import { Injectable } from '@angular/core';
import { NotificationsService } from '../../shared/notifications/notifications.service';
import { RemoteDataBuildService } from '../cache/builders/remote-data-build.service';
import { ObjectCacheService } from '../cache/object-cache.service';
import { MetadataSchema } from '../metadata/metadata-schema.model';
import { HALEndpointService } from '../shared/hal-endpoint.service';
import { RequestService } from './request.service';
import { Observable } from 'rxjs';
import { hasValue } from '../../shared/empty.util';
import { tap } from 'rxjs/operators';
import { RemoteData } from './remote-data';
import { PutData, PutDataImpl } from './base/put-data';
import { CreateData, CreateDataImpl } from './base/create-data';
import { NoContent } from '../shared/NoContent.model';
import { FindAllData, FindAllDataImpl } from './base/find-all-data';
import { FindListOptions } from './find-list-options.model';
import { FollowLinkConfig } from '../../shared/utils/follow-link-config.model';
import { PaginatedList } from './paginated-list.model';
import { IdentifiableDataService } from './base/identifiable-data.service';
import { DeleteData, DeleteDataImpl } from './base/delete-data';

/**
 * A service responsible for fetching/sending data from/to the REST API on the metadataschemas endpoint
 */
@Injectable({ providedIn: 'root' })
export class MetadataSchemaDataService extends IdentifiableDataService<MetadataSchema> implements FindAllData<MetadataSchema>, DeleteData<MetadataSchema> {
  private createData: CreateData<MetadataSchema>;
  private findAllData: FindAllData<MetadataSchema>;
  private putData: PutData<MetadataSchema>;
  private deleteData: DeleteData<MetadataSchema>;

  constructor(
    protected requestService: RequestService,
    protected rdbService: RemoteDataBuildService,
    protected objectCache: ObjectCacheService,
    protected halService: HALEndpointService,
    protected notificationsService: NotificationsService,
  ) {
    super('metadataschemas', requestService, rdbService, objectCache, halService);

    this.createData = new CreateDataImpl(this.linkPath, requestService, rdbService, objectCache, halService, notificationsService, this.responseMsToLive);
    this.putData = new PutDataImpl(this.linkPath, requestService, rdbService, objectCache, halService, this.responseMsToLive);
    this.deleteData = new DeleteDataImpl(this.linkPath, requestService, rdbService, objectCache, halService, notificationsService, this.responseMsToLive, this.constructIdEndpoint);
    this.findAllData = new FindAllDataImpl(this.linkPath, requestService, rdbService, objectCache, halService, this.responseMsToLive);
  }

  /**
   * Create or Update a MetadataSchema
   *  If the MetadataSchema contains an id, it is assumed the schema already exists and is updated instead
   *  Since creating or updating is nearly identical, the only real difference is the request (and slight difference in endpoint):
   *  - On creation, a CreateRequest is used
   *  - On update, a PutRequest is used
   * @param schema    The MetadataSchema to create or update
   */
  createOrUpdateMetadataSchema(schema: MetadataSchema): Observable<RemoteData<MetadataSchema>> {
    const isUpdate = hasValue(schema.id);

    if (isUpdate) {
      return this.putData.put(schema);
    } else {
      return this.createData.create(schema);
    }
  }

  /**
   * Clear all metadata schema requests
   * Used for refreshing lists after adding/updating/removing a metadata schema in the registry
   */
  clearRequests(): Observable<string> {
    return this.getBrowseEndpoint().pipe(
      tap((href: string) => this.requestService.removeByHrefSubstring(href)),
    );
  }

  /**
   * Returns {@link RemoteData} of all object with a list of {@link FollowLinkConfig}, to indicate which embedded
   * info should be added to the objects
   *
   * @param options                     Find list options object
   * @param useCachedVersionIfAvailable If this is true, the request will only be sent if there's
   *                                    no valid cached version. Defaults to true
   * @param reRequestOnStale            Whether or not the request should automatically be re-
   *                                    requested after the response becomes stale
   * @param linksToFollow               List of {@link FollowLinkConfig} that indicate which
   *                                    {@link HALLink}s should be automatically resolved
   * @return {Observable<RemoteData<PaginatedList<T>>>}
   *    Return an observable that emits object list
   */
  public findAll(options?: FindListOptions, useCachedVersionIfAvailable?: boolean, reRequestOnStale?: boolean, ...linksToFollow: FollowLinkConfig<MetadataSchema>[]): Observable<RemoteData<PaginatedList<MetadataSchema>>> {
    return this.findAllData.findAll(options, useCachedVersionIfAvailable, reRequestOnStale, ...linksToFollow);
  }

  /**
   * Delete an existing object on the server
   * @param   objectId The id of the object to be removed
   * @param   copyVirtualMetadata (optional parameter) the identifiers of the relationship types for which the virtual
   *                            metadata should be saved as real metadata
   * @return  A RemoteData observable with an empty payload, but still representing the state of the request: statusCode,
   *          errorMessage, timeCompleted, etc
   */
  public delete(objectId: string, copyVirtualMetadata?: string[]): Observable<RemoteData<NoContent>> {
    return this.deleteData.delete(objectId, copyVirtualMetadata);
  }

  /**
   * Delete an existing object on the server
   * @param   href The self link of the object to be removed
   * @param   copyVirtualMetadata (optional parameter) the identifiers of the relationship types for which the virtual
   *                            metadata should be saved as real metadata
   * @return  A RemoteData observable with an empty payload, but still representing the state of the request: statusCode,
   *          errorMessage, timeCompleted, etc
   *          Only emits once all request related to the DSO has been invalidated.
   */
  public deleteByHref(href: string, copyVirtualMetadata?: string[]): Observable<RemoteData<NoContent>> {
    return this.deleteData.deleteByHref(href, copyVirtualMetadata);
  }
}
