EnumeratedStateViewModel

EnumeratedStateViewModel.swift

class EnumeratedStateViewModel {

    public let state: Observable<State>

    enum State: Equatable {
        case initial
        case loading
        case loaded(UIImage)
        case empty(String)
        case error(String)
        case cancel
    }

    private let privateState = BehaviorRelay(value: State.initial)
    private let disposeBag = DisposeBag()

    init() {
        self.state = privateState.observeOn(MainScheduler.instance)
    }

    public func load(_ id: String) {
        privateState.accept(.loading)
        fetchData()
            .subscribe(onSuccess: { [weak self] (image) in
                if image.size.width == 0 {
                    self?.privateState.accept(.empty("Nothing to see here, move along."))
                } else {
                    self?.privateState.accept(.loaded(image))
                }
            }, onError: { [weak self] (error) in
                self?.privateState.accept(.error(error.localizedDescription)
            })
            .disposed(by: disposeBag)
    }

    public func cancel() {
        privateState.accept(.cancel)
    }

    private func fetchData() -> Single<UIImage> {
        return Single.just(UIImage())
    }

}