wongjiahau/ttap-web

import { MasterStateAction } from "../reducers/masterState";
import { IMasterState } from "./../reducers/masterState";

export class GoToPreviousSubTimetable extends MasterStateAction {
  public TypeName(): string {
    return "go to previous sub timetable";
  }

  protected GenerateNewState(state: IMasterState): IMasterState {
    const s = state.TimetableListState;
    let newIndex = s.CurrentSubIndex - 1;
    if (newIndex < 0) {
      newIndex = s.FiltrateTimetables[s.CurrentIndex].ListOfSlotUids.length - 1;
    }
    return {
      ...state,
      TimetableListState: {
        ...state.TimetableListState,
        ShowingAlternateSlotOf: null,
        CurrentSubIndex: newIndex,
      },
    };
  }
}