const STUN_CONFIG = { iceServers: [{ urls: 'stun:stun.l.google.com:19302' }] };

let ws = null;
let myId = null;
let myName = '';
let localStream = null;
const peers = new Map(); // peerId -> RTCPeerConnection

// --- DOM ---
const joinScreen   = document.getElementById('join-screen');
const talkieScreen = document.getElementById('talkie-screen');
const inputName    = document.getElementById('input-name');
const inputRoom    = document.getElementById('input-room');
const btnJoin      = document.getElementById('btn-join');
const btnLeave     = document.getElementById('btn-leave');
const roomLabel    = document.getElementById('room-label');
const peersList    = document.getElementById('peers-list');
const pttBtn       = document.getElementById('ptt-btn');
const btnLockMic   = document.getElementById('btn-lock-mic');
const statusText   = document.getElementById('status-text');

let micLocked = false;

// --- JOIN ---
btnJoin.addEventListener('click', joinRoom);
inputRoom.addEventListener('keydown', e => { if (e.key === 'Enter') joinRoom(); });

async function joinRoom() {
  const name = inputName.value.trim() || 'Anonimo';
  const room = inputRoom.value.trim().toUpperCase();
  if (!room) { inputRoom.focus(); return; }

  myName = name;

  try {
    localStream = await navigator.mediaDevices.getUserMedia({ audio: true, video: false });
  } catch {
    alert('Impossibile accedere al microfono. Controlla i permessi del browser.');
    return;
  }

  // Mute microphone until PTT pressed
  setMic(false);

  connectWS(room, name);
}

// --- WEBSOCKET ---
function connectWS(room, name) {
  const proto = location.protocol === 'https:' ? 'wss' : 'ws';
  ws = new WebSocket(`${proto}://${location.host}`);

  ws.onopen = () => {
    ws.send(JSON.stringify({ type: 'join', room, name }));
    showTalkieScreen(room);
  };

  ws.onmessage = ({ data }) => {
    const msg = JSON.parse(data);
    handleSignal(msg);
  };

  ws.onclose = () => {
    leaveRoom();
  };
}

async function handleSignal(msg) {
  switch (msg.type) {
    case 'id':
      myId = msg.id;
      break;

    case 'peers':
      // Existing peers: I (new joiner) initiate offers to each
      for (const peer of msg.peers) {
        addPeerToUI(peer.id, peer.name);
        await createOffer(peer.id);
      }
      break;

    case 'peer-joined':
      addPeerToUI(msg.id, msg.name);
      // They will send us an offer; just prep the connection
      getOrCreatePC(msg.id);
      break;

    case 'offer':
      await handleOffer(msg.from, msg.sdp);
      break;

    case 'answer':
      await peers.get(msg.from)?.setRemoteDescription(new RTCSessionDescription(msg.sdp));
      break;

    case 'ice':
      try {
        await peers.get(msg.from)?.addIceCandidate(new RTCIceCandidate(msg.candidate));
      } catch {}
      break;

    case 'peer-left':
      peers.get(msg.id)?.close();
      peers.delete(msg.id);
      removePeerFromUI(msg.id);
      break;

    case 'talking':
      setPeerTalking(msg.id, msg.active);
      break;
  }
}

// --- WEBRTC ---
function getOrCreatePC(peerId) {
  if (peers.has(peerId)) return peers.get(peerId);

  const pc = new RTCPeerConnection(STUN_CONFIG);
  peers.set(peerId, pc);

  // Add local tracks
  localStream.getTracks().forEach(track => pc.addTrack(track, localStream));

  // Remote audio
  pc.ontrack = ({ streams }) => {
    attachAudio(peerId, streams[0]);
  };

  // ICE candidates
  pc.onicecandidate = ({ candidate }) => {
    if (candidate) {
      ws.send(JSON.stringify({ type: 'ice', to: peerId, candidate }));
    }
  };

  pc.onconnectionstatechange = () => {
    if (['failed', 'disconnected', 'closed'].includes(pc.connectionState)) {
      peers.delete(peerId);
    }
  };

  return pc;
}

async function createOffer(peerId) {
  const pc = getOrCreatePC(peerId);
  const offer = await pc.createOffer();
  await pc.setLocalDescription(offer);
  ws.send(JSON.stringify({ type: 'offer', to: peerId, sdp: pc.localDescription }));
}

async function handleOffer(peerId, sdp) {
  const pc = getOrCreatePC(peerId);
  await pc.setRemoteDescription(new RTCSessionDescription(sdp));
  const answer = await pc.createAnswer();
  await pc.setLocalDescription(answer);
  ws.send(JSON.stringify({ type: 'answer', to: peerId, sdp: pc.localDescription }));
}

function attachAudio(peerId, stream) {
  let audio = document.getElementById(`audio-${peerId}`);
  if (!audio) {
    audio = document.createElement('audio');
    audio.id = `audio-${peerId}`;
    audio.autoplay = true;
    audio.style.display = 'none';
    document.body.appendChild(audio);
  }
  audio.srcObject = stream;
}

// --- PTT ---
function setMic(enabled) {
  if (!localStream) return;
  localStream.getAudioTracks().forEach(t => t.enabled = enabled);
}

function startTalking() {
  if (micLocked) return;
  setMic(true);
  pttBtn.classList.add('active');
  statusText.textContent = 'Stai trasmettendo...';
  statusText.style.color = '#22c55e';
  ws?.send(JSON.stringify({ type: 'talking', active: true }));
}

function stopTalking() {
  if (micLocked) return;
  setMic(false);
  pttBtn.classList.remove('active');
  statusText.textContent = 'Rilascia per ascoltare';
  statusText.style.color = '';
  ws?.send(JSON.stringify({ type: 'talking', active: false }));
}

function toggleMicLock() {
  micLocked = !micLocked;
  if (micLocked) {
    setMic(true);
    pttBtn.classList.add('active');
    btnLockMic.classList.add('locked');
    btnLockMic.querySelector('svg').innerHTML = `
      <rect x="3" y="11" width="18" height="11" rx="2" ry="2"/>
      <path d="M7 11V7a5 5 0 0 1 10 0v4"/>
      <line x1="12" y1="15" x2="12" y2="17"/>
    `;
    btnLockMic.childNodes[2].textContent = ' Mic attivo — clicca per disattivare';
    statusText.textContent = 'Microfono sempre attivo';
    statusText.style.color = '#e05252';
    ws?.send(JSON.stringify({ type: 'talking', active: true }));
  } else {
    setMic(false);
    pttBtn.classList.remove('active');
    btnLockMic.classList.remove('locked');
    btnLockMic.querySelector('svg').innerHTML = `
      <rect x="3" y="11" width="18" height="11" rx="2" ry="2"/>
      <path d="M7 11V7a5 5 0 0 1 10 0v4"/>
    `;
    btnLockMic.childNodes[2].textContent = ' Microfono sempre attivo';
    statusText.textContent = 'Rilascia per ascoltare';
    statusText.style.color = '';
    ws?.send(JSON.stringify({ type: 'talking', active: false }));
  }
}

btnLockMic.addEventListener('click', toggleMicLock);

// Mouse events
pttBtn.addEventListener('mousedown', startTalking);
pttBtn.addEventListener('mouseup', stopTalking);
pttBtn.addEventListener('mouseleave', stopTalking);

// Touch events (mobile)
pttBtn.addEventListener('touchstart', e => { e.preventDefault(); startTalking(); }, { passive: false });
pttBtn.addEventListener('touchend', e => { e.preventDefault(); stopTalking(); }, { passive: false });

// Space bar shortcut
document.addEventListener('keydown', e => {
  if (e.code === 'Space' && !e.repeat && talkieScreen.classList.contains('active')) {
    e.preventDefault();
    startTalking();
  }
});
document.addEventListener('keyup', e => {
  if (e.code === 'Space' && talkieScreen.classList.contains('active')) {
    stopTalking();
  }
});

// --- UI ---
function showTalkieScreen(room) {
  joinScreen.classList.remove('active');
  talkieScreen.classList.add('active');
  roomLabel.textContent = `# ${room}`;
  peersList.innerHTML = '';
}

function addPeerToUI(peerId, name) {
  if (document.getElementById(`peer-${peerId}`)) return;
  const initial = (name || '?')[0].toUpperCase();
  const el = document.createElement('div');
  el.className = 'peer-item';
  el.id = `peer-${peerId}`;
  el.innerHTML = `
    <div class="peer-avatar">${initial}</div>
    <span class="peer-name">${escapeHtml(name)}</span>
    <span class="talking-badge">● parlando</span>
  `;
  peersList.appendChild(el);
}

function removePeerFromUI(peerId) {
  document.getElementById(`peer-${peerId}`)?.remove();
  document.getElementById(`audio-${peerId}`)?.remove();
}

function setPeerTalking(peerId, active) {
  const el = document.getElementById(`peer-${peerId}`);
  if (!el) return;
  el.classList.toggle('talking', active);
}

function escapeHtml(str) {
  return str.replace(/&/g,'&amp;').replace(/</g,'&lt;').replace(/>/g,'&gt;');
}

// --- LEAVE ---
btnLeave.addEventListener('click', leaveRoom);

function leaveRoom() {
  ws?.close();
  ws = null;
  peers.forEach(pc => pc.close());
  peers.clear();
  localStream?.getTracks().forEach(t => t.stop());
  localStream = null;
  document.querySelectorAll('audio[id^="audio-"]').forEach(a => a.remove());

  talkieScreen.classList.remove('active');
  joinScreen.classList.add('active');
  peersList.innerHTML = '';
  if (micLocked) toggleMicLock();
  stopTalking();
}