import { useEffect, useRef, useCallback } from 'react';
import videojs from 'video.js';
import type Player from 'video.js/dist/types/player';
import Hls from 'hls.js';
import { usePlayerStore } from '../store/playerStore';

const HLS_CONFIG = {
  maxBufferLength: 30,
  maxMaxBufferLength: 600,
  maxBufferSize: 60 * 1024 * 1024,
  backBufferLength: 30,
  enableWorker: true,
};

// PC 브라우저(Chrome/Firefox/Edge)가 HTML5 video로 직접 디코딩 못 하는 코덱.
// 이런 영상은 원본 대신 (트랜스코딩된) HLS로 재생해야 한다.
const UNSUPPORTED_CODECS = new Set(['hevc', 'h265', 'hvc1', 'hev1']);

export function useVideoPlayer(containerRef: React.RefObject<HTMLDivElement | null>) {
  const playerRef = useRef<Player | null>(null);
  const hlsRef = useRef<Hls | null>(null);
  const store = usePlayerStore();

  useEffect(() => {
    if (!containerRef.current || playerRef.current) return;

    const videoEl = document.createElement('video-js');
    // fill: 컨테이너를 꽉 채움(사이니지처럼 화면 가득). object-fit:cover 로 비율 유지 크롭.
    videoEl.classList.add('vjs-big-play-centered', 'vjs-fill');
    containerRef.current.appendChild(videoEl);

    const player = videojs(videoEl, {
      // 하단 시간 스크러버는 측점 기반 StationBar 로 대체하므로 Video.js 기본 컨트롤바 숨김
      controls: false,
      fill: true,
      responsive: true,
      playbackRates: [0.25, 0.5, 0.75, 1, 1.25, 1.5, 2, 4],
      html5: { vhs: { overrideNative: true } },
    });

    player.on('play', () => store.setPlaying(true));
    player.on('pause', () => store.setPlaying(false));
    player.on('timeupdate', () => store.setCurrentTime(player.currentTime() ?? 0));
    player.on('durationchange', () => store.setDuration(player.duration() ?? 0));
    player.on('volumechange', () => {
      store.setVolume(player.volume() ?? 1);
      store.setMuted(player.muted() ?? false);
    });
    player.on('ratechange', () => store.setPlaybackRate(player.playbackRate() ?? 1));

    playerRef.current = player;

    return () => {
      hlsRef.current?.destroy();
      hlsRef.current = null;
      if (playerRef.current && !playerRef.current.isDisposed()) {
        playerRef.current.dispose();
        playerRef.current = null;
      }
    };
  // eslint-disable-next-line react-hooks/exhaustive-deps
  }, []);

  const loadLocalFile = useCallback((file: File) => {
    const player = playerRef.current;
    if (!player) return;

    // Clean up previous hls
    hlsRef.current?.destroy();
    hlsRef.current = null;

    const objectUrl = URL.createObjectURL(file);
    player.src({ src: objectUrl, type: file.type || 'video/mp4' });
    store.setSource({ kind: 'local', file, objectUrl });
    store.setHlsReady(false);

    // Revoke objectUrl when video element is reset
    player.one('emptied', () => {
      URL.revokeObjectURL(objectUrl);
    });
  // eslint-disable-next-line react-hooks/exhaustive-deps
  }, []);

  const loadServerStream = useCallback(async (videoId: string, filename: string) => {
    const player = playerRef.current;
    if (!player) return;

    hlsRef.current?.destroy();
    hlsRef.current = null;

    store.setSource({ kind: 'server', videoId, filename });
    store.setHlsReady(false);
    const playRaw = () => player.src({ src: `/api/stream/${videoId}`, type: 'video/mp4' });

    // 코덱 확인 — 브라우저가 직접 못 푸는 코덱(HEVC 등)이면 HLS로 자동 재생
    let needsHls = false;
    try {
      const meta = await fetch(`/api/meta/${videoId}`).then((r) => r.json());
      needsHls = UNSUPPORTED_CODECS.has(String(meta?.codec ?? '').toLowerCase());
    } catch {
      // meta 조회 실패 시 일단 원본으로 시도
    }

    // await 사이에 사용자가 다른 영상을 선택했으면 중단
    const stillCurrent = () => {
      const s = usePlayerStore.getState().source;
      return s?.kind === 'server' && s.videoId === videoId;
    };

    if (needsHls) {
      if (!stillCurrent()) return;
      const hlsId = videoId.replace(/\.[^.]+$/, '');
      const ready = await fetch(`/api/hls/${hlsId}/index.m3u8`, { method: 'HEAD' })
        .then((r) => r.ok)
        .catch(() => false);
      if (!stillCurrent()) return;
      if (ready) {
        switchToHls(videoId, 0);
        return;
      }
      // HLS 미생성 상태: 원본을 시도(에러 표시)하고, 사용자가 'HLS 변환' 버튼으로 생성하도록 유도
    }

    // 지원 코덱이거나 HLS가 아직 없으면 원본 즉시 재생 (Range Request)
    playRaw();
  // eslint-disable-next-line react-hooks/exhaustive-deps
  }, []);

  const switchToHls = useCallback((videoId: string, seekTo?: number) => {
    const player = playerRef.current;
    if (!player) return;

    const hlsId = videoId.replace(/\.[^.]+$/, '');
    const hlsUrl = `/api/hls/${hlsId}/index.m3u8`;
    const savedTime = seekTo ?? player.currentTime() ?? 0;

    if (Hls.isSupported()) {
      const hls = new Hls(HLS_CONFIG);
      hls.loadSource(hlsUrl);
      const videoEl = player.tech(true)?.el() as HTMLVideoElement;
      hls.attachMedia(videoEl);
      hls.on(Hls.Events.MANIFEST_PARSED, () => {
        player.currentTime(savedTime);
        hlsRef.current = hls;
        store.setHlsReady(true);
      });
    } else {
      player.src({ src: hlsUrl, type: 'application/x-mpegURL' });
      player.currentTime(savedTime);
      store.setHlsReady(true);
    }
  // eslint-disable-next-line react-hooks/exhaustive-deps
  }, []);

  const getVideoElement = useCallback((): HTMLVideoElement | null => {
    return (playerRef.current?.tech(true)?.el() as HTMLVideoElement | null) ?? null;
  }, []);

  return { playerRef, loadLocalFile, loadServerStream, switchToHls, getVideoElement };
}