import { Injectable } from '@angular/core';
import { SocketsService } from '../sockets/sockets.service';
import { Observable, Subject, BehaviorSubject } from 'rxjs';

const ON_PERMISSIONS_EVENT = 'currentPermissions';
const PERMISSIONS_ACTION = 'getPerms';

@Injectable()
export class PermissionsService {
  private subject: Subject<any> = new BehaviorSubject({
    canWrite: false,
    canRead: false,
    isOwner: false
  });

  constructor(private sockets: SocketsService) {}

  /**
   * parse permission object
   * @param permissions
   */
  private _parsePermissions(permissions: any) {
    const permLvl: string = permissions.level.toLowerCase();
    const permissionsObj = {
      canWrite: false,
      canRead: false,
      isOwner: false
    };
    switch (permLvl) {
      case 'own':
        permissionsObj.canWrite = true;
        permissionsObj.canRead = true;
        permissionsObj.isOwner = true;
        break;
      case 'r':
        permissionsObj.canWrite = false;
        permissionsObj.canRead = true;
        permissionsObj.isOwner = false;
        break;
      case 'rw':
        permissionsObj.canWrite = true;
        permissionsObj.canRead = true;
        permissionsObj.isOwner = false;
        break;
    }
    return permissionsObj;
  }

  /**
   * load users permissions
   * @param bomId
   */
  public loadPermissions(bomId: string) {
    this.sockets.emitAction(PERMISSIONS_ACTION, { bomId });
    this.sockets
      .observeAction(ON_PERMISSIONS_EVENT)
      .subscribe((permissions: any) => {
        this.subject.next(this._parsePermissions(permissions));
      });
  }

  public getPermissions(): Observable<any> {
    return this.subject;
  }
}