8 files changed, 234 insertions, 0 deletions

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)
+  }
+}