// @flow
import React, { useRef, useEffect, useState } from 'react';
import { stopContextMenu } from 'util/context-menu';
import videojs from 'video.js/dist/alt/video.core.novtt.min.js';
import 'video.js/dist/alt/video-js-cdn.min.css';
import eventTracking from 'videojs-event-tracking';
import isUserTyping from 'util/detect-typing';
import analytics from 'analytics';

const F11_KEYCODE = 122;
const SPACE_BAR_KEYCODE = 32;
const SMALL_F_KEYCODE = 70;
const SMALL_M_KEYCODE = 77;
const ARROW_LEFT_KEYCODE = 37;
const ARROW_RIGHT_KEYCODE = 39;

const FULLSCREEN_KEYCODE = SMALL_F_KEYCODE;
const MUTE_KEYCODE = SMALL_M_KEYCODE;

const SEEK_FORWARD_KEYCODE = ARROW_RIGHT_KEYCODE;
const SEEK_BACKWARD_KEYCODE = ARROW_LEFT_KEYCODE;

const SEEK_STEP = 10; // time to seek in seconds

const VIDEO_JS_OPTIONS: { poster?: string } = {
  controls: true,
  autoplay: true,
  preload: 'auto',
  playbackRates: [0.25, 0.5, 0.75, 1, 1.1, 1.25, 1.5, 2],
  responsive: true,
};

type Props = {
  volume: number,
  position: number,
  muted: boolean,
  hasFileInfo: boolean,
  changeVolume: number => void,
  savePosition: (string, number) => void,
  changeMute: boolean => void,
  source: string,
  contentType: string,
  thumbnail: string,
  hasFileInfo: boolean,
  onEndedCB: any,
  claim: Claim,
};

function VideoViewer(props: Props) {
  const { contentType, source, onEndedCB, changeVolume, changeMute, volume, muted, thumbnail, claim } = props;
  const claimId = claim && claim.claim_id;
  const videoRef = useRef();
  const isAudio = contentType.includes('audio');
  let forceTypes = [
    'video/quicktime',
    'application/x-ext-mkv',
    'video/x-matroska',
    'application/octet-stream',
    'video/x-ms-wmv',
    'video/x-msvideo',
    'video/mpeg',
    'video/m4v',
  ];
  const forceMp4 = forceTypes.includes(contentType);
  const [requireRedraw, setRequireRedraw] = useState(false);
  let player;

  useEffect(() => {
    const currentVideo: HTMLVideoElement | null = document.querySelector('video');

    if (!Object.keys(videojs.getPlugins()).includes('eventTracking')) {
      videojs.registerPlugin('eventTracking', eventTracking);
    }

    function doEnded() {
      onEndedCB();
    }

    function doPause(e: Event) {
      // store position e.target.currentTime
    }

    function doVolume(e: Event) {
      // $FlowFixMe volume is missing in EventTarget
      changeVolume(e.target.volume);
      // $FlowFixMe muted is missing in EventTarget
      changeMute(e.target.muted);
    }

    if (currentVideo) {
      currentVideo.addEventListener('ended', doEnded);
      currentVideo.addEventListener('pause', doPause);
      currentVideo.addEventListener('volumechange', doVolume);
    }
    // cleanup function:
    return () => {
      if (currentVideo) {
        currentVideo.removeEventListener('ended', doEnded);
        currentVideo.removeEventListener('pause', doPause);
        currentVideo.removeEventListener('volumechange', doVolume);
      }
    };
  }, []);

  useEffect(() => {
    const videoNode = videoRef.current;
    const videoJsOptions = {
      ...VIDEO_JS_OPTIONS,
      sources: [
        {
          src: source,
          type: forceMp4 ? 'video/mp4' : contentType,
        },
      ],
      plugins: { eventTracking: true },
    };

    if (isAudio) {
      videoJsOptions.poster = thumbnail;
    }

    if (!requireRedraw) {
      player = videojs(videoNode, videoJsOptions, function() {
        player.volume(volume);
        player.muted(muted);
      });
    }

    return () => {
      if (!player) {
        return;
      }

      // Video.js has a player.dispose() function that is meant to cleanup a previous video
      // We can't use this because it does some weird stuff to remove the video element from the page
      // This makes it really hard to use because the ref we keep still thinks it's on the page
      // requireRedraw just makes it so the video component is removed from the page _by react_
      // Then it's set to false immediately after so we can re-mount a new player
      setRequireRedraw(true);
    };
  }, [videoRef, source, contentType, setRequireRedraw, requireRedraw]);

  useEffect(() => {
    if (requireRedraw) {
      setRequireRedraw(false);
    }
  }, [requireRedraw]);

  useEffect(() => {
    function handleKeyDown(e: KeyboardEvent) {
      const videoNode = videoRef.current;

      if (!videoNode || isUserTyping()) {
        return;
      }

      if (e.keyCode === SPACE_BAR_KEYCODE) {
        videoNode.paused ? videoNode.play() : videoNode.pause();
      }

      // Fullscreen toggle shortcuts
      if (e.keyCode === FULLSCREEN_KEYCODE || e.keyCode === F11_KEYCODE) {
        if (!player.isFullscreen()) {
          player.requestFullscreen();
        } else {
          player.exitFullscreen();
        }
      }

      // Mute/Unmute Shortcuts
      if (e.keyCode === MUTE_KEYCODE) {
        videoNode.muted = !videoNode.muted;
      }

      // Seeking Shortcuts
      const duration = videoNode.duration;
      const currentTime = videoNode.currentTime;
      if (e.keyCode === SEEK_FORWARD_KEYCODE) {
        const newDuration = currentTime + SEEK_STEP;
        videoNode.currentTime = newDuration > duration ? duration : newDuration;
      }
      if (e.keyCode === SEEK_BACKWARD_KEYCODE) {
        const newDuration = currentTime - SEEK_STEP;
        videoNode.currentTime = newDuration < 0 ? 0 : newDuration;
      }
    }

    window.addEventListener('keydown', handleKeyDown);
    return () => {
      window.removeEventListener('keydown', handleKeyDown);
    };

    // include requireRedraw here so the event listener is re-added when we need to manually remove/add the video player
  }, [videoRef, requireRedraw]);

  // player analytics
  useEffect(() => {
    function doTrackingBuffered(e: Event, data: any) {
      analytics.videoBufferEvent(claimId, data.currentTime);
    }
    function doTrackingFirstPlay(e: Event, data: any) {
      analytics.videoStartEvent(claimId, data.secondsToLoad);
    }
    if (player) {
      player.on('tracking:buffered', (e, d) => doTrackingBuffered(e, d));
      player.on('tracking:firstplay', (e, d) => doTrackingFirstPlay(e, d));
    }
    return () => {
      if (player) {
        player.off();
      }
    };
  }, [player]);

  return (
    <div className="file-render__viewer" onContextMenu={stopContextMenu}>
      {!requireRedraw && (
        <div data-vjs-player>
          {isAudio ? <audio ref={videoRef} className="video-js" /> : <video ref={videoRef} className="video-js" />}
        </div>
      )}
    </div>
  );
}

export default VideoViewer;