import { AlbumAsset, AlbumAssetCount, AlbumAssets, AlbumInfoOptions, IAlbumRepository } from '@app/domain';
import { Injectable } from '@nestjs/common';
import { InjectDataSource, InjectRepository } from '@nestjs/typeorm';
import { DataSource, FindOptionsOrder, FindOptionsRelations, In, IsNull, Not, Repository } from 'typeorm';
import { dataSource } from '../database.config';
import { AlbumEntity, AssetEntity } from '../entities';

@Injectable()
export class AlbumRepository implements IAlbumRepository {
  constructor(
    @InjectRepository(AssetEntity) private assetRepository: Repository<AssetEntity>,
    @InjectRepository(AlbumEntity) private repository: Repository<AlbumEntity>,
    @InjectDataSource() private dataSource: DataSource,
  ) {}

  getById(id: string, options: AlbumInfoOptions): Promise<AlbumEntity | null> {
    const relations: FindOptionsRelations<AlbumEntity> = {
      owner: true,
      sharedUsers: true,
      assets: false,
      sharedLinks: true,
    };

    const order: FindOptionsOrder<AlbumEntity> = {};

    if (options.withAssets) {
      relations.assets = {
        exifInfo: true,
      };

      order.assets = {
        fileCreatedAt: 'DESC',
      };
    }

    return this.repository.findOne({ where: { id }, relations, order });
  }

  getByIds(ids: string[]): Promise<AlbumEntity[]> {
    return this.repository.find({
      where: {
        id: In(ids),
      },
      relations: {
        owner: true,
        sharedUsers: true,
      },
    });
  }

  getByAssetId(ownerId: string, assetId: string): Promise<AlbumEntity[]> {
    return this.repository.find({
      where: [
        { ownerId, assets: { id: assetId } },
        { sharedUsers: { id: ownerId }, assets: { id: assetId } },
      ],
      relations: { owner: true, sharedUsers: true },
      order: { createdAt: 'DESC' },
    });
  }

  async getAssetCountForIds(ids: string[]): Promise<AlbumAssetCount[]> {
    // Guard against running invalid query when ids list is empty.
    if (!ids.length) {
      return [];
    }

    // Only possible with query builder because of GROUP BY.
    const countByAlbums = await this.repository
      .createQueryBuilder('album')
      .select('album.id')
      .addSelect('COUNT(albums_assets.assetsId)', 'asset_count')
      .leftJoin('albums_assets_assets', 'albums_assets', 'albums_assets.albumsId = album.id')
      .where('album.id IN (:...ids)', { ids })
      .groupBy('album.id')
      .getRawMany();

    return countByAlbums.map<AlbumAssetCount>((albumCount) => ({
      albumId: albumCount['album_id'],
      assetCount: Number(albumCount['asset_count']),
    }));
  }

  /**
   * Returns the album IDs that have an invalid thumbnail, when:
   *  - Thumbnail references an asset outside the album
   *  - Empty album still has a thumbnail set
   */
  async getInvalidThumbnail(): Promise<string[]> {
    // Using dataSource, because there is no direct access to albums_assets_assets.
    const albumHasAssets = this.dataSource
      .createQueryBuilder()
      .select('1')
      .from('albums_assets_assets', 'albums_assets')
      .where('"albums"."id" = "albums_assets"."albumsId"');

    const albumContainsThumbnail = albumHasAssets
      .clone()
      .andWhere('"albums"."albumThumbnailAssetId" = "albums_assets"."assetsId"');

    const albums = await this.repository
      .createQueryBuilder('albums')
      .select('albums.id')
      .where(`"albums"."albumThumbnailAssetId" IS NULL AND EXISTS (${albumHasAssets.getQuery()})`)
      .orWhere(`"albums"."albumThumbnailAssetId" IS NOT NULL AND NOT EXISTS (${albumContainsThumbnail.getQuery()})`)
      .getMany();

    return albums.map((album) => album.id);
  }

  getOwned(ownerId: string): Promise<AlbumEntity[]> {
    return this.repository.find({
      relations: { sharedUsers: true, sharedLinks: true, owner: true },
      where: { ownerId },
      order: { createdAt: 'DESC' },
    });
  }

  /**
   * Get albums shared with and shared by owner.
   */
  getShared(ownerId: string): Promise<AlbumEntity[]> {
    return this.repository.find({
      relations: { sharedUsers: true, sharedLinks: true, owner: true },
      where: [
        { sharedUsers: { id: ownerId } },
        { sharedLinks: { userId: ownerId } },
        { ownerId, sharedUsers: { id: Not(IsNull()) } },
      ],
      order: { createdAt: 'DESC' },
    });
  }

  /**
   * Get albums of owner that are _not_ shared
   */
  getNotShared(ownerId: string): Promise<AlbumEntity[]> {
    return this.repository.find({
      relations: { sharedUsers: true, sharedLinks: true, owner: true },
      where: { ownerId, sharedUsers: { id: IsNull() }, sharedLinks: { id: IsNull() } },
      order: { createdAt: 'DESC' },
    });
  }

  async restoreAll(userId: string): Promise<void> {
    await this.repository.restore({ ownerId: userId });
  }

  async softDeleteAll(userId: string): Promise<void> {
    await this.repository.softDelete({ ownerId: userId });
  }

  async deleteAll(userId: string): Promise<void> {
    await this.repository.delete({ ownerId: userId });
  }

  getAll(): Promise<AlbumEntity[]> {
    return this.repository.find({
      relations: {
        owner: true,
      },
    });
  }

  async removeAsset(assetId: string): Promise<void> {
    // Using dataSource, because there is no direct access to albums_assets_assets.
    await this.dataSource
      .createQueryBuilder()
      .delete()
      .from('albums_assets_assets')
      .where('"albums_assets_assets"."assetsId" = :assetId', { assetId });
  }

  async removeAssets(asset: AlbumAssets): Promise<void> {
    await this.dataSource
      .createQueryBuilder()
      .delete()
      .from('albums_assets_assets')
      .where({
        albumsId: asset.albumId,
        assetsId: In(asset.assetIds),
      })
      .execute();
  }

  /**
   * Get asset IDs for the given album ID.
   *
   * @param albumId Album ID to get asset IDs for.
   * @param assetIds Optional list of asset IDs to filter on.
   * @returns Set of Asset IDs for the given album ID.
   */
  async getAssetIds(albumId: string, assetIds?: string[]): Promise<Set<string>> {
    const query = this.dataSource
      .createQueryBuilder()
      .select('albums_assets.assetsId', 'assetId')
      .from('albums_assets_assets', 'albums_assets')
      .where('"albums_assets"."albumsId" = :albumId', { albumId });

    if (assetIds?.length) {
      query.andWhere('"albums_assets"."assetsId" IN (:...assetIds)', { assetIds });
    }

    const result = await query.getRawMany();
    return new Set(result.map((row) => row['assetId']));
  }

  hasAsset(asset: AlbumAsset): Promise<boolean> {
    return this.repository.exist({
      where: {
        id: asset.albumId,
        assets: {
          id: asset.assetId,
        },
      },
      relations: {
        assets: true,
      },
    });
  }

  async addAssets({ albumId, assetIds }: AlbumAssets): Promise<void> {
    await this.dataSource
      .createQueryBuilder()
      .insert()
      .into('albums_assets_assets', ['albumsId', 'assetsId'])
      .values(assetIds.map((assetId) => ({ albumsId: albumId, assetsId: assetId })))
      .execute();
  }

  async create(album: Partial<AlbumEntity>): Promise<AlbumEntity> {
    return this.save(album);
  }

  async update(album: Partial<AlbumEntity>): Promise<AlbumEntity> {
    return this.save(album);
  }

  async delete(album: AlbumEntity): Promise<void> {
    await this.repository.remove(album);
  }

  private async save(album: Partial<AlbumEntity>) {
    const { id } = await this.repository.save(album);
    return this.repository.findOneOrFail({
      where: { id },
      relations: {
        owner: true,
        sharedUsers: true,
        sharedLinks: true,
        assets: true,
      },
    });
  }

  /**
   * Makes sure all thumbnails for albums are updated by:
   * - Removing thumbnails from albums without assets
   * - Removing references of thumbnails to assets outside the album
   * - Setting a thumbnail when none is set and the album contains assets
   *
   * @returns Amount of updated album thumbnails or undefined when unknown
   */
  async updateThumbnails(): Promise<number | undefined> {
    // Subquery for getting a new thumbnail.
    const newThumbnail = this.assetRepository
      .createQueryBuilder('assets')
      .select('albums_assets2.assetsId')
      .addFrom('albums_assets_assets', 'albums_assets2')
      .where('albums_assets2.assetsId = assets.id')
      .andWhere('albums_assets2.albumsId = "albums"."id"') // Reference to albums.id outside this query
      .orderBy('assets.fileCreatedAt', 'DESC')
      .limit(1);

    // Using dataSource, because there is no direct access to albums_assets_assets.
    const albumHasAssets = dataSource
      .createQueryBuilder()
      .select('1')
      .from('albums_assets_assets', 'albums_assets')
      .where('"albums"."id" = "albums_assets"."albumsId"');

    const albumContainsThumbnail = albumHasAssets
      .clone()
      .andWhere('"albums"."albumThumbnailAssetId" = "albums_assets"."assetsId"');

    const updateAlbums = this.repository
      .createQueryBuilder('albums')
      .update(AlbumEntity)
      .set({ albumThumbnailAssetId: () => `(${newThumbnail.getQuery()})` })
      .where(`"albums"."albumThumbnailAssetId" IS NULL AND EXISTS (${albumHasAssets.getQuery()})`)
      .orWhere(`"albums"."albumThumbnailAssetId" IS NOT NULL AND NOT EXISTS (${albumContainsThumbnail.getQuery()})`);

    const result = await updateAlbums.execute();

    return result.affected;
  }
}