Kotlin middleware

middleware_kotlin.kt

internal val deviceMiddleware: Middleware<AppState> = { dispatch, state ->
    // dispatch: Function that send actions to the begining of the middleware list
    // state: Function that returns an atomic copy of the state  
    // next: Function to send the action to the next middleware                                                   
    // action: New incoming action 
    { next ->
        { action ->
            when (action) {
                is DeviceConnected -> {
                    val currentState = state()?.appStoreState
                    when {
                        appState === currentState.WaitingForData ->  {
                            // dispatch an action inmediatelly 
                            // the action will be inserted at the begining of the middleware list
                            dispatch(SetStoreApps(Result.loading))
                            
                            // Async task call
                            fetchStoreApps(dispatch)
                        }
                        else -> { } 
                    }
                }
                is SetActiveMifare -> { }
                is UpdateDelivery -> { }
            }
            // Dispatch the action to the next middleware
            // if exist or to the reducers
            next(action)
        }
    }
}

fun fetchAppsFromStore(dispatch: DispatchAction) { 
    
    RemoteApiManager.getStoreApps()
        .compose(asRemoteRequest())
        .subscribe({ result ->

            // Asycn result dispatched inside an action                 
            dispatch(SetStoreApps(Result.finished(apps)))
        }, { error ->
            
            // Asycn error dispatched inside an action           
            dispatch(SetStoreApps(Result.failed(reason: error)))
        })
        .disposed(disposer)
}


// adding multiples middlewares:
val store = Store(
        reducer = ::appReducer,
        state = null,
        middleware = listOf(loggingMiddleware, deviceMiddleware, deliveryMiddleware))