import { useEffect, useRef } from 'react'

// Signaling host for the GStreamer WebRTC server (hostname only, e.g. rapsbot-v2.local).
// Set VITE_WEBRTC_HOST in .env.local or as an env var; defaults to the current page host.
const signalingHost = import.meta.env.VITE_WEBRTC_HOST || window.location.hostname
const SIGNALING_WS_URL = `ws://${signalingHost}:8443`

export function VideoStream() {
  const videoRef = useRef(null)
  const pcRef = useRef(null)
  const wsRef = useRef(null)

  useEffect(() => {
    console.log('[WebRTC] Connecting to', SIGNALING_WS_URL)
    const pc = new RTCPeerConnection({})
    const ws = new WebSocket(SIGNALING_WS_URL)

    pcRef.current = pc
    wsRef.current = ws

    pc.onconnectionstatechange = () => console.log('[WebRTC] PC state:', pc.connectionState)
    pc.oniceconnectionstatechange = () => console.log('[WebRTC] ICE state:', pc.iceConnectionState)

    pc.ontrack = ({ streams }) => {
      console.log('[WebRTC] Track received, streams:', streams.length)
      if (videoRef.current) videoRef.current.srcObject = streams[0]
    }

    pc.onicecandidate = ({ candidate }) => {
      if (candidate && ws.readyState === WebSocket.OPEN) {
        ws.send(JSON.stringify({
          type: 'ice',
          mlineindex: candidate.sdpMLineIndex,
          candidate: candidate.candidate,
        }))
      }
    }

    ws.onopen = () => console.log('[WebRTC] Signaling connected')
    ws.onclose = () => console.log('[WebRTC] Signaling closed')

    ws.onmessage = async (event) => {
      const msg = JSON.parse(event.data)
      console.log('[WebRTC] Signal:', msg.type, msg)

      if (msg.type === 'offer') {
        await pc.setRemoteDescription({ type: 'offer', sdp: msg.sdp })
        const answer = await pc.createAnswer()
        await pc.setLocalDescription(answer)
        ws.send(JSON.stringify({ type: 'answer', sdp: answer.sdp }))
        console.log('[WebRTC] Answer sent')
      } else if (msg.type === 'ice') {
        await pc.addIceCandidate({ sdpMLineIndex: msg.mlineindex, candidate: msg.candidate })
      }
    }

    let cleanedUp = false
    ws.onerror = (e) => {
      if (!cleanedUp) console.error('[WebRTC] Signaling error', e)
    }

    return () => {
      cleanedUp = true
      pc.close()
      ws.close()
    }
  }, [])

  return (
    <video
      ref={videoRef}
      autoPlay
      playsInline
      muted
      style={{ width: '100%', maxHeight: '60vh', background: '#000', display: 'block' }}
    />
  )
}