class Program {

    static void Main(string[] args) {

        // Create a new game to play.

        var game = new Game();



        // Set the scroll of the surfaces to 0 so they never scroll on the camera.

        Global.SurfaceGameplay.Scroll = 0;

        Global.SurfaceHud.Scroll = 0;



        // Start the game with a new GameScene.

        game.Start(new GameScene(1000, 1000));



    }

}



class GridBackground : Entity {

    public GridBackground() : base() {

        Layer = 10;

        Surface = Global.SurfaceGameplay;

    }



    public override void Added() {

        base.Added();



        // Just render a simple grid background so when the camera scrolls we can see it.

        AddGraphic(new Grid(Scene.Width, Scene.Height, 40, 40, Color.Cyan));

        Graphic.Alpha = 0.4f;

    }

}



class Player : Entity {

    public Player(float x, float y) : base(x, y) {

        // Add a basic red box for the graphic.

        AddGraphic(Image.CreateRectangle(20, 20, Color.Red));

        Graphic.CenterOrigin();



        // Assign this entity to render to Global.SurfaceGameplay instead of the default game surface.

        Surface = Global.SurfaceGameplay;



        // Set up a collider for movement.

        var collider = AddCollider(new BoxCollider(20, 20));



        // Set up the rest of the movement stuff.

        var axis = AddComponent(Axis.CreateWASD());

        var movement = AddComponent(new BasicMovement(400, 400, 30));

        movement.Axis = axis;

        movement.Collider = collider;

    }

}



class PlayerHud : Entity {

    public PlayerHud() : base() {

        // Basic hud test with just some text.

        AddGraphic(new Text("This is the HUD!", 20));



        Surface = Global.SurfaceHud;

    }

}



class GameScene : Scene {

    public GameScene(int width, int height) : base(width, height) {

        // Add the entities to the scene when the scene is created.

        Add(new Player(HalfWidth, HalfHeight));

        Add(new GridBackground());

        Add(new PlayerHud());

    }



    public override void UpdateLast() {

        base.UpdateLast();



        // Set the scene's camera to follow the player.

        var player = GetEntity<Player>();

        CenterCamera(player.X, player.Y);



        // Set the surface's camera to follow the scene's camera.

        Global.SurfaceGameplay.CameraX = CameraX;

        Global.SurfaceGameplay.CameraY = CameraY;



        // Zoom the surface up and down with the arrow keys.

        if (Input.KeyDown(Key.Down)) {

            Global.SurfaceGameplay.CameraZoom -= 0.005f;

        }

        if (Input.KeyDown(Key.Up)) {

            Global.SurfaceGameplay.CameraZoom += 0.005f;

        }

    }



    public override void Render() {

        base.Render();



        // Render the surfaces.

        Draw.Graphic(Global.SurfaceGameplay);

        Draw.Graphic(Global.SurfaceHud);

    }

}



class Global {

    // Keep global references to the surfaces used for rendering the game.

    public static Surface SurfaceHud = new Surface(640, 480);

    public static Surface SurfaceGameplay = new Surface(640, 480, Color.Gray);

}