import { Injectable } from '@angular/core';
import { SystemConfigService } from './system-config.service';
import { Observable, Subscriber } from 'rxjs';
import Folder from '../folder';
import { DbStatusService } from './db-status.service';
import { ProgressService } from './progress.service';
import { DbCompletionService } from './db-completion.service';
import { StType } from '../type';

@Injectable({
  providedIn: 'root'
})
export class FolderService {
  private folders: Folder[];

  constructor(
    private systemConfigService: SystemConfigService,
    private dbStatusService: DbStatusService,
    private dbCompletionService: DbCompletionService,
    private progressService: ProgressService,
  ) { }

  getFolderStatusInOrder(observer: Subscriber<Folder>, startIndex: number) {
    // Return if there aren't any folders at the index
    if (startIndex >= (this.folders.length)) {
      observer.complete();
      return;
    }
    const folder: Folder = this.folders[startIndex];
    startIndex = startIndex + 1;
    this.dbStatusService.getFolderStatus(folder.id).subscribe(
      status => {
        folder.status = status;

        this.dbCompletionService.getCompletion(StType.Folder, folder.id).subscribe(
          c => {
            folder.completion = c;
            folder.stateType = Folder.getStateType(folder);
            folder.state = Folder.stateTypeToString(folder.stateType);
            observer.next(folder);

            this.progressService.addToProgress(1);

            // recursively get the status of the next folder
            this.getFolderStatusInOrder(observer, startIndex);
          });
      }
    );
  }

  /**
   * getAll() finds all folders and uses db status service to 
   * set all their statuses
   */
  getAll(): Observable<Folder> {
    // TODO return this.folders if cached

    const folderObservable: Observable<Folder> = new Observable((observer) => {
      this.systemConfigService.getFolders().subscribe(
        folders => {
          this.folders = folders;

          // Synchronously get the status of each folder
          this.getFolderStatusInOrder(observer, 0);
        },
        err => { console.log("getAll error!", err) },
        () => { console.log("get all complete!") }
      );
    });
    return folderObservable
  }
}