From 537a38a79a35840951602ab359fb19a8ee6f01cd Mon Sep 17 00:00:00 2001
From: Mirlan <m.maksitaliev@gmail.com>
Date: Wed, 27 Jan 2021 14:25:21 +0600
Subject: [PATCH] feat(703): preloading next episode (#277)

---
 .../MultiSourcePlayer/hooks/index.tsx         | 39 ++++++++++-----
 .../hooks/usePlayingHandlers.tsx              |  7 ++-
 .../hooks/useProgressChangeHandler.tsx        | 49 ++++++++++---------
 src/features/MultiSourcePlayer/index.tsx      | 37 +++++++++++---
 src/features/MultiSourcePlayer/types.tsx      |  5 ++
 src/features/VideoPlayer/hooks/index.tsx      |  3 +-
 src/features/VideoPlayer/index.tsx            |  2 +
 7 files changed, 98 insertions(+), 44 deletions(-)

diff --git a/src/features/MultiSourcePlayer/hooks/index.tsx b/src/features/MultiSourcePlayer/hooks/index.tsx
index 85ddeae2..f4c57d24 100644
--- a/src/features/MultiSourcePlayer/hooks/index.tsx
+++ b/src/features/MultiSourcePlayer/hooks/index.tsx
@@ -19,24 +19,30 @@ import { usePlayingHandlers } from './usePlayingHandlers'
 import { useVideoQuality } from './useVideoQuality'
 import { useDuration } from './useDuration'
 import type { Chapters } from '../types'
+import { Players } from '../types'
 
 export type PlayerState = {
   activeChapterIndex: number,
+  activePlayer: Players,
   loadedProgress: number,
   playedProgress: number,
   playing: boolean,
   ready: boolean,
-  seek: number,
+  seek: Record<Players, number>,
   seeking: boolean,
 }
 
 const initialState: PlayerState = {
   activeChapterIndex: 0,
+  activePlayer: 0,
   loadedProgress: 0,
   playedProgress: 0,
   playing: false,
   ready: false,
-  seek: 0,
+  seek: {
+    [Players.PLAYER1]: 0,
+    [Players.PLAYER2]: 0,
+  },
   seeking: false,
 }
 
@@ -59,6 +65,7 @@ export const useMultiSourcePlayer = ({
   const [
     {
       activeChapterIndex,
+      activePlayer,
       loadedProgress,
       playedProgress,
       playing,
@@ -68,7 +75,8 @@ export const useMultiSourcePlayer = ({
     },
     setPlayerState,
   ] = useObjectState({ ...initialState, activeChapterIndex: resumeFrom.half })
-  const videoRef = useRef<HTMLVideoElement>(null)
+  const video1Ref = useRef<HTMLVideoElement>(null)
+  const video2Ref = useRef<HTMLVideoElement>(null)
   const {
     onReady,
     playNextChapter,
@@ -92,20 +100,24 @@ export const useMultiSourcePlayer = ({
   }, [onError, stopPlaying])
 
   const onProgressChange = useProgressChangeHandler({
-    activeChapterIndex,
     chapters,
     duration,
     setPlayerState,
   })
 
-  const getActiveChapterUrl = useCallback((quality: string = selectedQuality) => (
-    chapters[activeChapterIndex].urls[quality]
-  ), [selectedQuality, chapters, activeChapterIndex])
+  const getChapterUrl = useCallback((index: number, quality: string = selectedQuality) => (
+    chapters[index]?.urls[quality]
+  ), [selectedQuality, chapters])
+
+  const videoRef = [video1Ref, video2Ref][activePlayer]
 
   const onQualitySelect = (quality: string) => {
-    setPlayerState({
-      seek: videoRef.current?.currentTime ?? 0,
-    })
+    setPlayerState((state) => ({
+      seek: {
+        ...state.seek,
+        [state.activePlayer]: videoRef.current?.currentTime ?? 0,
+      },
+    }))
     setSelectedQuality(quality)
   }
 
@@ -159,12 +171,14 @@ export const useMultiSourcePlayer = ({
 
   return {
     activeChapterIndex,
-    activeSrc: getActiveChapterUrl(),
+    activePlayer,
+    activeSrc: getChapterUrl(activeChapterIndex),
     chapters,
     duration,
     isFirstChapterPlaying: activeChapterIndex === 0,
     isLastChapterPlaying: activeChapterIndex === numberOfChapters - 1,
     loadedProgress,
+    nextSrc: getChapterUrl(activeChapterIndex + 1),
     onError: handleError,
     onLoadedProgress,
     onPlayedProgress,
@@ -181,8 +195,9 @@ export const useMultiSourcePlayer = ({
     selectedQuality,
     startPlaying,
     togglePlaying,
+    video1Ref,
+    video2Ref,
     videoQualities,
-    videoRef,
     ...useFullscreen(),
     ...useVolume(),
   }
diff --git a/src/features/MultiSourcePlayer/hooks/usePlayingHandlers.tsx b/src/features/MultiSourcePlayer/hooks/usePlayingHandlers.tsx
index 642f7094..ef5cf692 100644
--- a/src/features/MultiSourcePlayer/hooks/usePlayingHandlers.tsx
+++ b/src/features/MultiSourcePlayer/hooks/usePlayingHandlers.tsx
@@ -2,7 +2,10 @@ import { useCallback } from 'react'
 
 import { SetPartialState } from 'hooks'
 
-import { PlayerState } from '.'
+import type { PlayerState } from '.'
+import { Players } from '../types'
+
+const getNextPlayer = (player: Players): Players => (player + 1) % 2
 
 export const usePlayingHandlers = (
   setPlayerState: SetPartialState<PlayerState>,
@@ -43,6 +46,7 @@ export const usePlayingHandlers = (
       const isLastChapter = state.activeChapterIndex + 1 === numberOfChapters
       return {
         activeChapterIndex: isLastChapter ? 0 : state.activeChapterIndex + 1,
+        activePlayer: getNextPlayer(state.activeChapterIndex),
         loadedProgress: 0,
         playedProgress: 0,
         playing: isLastChapter ? false : state.playing,
@@ -55,6 +59,7 @@ export const usePlayingHandlers = (
       if (!state.ready || state.activeChapterIndex === 0) return state
       return {
         activeChapterIndex: state.activeChapterIndex - 1,
+        activePlayer: getNextPlayer(state.activeChapterIndex),
         loadedProgress: 0,
         playedProgress: 0,
       }
diff --git a/src/features/MultiSourcePlayer/hooks/useProgressChangeHandler.tsx b/src/features/MultiSourcePlayer/hooks/useProgressChangeHandler.tsx
index 7e55f160..ed1883d3 100644
--- a/src/features/MultiSourcePlayer/hooks/useProgressChangeHandler.tsx
+++ b/src/features/MultiSourcePlayer/hooks/useProgressChangeHandler.tsx
@@ -7,42 +7,45 @@ import type { PlayerState } from '.'
 import { findChapterByProgress } from '../helpers'
 
 type Args = {
-  activeChapterIndex: number,
   chapters: Chapters,
   duration: number,
   setPlayerState: SetPartialState<PlayerState>,
 }
 
 export const useProgressChangeHandler = ({
-  activeChapterIndex,
   chapters,
   duration,
   setPlayerState,
 }: Args) => {
   const onProgressChange = useCallback((progress: number, seeking: boolean) => {
-    // значение новой позиции ползунка в миллисекундах
-    const progressMs = progress * duration
-    const chapterIndex = findChapterByProgress(chapters, progressMs)
-    const chapter = chapters[chapterIndex]
-    const isProgressOnDifferentChapter = (
-      chapterIndex !== -1
-      && chapterIndex !== activeChapterIndex
-    )
-    const nextChapter = isProgressOnDifferentChapter
-      ? chapterIndex
-      : activeChapterIndex
+    setPlayerState((state) => {
+      // значение новой позиции ползунка в миллисекундах
+      const progressMs = progress * duration
+      const chapterIndex = findChapterByProgress(chapters, progressMs)
+      const chapter = chapters[chapterIndex]
+      const isProgressOnDifferentChapter = (
+        chapterIndex !== -1
+        && chapterIndex !== state.activeChapterIndex
+      )
+      const nextChapter = isProgressOnDifferentChapter
+        ? chapterIndex
+        : state.activeChapterIndex
 
-    // отнимаем начало главы на котором остановились от общего прогресса
-    // чтобы получить прогресс текущей главы
-    const chapterProgressMs = (progressMs - chapter.startMs)
-    const seekMs = chapterProgressMs + chapter.startOffsetMs
-    setPlayerState({
-      activeChapterIndex: nextChapter,
-      playedProgress: chapterProgressMs,
-      seek: seekMs / 1000,
-      seeking,
+      // отнимаем начало главы на котором остановились от общего прогресса
+      // чтобы получить прогресс текущей главы
+      const chapterProgressMs = (progressMs - chapter.startMs)
+      const seekMs = chapterProgressMs + chapter.startOffsetMs
+      return {
+        activeChapterIndex: nextChapter,
+        playedProgress: chapterProgressMs,
+        seek: {
+          ...state.seek,
+          [state.activePlayer]: seekMs / 1000,
+        },
+        seeking,
+      }
     })
-  }, [duration, chapters, activeChapterIndex, setPlayerState])
+  }, [duration, chapters, setPlayerState])
 
   return onProgressChange
 }
diff --git a/src/features/MultiSourcePlayer/index.tsx b/src/features/MultiSourcePlayer/index.tsx
index 93c0294d..433b1dbe 100644
--- a/src/features/MultiSourcePlayer/index.tsx
+++ b/src/features/MultiSourcePlayer/index.tsx
@@ -15,10 +15,12 @@ import { ProgressBar } from './components/ProgressBar'
 import { Settings } from './components/Settings'
 import type { Props } from './hooks'
 import { useMultiSourcePlayer } from './hooks'
+import { Players } from './types'
 
 export const MultiSourcePlayer = (props: Props) => {
   const {
     activeChapterIndex,
+    activePlayer,
     activeSrc,
     chapters,
     duration,
@@ -27,6 +29,7 @@ export const MultiSourcePlayer = (props: Props) => {
     isLastChapterPlaying,
     loadedProgress,
     muted,
+    nextSrc,
     onError,
     onFullscreenClick,
     onLoadedProgress,
@@ -45,12 +48,16 @@ export const MultiSourcePlayer = (props: Props) => {
     seek,
     selectedQuality,
     togglePlaying,
+    video1Ref,
+    video2Ref,
     videoQualities,
-    videoRef,
     volume,
     volumeInPercent,
     wrapperRef,
   } = useMultiSourcePlayer(props)
+
+  const firstPlayerActive = activePlayer === Players.PLAYER1
+
   return (
     <PlayerWrapper
       ref={wrapperRef}
@@ -65,15 +72,31 @@ export const MultiSourcePlayer = (props: Props) => {
         )
       }
       <VideoPlayer
-        src={activeSrc}
-        playing={playing}
+        src={firstPlayerActive ? activeSrc : nextSrc}
+        playing={firstPlayerActive ? playing : false}
+        hidden={!firstPlayerActive}
+        muted={muted}
+        volume={volume}
+        ref={video1Ref}
+        seek={seek[Players.PLAYER1]}
+        isFullscreen={isFullscreen}
+        onLoadedProgress={firstPlayerActive ? onLoadedProgress : undefined}
+        onPlayedProgress={firstPlayerActive ? onPlayedProgress : undefined}
+        onEnded={playNextChapter}
+        onError={onError}
+        onReady={onReady}
+      />
+      <VideoPlayer
+        src={!firstPlayerActive ? activeSrc : nextSrc}
+        playing={!firstPlayerActive ? playing : false}
+        hidden={firstPlayerActive}
         muted={muted}
         volume={volume}
-        ref={videoRef}
-        seek={seek}
+        ref={video2Ref}
+        seek={seek[Players.PLAYER2]}
         isFullscreen={isFullscreen}
-        onLoadedProgress={onLoadedProgress}
-        onPlayedProgress={onPlayedProgress}
+        onLoadedProgress={!firstPlayerActive ? onLoadedProgress : undefined}
+        onPlayedProgress={!firstPlayerActive ? onPlayedProgress : undefined}
         onEnded={playNextChapter}
         onError={onError}
         onReady={onReady}
diff --git a/src/features/MultiSourcePlayer/types.tsx b/src/features/MultiSourcePlayer/types.tsx
index c0976269..e880843e 100644
--- a/src/features/MultiSourcePlayer/types.tsx
+++ b/src/features/MultiSourcePlayer/types.tsx
@@ -10,3 +10,8 @@ export type Chapter = {
 }
 
 export type Chapters = Array<Chapter>
+
+export enum Players {
+  PLAYER1 = 0,
+  PLAYER2 = 1,
+}
diff --git a/src/features/VideoPlayer/hooks/index.tsx b/src/features/VideoPlayer/hooks/index.tsx
index 470488c0..6985b3c0 100644
--- a/src/features/VideoPlayer/hooks/index.tsx
+++ b/src/features/VideoPlayer/hooks/index.tsx
@@ -15,6 +15,7 @@ type Ref = Parameters<ForwardRefRenderFunction<HTMLVideoElement>>[1]
 export type Props = {
   className?: string,
   height?: string,
+  hidden?: boolean,
   isFullscreen?: boolean,
   muted?: boolean,
   onDurationChange?: (durationMs: number) => void,
@@ -63,7 +64,7 @@ export const useVideoPlayer = ({
 
   useEffect(() => {
     const video = videoRef.current
-    if (!video) return
+    if (!video || !src) return
 
     video.src = src
     video.load()
diff --git a/src/features/VideoPlayer/index.tsx b/src/features/VideoPlayer/index.tsx
index a5953ee4..24901c44 100644
--- a/src/features/VideoPlayer/index.tsx
+++ b/src/features/VideoPlayer/index.tsx
@@ -8,6 +8,7 @@ export const VideoPlayer = forwardRef<HTMLVideoElement, Props>((props: Props, re
   const {
     className,
     height,
+    hidden,
     onEnded,
     onError,
     src,
@@ -26,6 +27,7 @@ export const VideoPlayer = forwardRef<HTMLVideoElement, Props>((props: Props, re
       className={className}
       width={width}
       height={height}
+      hidden={hidden}
       ref={videoRef}
       src={src}
       muted={volume === 0}