import { AnyAction, Dispatch } from 'redux';

export enum AsyncEventType {
    onStart = 'onStart',
    onFinished = 'onFinished',
    onSuccess = 'onSuccess',
    onError = 'onError',
}

export interface AsyncAction<PayloadType = any> extends AnyAction {
    eventType: AsyncEventType;
    payload?: PayloadType;
    error?: any;
}

export type AsyncActionFn = <PayloadType = any>(dispatch: Dispatch<AsyncAction<PayloadType>>) => void;
export type AsyncStatusHandler<T> = { [K in AsyncEventType]?: (state: T) => T };

export function handleAsyncAction<S>(state: S, action: AsyncAction, handler: AsyncStatusHandler<S>): S {
    let fn = handler[action.eventType];
    if (!fn) {
        fn = (s) => {
            return s;
        };
    }
    return fn(state);
}