state.jobId)) {
    downloadSrtOffline();
    return;
  }

  if (burnIn && !state.isOnline) {
    setStatus(
      IS_FILE_PROTOCOL
        ? "Xuất MP4 burn sub cần server HF Space. Hãy deploy ứng dụng lên HF Space trước."
        : "Server không phản hồi. Xuất MP4 cần kết nối server.",
      "error"
    );
    return;
  }

  if (!state.jobId) {
    setStatus("Chưa có job để xuất file. Hãy bấm Auto sub trước.", "error");
    return;
  }

  const ks = getKaraokeStyle();
  const payload = {
    job_id: state.jobId,
    burn_in: burnIn,
    segments: collectSegmentsFromTable(),
    style: {
      font_name: ks.font,
      font_color: ks.color,
      highlight_color: ks.highlight,
      outline_color: ks.outline,
      outline_width: ks.outlineWidth,
      font_size_pct: ks.sizePct,
      position_pct: ks.positionPct,
      karaoke_mode: ks.karaokeMode,
    },
  };

  const label = burnIn ? "Đang xuất MP4 có sub..." : "Đang tạo file SRT...";
  setStatus(label, "loading");
  startProgress(label);
  setStep(4);
  els.btnExportSrt.disabled = true;
  els.btnExportMp4.disabled = true;

  try {
    const res = await fetch("/api/export", {
      method: "POST",
      headers: { "Content-Type": "application/json" },
      body: JSON.stringify(payload),
    });
    const data = await res.json();
    if (!res.ok) throw new Error(data.detail || "Xuất file thất bại.");

    finishProgress();
    showDownloadGroup(true);
    showDownload(els.downloadSrt, data.srt_url, true);
    if (data.mp4_url) {
      showDownload(els.downloadMp4, data.mp4_url, true);
    }

    const msg = burnIn
      ? `Xuất MP4 thành công${data.mp4_size_mb ? ` (${data.mp4_size_mb} MB)` : ""}.`
      : "Đã tạo file SRT thành công.";
    setStatus(msg, "success");
  } catch (err) {
    cancelProgress();
    const msg = err.message.includes("Failed to fetch")
      ? "Mất kết nối server. Kiểm tra lại mạng hoặc server HF Space."
      : (err.message || "Có lỗi khi xuất file.");
    setStatus(msg, "error");
    checkHealth();
  } finally {
    setEditButtons(true);
  }
}

/* --- File selection ---------------------------------------- */
function handleFile(file) {
  if (!file) return;
  state.file = file;
  state.jobId = null;
  state.segments = [];
  renderTable();
  showDownload(els.downloadSrt, "#", false);
  showDownload(els.downloadMp4, "#", false);
  showDownloadGroup(false);
  hideCoverage();

  const url = URL.createObjectURL(file);
  els.preview.src = url;
  els.preview.classList.add("has-src");
  els.videoPlaceholder.classList.add("hidden");

  els.fileInfo.hidden = false;
  els.fileName.textContent = file.name;
  els.fileSize.textContent = formatSize(file.size);

  setStatus(`Đã chọn: ${file.name}`, "idle");
  setStep(1);
}

function clearFile() {
  state.file = null;
  state.jobId = null;
  state.segments = [];
  renderTable();
  els.preview.removeAttribute("src");
  els.preview.classList.remove("has-src");
  els.videoPlaceholder.classList.remove("hidden");
  els.fileInfo.hidden = true;
  els.fileInput.value = "";
  showDownloadGroup(false);
  hideCoverage();
  setStatus("Sẵn sàng. Hãy upload video để bắt đầu.", "idle");
  setStep(1);
}

/* --- Event listeners --------------------------------------- */

els.fileInput.addEventListener("change", (e) => {
  const [file] = e.target.files || [];
  if (file) handleFile(file);
});

els.dropZone.addEventListener("click", () => els.fileInput.click());

els.dropZone.addEventListener("dragover", (e) => {
  e.preventDefault();
  els.dropZone.classList.add("drag-over");
});
els.dropZone.addEventListener("dragleave", () => {
  els.dropZone.classList.remove("drag-over");
});
els.dropZone.addEventListener("drop", (e) => {
  e.preventDefault();
  els.dropZone.classList.remove("drag-over");
  const file = e.dataTransfer.files[0];
  if (file) {
    const dt = new DataTransfer();
    dt.items.add(file);
    els.fileInput.files = dt.files;
    handleFile(file);
  }
});

els.btnClearFile.addEventListener("click", clearFile);
els.btnTranscribe.addEventListener("click", transcribeVideo);
els.btnExportSrt.addEventListener("click", () => exportResult(false));
els.btnExportMp4.addEventListener("click", () => exportResult(true));

els.btnAddRow.addEventListener("click", () => {
  state.segments = collectSegmentsFromTable();
  state.segments.push({
    id: state.segments.length + 1,
    start: "00:00:00,000",
    end: "00:00:02,000",
    text: "Subtitle mới",
  });
  renderTable();
  const scroll = $("tableScroll");
  if (scroll) scroll.scrollTop = scroll.scrollHeight;
});

const btnCollapse = $("btnCollapseTable");
const tableScroll = $("tableScroll");
if (btnCollapse && tableScroll) {
  btnCollapse.addEventListener("click", () => {
    const collapsed = tableScroll.style.display === "none";
    tableScroll.style.display = collapsed ? "" : "none";
    btnCollapse.querySelector("svg").style.transform = collapsed ? "" : "rotate(180deg)";
  });
}

/* --- Karaoke Style ----------------------------------------- */

function getKaraokeStyle() {
  return {
    font: els.ksFont ? els.ksFont.value : "Bangers",
    color: els.ksColor ? els.ksColor.value : "#FFFFFF",
    highlight: els.ksHighlight ? els.ksHighlight.value : "#FFD700",
    outline: els.ksOutline ? els.ksOutline.value : "#000000",
    outlineWidth: els.ksOutlineWidth ? parseInt(els.ksOutlineWidth.value, 10) : 2,
    sizePct: els.ksSize ? parseInt(els.ksSize.value, 10) : 100,
    positionPct: els.ksPosition ? parseInt(els.ksPosition.value, 10) : 90,
    karaokeMode: els.ksKaraokeMode ? els.ksKaraokeMode.checked : false,
  };
}

function updatePreviewOverlay() {
  const ks = getKaraokeStyle();
  state.karaokeStyle = ks;

  const overlay = els.subPreviewOverlay;
  const textEl = els.subPreviewText;
  if (!overlay || !textEl) return;

  // Position: convert 0-100% to bottom offset
  // 0% = top (bottom: 90%), 100% = bottom (bottom: 2%)
  const bottomPct = Math.max(2, 90 - (ks.positionPct / 100) * 88);
  overlay.style.bottom = bottomPct + "%";

  // Font
  textEl.style.fontFamily = "'" + ks.font + "', sans-serif";

  // Size: base 1.3rem * sizePct / 100
  textEl.style.fontSize = (1.3 * ks.sizePct / 100) + "rem";

  // Color
  textEl.style.color = ks.color;

  // Text shadow for outline
  const ow = ks.outlineWidth;
  const oc = ks.outline;
  if (ow > 0) {
    textEl.style.textShadow = [
      `${ow}px ${ow}px 0 ${oc}`,
      `-${ow}px -${ow}px 0 ${oc}`,
      `${ow}px -${ow}px 0 ${oc}`,
      `-${ow}px ${ow}px 0 ${oc}`,
      `0 0 8px rgba(0,0,0,0.7)`,
    ].join(", ");
  } else {
    textEl.style.textShadow = "0 0 8px rgba(0,0,0,0.7)";
  }

  // Demo text with karaoke highlight
  if (ks.karaokeMode) {
    textEl.innerHTML = 'Phụ đề <span class="ks-word-active" style="color:' + ks.highlight + '">mẫu</span> — Xem trước <span class="ks-word-active" style="color:' + ks.highlight + '">Karaoke</span>';
  } else {
    textEl.textContent = "Phụ đề mẫu — Xem trước Karaoke";
  }
}

function showSubtitlePreview() {
  if (els.subPreviewOverlay) {
    els.subPreviewOverlay.hidden = false;
    updatePreviewOverlay();
  }
}

function hideSubtitlePreview() {
  if (els.subPreviewOverlay) els.subPreviewOverlay.hidden = true;
}

// Wire up karaoke control events
function setupKaraokeEvents() {
  // Font selector → update preview font display
  if (els.ksFont) {
    els.ksFont.addEventListener("change", () => {
      els.ksFont.style.fontFamily = "'" + els.ksFont.value + "', sans-serif";
      updatePreviewOverlay();
    });
    // Set initial font display
    els.ksFont.style.fontFamily = "'" + els.ksFont.value + "', sans-serif";
  }

  // Color pickers
  if (els.ksColor) {
    els.ksColor.addEventListener("input", () => {
      if (els.ksColorHex) els.ksColorHex.textContent = els.ksColor.value.toUpperCase();
      updatePreviewOverlay();
    });
  }
  if (els.ksHighlight) {
    els.ksHighlight.addEventListener("input", () => {
      if (els.ksHighlightHex) els.ksHighlightHex.textContent = els.ksHighlight.value.toUpperCase();
      updatePreviewOverlay();
    });
  }
  if (els.ksOutline) {
    els.ksOutline.addEventListener("input", () => {
      if (els.ksOutlineHex) els.ksOutlineHex.textContent = els.ksOutline.value.toUpperCase();
      updatePreviewOverlay();
    });
  }
  if (els.ksOutlineWidth) {
    els.ksOutlineWidth.addEventListener("input", () => {
      if (els.ksOutlineWidthVal) els.ksOutlineWidthVal.textContent = els.ksOutlineWidth.value + "px";
      updatePreviewOverlay();
    });
  }

  // Size slider
  if (els.ksSize) {
    els.ksSize.addEventListener("input", () => {
      if (els.ksSizeVal) els.ksSizeVal.textContent = els.ksSize.value + "%";
      updatePreviewOverlay();
    });
  }

  // Position slider
  if (els.ksPosition) {
    els.ksPosition.addEventListener("input", () => {
      if (els.ksPositionVal) els.ksPositionVal.textContent = els.ksPosition.value + "%";
      updatePreviewOverlay();
    });
  }

  // Karaoke mode toggle
  if (els.ksKaraokeMode) {
    els.ksKaraokeMode.addEventListener("change", () => {
      updatePreviewOverlay();
    });
  }

  // Preview button
  if (els.btnPreviewStyle) {
    let previewVisible = false;
    els.btnPreviewStyle.addEventListener("click", () => {
      previewVisible = !previewVisible;
      if (previewVisible) {
        showSubtitlePreview();
        els.btnPreviewStyle.innerHTML = '<svg viewBox="0 0 20 20" fill="currentColor" class="icon-btn"><path fill-rule="evenodd" d="M3.707 2.293a1 1 0 00-1.414 1.414l14 14a1 1 0 001.414-1.414l-1.473-1.473A10.014 10.014 0 0019.542 10C18.268 5.943 14.478 3 10 3a9.958 9.958 0 00-4.512 1.074l-1.78-1.781zm4.261 4.26l1.514 1.515a2.003 2.003 0 012.45 2.45l1.514 1.514a4 4 0 00-5.478-5.478z" clip-rule="evenodd"/><path d="M12.454 16.697L9.75 13.992a4 4 0 01-3.742-3.741L2.335 6.578A9.98 9.98 0 00.458 10c1.274 4.057 5.065 7 9.542 7 .847 0 1.669-.105 2.454-.303z"/></svg> Ẩn phụ đề';
      } else {
        hideSubtitlePreview();
        els.btnPreviewStyle.innerHTML = '<svg viewBox="0 0 20 20" fill="currentColor" class="icon-btn"><path d="M10 12a2 2 0 100-4 2 2 0 000 4z"/><path fill-rule="evenodd" d="M.458 10C1.732 5.943 5.522 3 10 3s8.268 2.943 9.542 7c-1.274 4.057-5.064 7-9.542 7S1.732 14.057.458 10zM14 10a4 4 0 11-8 0 4 4 0 018 0z" clip-rule="evenodd"/></svg> Xem trước phụ đề';
      }
    });
  }
}

/* --- Init -------------------------------------------------- */
setStep(1);
setMode("music");
renderTable();
checkHealth();
setupKaraokeEvents();