'use strict';

const ICE_SERVERS = [
  { urls: 'stun:stun.l.google.com:19302' },
  { urls: 'stun:stun1.l.google.com:19302' },
];

// Wartet bis ICE-Gathering fertig ist (max timeoutMs)
function waitIceComplete(pc, timeoutMs = 5000) {
  return new Promise(resolve => {
    if (pc.iceGatheringState === 'complete') { resolve(); return; }
    const check = () => { if (pc.iceGatheringState === 'complete') resolve(); };
    pc.addEventListener('icegatheringstatechange', check);
    setTimeout(() => { pc.removeEventListener('icegatheringstatechange', check); resolve(); }, timeoutMs);
  });
}

async function startWebRTC(camId, videoEl, statusEl) {
  statusEl.textContent = 'Verbinde...';

  let pc;
  try {
    pc = new RTCPeerConnection({ iceServers: ICE_SERVERS });

    // Nur Video empfangen, kein Audio
    pc.addTransceiver('video', { direction: 'recvonly' });

    pc.ontrack = ({ streams }) => {
      if (!streams[0]) return;
      videoEl.srcObject = streams[0];
      videoEl.play().catch(() => {});
    };

    pc.oniceconnectionstatechange = () => {
      const s = pc.iceConnectionState;
      statusEl.textContent = { connected: 'Live ✓', completed: 'Live ✓' }[s] ?? s;
      if (s === 'failed' || s === 'closed') {
        pc.close();
        setTimeout(() => startWebRTC(camId, videoEl, statusEl), 4000);
      }
    };

    // SDP Offer erstellen und warten bis alle ICE-Kandidaten gesammelt sind
    const offer = await pc.createOffer();
    await pc.setLocalDescription(offer);
    await waitIceComplete(pc);

    // Signaling über Node.js-Proxy (kein separater go2rtc-Port nach aussen nötig)
    const resp = await fetch(`/api/webrtc?src=${encodeURIComponent(camId)}`, {
      method:  'POST',
      headers: { 'Content-Type': 'application/sdp' },
      body:    pc.localDescription.sdp,
    });

    if (!resp.ok) throw new Error(`Signaling HTTP ${resp.status}: ${await resp.text()}`);

    await pc.setRemoteDescription({ type: 'answer', sdp: await resp.text() });

  } catch (err) {
    statusEl.textContent = `Fehler: ${err.message}`;
    console.error(`[${camId}]`, err);
    pc?.close();
    setTimeout(() => startWebRTC(camId, videoEl, statusEl), 5000);
  }
}

function createCameraView(camId, container) {
  const box = document.createElement('div');
  box.className = 'cam-box';

  const video = document.createElement('video');
  video.autoplay    = true;
  video.playsInline = true;
  video.muted       = true;
  video.style.cssText = 'display:block;width:640px;height:480px;background:#000';
  box.appendChild(video);

  const label = document.createElement('div');
  label.className   = 'cam-label';
  label.textContent = camId;
  box.appendChild(label);

  const status = document.createElement('div');
  status.className = 'cam-info';
  box.appendChild(status);

  const actions = document.createElement('div');
  actions.className = 'cam-actions';
  const snapBtn = document.createElement('button');
  snapBtn.textContent = 'Snapshot';
  snapBtn.onclick = () => {
    const a = document.createElement('a');
    a.href     = `/api/snapshot/${camId}`;
    a.download = `${camId}_${Date.now()}.jpg`;
    a.click();
  };
  actions.appendChild(snapBtn);
  box.appendChild(actions);

  container.appendChild(box);
  startWebRTC(camId, video, status);
}

// Kamera-Liste von go2rtc (via Node.js-Proxy), dann Views aufbauen
fetch('/api/snapshot')
  .then(r => r.json())
  .then(data => {
    const container = document.getElementById('cameras');
    const cams = data.cameras ?? [];
    if (cams.length === 0) {
      document.getElementById('statusText').textContent = 'Keine Kameras in go2rtc';
      return;
    }
    cams.forEach(c => createCameraView(c.id, container));
    document.getElementById('statusText').textContent =
      `${cams.length} Kamera${cams.length !== 1 ? 's' : ''} · WebRTC`;
  })
  .catch(() => {
    // Fallback wenn go2rtc noch nicht läuft
    const container = document.getElementById('cameras');
    ['cam0', 'cam1'].forEach(id => createCameraView(id, container));
    document.getElementById('statusText').textContent = 'go2rtc nicht erreichbar – versuche trotzdem';
  });