(function () {
  const BASE = '/realtimechat';
  const params = new URLSearchParams(location.search);
  const roomId = params.get('room');
  const password = params.get('password') || '';

  const socket = io({ path: BASE + '/socket.io' });
  let localStream = null;
  const peers = new Map();
  const names = new Map();

  // ลดเสียงสะท้อนและเสียงรบกวนจากไมค์ (ใช้ทั้งตอนเริ่มและตอนเปลี่ยนอุปกรณ์)
  function audioConstraints(deviceId) {
    const base = { echoCancellation: true, noiseSuppression: true, autoGainControl: true };
    if (deviceId) base.deviceId = { exact: deviceId };
    return base;
  }
  const pendingOffers = new Map();
  const pendingIceByFrom = new Map();

  if (!roomId) {
    document.getElementById('form-create')?.addEventListener('submit', (e) => {
      e.preventDefault();
      const id = (document.getElementById('room-id').value || '').trim();
      const pw = document.getElementById('room-password').value || '';
      const nick = (document.getElementById('nick').value || '').trim();
      socket.emit('create-room', { roomId: id || undefined, password: pw }, (res) => {
        if (res && res.ok) {
          let url = 'room.html?room=' + encodeURIComponent(res.roomId);
          if (pw) url += '&password=' + encodeURIComponent(pw);
          if (nick) url += '&nick=' + encodeURIComponent(nick);
          window.location.href = url;
        }
        else alert(res?.error || 'สร้างห้องไม่ได้');
      });
    });
    document.getElementById('form-join')?.addEventListener('submit', (e) => {
      e.preventDefault();
      const id = document.getElementById('join-id').value.trim();
      const pw = document.getElementById('join-password').value || '';
      const nick = (document.getElementById('nick').value || '').trim();
      socket.emit('join-room', { roomId: id, password: pw }, (res) => {
        if (res && res.ok) {
          let url = 'room.html?room=' + encodeURIComponent(id);
          if (pw) url += '&password=' + encodeURIComponent(pw);
          if (nick) url += '&nick=' + encodeURIComponent(nick);
          window.location.href = url;
        }
        else alert(res?.error || 'เข้าร่วมไม่ได้');
      });
    });
    return;
  }

  const nick = params.get('nick') || '';

  const videosEl = document.getElementById('videos');
  const roomLabel = document.getElementById('room-label');
  const chatMessages = document.getElementById('chat-messages');
  const chatForm = document.getElementById('chat-form');
  const chatInput = document.getElementById('chat-input');

  if (roomLabel) roomLabel.textContent = 'ห้อง: ' + roomId;
  document.getElementById('btn-copy')?.addEventListener('click', () => {
    const url = location.origin + BASE + '/room.html?room=' + encodeURIComponent(roomId);
    navigator.clipboard.writeText(url).then(() => alert('คัดลอกลิงก์แล้ว'));
  });
  document.getElementById('btn-leave')?.addEventListener('click', (e) => { e.preventDefault(); location.href = BASE + '/index.html'; });

  const btnMute = document.getElementById('btn-mute');
  const btnVideo = document.getElementById('btn-video');
  const micSelect = document.getElementById('mic-select');
  const camSelect = document.getElementById('cam-select');

  function updateMuteVideoLabels() {
    if (!localStream) return;
    const audioTrack = localStream.getAudioTracks()[0];
    const videoTrack = localStream.getVideoTracks()[0];
    if (btnMute) btnMute.textContent = audioTrack && !audioTrack.enabled ? 'เปิดไมค์' : 'ปิดไมค์';
    if (btnVideo) btnVideo.textContent = videoTrack && !videoTrack.enabled ? 'เปิดกล้อง' : 'ปิดกล้อง';
  }

  btnMute?.addEventListener('click', () => {
    if (!localStream) return;
    const t = localStream.getAudioTracks()[0];
    if (t) { t.enabled = !t.enabled; updateMuteVideoLabels(); }
  });

  btnVideo?.addEventListener('click', () => {
    if (!localStream) return;
    const t = localStream.getVideoTracks()[0];
    if (t) { t.enabled = !t.enabled; updateMuteVideoLabels(); }
  });

  async function fillDeviceSelects() {
    try {
      const devices = await navigator.mediaDevices.enumerateDevices();
      const mics = devices.filter(d => d.kind === 'audioinput');
      const cams = devices.filter(d => d.kind === 'videoinput');
      const curAudio = localStream?.getAudioTracks()[0]?.getSettings()?.deviceId;
      const curVideo = localStream?.getVideoTracks()[0]?.getSettings()?.deviceId;

      if (micSelect) {
        micSelect.innerHTML = '';
        mics.forEach(d => {
          const opt = document.createElement('option');
          opt.value = d.deviceId;
          opt.textContent = d.label || 'ไมค์ ' + (micSelect.options.length + 1);
          if (d.deviceId === curAudio) opt.selected = true;
          micSelect.appendChild(opt);
        });
      }
      if (camSelect) {
        camSelect.innerHTML = '';
        cams.forEach(d => {
          const opt = document.createElement('option');
          opt.value = d.deviceId;
          opt.textContent = d.label || 'กล้อง ' + (camSelect.options.length + 1);
          if (d.deviceId === curVideo) opt.selected = true;
          camSelect.appendChild(opt);
        });
      }
    } catch (e) { console.error('enumerateDevices', e); }
  }

  async function switchDevice(kind, deviceId) {
    if (!localStream) return;
    try {
      const stream = await navigator.mediaDevices.getUserMedia(
        kind === 'audio' ? { audio: audioConstraints(deviceId), video: false } : { video: deviceId ? { deviceId: { exact: deviceId } } : true, audio: false }
      );
      const newTrack = stream.getTracks()[0];
      const oldTrack = kind === 'audio' ? localStream.getAudioTracks()[0] : localStream.getVideoTracks()[0];
      if (oldTrack) {
        localStream.removeTrack(oldTrack);
        oldTrack.stop();
      }
      localStream.addTrack(newTrack);

      peers.forEach((pc) => {
        const sender = pc.getSenders().find(s => s.track && s.track.kind === kind);
        if (sender) sender.replaceTrack(newTrack);
      });

      const localWrap = videosEl.querySelector('[data-peer-id="' + socket.id + '"]');
      const localVid = localWrap?.querySelector('video');
      if (localVid) localVid.srcObject = localStream;
      updateMuteVideoLabels();
    } catch (e) { console.error('switchDevice', e); }
  }

  micSelect?.addEventListener('change', () => switchDevice('audio', micSelect.value));
  camSelect?.addEventListener('change', () => switchDevice('video', camSelect.value));

  function addVideo(id, stream, isLocal) {
    const vid = document.createElement('video');
    vid.autoplay = true;
    vid.playsInline = true;
    if (isLocal) {
      vid.muted = true;
      vid.volume = 0;
    } else {
      vid.muted = false;
    }
    if (stream) {
      vid.srcObject = stream;
      vid.play().catch(() => {});
    }
    vid.style.border = isLocal ? '3px solid #7aa2f7' : '2px solid #9ece6a';
    const wrap = document.createElement('div');
    wrap.dataset.peerId = id;
    wrap.appendChild(vid);
    const label = names.get(id) || (isLocal ? (nick || 'คุณ') : id.slice(0, 8));
    wrap.appendChild(document.createElement('span')).textContent = label;
    videosEl.appendChild(wrap);
    return vid;
  }

  async function startLocal() {
    try {
      localStream = await navigator.mediaDevices.getUserMedia({
        audio: audioConstraints(),
        video: true
      });
      addVideo(socket.id, localStream, true);
      await fillDeviceSelects();
      updateMuteVideoLabels();
    } catch (e) {
      console.error('getUserMedia', e);
    }
  }

  function createPeer(remoteId) {
    const pc = new RTCPeerConnection({
      iceServers: [
        { urls: 'stun:stun.l.google.com:19302' },
        { urls: 'stun:stun1.l.google.com:19302' }
      ]
    });
    if (localStream) localStream.getTracks().forEach(t => pc.addTrack(t, localStream));
    pc.onicecandidate = (e) => { if (e.candidate) socket.emit('webrtc-ice', { to: remoteId, candidate: e.candidate }); };
    pc.ontrack = (e) => {
      const wrap = videosEl.querySelector('[data-peer-id="' + remoteId + '"]');
      const vid = wrap ? wrap.querySelector('video') : null;
      const stream = e.streams[0];
      if (vid) {
        vid.srcObject = stream;
        vid.play().catch(() => {});
      } else {
        addVideo(remoteId, stream, false);
      }
    };
    return pc;
  }

  async function handleOffer(from, offer) {
    let pc = peers.get(from);
    if (!pc) {
      pc = createPeer(from);
      peers.set(from, pc);
    }
    await pc.setRemoteDescription(new RTCSessionDescription(offer));
    const answer = await pc.createAnswer();
    await pc.setLocalDescription(answer);
    socket.emit('webrtc-answer', { to: from, answer: pc.localDescription });
    const pending = pendingIceByFrom.get(from);
    if (pending) { pending.forEach(c => pc.addIceCandidate(new RTCIceCandidate(c))); pendingIceByFrom.delete(from); }
  }

  async function handleAnswer(from, answer) {
    let pc = peers.get(from);
    if (!pc) return;
    await pc.setRemoteDescription(new RTCSessionDescription(answer));
    const pending = pendingIceByFrom.get(from);
    if (pending) { pending.forEach(c => pc.addIceCandidate(new RTCIceCandidate(c))); pendingIceByFrom.delete(from); }
  }

  socket.on('user-joined', async (data) => {
    if (data.nickname) names.set(data.id, data.nickname);
    addVideo(data.id, null, false);
    const pc = createPeer(data.id);
    peers.set(data.id, pc);
    const offer = await pc.createOffer();
    await pc.setLocalDescription(offer);
    if (!localStream) {
      pendingOffers.set(data.id, offer);
      return;
    }
    socket.emit('webrtc-offer', { to: data.id, offer });
  });

  socket.on('user-left', (data) => {
    const pc = peers.get(data.id);
    if (pc) { pc.close(); peers.delete(data.id); }
    pendingOffers.delete(data.id);
    pendingIceByFrom.delete(data.id);
    names.delete(data.id);
    const wrap = videosEl.querySelector('[data-peer-id="' + data.id + '"]');
    if (wrap) wrap.remove();
  });

  socket.on('webrtc-offer', async (data) => {
    if (!localStream) {
      pendingOffers.set(data.from, data.offer);
      return;
    }
    await handleOffer(data.from, data.offer);
  });

  socket.on('webrtc-answer', (data) => {
    if (pendingOffers.has(data.from)) pendingOffers.delete(data.from);
    handleAnswer(data.from, data.answer);
  });

  socket.on('webrtc-ice', (data) => {
    let pc = peers.get(data.from);
    if (!pc) {
      if (!pendingIceByFrom.has(data.from)) pendingIceByFrom.set(data.from, []);
      pendingIceByFrom.get(data.from).push(data.candidate);
      return;
    }
    pc.addIceCandidate(new RTCIceCandidate(data.candidate)).catch(() => {});
  });

  socket.on('chat', (data) => {
    const div = document.createElement('div');
    div.className = 'chat-msg';
    const label = data.nickname || names.get(data.id) || (data.id === socket.id ? (nick || 'คุณ') : data.id.slice(0, 8));
    div.textContent = label + ': ' + (data.text || '');
    chatMessages.appendChild(div);
    chatMessages.scrollTop = chatMessages.scrollHeight;
  });

  chatForm?.addEventListener('submit', (e) => {
    e.preventDefault();
    const t = (chatInput.value || '').trim();
    if (t) { socket.emit('chat', t); chatInput.value = ''; }
  });

  async function doJoin() {
    // เปิดไมค์/กล้องให้พร้อมก่อน แล้วค่อย join ห้อง
    await startLocal();
    socket.emit('join-room', { roomId, password, nickname: nick || undefined }, async (res) => {
      if (!res || !res.ok) {
        alert(res?.error || 'ไม่พบห้อง');
        location.href = BASE + '/index.html';
        return;
      }
      names.set(socket.id, nick || 'คุณ');
      (res.peers || []).forEach((p) => {
        names.set(p.id, p.nickname || p.id.slice(0, 8));
      });
      for (const [from, offer] of pendingOffers) await handleOffer(from, offer);
      pendingOffers.clear();
    });
  }
  if (socket.connected) doJoin(); else socket.once('connect', doJoin);
})();