/**
 * Service to interact with the diary database
 */
@Injectable()
export class LogDiaryService {
  private diary: MongoRepository<Diary>;

  private user: Repository<User>;

  public constructor(
    @InjectRepository(Diary, DATA_SOURCE_MONGO) diary: MongoRepository<Diary>,
    @InjectRepository(User, DATA_SOURCE_DEFAULT) user: Repository<User>
  ) {
    this.diary = diary;
    this.user = user;
  }
  /**
   * Retrive a diary by mongo ID
   */
  public async getById(id: string): Promise<DiaryResponse> {
    const diary = await this.diary.findOneByOrFail({
      _id: ObjectId.createFromHexString(id),
    });
    const [response] = await this.reformat([diary]);
    return response;
  }

  /**
   * Get all diaries in mongo
   */
  public async getAll(): Promise<DiaryResponse[]> {
    const diaries = await this.diary.find({});
    return this.reformat(diaries);
  }

  /**
   * Reformat log diaries to resolve all users both the owner AND reviewers
   */
  private async reformat (diaries: Diary[] = []): Promise<DiaryResponse[]> {
    const userIds = [...new Set(
      ...diaries.map(({ userId, reviews, markers }) => [
        userId,
        ...reviews.map(({ userId }) => userId),
        ...markers.map((userId) => userId),
      ])
    )];

    const users = await this.user.findBy({
      id: In(userIds),
    });

    return diaries.map(({ userId, ...diary }) => ({
      ...diary,
      id: diary.id.toString(),
      user: users.find(({ id }) => id === userId),
      markers: diary.markers.map((marker) => users.find(({ id }) => id === marker)),
      reviews: diary.reviews.map(({ userId: uId, ...review }) => ({
        ...review,
        user: users.find(({ id }) => uId === id),
      })),
    }));
  }
}