import { useEffect, useRef, useState } from 'react';
import { useParams, Link } from 'react-router-dom';
import { Loader2, Maximize, Minimize, AlertCircle, Eye } from 'lucide-react';
import { Button } from '@/components/ui/button';
import { supabase } from '@/integrations/supabase/client';
import { joinAsViewer, type ViewerHandle } from '@/lib/webrtc/viewer';

type ConnState = 'checking' | 'connecting' | 'waiting' | 'live' | 'error' | 'not-found';

export default function Watch() {
  const { code = '' } = useParams();
  const videoRef = useRef<HTMLVideoElement>(null);
  const handleRef = useRef<ViewerHandle | null>(null);
  const [state, setState] = useState<ConnState>('checking');
  const [error, setError] = useState<string>('');
  const [fullscreen, setFullscreen] = useState(false);
  const [fallbackFrame, setFallbackFrame] = useState<string>('');

  useEffect(() => {
    let cancelled = false;

    (async () => {
      const { data, error: dbErr } = await supabase
        .from('share_rooms')
        .select('code, is_active, expires_at')
        .eq('code', code.toUpperCase())
        .maybeSingle();

      if (cancelled) return;

      if (dbErr) {
        setError(dbErr.message);
        setState('error');
        return;
      }
      if (!data) {
        setState('not-found');
        return;
      }

      if (!videoRef.current) return;
      try {
        const handle = await joinAsViewer(
          code.toUpperCase(),
          videoRef.current,
          (s, detail) => {
            setState(s as ConnState);
            if (detail) setError(detail);
          },
          setFallbackFrame,
        );
        handleRef.current = handle;
      } catch (e) {
        setError(e instanceof Error ? e.message : String(e));
        setState('error');
      }
    })();

    return () => {
      cancelled = true;
      if (handleRef.current) handleRef.current.stop();
    };
  }, [code]);

  const toggleFullscreen = async () => {
    const el = videoRef.current;
    if (!el) return;
    if (document.fullscreenElement) {
      await document.exitFullscreen();
      setFullscreen(false);
    } else {
      await el.requestFullscreen();
      setFullscreen(true);
    }
  };

  return (
    <div className="min-h-screen bg-background flex flex-col">
      <header className="border-b bg-card/50 backdrop-blur px-4 py-3 flex items-center justify-between">
        <Link to="/" className="font-mono text-sm font-bold text-foreground">
          TrackSteel<span className="text-primary">XR</span>
        </Link>
        <div className="flex items-center gap-3">
          <span className="font-mono text-[10px] text-muted-foreground">SALA</span>
          <span className="font-mono text-sm font-bold tracking-widest text-primary">
            {code.toUpperCase()}
          </span>
          {state === 'live' && (
            <span className="flex items-center gap-1.5">
              <span className="relative flex h-2 w-2">
                <span className="animate-ping absolute inline-flex h-full w-full rounded-full bg-red-500 opacity-75" />
                <span className="relative inline-flex rounded-full h-2 w-2 bg-red-500" />
              </span>
              <span className="font-mono text-[10px] text-red-500">AO VIVO</span>
            </span>
          )}
        </div>
      </header>

      <div className="flex-1 relative bg-black flex items-center justify-center">
        <video
          ref={videoRef}
          autoPlay
          playsInline
          muted
          className="max-w-full max-h-full object-contain"
        />

        {fallbackFrame && (
          <img
            src={fallbackFrame}
            alt="Transmissão ao vivo da sessão XR"
            className="absolute inset-0 h-full w-full object-contain"
          />
        )}

        {(state === 'checking' || state === 'connecting' || state === 'waiting') && (
          <div className="absolute inset-0 flex flex-col items-center justify-center gap-3 bg-black/80">
            <Loader2 className="h-8 w-8 animate-spin text-primary" />
            <p className="font-mono text-xs text-muted-foreground">
              {state === 'checking' && 'Verificando sala…'}
              {state === 'connecting' && 'Conectando…'}
              {state === 'waiting' && 'Aguardando o inspetor iniciar…'}
            </p>
          </div>
        )}

        {state === 'not-found' && (
          <div className="absolute inset-0 flex flex-col items-center justify-center gap-3 bg-black/90 px-6 text-center">
            <AlertCircle className="h-10 w-10 text-destructive" />
            <h2 className="font-mono text-base font-bold">Sala não encontrada</h2>
            <p className="font-mono text-xs text-muted-foreground max-w-sm">
              A sala <span className="text-primary">{code.toUpperCase()}</span> não existe,
              expirou ou foi encerrada pelo inspetor.
            </p>
          </div>
        )}

        {state === 'error' && (
          <div className="absolute inset-0 flex flex-col items-center justify-center gap-3 bg-black/90 px-6 text-center">
            <AlertCircle className="h-10 w-10 text-destructive" />
            <h2 className="font-mono text-base font-bold">Erro de conexão</h2>
            <p className="font-mono text-xs text-muted-foreground max-w-sm">{error}</p>
          </div>
        )}

        {state === 'live' && (
          <Button
            onClick={toggleFullscreen}
            variant="outline"
            size="icon"
            className="absolute bottom-4 right-4 h-9 w-9 bg-card/80 backdrop-blur"
          >
            {fullscreen ? <Minimize className="h-4 w-4" /> : <Maximize className="h-4 w-4" />}
          </Button>
        )}
      </div>

      <footer className="border-t bg-card/50 backdrop-blur px-4 py-2 flex items-center justify-center gap-2">
        <Eye className="h-3 w-3 text-muted-foreground" />
        <span className="font-mono text-[10px] text-muted-foreground">
          Modo somente visualização · TrackSteelXR
        </span>
      </footer>
    </div>
  );
}