const DB_NAME = 'faerro-kb-local';
const STORE_NAME = 'recordings';
const MAX_RECORDING_MS = 30 * 60 * 1000;
const elements = Object.fromEntries([
  'record-button', 'record-title', 'record-help', 'record-time', 'record-meter-fill', 'capture-message',
  'queue-list', 'queue-empty', 'queue-count', 'sync-button', 'archive-list', 'archive-empty',
  'network-state', 'storage-status',
].map((id) => [id, document.getElementById(id)]));

let databasePromise;
let mediaRecorder;
let activeStream;
let recordingChunks = [];
let recordingStartedAt = 0;
let recordingTimer;
let syncing = false;

function openDatabase() {
  if (databasePromise) return databasePromise;
  databasePromise = new Promise((resolve, reject) => {
    const request = indexedDB.open(DB_NAME, 1);
    request.onupgradeneeded = () => request.result.createObjectStore(STORE_NAME, { keyPath: 'id' });
    request.onsuccess = () => resolve(request.result);
    request.onerror = () => reject(request.error);
  });
  return databasePromise;
}

async function queueTransaction(mode, operation) {
  const db = await openDatabase();
  return new Promise((resolve, reject) => {
    const transaction = db.transaction(STORE_NAME, mode);
    const store = transaction.objectStore(STORE_NAME);
    const request = operation(store);
    transaction.oncomplete = () => resolve(request?.result);
    transaction.onerror = () => reject(transaction.error);
    transaction.onabort = () => reject(transaction.error);
  });
}

const getQueued = () => queueTransaction('readonly', (store) => store.getAll());
const putQueued = (recording) => queueTransaction('readwrite', (store) => store.put(recording));
const deleteQueued = (id) => queueTransaction('readwrite', (store) => store.delete(id));

function setMessage(message, isError = false) {
  elements['capture-message'].textContent = message;
  elements['capture-message'].style.color = isError ? 'var(--coral)' : '';
}

function updateNetwork() {
  const online = navigator.onLine;
  elements['network-state'].classList.toggle('online', online);
  elements['network-state'].innerHTML = `<i></i>${online ? 'Connected' : 'Offline'}`;
  elements['storage-status'].textContent = online ? 'Pending audio stays here until server confirmation.' : 'Offline: new audio is saved on this device.';
}

function formatDuration(milliseconds) {
  const seconds = Math.floor(milliseconds / 1000);
  return `${String(Math.floor(seconds / 60)).padStart(2, '0')}:${String(seconds % 60).padStart(2, '0')}`;
}

function preferredMimeType() {
  return ['audio/mp4', 'audio/webm;codecs=opus', 'audio/webm', 'audio/ogg;codecs=opus']
    .find((type) => window.MediaRecorder?.isTypeSupported(type));
}

async function startRecording() {
  if (!navigator.mediaDevices?.getUserMedia || !window.MediaRecorder) {
    setMessage('This browser cannot record audio. Open the app in current iOS Safari.', true);
    return;
  }
  try {
    activeStream = await navigator.mediaDevices.getUserMedia({ audio: true });
    const mimeType = preferredMimeType();
    mediaRecorder = new MediaRecorder(activeStream, mimeType ? { mimeType } : undefined);
    recordingChunks = [];
    mediaRecorder.ondataavailable = (event) => { if (event.data.size) recordingChunks.push(event.data); };
    mediaRecorder.onstop = saveRecording;
    mediaRecorder.start(1000);
    recordingStartedAt = Date.now();
    elements['record-button'].classList.add('recording');
    elements['record-button'].setAttribute('aria-label', 'Stop recording');
    elements['record-title'].textContent = 'Recording in progress';
    elements['record-help'].textContent = 'Tap the square to finish and save';
    setMessage('Audio is being recorded on this device.');
    recordingTimer = window.setInterval(() => {
      const elapsed = Date.now() - recordingStartedAt;
      elements['record-time'].textContent = formatDuration(elapsed);
      elements['record-meter-fill'].style.width = `${Math.min(100, elapsed / MAX_RECORDING_MS * 100)}%`;
      if (elapsed >= MAX_RECORDING_MS) stopRecording();
    }, 250);
  } catch (error) {
    setMessage(error.name === 'NotAllowedError' ? 'Microphone access was denied.' : 'Could not start microphone recording.', true);
  }
}

function stopRecording() {
  if (mediaRecorder?.state === 'recording') mediaRecorder.stop();
  activeStream?.getTracks().forEach((track) => track.stop());
  activeStream = undefined;
  clearInterval(recordingTimer);
  elements['record-button'].classList.remove('recording');
  elements['record-button'].setAttribute('aria-label', 'Start recording');
  elements['record-title'].textContent = 'Recording saved';
  elements['record-help'].textContent = 'Adding it to the upload queue';
  elements['record-time'].textContent = '00:00';
  elements['record-meter-fill'].style.width = '0';
}

async function saveRecording() {
  const blob = new Blob(recordingChunks, { type: mediaRecorder.mimeType || 'audio/mp4' });
  if (!blob.size) {
    setMessage('No audio was captured. Please try again.', true);
    return;
  }
  const extension = blob.type.includes('webm') ? 'webm' : blob.type.includes('ogg') ? 'ogg' : 'm4a';
  const createdAt = new Date(recordingStartedAt).toISOString();
  const recording = {
    id: crypto.randomUUID(),
    blob,
    createdAt,
    filename: `voice-note-${createdAt.replaceAll(':', '-')}.${extension}`,
    durationMs: Date.now() - recordingStartedAt,
    createdAtMs: recordingStartedAt,
  };
  try {
    await putQueued(recording);
    setMessage(navigator.onLine ? 'Saved on device. Uploading now…' : 'Saved on device. It will upload when you reconnect.');
    await renderQueue();
    await syncQueue();
  } catch {
    setMessage('Could not save this recording in browser storage. Keep this page open and try again.', true);
  }
}

async function syncQueue() {
  if (syncing || !navigator.onLine) return;
  syncing = true;
  elements['sync-button'].disabled = true;
  elements['queue-list'].querySelectorAll('.delete-note').forEach((button) => { button.disabled = true; });
  try {
    const recordings = await getQueued();
    for (const recording of recordings.sort((a, b) => a.createdAtMs - b.createdAtMs)) {
      const form = new FormData();
      form.append('recording_id', recording.id);
      form.append('audio', recording.blob, recording.filename);
      form.append('created_at', recording.createdAt);
      try {
        const response = await fetch('/api/notes', { method: 'POST', body: form });
        if (!response.ok) throw new Error(`Upload failed: ${response.status}`);
        await deleteQueued(recording.id);
        setMessage('Server confirmed the recording is stored.');
      } catch {
        setMessage('Upload paused. Your recording is still saved on this device.');
        break;
      }
    }
  } finally {
    syncing = false;
    elements['sync-button'].disabled = false;
    await renderQueue();
    await loadAwaitingNotes();
  }
}

function prettyDate(value) {
  return new Intl.DateTimeFormat(undefined, { dateStyle: 'medium', timeStyle: 'short' }).format(new Date(value));
}

async function renderQueue() {
  const recordings = (await getQueued()).sort((a, b) => b.createdAtMs - a.createdAtMs);
  elements['queue-list'].replaceChildren();
  elements['queue-count'].textContent = recordings.length;
  elements['queue-empty'].hidden = recordings.length > 0;
  for (const recording of recordings) {
    const item = document.createElement('li');
    item.className = 'queue-item';
    const icon = document.createElement('span');
    icon.className = 'queue-icon';
    icon.textContent = '◖';
    const body = document.createElement('div');
    body.className = 'item-body';
    const top = document.createElement('div');
    top.className = 'item-top';
    const name = document.createElement('span');
    name.className = 'item-name';
    name.textContent = recording.filename;
    const status = document.createElement('span');
    status.className = 'item-status';
    status.textContent = navigator.onLine ? 'WAITING TO SYNC' : 'SAVED OFFLINE';
    const meta = document.createElement('div');
    meta.className = 'item-meta';
    meta.textContent = `${prettyDate(recording.createdAt)} · ${formatDuration(recording.durationMs)}`;
    const remove = createDeleteButton(`Delete queued note ${recording.filename}`);
    remove.disabled = syncing;
    remove.addEventListener('click', async () => {
      if (syncing) return;
      remove.disabled = true;
      try {
        await deleteQueued(recording.id);
        await renderQueue();
      } catch {
        setMessage('Could not remove the queued recording.', true);
        remove.disabled = false;
      }
    });
    top.append(name, status);
    body.append(top, meta);
    item.append(icon, body, remove);
    elements['queue-list'].append(item);
  }
}

function createDeleteButton(label) {
  const button = document.createElement('button');
  button.className = 'delete-note';
  button.type = 'button';
  button.textContent = '×';
  button.title = label;
  button.setAttribute('aria-label', label);
  return button;
}

function renderArchive(notes) {
  elements['archive-list'].replaceChildren();
  elements['archive-empty'].hidden = notes.length > 0;
  if (!navigator.onLine) elements['archive-empty'].textContent = 'Reconnect to view notes awaiting transcription.';
  else elements['archive-empty'].textContent = 'No notes awaiting transcription.';
  for (const note of notes) {
    const item = document.createElement('article');
    item.className = 'archive-item';
    const date = document.createElement('time');
    date.className = 'archive-date';
    date.textContent = prettyDate(note.created_at);
    const body = document.createElement('div');
    body.className = 'item-body';
    const name = document.createElement('div');
    name.className = 'item-name';
    name.textContent = note.filename;
    const transcript = document.createElement('textarea');
    transcript.className = 'archive-transcript';
    transcript.placeholder = note.status === 'transcribing' ? 'Transcription in progress…' : 'Transcript not available yet. Add or correct it here.';
    transcript.value = note.transcript;
    transcript.setAttribute('aria-label', `Transcript for ${note.filename}`);
    const save = document.createElement('button');
    save.className = 'save-transcript';
    save.type = 'button';
    save.textContent = 'SAVE TRANSCRIPT';
    save.addEventListener('click', async () => {
      save.disabled = true;
      try {
        const response = await fetch(`/api/notes/${encodeURIComponent(note.id)}/transcript`, {
          method: 'PUT', headers: { 'Content-Type': 'application/json' }, body: JSON.stringify({ transcript: transcript.value }),
        });
        if (!response.ok) throw new Error('Save failed');
        await loadAwaitingNotes();
      } catch {
        save.textContent = 'RETRY SAVE';
      } finally {
        save.disabled = false;
      }
    });
    const status = document.createElement('div');
    status.className = 'archive-status';
    status.textContent = 'AWAITING TRANSCRIPTION';
    const remove = createDeleteButton(`Delete note ${note.filename}`);
    remove.addEventListener('click', async () => {
      remove.disabled = true;
      try {
        const response = await fetch(`/api/notes/${encodeURIComponent(note.id)}`, { method: 'DELETE' });
        if (!response.ok) throw new Error('Delete failed');
        await loadAwaitingNotes();
      } catch {
        remove.disabled = false;
        setMessage('Could not delete this note. Please try again.', true);
      }
    });
    body.append(name, transcript, save, status);
    item.append(date, body, remove);
    elements['archive-list'].append(item);
  }
}

async function loadAwaitingNotes() {
  if (!navigator.onLine) {
    renderArchive([]);
    return;
  }
  try {
    const response = await fetch('/api/notes?status=awaiting_transcription');
    if (!response.ok) throw new Error('Archive unavailable');
    renderArchive(await response.json());
  } catch {
    elements['archive-list'].replaceChildren();
    elements['archive-empty'].hidden = false;
    elements['archive-empty'].textContent = 'Could not reach the archive. Pending recordings remain on this device.';
  }
}

elements['record-button'].addEventListener('click', () => mediaRecorder?.state === 'recording' ? stopRecording() : startRecording());
elements['sync-button'].addEventListener('click', syncQueue);
window.addEventListener('online', () => { updateNetwork(); syncQueue(); loadAwaitingNotes(); });
window.addEventListener('offline', updateNetwork);
window.addEventListener('focus', () => { updateNetwork(); syncQueue(); loadAwaitingNotes(); });
document.addEventListener('visibilitychange', () => { if (document.visibilityState === 'visible') syncQueue(); });

updateNetwork();
renderQueue().then(syncQueue).catch(() => setMessage('Browser storage is unavailable. Check Safari storage settings.', true));
loadAwaitingNotes();
if ('serviceWorker' in navigator) navigator.serviceWorker.register('/sw.js').catch(() => {});