import { err, ok, Result } from 'src/shared/core/Result';
import { UseCase } from 'src/shared/core/UseCase';
import {
  ICollectionQueryRepository,
  CollectionSortField,
  SortOrder,
} from '../../../domain/ICollectionQueryRepository';
import { IProfileService } from 'src/modules/cards/domain/services/IProfileService';
import { DIDOrHandle } from 'src/modules/atproto/domain/DIDOrHandle';
import { IIdentityResolutionService } from 'src/modules/atproto/domain/services/IIdentityResolutionService';

export interface GetCollectionsQuery {
  curatorId: string;
  page?: number;
  limit?: number;
  sortBy?: CollectionSortField;
  sortOrder?: SortOrder;
  searchText?: string;
}

// Enriched data for the final use case result
export interface CollectionListItemDTO {
  id: string;
  uri?: string;
  name: string;
  description?: string;
  updatedAt: Date;
  createdAt: Date;
  cardCount: number;
  createdBy: {
    id: string;
    name: string;
    handle: string;
    avatarUrl?: string;
  };
}
export interface GetCollectionsResult {
  collections: CollectionListItemDTO[];
  pagination: {
    currentPage: number;
    totalPages: number;
    totalCount: number;
    hasMore: boolean;
    limit: number;
  };
  sorting: {
    sortBy: CollectionSortField;
    sortOrder: SortOrder;
  };
}

export class ValidationError extends Error {
  constructor(message: string) {
    super(message);
    this.name = 'ValidationError';
  }
}

export class GetCollectionsUseCase
  implements UseCase<GetCollectionsQuery, Result<GetCollectionsResult>>
{
  constructor(
    private collectionQueryRepo: ICollectionQueryRepository,
    private profileService: IProfileService,
    private identityResolver: IIdentityResolutionService,
  ) {}

  async execute(
    query: GetCollectionsQuery,
  ): Promise<Result<GetCollectionsResult>> {
    // Set defaults
    const page = query.page || 1;
    const limit = Math.min(query.limit || 20, 100); // Cap at 100
    const sortBy = query.sortBy || CollectionSortField.UPDATED_AT;
    const sortOrder = query.sortOrder || SortOrder.DESC;

    // Parse and validate curator identifier
    const identifierResult = DIDOrHandle.create(query.curatorId);
    if (identifierResult.isErr()) {
      return err(new ValidationError('Invalid curator identifier'));
    }

    // Resolve to DID
    const didResult = await this.identityResolver.resolveToDID(
      identifierResult.value,
    );
    if (didResult.isErr()) {
      return err(
        new ValidationError(
          `Could not resolve curator identifier: ${didResult.error.message}`,
        ),
      );
    }

    const resolvedDid = didResult.value.value;

    try {
      // Execute query to get raw collection data using the resolved DID
      const result = await this.collectionQueryRepo.findByCreator(resolvedDid, {
        page,
        limit,
        sortBy,
        sortOrder,
        searchText: query.searchText,
      });

      // Get user profile for the curator using the resolved DID
      const profileResult = await this.profileService.getProfile(resolvedDid);

      if (profileResult.isErr()) {
        return err(
          new Error(
            `Failed to fetch user profile: ${profileResult.error instanceof Error ? profileResult.error.message : 'Unknown error'}`,
          ),
        );
      }
      const profile = profileResult.value;

      // Transform raw data to enriched DTOs
      const enrichedCollections: CollectionListItemDTO[] = result.items.map(
        (item) => {
          return {
            id: item.id,
            uri: item.uri,
            name: item.name,
            description: item.description,
            updatedAt: item.updatedAt,
            createdAt: item.createdAt,
            cardCount: item.cardCount,
            createdBy: {
              id: profile.id,
              name: profile.name,
              handle: profile.handle,
              avatarUrl: profile.avatarUrl,
            },
          };
        },
      );

      return ok({
        collections: enrichedCollections,
        pagination: {
          currentPage: page,
          totalPages: Math.ceil(result.totalCount / limit),
          totalCount: result.totalCount,
          hasMore: page * limit < result.totalCount,
          limit,
        },
        sorting: {
          sortBy,
          sortOrder,
        },
      });
    } catch (error) {
      return err(
        new Error(
          `Failed to retrieve collections: ${error instanceof Error ? error.message : 'Unknown error'}`,
        ),
      );
    }
  }
}