let initialState = {
  // Simplified for the purpose of this example ...
  applicants:   { data: null, isFetching : false },
  applications: { data: null, isFetching : false },
  courses:      { data: null, isFetching : false },
  assignments:  { data: null, isFetching : false },
};



class AppState {

  // Use composition (instead of inheritance) with the Backbone model
  constructor(){
    this._data = new Backbone.NestedModel(initialState);
  }

  // Subscribe a listener, by subscribing it to the underlying Backbone model
  subscribe(listener){
    this._data.bind('change', listener);
  }


  // -------------------------- Public getters and setters -----------------------------------


  getApplicants(){
    return this._data.get('applicants.data');
  }

  isFetchingApplicants(){
    return this._data.get('applicants.isFetching');
  }

  setApplicants(applicants, isFetching=false){
    this._data.set('applicants.data', applicants);
    this._data.set('applicants.isFetching', isFetching);
  }

  setIsFetchingApplicants(isFetching){
    this._data.set('applicants.isFetching', isFetching);
  }

  // TODO: More getters and setters ...
}


let appState = new AppState();
export {appState};