refactor: pretty much the whole backend module hierarchy

backend/src/user-data/library/library.service.ts

@@ -0,0 +1,83 @@
+import { Inject, Injectable } from '@nestjs/common';
+import { Repository } from 'typeorm';
+import { LibraryItem } from './library.entity';
+import { MediaType, PaginationParamsDto } from 'src/common/common.dto';
+import { LibraryItemDto } from './library.dto';
+import { MetadataService } from 'src/metadata/metadata.service';
+import { USER_LIBRARY_REPOSITORY } from './library.providers';
+
+@Injectable()
+export class LibraryService {
+  constructor(
+    @Inject(USER_LIBRARY_REPOSITORY)
+    private readonly libraryRepository: Repository<LibraryItem>,
+    private readonly metadataService: MetadataService,
+  ) {}
+
+  async getLibraryItemsWithMetadata(
+    userId: string,
+    pagination: PaginationParamsDto,
+  ): Promise<LibraryItemDto[]> {
+    const items = await this.getLibraryItems(userId, pagination);
+
+    return Promise.all(
+      items.map(async (item) => {
+        return {
+          ...item,
+          movieMetadata:
+            item.mediaType === MediaType.Movie
+              ? await this.metadataService.getMovieByTmdbId(item.tmdbId)
+              : undefined,
+          seriesMetadata:
+            item.mediaType === MediaType.Series
+              ? await this.metadataService.getSeriesByTmdbId(item.tmdbId)
+              : undefined,
+        };
+      }),
+    );
+  }
+
+  private async getLibraryItems(
+    userId: string,
+    pagination: PaginationParamsDto,
+  ): Promise<LibraryItem[]> {
+    return this.libraryRepository.find({
+      where: { userId },
+      relations: {
+        playStates: true,
+      },
+      take: pagination.itemsPerPage,
+      skip: pagination.itemsPerPage * (pagination.page - 1),
+    });
+  }
+
+  async findByTmdbId(
+    userId: string,
+    tmdbId: string,
+  ): Promise<LibraryItem | null> {
+    return this.libraryRepository.findOne({ where: { userId, tmdbId } });
+  }
+
+  async findOrCreateByTmdbId(
+    userId: string,
+    tmdbId: string,
+    mediaType: MediaType,
+  ): Promise<LibraryItem> {
+    let libraryItem = await this.findByTmdbId(userId, tmdbId);
+
+    if (!libraryItem) {
+      libraryItem = this.libraryRepository.create({
+        userId,
+        tmdbId,
+        mediaType,
+      });
+      await this.libraryRepository.save(libraryItem);
+    }
+
+    return libraryItem;
+  }
+
+  async deleteByTmdbId(userId: string, tmdbId: string) {
+    return await this.libraryRepository.delete({ userId, tmdbId });
+  }
+}