import javafx.application.Application;
import javafx.event.EventHandler;
import javafx.scene.Group;
import javafx.scene.Node;
import javafx.scene.Scene;
import javafx.scene.canvas.Canvas;
import javafx.scene.canvas.GraphicsContext;
import javafx.scene.image.Image;
import javafx.scene.image.ImageView;
import javafx.scene.image.PixelWriter;
import javafx.scene.image.WritableImage;
import javafx.scene.input.MouseEvent;
import javafx.scene.paint.Color;
import javafx.scene.paint.Paint;
import javafx.stage.Stage;

public class TestOOVram extends Application {
    static final int SCENEW = 640;
    static final int SCENEH = 480;
    static final int IMGVW = 100;
    static final int IMGVH = 100;

    static long imgmem;
    static long cvmem;

    @Override
    public void start(Stage stage) {
        final Group root = new Group();

        long m = imgmem;
        ImageView last = null;
        System.out.println(String.format("attempting to allocate %,d bytes of Image objects", imgmem));
        int numimages = 0;
        while (m >= 1024 * 1024 * 4) {
            root.getChildren().add(last = makeImageView(1024, 1024));
            m -= 1024 * 1024 * 4;
            numimages++;
        }
        if (m > 0) {
            int w = (int) Math.sqrt(m/4);
            if (w == 0) {
                w = 1;
            }
            int h = (int) ((m/4) / w);
            if (h > 0) {
                root.getChildren().add(last = makeImageView(w, h));
                m -= w * h * 4;
                numimages++;
            }
        }
        fix(last);
        System.out.println(String.format("%,d bytes of Image allocated in %d images", imgmem-m, numimages));

        Scene scene = new Scene(root, SCENEW, SCENEH, Color.GREY);
        scene.addEventHandler(MouseEvent.MOUSE_CLICKED, new EventHandler<MouseEvent>() {
            @Override
            public void handle(MouseEvent event) {
                System.out.println(String.format("attempting to allocate %,d bytes of Canvas objects", cvmem));
                long m = cvmem;
                Canvas last = null;
                int numcvs = 0;
                try {
                    while (m >= 1024 * 1024 * 4) {
                        root.getChildren().add(last = makeCanvas(1024, 1024));
                        m -= 1024 * 1024 * 4;
                        numcvs++;
                    }
                    if (m > 0) {
                        int w = (int) Math.sqrt(m/4);
                        if (w == 0) {
                            w = 1;
                        }
                        int h = (int) ((m/4) / w);
                        if (h > 0) {
                            root.getChildren().add(last = makeCanvas(w, h));
                            m -= w * h * 4;
                            numcvs++;
                        }
                    }
                } catch (OutOfMemoryError e) {
                }
                fix(last);
                System.out.println(String.format("%,d bytes of Canvas allocated in %d canvases", cvmem-m, numcvs));
            }
        });

        stage.setScene(scene);
        stage.show();
    }

    static Canvas makeCanvas(int w, int h) {
        Canvas cv = new Canvas(w, h);
        cv.setScaleX(IMGVW / (double) w);
        cv.setScaleY(IMGVH / (double) h);
        cv.setTranslateX(Math.random() * (SCENEW - IMGVW) + (IMGVW - w)/2.0);
        cv.setTranslateY(Math.random() * (SCENEH - IMGVH) + (IMGVH - h)/2.0);
        fillCheckerboard(cv, Color.BLUE, Color.GREEN);
        return cv;
    }

    static void fix(Canvas cv) {
        fillCheckerboard(cv, Color.ORANGE, Color.PURPLE);
    }

    static void fillCheckerboard(Canvas cv, Paint p1, Paint p2) {
        int w = (int) cv.getWidth();
        int h = (int) cv.getHeight();
        GraphicsContext gc = cv.getGraphicsContext2D();
        int hw = w / 2;
        int hh = h / 2;
        gc.setFill(p1);
        gc.fillRect(0, 0, w, h);
        gc.setFill(p2);
        gc.fillRect(0, 0, hw, hh);
        gc.fillRect(hw, hh, w, h);
    }

    static ImageView makeImageView(int w, int h) {
        Image img = makeImage(w, h);
        ImageView imgv = new ImageView(img);
        imgv.setX(Math.random() * (SCENEW - IMGVW));
        imgv.setY(Math.random() * (SCENEH - IMGVH));
        imgv.setFitWidth(IMGVW);
        imgv.setFitHeight(IMGVH);
        return imgv;
    }

    static Image makeImage(int w, int h) {
        WritableImage wimg = new WritableImage(w, h);
        writeCheckerboard(wimg, 0xff000000, 0xffffffff);
        return wimg;
    }

    static void fix(ImageView last) {
        WritableImage wimg = (WritableImage) last.getImage();
        writeCheckerboard(wimg, 0xff00ffff, 0xffff00ff);
    }

    static void writeCheckerboard(WritableImage wimg, int black, int white) {
        int w = (int) wimg.getWidth();
        int h = (int) wimg.getHeight();
        PixelWriter pw = wimg.getPixelWriter();
        for (int y = 0; y < h; y++) {
            boolean top = y < h/2;
            for (int x = 0; x < w; x++) {
                boolean left = x < w/2;
                pw.setArgb(x, y, (top == left) ? black : white);
            }
        }
    }

    static long parseSize(String s) {
        s = s.toLowerCase();
        long units = 1;
        if (s.endsWith("g")) {
            units = 1024 * 1024 * 1024;
            s = s.substring(0, s.length()-1);
        } else if (s.endsWith("m")) {
            units = 1024 * 1024;
            s = s.substring(0, s.length()-1);
        } else if (s.endsWith("k")) {
            units = 1024;
            s = s.substring(0, s.length()-1);
        }
        return Long.parseLong(s) * units;
    }

    public static void main(String argv[]) {
        if (argv.length == 1) {
            long mem = parseSize(argv[0]);
            imgmem = mem/4;
            cvmem = mem - imgmem/2;
        } else if (argv.length == 2) {
            imgmem = parseSize(argv[0]);
            cvmem = parseSize(argv[1]);
        } else {
            imgmem = parseSize("64m");
            cvmem = parseSize("256m") - imgmem/2;
        }
        launch(argv);
    }
}