'use strict';

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

function log(camId, msg) {
  console.log(`[${camId}] ${msg}`);
}

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);
      log('ice', `gathering timeout nach ${timeoutMs}ms – sende trotzdem`);
      resolve();
    }, timeoutMs);
  });
}

async function startWebRTC(camId, videoEl, statusEl) {
  setStatus(statusEl, 'Verbinde...', '#888');
  log(camId, `WebRTC start → /api/webrtc?src=${camId}`);

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

    pc.addTransceiver('video', { direction: 'recvonly' });

    pc.onicecandidate = ({ candidate }) => {
      if (candidate) log(camId, `ICE candidate: ${candidate.type} ${candidate.address ?? '?'}`);
    };

    pc.onicegatheringstatechange = () =>
      log(camId, `ICE gathering: ${pc.iceGatheringState}`);

    pc.oniceconnectionstatechange = () => {
      const s = pc.iceConnectionState;
      log(camId, `ICE connection: ${s}`);
      const colors = { connected: '#4c4', completed: '#4c4', checking: '#fa0', failed: '#c44', disconnected: '#c44' };
      setStatus(statusEl, s, colors[s] ?? '#888');
      if (s === 'failed' || s === 'closed') {
        pc.close();
        setTimeout(() => startWebRTC(camId, videoEl, statusEl), 4000);
      }
    };

    pc.onconnectionstatechange = () =>
      log(camId, `connection: ${pc.connectionState}`);

    pc.ontrack = ({ streams }) => {
      log(camId, `Track erhalten: ${streams.length} stream(s)`);
      if (streams[0]) {
        videoEl.srcObject = streams[0];
        videoEl.play().catch(e => log(camId, `play() Fehler: ${e.message}`));
        setStatus(statusEl, 'Live ✓', '#4c4');
      }
    };

    log(camId, 'Erstelle SDP Offer...');
    const offer = await pc.createOffer();
    await pc.setLocalDescription(offer);

    log(camId, `ICE gathering wartet (max 5s)...`);
    await waitIceComplete(pc);

    log(camId, `Sende Offer (${pc.localDescription.sdp.length} Bytes) an Server...`);
    const resp = await fetch(`/api/webrtc?src=${encodeURIComponent(camId)}`, {
      method:  'POST',
      headers: { 'Content-Type': 'application/sdp' },
      body:    pc.localDescription.sdp,
    });

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

    const sdpAnswer = await resp.text();
    log(camId, `Answer erhalten (${sdpAnswer.length} Bytes)`);
    await pc.setRemoteDescription({ type: 'answer', sdp: sdpAnswer });
    log(camId, 'Remote description gesetzt – warte auf ICE...');

  } catch (err) {
    console.error(`[${camId}] Fehler:`, err);
    setStatus(statusEl, `${err.message}`, '#c44');
    pc?.close();
    setTimeout(() => startWebRTC(camId, videoEl, statusEl), 5000);
  }
}

function setStatus(el, text, color) {
  el.textContent = text;
  el.style.color = color ?? '#999';
}

function createCameraView(camId, container) {
  log(camId, 'View erstellt');

  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:#111';
  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 via /api/snapshot (proxied go2rtc /api/streams)
log('init', 'Frage Kamera-Liste ab...');
fetch('/api/snapshot')
  .then(r => {
    log('init', `/api/snapshot → HTTP ${r.status}`);
    return r.json();
  })
  .then(data => {
    log('init', `Kameras: ${JSON.stringify(data.cameras)}`);
    const container = document.getElementById('cameras');
    const cams = data.cameras ?? [];
    if (cams.length === 0) {
      document.getElementById('statusText').textContent = 'Keine Kameras (go2rtc läuft?)';
      console.warn('go2rtc meldet keine Streams. Prüfe http://server:1984');
      return;
    }
    cams.forEach(c => createCameraView(c.id, container));
    document.getElementById('statusText').textContent =
      `${cams.length} Kamera${cams.length !== 1 ? 's' : ''} · WebRTC`;
  })
  .catch(err => {
    console.error('[init] /api/snapshot Fehler:', err);
    document.getElementById('statusText').textContent = 'API-Fehler – Fallback';
    const container = document.getElementById('cameras');
    ['cam0', 'cam1'].forEach(id => createCameraView(id, container));
  });