@using Sandbox
@using Sandbox.UI

@namespace Emulotl

@inherits PanelComponent

@{
	bool homeVisible = HomeScreen.Current?.IsVisible == true;
	EmulatorComponent emulator = EmulatorComponent.Current;
	IReadOnlyList<Texture> screens = homeVisible ? null : emulator?.ScreenTextures;
	bool showBackdrop = !homeVisible && (emulator?.IsReady == true || !string.IsNullOrEmpty( emulator?.RomPath ));
	bool touch = emulator?.HasTouchscreen == true && screens != null && screens.Count >= 2;
	string rootClass = GamePreferences.DisplayWithSmallScreen ? "small-screen" : string.Empty;
}

<root class="@rootClass">
	@if ( showBackdrop )
	{
		<div class="screen-backdrop" />
	}
	@if ( screens != null && screens.Count > 0 )
	{
		<div class="screen-stack @(touch ? "touchable" : "")" @ref=_stackPanel
			onmousedown=@OnTouchDown onmousemove=@OnTouchMove onmouseup=@OnTouchUp onmouseout=@OnTouchUp>
			@foreach ( Texture screen in screens )
			{
				<TextureImage Texture=@screen class="screen" />
			}
		</div>
	}
</root>

@code
{
	private Panel _stackPanel;
	private bool _touchDown;

	private void OnTouchDown()
	{
		_touchDown = true;
		UpdateTouch();
	}

	private void OnTouchMove()
	{
		if ( _touchDown )
			UpdateTouch();
	}

	private void OnTouchUp()
	{
		_touchDown = false;
		EmulatorComponent.Current?.SetUiTouch( false, 0, 0 );
	}

	private void UpdateTouch()
	{
		EmulatorComponent emulator = EmulatorComponent.Current;
		if ( emulator == null || _stackPanel == null || emulator.HasTouchscreen != true )
			return;

		Rect s = _stackPanel.Box.Rect;
		if ( s.Width <= 0 || s.Height <= 0 )
			return;

		float ex = s.Left;
		float ey = s.Top + s.Height * 0.5f;
		float ew = s.Width;
		float eh = s.Height * 0.5f;

		const float texAspect = 256f / 192f;
		float elemAspect = ew / eh;
		float tw, th, tx, ty;
		if ( elemAspect > texAspect )
		{
			th = eh;
			tw = th * texAspect;
			tx = ex + (ew - tw) * 0.5f;
			ty = ey;
		}
		else
		{
			tw = ew;
			th = tw / texAspect;
			tx = ex;
			ty = ey + (eh - th) * 0.5f;
		}

		float fx = (Mouse.Position.x - tx) / tw;
		float fy = (Mouse.Position.y - ty) / th;

		if ( fx < 0f || fx > 1f || fy < 0f || fy > 1f )
		{
			emulator.SetUiTouch( false, 0, 0 );
			return;
		}

		emulator.SetUiTouch( true, fx, fy );
	}

	protected override int BuildHash()
	{
		EmulatorComponent emulator = EmulatorComponent.Current;
		bool homeVisible = HomeScreen.Current?.IsVisible == true;
		IReadOnlyList<Texture> screens = homeVisible ? null : emulator?.ScreenTextures;
		bool showBackdrop = !homeVisible && (emulator?.IsReady == true || !string.IsNullOrEmpty( emulator?.RomPath ));
		int screenHash = 0;
		if ( screens != null )
			foreach ( Texture screen in screens )
				screenHash = HashCode.Combine( screenHash, screen );
		return HashCode.Combine( screenHash, showBackdrop, homeVisible, GamePreferences.DisplayWithSmallScreen, emulator?.HasTouchscreen );
	}
}