class DrunkInvaders : AbstractProducer {

    static var instance : DrunkInvaders

    // Reset when returning to the menu
    var lives = 4

    // Reset when returning to the menu
    var score = 0

    // The overlapping strategy used within this game.
    var overlapping : Overlapping


    init {
        instance = this
    }

    override fun begin() {
        loadWindowSize()

        // Note, if we have bigger objects later, then we'll need to increase the size.
        overlapping = PixelOverlapping( 200 /*size*/ , 128 /*threshold*/ )
    }

    // Stores a boolean indicating that the scene has been completed, and is therefore unlocked
    // i.e. a player can start the game at that scene.
    // The data is stored in the "Registry", so it available the next time the game is started.
    fun unlockScene( sceneName : String ) {
        Game.instance.preferences.node( "scenes/$sceneName" ).putBoolean( "unlocked", true )
    }

    // Reads the data from the registry, which may have been written by unlockScene (above).
    fun isSceneUnlocked( sceneName : String) = Game.instance.preferences.node( "scenes/$sceneName" ).getBoolean( "unlocked", false )


    // The window can be resized, and the views are resized according to the details in the "Layouts" section.
    override fun layout() {
        super.layout()
        arrangeViews()
    }

    override fun onResize( event : ResizeEvent ) {
        super.onResize( event )
        saveWindowSize()
    }

    // Scene Transitions...

    val sceneTransition = SceneTransition()

    override fun sceneEnding() {
        sceneTransition.prepareTransition()    
    }

    override fun sceneLoaded() {
        val actor = sceneTransition.actor
        if (actor != null) {
            sceneTransition.beginTransition( randomTransition( actor ) )
        }
    }
    
    fun randomTransition(actor : Actor) : Action {
        val seconds = 0.5
        val i = Rand.randomInt( 3 )

        return if ( i == 0 ) {
            MoveXBy( actor.position, seconds, actor.appearance.width() )
        } else if ( i == 1 ) {
            MoveYBy( actor.position, seconds, actor.appearance.height() )
        } else {
            Fade( actor, seconds, 0 )
        }
    }

    // Make a "shake" effect, by moving a screenshot rapidly left and right
    fun shake(scale : float) {
        sceneTransition.apply {
            prepareTransition()
            actor.color.alpha = 0.5
            val seconds = 0.03
            val distance = 20 * scale
            beginTransition(
                (
                    MoveXBy( actor.position, seconds, distance ) then
                    MoveXBy( actor.position, seconds*2, -2*distance ) then
                    MoveXBy( actor.position, seconds, distance )
                ).repeat(5 * scale)
            )
        }
    }

}