// SDL2_17 [Touch Events].nova


using namespace lib.emscripten;
using namespace lib.math;
using namespace lib.sdl2;


class TouchEvents
{
    private static SDL_Window window;
    private static SDL_Renderer renderer;
    private static bool runFlag = true;

    // Viewport and Square properties
    private static int SCREEN_WIDTH = 800;
    private static int SCREEN_HEIGHT = 600;
    private static float zoomLevel = 1.0f;
    private static float BASE_SQUARE_SIZE = 200.0f;

    public static void main( String[] args )
    {
        Stream.writeLine( "SDL2_17 [Touch Events].nova" );


        // Disable the emscripten full-screen controls.
        Emscripten.disableControls( );

        // Setup SDL.
        SDL2.SDL_Init( SDL2.SDL_INIT_VIDEO );

        window = SDL2.SDL_CreateWindow( "Cross-Platform Zoom Test",
                                        SDL2.SDL_WINDOWPOS_CENTERED,
                                        SDL2.SDL_WINDOWPOS_CENTERED,
                                        SCREEN_WIDTH,
                                        SCREEN_HEIGHT,
                                        SDL2.SDL_WINDOW_SHOWN );

        // Check for a null reference.
        if ( window == null )
        {
            // Output an error message.
            Stream.writeLine( "Failed to create window: " + SDL2.SDL_GetError( ) );

            // Abort the application.
            return;
        }

        renderer = SDL2.SDL_CreateRenderer( window, -1, SDL2.SDL_RENDERER_ACCELERATED | SDL2.SDL_RENDERER_PRESENTVSYNC );

        // Dual-purpose main loop setup.
        if ( Emscripten.isActive( ) )
        {
            // Initialize our native JavaScript trackpad/mouse listener.
            Emscripten.initNativeZoomListener( );

            int simulate_infinite_loop = 1;
            int fps = -1;  
            Emscripten.setMainLoop( mainLoop, fps, simulate_infinite_loop );
        }
        else 
        {
            do
            {
                mainLoop( );
            }
            while ( runFlag );
        }

        // Cleanup
        SDL2.SDL_DestroyRenderer( renderer );
        SDL2.SDL_DestroyWindow( window );
        SDL2.SDL_Quit( );
    }

    public static void mainLoop( )
    {
        // --- 1. BROWSER MOUSE WHEEL (Polled from JS Runtime) ---
        if ( Emscripten.isActive( ) )
        {
            float zoomDelta = Emscripten.getNativeZoomDelta( );

//            Stream.writeLine( "zoomLevel = " + Float.toString( zoomLevel ) );
//            Stream.writeLine( "zoomDelta = " + Float.toString( zoomDelta ) );

            if ( zoomDelta != 0.0f )
            {
                zoomLevel += zoomDelta;
            }

//            Stream.writeLine( "zoomLevel (after update) = " + Float.toString( zoomLevel ) );
        }

        SDL_Event e = SDL2.SDL_PollEvent( );

        if ( e != null )
        {
            if ( e.id == SDL2.SDL_QUIT )
            {
                runFlag = false;
            }
            // --- 2. DESKTOP MOUSE WHEEL (Standard SDL) ---
            else if ( e.id == SDL2.SDL_MOUSEWHEEL )
            {
                if ( !Emscripten.isActive( ) )
                {
                    SDL_MouseWheelEvent mwEvent = (SDL_MouseWheelEvent)e;
                    zoomLevel += (float)mwEvent.y * 0.1f; 
                }
            }
            // --- 3. HYBRID FILTERING (Windows Surface) ---
            // SDL mouse motion event.
            else if ( e.id == SDL2.SDL_MOUSEMOTION )
            {
                SDL_MouseMotionEvent mmEvent = (SDL_MouseMotionEvent)e;
                
                if ( mmEvent.which == SDL2.SDL_TOUCH_MOUSEID ) 
                {
                    // Ignore synthetic touch event.
                }
            }
            // SDL mouse button event.
            else if ( e.id == SDL2.SDL_MOUSEBUTTONDOWN || e.id == SDL2.SDL_MOUSEBUTTONUP )
            {
                SDL_MouseButtonEvent mbEvent = (SDL_MouseButtonEvent)e;
                
                if ( mbEvent.which == SDL2.SDL_TOUCH_MOUSEID ) 
                {
                    // Ignore synthetic touch event.
                }
            }
            // --- 4. PINCH TO ZOOM (Android, iOS, Surface Touch) ---
            else if ( e.id == SDL2.SDL_MULTIGESTURE )
            {
//                Stream.writeLine( "e.id == SDL2.SDL_MULTIGESTURE" );

                SDL_MultiGestureEvent mgEvent = (SDL_MultiGestureEvent)e;
                zoomLevel += mgEvent.dDist * 5.0f; 
            }
        }

        // Clamp zoom level
        zoomLevel = Math.max( 0.1f, Math.min( zoomLevel, 3.0f ) );

        // --- RENDERING ---
        SDL2.SDL_SetRenderDrawColor( renderer, 30, 30, 30, 255 );
        SDL2.SDL_RenderClear( renderer );

        float currentSize = BASE_SQUARE_SIZE * zoomLevel;
        int w = (int)currentSize;
        int h = (int)currentSize;
        int x = ( SCREEN_WIDTH - w ) / 2;
        int y = ( SCREEN_HEIGHT - h ) / 2;

        SDL_Rect squareRect = new SDL_Rect( x, y, w, h );

        SDL2.SDL_SetRenderDrawColor( renderer, 0, 255, 100, 255 );
        SDL2.SDL_RenderFillRect( renderer, squareRect );

        SDL2.SDL_RenderPresent( renderer );
    }
}