11 files changed, 240 insertions, 35 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 2c8305777..16d657a65 100644
--- a/client/src/app/videos/+video-watch/video-watch.component.html
+++ b/client/src/app/videos/+video-watch/video-watch.component.html
@@ -197,19 +197,10 @@
           </div>
         </div>
 
-        <my-video-comments [video]="video" [user]="user"></my-video-comments>
-      </div>
-
-      <div class="ml-3 ml-sm-0 col-12 col-md-3 other-videos">
-        <div i18n class="title-page title-page-single">
-          Other videos
-        </div>
-
-        <div *ngFor="let video of otherVideosDisplayed">
-          <my-video-miniature [video]="video" [user]="user"></my-video-miniature>
-        </div>
-      </div>
+      <my-video-comments [video]="video" [user]="user"></my-video-comments>
     </div>
+    <my-recommended-videos class="ml-3 ml-sm-0 col-12 col-md-3"
+                           [inputVideo]="video" [user]="user"></my-recommended-videos>
   </div>
 
 
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 d838ebe79..25643cfde 100644
--- a/client/src/app/videos/+video-watch/video-watch.component.ts
+++ b/client/src/app/videos/+video-watch/video-watch.component.ts
@@ -15,7 +15,6 @@ import '../../../assets/player/peertube-videojs-plugin'
 import { AuthService, ConfirmService } from '../../core'
 import { RestExtractor, VideoBlacklistService } from '../../shared'
 import { VideoDetails } from '../../shared/video/video-details.model'
-import { Video } from '../../shared/video/video.model'
 import { VideoService } from '../../shared/video/video.service'
 import { MarkdownService } from '../shared'
 import { VideoDownloadComponent } from './modal/video-download.component'
@@ -43,8 +42,6 @@ export class VideoWatchComponent implements OnInit, OnDestroy {
   @ViewChild('videoSupportModal') videoSupportModal: VideoSupportComponent
   @ViewChild('videoBlacklistModal') videoBlacklistModal: VideoBlacklistComponent
 
-  otherVideosDisplayed: Video[] = []
-
   player: videojs.Player
   playerElement: HTMLVideoElement
   userRating: UserVideoRateType = null
@@ -60,7 +57,6 @@ export class VideoWatchComponent implements OnInit, OnDestroy {
   remoteServerDown = false
 
   private videojsLocaleLoaded = false
-  private otherVideos: Video[] = []
   private paramsSub: Subscription
 
   constructor (
@@ -96,16 +92,6 @@ export class VideoWatchComponent implements OnInit, OnDestroy {
       this.hasAlreadyAcceptedPrivacyConcern = true
     }
 
-    this.videoService.getVideos({ currentPage: 1, itemsPerPage: 5 }, '-createdAt')
-        .subscribe(
-          data => {
-            this.otherVideos = data.videos
-            this.updateOtherVideosDisplayed()
-          },
-
-          err => console.error(err)
-        )
-
     this.paramsSub = this.route.params.subscribe(routeParams => {
       const uuid = routeParams[ 'uuid' ]
 
@@ -365,8 +351,6 @@ export class VideoWatchComponent implements OnInit, OnDestroy {
     this.completeDescriptionShown = false
     this.remoteServerDown = false
 
-    this.updateOtherVideosDisplayed()
-
     if (this.video.isVideoNSFWForUser(this.user, this.serverService.getConfig())) {
       const res = await this.confirmService.confirm(
         this.i18n('This video contains mature or explicit content. Are you sure you want to watch it?'),
@@ -474,12 +458,6 @@ export class VideoWatchComponent implements OnInit, OnDestroy {
     this.setVideoLikesBarTooltipText()
   }
 
-  private updateOtherVideosDisplayed () {
-    if (this.video && this.otherVideos && this.otherVideos.length > 0) {
-      this.otherVideosDisplayed = this.otherVideos.filter(v => v.uuid !== this.video.uuid)
-    }
-  }
-
   private setOpenGraphTags () {
     this.metaService.setTitle(this.video.name)
 
diff --git a/client/src/app/videos/+video-watch/video-watch.module.ts b/client/src/app/videos/+video-watch/video-watch.module.ts
index 7920147b2..5582ab40f 100644
--- a/client/src/app/videos/+video-watch/video-watch.module.ts
+++ b/client/src/app/videos/+video-watch/video-watch.module.ts
@@ -16,6 +16,7 @@ import { VideoWatchComponent } from './video-watch.component'
 import { NgxQRCodeModule } from 'ngx-qrcode2'
 import { NgbTooltipModule } from '@ng-bootstrap/ng-bootstrap'
 import { VideoBlacklistComponent } from '@app/videos/+video-watch/modal/video-blacklist.component'
+import { RecommendationsModule } from '@app/videos/recommendations/recommendations.module'
 import { TextareaAutosizeModule } from 'ngx-textarea-autosize'
 
 @NgModule({
@@ -25,7 +26,8 @@ import { TextareaAutosizeModule } from 'ngx-textarea-autosize'
     ClipboardModule,
     NgbTooltipModule,
     NgxQRCodeModule,
-    TextareaAutosizeModule
+    TextareaAutosizeModule,
+    RecommendationsModule
   ],
 
   declarations: [
diff --git a/client/src/app/videos/recommendations/recent-videos-recommendation.service.spec.ts b/client/src/app/videos/recommendations/recent-videos-recommendation.service.spec.ts
new file mode 100644
index 000000000..f9055b82c
--- /dev/null
+++ b/client/src/app/videos/recommendations/recent-videos-recommendation.service.spec.ts
@@ -0,0 +1,66 @@
+import { RecentVideosRecommendationService } from '@app/videos/recommendations/recent-videos-recommendation.service'
+import { VideosProvider } from '@app/shared/video/video.service'
+import { EMPTY, of } from 'rxjs'
+import Mock = jest.Mock
+
+describe('"Recent Videos" Recommender', () => {
+  describe('getRecommendations', () => {
+    let videosService: VideosProvider
+    let service: RecentVideosRecommendationService
+    let getVideosMock: Mock<any>
+    beforeEach(() => {
+      getVideosMock = jest.fn(() => EMPTY)
+      videosService = {
+        getVideos: getVideosMock
+      }
+      service = new RecentVideosRecommendationService(videosService)
+    })
+    it('should filter out the given UUID from the results', async (done) => {
+      const vids = [
+        { uuid: 'uuid1' },
+        { uuid: 'uuid2' }
+      ]
+      getVideosMock.mockReturnValueOnce(of({ videos: vids }))
+      const result = await service.getRecommendations('uuid1').toPromise()
+      const uuids = result.map(v => v.uuid)
+      expect(uuids).toEqual(['uuid2'])
+      done()
+    })
+    it('should return 5 results when the given UUID is NOT in the first 5 results', async (done) => {
+      const vids = [
+        { uuid: 'uuid2' },
+        { uuid: 'uuid3' },
+        { uuid: 'uuid4' },
+        { uuid: 'uuid5' },
+        { uuid: 'uuid6' },
+        { uuid: 'uuid7' }
+      ]
+      getVideosMock.mockReturnValueOnce(of({ videos: vids }))
+      const result = await service.getRecommendations('uuid1').toPromise()
+      expect(result.length).toEqual(5)
+      done()
+    })
+    it('should return 5 results when the given UUID IS PRESENT in the first 5 results', async (done) => {
+      const vids = [
+        { uuid: 'uuid1' },
+        { uuid: 'uuid2' },
+        { uuid: 'uuid3' },
+        { uuid: 'uuid4' },
+        { uuid: 'uuid5' },
+        { uuid: 'uuid6' }
+      ]
+      getVideosMock
+        .mockReturnValueOnce(of({ videos: vids }))
+      const result = await service.getRecommendations('uuid1').toPromise()
+      expect(result.length).toEqual(5)
+      done()
+    })
+    it('should fetch an extra result in case the given UUID is in the list', async (done) => {
+      await service.getRecommendations('uuid1').toPromise()
+      let expectedSize = service.pageSize + 1
+      let params = { currentPage: jasmine.anything(), itemsPerPage: expectedSize }
+      expect(getVideosMock).toHaveBeenCalledWith(params, jasmine.anything())
+      done()
+    })
+  })
+})
diff --git a/client/src/app/videos/recommendations/recent-videos-recommendation.service.ts b/client/src/app/videos/recommendations/recent-videos-recommendation.service.ts
new file mode 100644
index 000000000..708d67699
--- /dev/null
+++ b/client/src/app/videos/recommendations/recent-videos-recommendation.service.ts
@@ -0,0 +1,39 @@
+import { Inject, Injectable } from '@angular/core'
+import { RecommendationService } from '@app/videos/recommendations/recommendations.service'
+import { Video } from '@app/shared/video/video.model'
+import { VideoService, VideosProvider } from '@app/shared/video/video.service'
+import { map } from 'rxjs/operators'
+import { Observable } from 'rxjs'
+
+/**
+ * Provides "recommendations" by providing the most recently uploaded videos.
+ */
+@Injectable()
+export class RecentVideosRecommendationService implements RecommendationService {
+
+  readonly pageSize = 5
+
+  constructor (
+    @Inject(VideoService) private videos: VideosProvider
+  ) {
+  }
+
+  getRecommendations (uuid: string): Observable<Video[]> {
+    return this.fetchPage(1)
+      .pipe(
+        map(vids => {
+          const otherVideos = vids.filter(v => v.uuid !== uuid)
+          return otherVideos.slice(0, this.pageSize)
+        })
+      )
+  }
+
+  private fetchPage (page: number): Observable<Video[]> {
+    let pagination = { currentPage: page, itemsPerPage: this.pageSize + 1 }
+    return this.videos.getVideos(pagination, '-createdAt')
+      .pipe(
+        map(v => v.videos)
+      )
+  }
+
+}
diff --git a/client/src/app/videos/recommendations/recommendations.module.ts b/client/src/app/videos/recommendations/recommendations.module.ts
new file mode 100644
index 000000000..5a46ea739
--- /dev/null
+++ b/client/src/app/videos/recommendations/recommendations.module.ts
@@ -0,0 +1,25 @@
+import { NgModule } from '@angular/core'
+import { RecommendedVideosComponent } from '@app/videos/recommendations/recommended-videos.component'
+import { RecommendedVideosStore } from '@app/videos/recommendations/recommended-videos.store'
+import { CommonModule } from '@angular/common'
+import { SharedModule } from '@app/shared'
+import { RecentVideosRecommendationService } from '@app/videos/recommendations/recent-videos-recommendation.service'
+
+@NgModule({
+  imports: [
+    SharedModule,
+    CommonModule
+  ],
+  declarations: [
+    RecommendedVideosComponent
+  ],
+  exports: [
+    RecommendedVideosComponent
+  ],
+  providers: [
+    RecommendedVideosStore,
+    RecentVideosRecommendationService
+  ]
+})
+export class RecommendationsModule {
+}
diff --git a/client/src/app/videos/recommendations/recommendations.service.ts b/client/src/app/videos/recommendations/recommendations.service.ts
new file mode 100644
index 000000000..44cbda9b7
--- /dev/null
+++ b/client/src/app/videos/recommendations/recommendations.service.ts
@@ -0,0 +1,8 @@
+import { Video } from '@app/shared/video/video.model'
+import { Observable } from 'rxjs'
+
+export type UUID = string
+
+export interface RecommendationService {
+  getRecommendations (uuid: UUID): Observable<Video[]>
+}
diff --git a/client/src/app/videos/recommendations/recommended-videos.component.html b/client/src/app/videos/recommendations/recommended-videos.component.html
new file mode 100644
index 000000000..7cfaffec2
--- /dev/null
+++ b/client/src/app/videos/recommendations/recommended-videos.component.html
@@ -0,0 +1,11 @@
+<div class="other-videos">
+    <div i18n class="title-page title-page-single">
+        Other videos
+    </div>
+
+    <ng-container *ngIf="hasVideos$ | async">
+        <div *ngFor="let video of (videos$ | async)">
+            <my-video-miniature [video]="video" [user]="user"></my-video-miniature>
+        </div>
+    </ng-container>
+</div>
diff --git a/client/src/app/videos/recommendations/recommended-videos.component.ts b/client/src/app/videos/recommendations/recommended-videos.component.ts
new file mode 100644
index 000000000..aa4dd0ee2
--- /dev/null
+++ b/client/src/app/videos/recommendations/recommended-videos.component.ts
@@ -0,0 +1,31 @@
+import { Component, Input, OnChanges } from '@angular/core'
+import { Observable } from 'rxjs'
+import { Video } from '@app/shared/video/video.model'
+import { RecommendedVideosStore } from '@app/videos/recommendations/recommended-videos.store'
+import { User } from '@app/shared'
+
+@Component({
+  selector: 'my-recommended-videos',
+  templateUrl: './recommended-videos.component.html'
+})
+export class RecommendedVideosComponent implements OnChanges {
+  @Input() inputVideo: Video
+  @Input() user: User
+
+  readonly hasVideos$: Observable<boolean>
+  readonly videos$: Observable<Video[]>
+
+  constructor (
+    private store: RecommendedVideosStore
+  ) {
+    this.videos$ = this.store.recommendations$
+    this.hasVideos$ = this.store.hasRecommendations$
+  }
+
+  public ngOnChanges (): void {
+    if (this.inputVideo) {
+      this.store.requestNewRecommendations(this.inputVideo.uuid)
+    }
+  }
+
+}
diff --git a/client/src/app/videos/recommendations/recommended-videos.store.spec.ts b/client/src/app/videos/recommendations/recommended-videos.store.spec.ts
new file mode 100644
index 000000000..e12a3f520
--- /dev/null
+++ b/client/src/app/videos/recommendations/recommended-videos.store.spec.ts
@@ -0,0 +1,22 @@
+import { RecommendedVideosStore } from '@app/videos/recommendations/recommended-videos.store'
+import { RecommendationService } from '@app/videos/recommendations/recommendations.service'
+
+describe('RecommendedVideosStore', () => {
+  describe('requestNewRecommendations', () => {
+    let store: RecommendedVideosStore
+    let service: RecommendationService
+    beforeEach(() => {
+      service = {
+        getRecommendations: jest.fn(() => new Promise((r) => r()))
+      }
+      store = new RecommendedVideosStore(service)
+    })
+    it('should pull new videos from the service one time when given the same UUID twice', () => {
+      store.requestNewRecommendations('some-uuid')
+      store.requestNewRecommendations('some-uuid')
+      // Requests aren't fulfilled until someone asks for them (ie: subscribes)
+      store.recommendations$.subscribe()
+      expect(service.getRecommendations).toHaveBeenCalledTimes(1)
+    })
+  })
+})
diff --git a/client/src/app/videos/recommendations/recommended-videos.store.ts b/client/src/app/videos/recommendations/recommended-videos.store.ts
new file mode 100644
index 000000000..689adeb1f
--- /dev/null
+++ b/client/src/app/videos/recommendations/recommended-videos.store.ts
@@ -0,0 +1,32 @@
+import { Inject, Injectable } from '@angular/core'
+import { Observable, ReplaySubject } from 'rxjs'
+import { Video } from '@app/shared/video/video.model'
+import { RecentVideosRecommendationService } from '@app/videos/recommendations/recent-videos-recommendation.service'
+import { RecommendationService, UUID } from '@app/videos/recommendations/recommendations.service'
+import { map, switchMap, take } from 'rxjs/operators'
+
+/**
+ * This store is intended to provide data for the RecommendedVideosComponent.
+ */
+@Injectable()
+export class RecommendedVideosStore {
+  public readonly recommendations$: Observable<Video[]>
+  public readonly hasRecommendations$: Observable<boolean>
+  private readonly requestsForLoad$$ = new ReplaySubject<UUID>(1)
+
+  constructor (
+    @Inject(RecentVideosRecommendationService) private recommendations: RecommendationService
+  ) {
+    this.recommendations$ = this.requestsForLoad$$.pipe(
+      switchMap(requestedUUID => recommendations.getRecommendations(requestedUUID)
+        .pipe(take(1))
+      ))
+    this.hasRecommendations$ = this.recommendations$.pipe(
+      map(otherVideos => otherVideos.length > 0)
+    )
+  }
+
+  requestNewRecommendations (videoUUID: string) {
+    this.requestsForLoad$$.next(videoUUID)
+  }
+}