import {Injectable} from '@angular/core';
import {ReplaySubject, Observable} from 'rxjs';
import {UploadTarget} from '../../model/upload-target.model';
import {PrepareService} from '../prepare/prepare.service';
import {ObjectType} from '../../model/object-type.model';

/**
 * Service for registration of upload targets. Any app component can register itself
 * to retrieve files dragged to the client. This way also plugins are able to fetch and
 * process uploaded files.
 */

@Injectable({
  providedIn: 'root'
})
export class UploadRegistryService {

  private _targets: UploadTarget[] = [];
  private targetsSource = new ReplaySubject<UploadTarget[]>(1);
  private overlayActive: boolean;
  /**
   * Stream of currently available upload targets
   */
  public uploadTargets$: Observable<UploadTarget[]> = this.targetsSource.asObservable();

  /**
   * @ignore
   */
  constructor(private prepareService: PrepareService) {
  }

  setOverlayActive(oa: boolean) {
    this.overlayActive = oa;
  }
  isOverlayActive() {
    return this.overlayActive;
  }

  /**
   * Registers a new upload target.
   * If there is an existing target with the same ID it will be updated.
   *
   * @param uploadTarget The target to be registered
   */
  register(uploadTarget: UploadTarget) {

    if (uploadTarget.referenceObject) {
      uploadTarget.description = `${(uploadTarget.type === 'object' && uploadTarget.referenceObject?.type?.label) ? `${uploadTarget.referenceObject.type.label}: ` : ''}${uploadTarget.referenceObject.title}`;
       if (uploadTarget.subFolder) {
        this.prepareService.getPrepareChildTypes(uploadTarget.referenceObject.id).subscribe((res) => { 
          if (this.isSubFolderAllowed(uploadTarget.subFolder.data, res.types)) {
            uploadTarget.description += '; ' + uploadTarget.subFolder.name;
          }
        });
      }
    }

    const target = this._targets.find(t => t.id === uploadTarget.id);
    if (target) {
      Object.assign(target, uploadTarget);
    } else {
      this._targets.push(uploadTarget);
    }
    this.targetsSource.next(this._targets);
  }

  /**
   * Checks if it is allowed to drop Files in SubFolders
   *
   * @param subFolder
   * @param ObjectType[] locationTypes
   * @returns boolean
   */
  isSubFolderAllowed(subFolder: any, locationTypes: ObjectType[]): boolean {
    return !!locationTypes.find(lt => lt.name === subFolder.type);
  }

  /**
   * Removes an upload target from the list of registered targets.
   *
   * @param uploadTargetId ID of the target to be removed
   */
  unregister(uploadTargetId: string) {
    this._targets = this._targets.filter((t) => t.id !== uploadTargetId);
    this.targetsSource.next(this._targets);
  }
}