Autoplay next recommended video (#2137)

* Start working on autoplay of next video

* Ignore changes made by gitpod

* Apply changes from PR#1370

* Correct the spelling of recommendations

* Fix linting errors

* Move boolean check to existing onEnded handler

* Pick a random video until the recommendations are improved

* Add simple tests for autoPlayNextVideo

* Fix lint

...again

3 files changed, 25 insertions, 2 deletions

diff --git a/client/src/app/videos/+video-watch/video-watch.component.html b/client/src/app/videos/+video-watch/video-watch.component.html
index 6a02f630a..cd60c407f 100644
--- a/client/src/app/videos/+video-watch/video-watch.component.html
+++ b/client/src/app/videos/+video-watch/video-watch.component.html
@@ -199,7 +199,11 @@
       <my-video-comments [video]="video" [user]="user"></my-video-comments>
     </div>
 
-    <my-recommended-videos [inputRecommendation]="{ uuid: video.uuid, tags: video.tags }" [user]="user"></my-recommended-videos>
+    <my-recommended-videos
+        [inputRecommendation]="{ uuid: video.uuid, tags: video.tags }"
+        [user]="user"
+        (gotRecommendations)="onRecommendations($event)"
+    ></my-recommended-videos>
   </div>
 
   <div class="row privacy-concerns" *ngIf="hasAlreadyAcceptedPrivacyConcern === false">
diff --git a/client/src/app/videos/+video-watch/video-watch.component.ts b/client/src/app/videos/+video-watch/video-watch.component.ts
index 21a24113f..1e7991738 100644
--- a/client/src/app/videos/+video-watch/video-watch.component.ts
+++ b/client/src/app/videos/+video-watch/video-watch.component.ts
@@ -35,6 +35,7 @@ import { getStoredTheater } from '../../../assets/player/peertube-player-local-s
 import { PluginService } from '@app/core/plugins/plugin.service'
 import { HooksService } from '@app/core/plugins/hooks.service'
 import { PlatformLocation } from '@angular/common'
+import { randomInt } from '@shared/core-utils/miscs/miscs'
 
 @Component({
   selector: 'my-video-watch',
@@ -69,6 +70,7 @@ export class VideoWatchComponent implements OnInit, OnDestroy {
   remoteServerDown = false
   hotkeys: Hotkey[]
 
+  private nextVideoUuid = ''
   private currentTime: number
   private paramsSub: Subscription
   private queryParamsSub: Subscription
@@ -217,6 +219,13 @@ export class VideoWatchComponent implements OnInit, OnDestroy {
     return this.video.tags
   }
 
+  onRecommendations (videos: Video[]) {
+    if (videos.length > 0) {
+      // Pick a random video until the recommendations are improved
+      this.nextVideoUuid = videos[randomInt(0,videos.length - 1)].uuid
+    }
+  }
+
   onVideoRemoved () {
     this.redirectService.redirectToHomepage()
   }
@@ -477,6 +486,8 @@ export class VideoWatchComponent implements OnInit, OnDestroy {
       this.player.one('ended', () => {
         if (this.playlist) {
           this.zone.run(() => this.videoWatchPlaylist.navigateToNextPlaylistVideo())
+        } else if (this.user && this.user.autoPlayNextVideo) {
+          this.zone.run(() => this.autoplayNext())
         }
       })
 
@@ -500,6 +511,12 @@ export class VideoWatchComponent implements OnInit, OnDestroy {
     this.hooks.runAction('action:video-watch.video.loaded', 'video-watch')
   }
 
+  private autoplayNext () {
+    if (this.nextVideoUuid) {
+      this.router.navigate([ '/videos/watch', this.nextVideoUuid ])
+    }
+  }
+
   private setRating (nextRating: UserVideoRateType) {
     const ratingMethods: { [id in UserVideoRateType]: (id: number) => Observable<any> } = {
       like: this.videoService.setVideoLike,
diff --git a/client/src/app/videos/recommendations/recommended-videos.component.ts b/client/src/app/videos/recommendations/recommended-videos.component.ts
index 68fd750cc..7e0fb8856 100644
--- a/client/src/app/videos/recommendations/recommended-videos.component.ts
+++ b/client/src/app/videos/recommendations/recommended-videos.component.ts
@@ -1,4 +1,4 @@
-import { Component, Input, OnChanges } from '@angular/core'
+import { Component, Input, Output, OnChanges, EventEmitter } from '@angular/core'
 import { Observable } from 'rxjs'
 import { Video } from '@app/shared/video/video.model'
 import { RecommendationInfo } from '@app/shared/video/recommendation-info.model'
@@ -12,6 +12,7 @@ import { User } from '@app/shared'
 export class RecommendedVideosComponent implements OnChanges {
   @Input() inputRecommendation: RecommendationInfo
   @Input() user: User
+  @Output() gotRecommendations = new EventEmitter<Video[]>()
 
   readonly hasVideos$: Observable<boolean>
   readonly videos$: Observable<Video[]>
@@ -21,6 +22,7 @@ export class RecommendedVideosComponent implements OnChanges {
   ) {
     this.videos$ = this.store.recommendations$
     this.hasVideos$ = this.store.hasRecommendations$
+    this.videos$.subscribe(videos => this.gotRecommendations.emit(videos))
   }
 
   public ngOnChanges (): void {