'use strict';
const token = location.pathname.split('/').filter(Boolean)[1] || '';
const log = $('#log');
let ws = null, everOpen = false, finished = false;
let pc = null, stream = null, actx = null, micAn = null, showAn = null, muted = false;

function fatal(msg){
  finished = true;
  $('#fatal').textContent = msg; $('#fatal').classList.remove('hidden');
  $('#conn').textContent = 'ended'; $('#conn').className = 'pill bad';
  hangup(false);
  for (const el of document.querySelectorAll('button, textarea, input, select')) el.disabled = true;
}
function send(o){ if (ws && ws.readyState === 1) ws.send(JSON.stringify(o)); }

function connect(){
  ws = new WebSocket(wsURL('/ws?t=' + encodeURIComponent(token)));
  ws.onopen = () => {
    everOpen = true;
    $('#conn').textContent = 'connected'; $('#conn').className = 'pill ok';
    const n = $('#name').value.trim(); if (n) send({t:'name', name:n});
  };
  ws.onclose = () => {
    if (finished) return;
    if (!everOpen) { fatal('This invite link is not active. Ask the host for a new one.'); return; }
    $('#conn').textContent = 'reconnecting…'; $('#conn').className = 'pill bad';
    setTimeout(connect, 2000);
  };
  ws.onmessage = async ev => {
    const m = JSON.parse(ev.data);
    switch (m.t) {
      case 'welcome': case 'history':
        log.textContent = ''; (m.history || []).forEach(x => renderMsg(log, x, 'guest')); break;
      case 'chat': renderMsg(log, m.msg, 'guest'); if (document.hidden && m.msg.who === 'host') flashTitle(); break;
      case 'notice': renderMsg(log, {who:'system', text:m.text, ts:Date.now()}, 'guest'); break;
      case 'answer': if (pc) await pc.setRemoteDescription({type:'answer', sdp:m.sdp}); break;
      case 'error': $('#callstate').textContent = m.text; hangup(false); break;
      case 'callended': hangup(false); $('#callstate').textContent = 'The host ended the audio. You can join again.'; break;
      case 'ended': fatal(m.reason || 'The session has ended.'); break;
    }
  };
}

let flashT = null;
function flashTitle(){
  if (flashT) return; const base = document.title; let on = false;
  flashT = setInterval(() => { document.title = (on = !on) ? '💬 New message' : base; }, 1000);
  const stop = () => { clearInterval(flashT); flashT = null; document.title = base; document.removeEventListener('visibilitychange', stop); };
  document.addEventListener('visibilitychange', stop);
}

// ---- devices
async function listDevices(){
  const devs = await navigator.mediaDevices.enumerateDevices();
  const fill = (sel, kind, saved) => {
    const cur = sel.value || saved || '';
    sel.length = 1;
    devs.filter(d => d.kind === kind && d.deviceId !== 'default' && d.deviceId !== 'communications')
        .forEach((d, i) => { const o = new Option(d.label || (kind + ' ' + (i+1)), d.deviceId); sel.add(o); });
    if ([...sel.options].some(o => o.value === cur)) sel.value = cur;
  };
  fill($('#mic'), 'audioinput', store('gl_mic'));
  if ('setSinkId' in HTMLMediaElement.prototype) fill($('#out'), 'audiooutput', store('gl_out'));
  else $('#outwrap').classList.add('hidden');
}
navigator.mediaDevices?.addEventListener?.('devicechange', listDevices);
$('#mic').onchange = () => store('gl_mic', $('#mic').value);
$('#out').onchange = async () => {
  store('gl_out', $('#out').value);
  try { await $('#player').setSinkId($('#out').value); } catch(e) {}
};

// ---- call
function munge(sdp){
  // Ask for stereo, full-band, high-bitrate Opus in both directions.
  const m = sdp.match(/a=rtpmap:(\d+) opus\/48000/i); if (!m) return sdp;
  const pt = m[1];
  return sdp.replace(new RegExp('a=fmtp:' + pt + ' (.*)'), (line, p) =>
    'a=fmtp:' + pt + ' ' + p.split(';').filter(x => !/^(stereo|sprop-stereo|maxaveragebitrate|cbr)=/.test(x)).join(';') +
    ';stereo=1;sprop-stereo=1;maxaveragebitrate=128000');
}

async function join(){
  if (!window.RTCPeerConnection || !navigator.mediaDevices) { $('#callstate').textContent = 'This browser cannot do live audio. Please use Chrome, Edge, Firefox or Safari.'; return; }
  $('#join').disabled = true; $('#callstate').textContent = 'Asking for your microphone…';
  const hp = $('#headphones').checked;
  try {
    stream = await navigator.mediaDevices.getUserMedia({audio: {
      deviceId: $('#mic').value ? {exact: $('#mic').value} : undefined,
      echoCancellation: !hp, noiseSuppression: false, autoGainControl: false,
      channelCount: {ideal: 1}, sampleRate: {ideal: 48000}
    }});
  } catch (e) {
    $('#join').disabled = false;
    $('#callstate').textContent = 'Microphone not available: ' + (e.message || e.name) + '. Check your browser\'s permission and try again.';
    return;
  }
  listDevices().catch(()=>{});
  actx = actx || new AudioContext();
  if (actx.state === 'suspended') await actx.resume();
  micAn = actx.createAnalyser(); micAn.fftSize = 1024;
  actx.createMediaStreamSource(stream).connect(micAn);

  pc = new RTCPeerConnection({iceServers: [{urls: 'stun:stun.l.google.com:19302'}]});
  const tr = pc.addTransceiver(stream.getAudioTracks()[0], {direction: 'sendrecv', streams: [stream]});
  pc.onicecandidate = e => { if (e.candidate) send({t:'candidate', candidate: e.candidate.toJSON()}); };
  pc.ontrack = e => {
    const s = e.streams[0] || new MediaStream([e.track]);
    const p = $('#player'); p.srcObject = s;
    if ($('#out').value && p.setSinkId) p.setSinkId($('#out').value).catch(()=>{});
    p.play().catch(()=>{});
    showAn = actx.createAnalyser(); showAn.fftSize = 1024;
    actx.createMediaStreamSource(s).connect(showAn);
  };
  pc.onconnectionstatechange = () => {
    const s = pc ? pc.connectionState : 'closed';
    const label = {connecting:'Connecting audio…', connected:'You are live with the host. 🎙', disconnected:'Audio interrupted - trying to recover…', failed:'Audio connection failed.'}[s];
    if (label) $('#callstate').textContent = label;
    if (s === 'connected') {
      const p = tr.sender.getParameters(); p.encodings = p.encodings && p.encodings.length ? p.encodings : [{}];
      p.encodings[0].maxBitrate = 128000; tr.sender.setParameters(p).catch(()=>{});
    }
    if (s === 'failed') { hangup(false); $('#callstate').textContent = 'Audio connection failed. Press Join to try again - if it keeps failing, tell the host in chat.'; }
  };
  const offer = await pc.createOffer();
  offer.sdp = munge(offer.sdp);
  await pc.setLocalDescription(offer);
  send({t:'offer', sdp: pc.localDescription.sdp});
  $('#callstate').textContent = 'Connecting audio…';
  $('#join').classList.add('hidden'); $('#join').disabled = false;
  $('#mute').classList.remove('hidden'); $('#leave').classList.remove('hidden');
  for (const s of ['#mic', '#headphones']) $(s).disabled = true;
}

function hangup(tell){
  if (tell) send({t:'hangup'});
  if (pc) { pc.close(); pc = null; }
  if (stream) { stream.getTracks().forEach(t => t.stop()); stream = null; }
  micAn = showAn = null; muted = false;
  $('#player').srcObject = null;
  $('#mute').textContent = 'Mute mic';
  $('#join').classList.remove('hidden'); $('#mute').classList.add('hidden'); $('#leave').classList.add('hidden');
  for (const s of ['#mic', '#headphones']) $(s).disabled = false;
  $('#callstate').textContent = 'Not connected to audio.';
}

$('#join').onclick = join;
$('#leave').onclick = () => hangup(true);
$('#mute').onclick = () => {
  if (!stream) return; muted = !muted;
  stream.getAudioTracks().forEach(t => t.enabled = !muted);
  $('#mute').textContent = muted ? 'Unmute mic' : 'Mute mic';
  $('#mute').classList.toggle('danger', muted);
};

// ---- meters
const buf = new Float32Array(1024);
function peak(an){ if (!an) return 0; an.getFloatTimeDomainData(buf); let p = 0; for (const v of buf) { const a = Math.abs(v); if (a > p) p = a; } return p; }
(function loop(){ setMeter($('#mMic'), muted ? 0 : peak(micAn)); setMeter($('#mShow'), peak(showAn)); requestAnimationFrame(loop); })();

// ---- name + chat
$('#name').value = store('gl_name') || '';
$('#name').addEventListener('change', () => { const n = $('#name').value.trim(); store('gl_name', n); send({t:'name', name:n}); });
chatForm($('#chatform'), $('#msg'), t => send({t:'chat', text:t}));
window.addEventListener('beforeunload', () => { if (pc) send({t:'hangup'}); });

if (!token) fatal('This link is incomplete. Ask the host for your invite link.');
else { connect(); if (navigator.mediaDevices) listDevices().catch(()=>{}); }