/*

    Copyright (C) 2016 Apple Inc. All Rights Reserved.

    See LICENSE.txt for this sample’s licensing information

    Abstract:

    The initial state of a `SceneLoader`. Determines which state should be entered at the beginning of the scene loading process.

*/

import GameplayKit

class SceneLoaderInitialState: GKState {

    // MARK: Properties

    unowned let sceneLoader: SceneLoader

    // MARK: Initialization

    init(sceneLoader: SceneLoader) {

        self.sceneLoader = sceneLoader

    }

    // MARK: GKState Life Cycle

    override func didEnter(from previousState: GKState?) {

        #if os(iOS) || os(tvOS)

        // Move the `stateMachine` to the available state if no on-demand resources are required.

        if !sceneLoader.sceneMetadata.requiresOnDemandResources {

            stateMachine!.enter(SceneLoaderResourcesAvailableState.self)

        }

        #elseif os(OSX)

        // On OS X the resources will always be in local storage available for download.

        _ = stateMachine!.enter(SceneLoaderResourcesAvailableState.self)

        #endif

    }

    override func isValidNextState(_  stateClass: AnyClass) -> Bool {

        #if os(iOS) || os(tvOS)

        if stateClass is SceneLoaderDownloadingResourcesState.Type {

            return true

        }

        #endif

        return stateClass is SceneLoaderResourcesAvailableState.Type

    }

}