createLightingFeatureabrrivated.swift

typealias  Input = (Message) -> ()
typealias Output = (Message) -> ()

func createLightingFeature(store      : Store,
                           lightsStack: LightsStack,
                           output     : @escaping Output) -> Input
{
    let loader      = LightsLoader    (lightsStack:lightsStack,store:store,responder:handle(output:output))
    let switcher    = LightSwitcher   (lightsStack:lightsStack,store:store,responder:handle(output:output))
    let valueSetter = LightValueSetter(lightsStack:lightsStack,store:store,responder:handle(output:output))
    let dimmer      = Dimmer          (lightsStack:lightsStack,store:store,responder:handle(output:output))
    let changer     = LightChanger    (lightsStack:lightsStack,store:store,responder:handle(output:output))
    
    func execute(command cmd: Message._Lighting) {
        //          |---------- Global Command ---------|         request |- UseCase -| to |<-------- UseCase Request -------->|
        if case let .load(lightsOrRooms)                  = cmd { request( loader,      to:.load(.all(lightsOrRooms))            ) }
        if case let .turn(light, onOrOff)                 = cmd { request( switcher,    to:.turn(light, onOrOff )                ) }
        if case let .apply(config,              on:light) = cmd { request( valueSetter, to:.apply(config,              on:light) ) }
        if case let .increase(value,by:increase,on:light) = cmd { request( dimmer,      to:.increase(value,by:increase,on:light) ) }
        if case let .decrease(value,by:decrease,on:light) = cmd { request( dimmer,      to:.decrease(value,by:decrease,on:light) ) }
        if case let .change(.name(name),        on:light) = cmd { request( changer,     to:.change(.name(name),        on:light) ) }
        if case let .change(.display(interface),on:light) = cmd { request( changer,     to:.change(.display(interface),on:light) ) }
    }
    return { // entry point
        if case .lighting(let c) = $0 { execute(command:c) } // execute if lighting is command's recipient
    }
}
// MARK: - UseCase response handler
// handling dimmer responses. other usecases omitted
private func handle(output: @escaping Output) -> (Dimmer.Response) -> () { { process(response:$0,output:output) } }

private func process(response:Dimmer.Response, output: @escaping Output) {
    switch response {
    case let .increase(value,by:increment,on:light,succeededOrFaild): output( .lighting(.increasing(value,by:increment,on:light,succeededOrFaild)) )
    case let .decrease(value,by:increment,on:light,succeededOrFaild): output( .lighting(.decreasing(value,by:increment,on:light,succeededOrFaild)) )
    }
}