import { ActionReducer, TypedAction, switchReduce } from '@ngrx/store';

export class AddAction implements TypedAction<number> {
  readonly type = 'ADD';
  constructor(public readonly payload: number) {}
}
export class SubtractAction implements TypedAction<number> {
  readonly type = 'SUBTRACT';
  constructor(public readonly payload: number) {}
}
export class ResetAction implements TypedAction<any> {
  readonly type = 'RESET';
  readonly payload: any;
  constructor() {}
}

export const counterReducer: ActionReducer<number> =
  (state: number = 0, action: TypedAction<any>) =>
    switchReduce(state, action)
      .byClass(AddAction, (num: number) => {
        return state + num;
      })
      .byClass(SubtractAction, (num: number) => {
        return state - num;
      })
      .byClass(ResetAction, () => {
        return 0;
      })
      .reduce();