import org.eclipse.swt.SWT;
import org.eclipse.swt.graphics.Font;
import org.eclipse.swt.graphics.FontData;
import org.eclipse.swt.graphics.GC;
import org.eclipse.swt.graphics.Image;
import org.eclipse.swt.graphics.ImageData;
import org.eclipse.swt.graphics.ImageDataProvider;
import org.eclipse.swt.graphics.ImageFileNameProvider;
import org.eclipse.swt.graphics.Point;
import org.eclipse.swt.layout.GridData;
import org.eclipse.swt.layout.GridLayout;
import org.eclipse.swt.widgets.Button;
import org.eclipse.swt.widgets.Canvas;
import org.eclipse.swt.widgets.Composite;
import org.eclipse.swt.widgets.Display;
import org.eclipse.swt.widgets.Label;
import org.eclipse.swt.widgets.Menu;
import org.eclipse.swt.widgets.MenuItem;
import org.eclipse.swt.widgets.Shell;

import java.util.ArrayList;

/**
 * Snippet to test the use of the DPI-aware Image constructors.
 * Work in progress in https://bugs.eclipse.org/399786
 * <p>
 * For a list of all SWT example snippets see
 * http://www.eclipse.org/swt/snippets/
 */
public class Snippet367 {
	private static final String IMAGE_100 = "eclipse16.png";
	private static final String IMAGE_150 = "eclipse24.png";
	private static final String IMAGE_200 = "eclipse32.png";
	private static final String IMAGES_ROOT = "bin/org/eclipse/swt/snippets/";

	private static final String IMAGE_PATH_100 = IMAGES_ROOT + IMAGE_100;
	private static final String IMAGE_PATH_150 = IMAGES_ROOT + IMAGE_150;
	private static final String IMAGE_PATH_200 = IMAGES_ROOT + IMAGE_200;

	public static void main (String [] args) {

		final ImageFileNameProvider filenameProvider = zoom -> {
			switch (zoom) {
			case 100:
				return IMAGE_PATH_100;
			case 150:
				return IMAGE_PATH_150;
			case 200:
				return IMAGE_PATH_200;
			default:
				return null;
			}
		};
		final ImageDataProvider imageDataProvider = zoom -> {
			switch (zoom) {
			case 100:
				return new ImageData (IMAGE_PATH_100);
			case 150:
				return new ImageData (IMAGE_PATH_150);
			case 200:
				return new ImageData (IMAGE_PATH_200);
			default:
				return null;
			}
		};

		final Display display = new Display ();

		int numWarmupIters = 10;
		int numIters = numWarmupIters + 200;
		int totalTests = 0;
		double totalElapsed = 0;

		for (int iIter = 0; iIter < numIters; iIter++) {
			long start = System.nanoTime ();
			final Shell shell = new Shell (display, SWT.TOOL);
			shell.setText("Snippet367");
			shell.setLayout (new GridLayout (3, false));

			Menu menuBar = new Menu(shell, SWT.BAR);
			shell.setMenuBar(menuBar);
			MenuItem fileItem = new MenuItem(menuBar, SWT.CASCADE);
			fileItem.setText("&File");
			Menu fileMenu = new Menu(menuBar);
			fileItem.setMenu(fileMenu);
			MenuItem exitItem = new MenuItem(fileMenu, SWT.PUSH);
			exitItem.setText("&Exit");
			exitItem.addListener(SWT.Selection, e -> shell.close());

			new Label (shell, SWT.NONE).setText (IMAGE_200 + ":");
			new Label (shell, SWT.NONE).setImage (trackImage(new Image (display, IMAGE_PATH_200)));
			new Button(shell, SWT.PUSH).setImage (trackImage(new Image (display, IMAGE_PATH_200)));

			new Label (shell, SWT.NONE).setText (IMAGE_150 + ":");
			new Label (shell, SWT.NONE).setImage (trackImage(new Image (display, IMAGE_PATH_150)));
			new Button(shell, SWT.NONE).setImage (trackImage(new Image (display, IMAGE_PATH_150)));

			new Label (shell, SWT.NONE).setText (IMAGE_100 + ":");
			new Label (shell, SWT.NONE).setImage (trackImage(new Image (display, IMAGE_PATH_100)));
			new Button(shell, SWT.NONE).setImage (trackImage(new Image (display, IMAGE_PATH_100)));

			createSeparator(shell);

			new Label (shell, SWT.NONE).setText ("ImageFileNameProvider:");
			new Label (shell, SWT.NONE).setImage (trackImage(new Image (display, filenameProvider)));
			new Button(shell, SWT.NONE).setImage (trackImage(new Image (display, filenameProvider)));

			new Label (shell, SWT.NONE).setText ("ImageDataProvider:");
			new Label (shell, SWT.NONE).setImage (trackImage(new Image (display, imageDataProvider)));
			new Button(shell, SWT.NONE).setImage (trackImage(new Image (display, imageDataProvider)));

			createSeparator(shell);

			new Label (shell, SWT.NONE).setText ("1. Canvas\n(PaintListener)");
			final Point size = new Point (550, 40);
			final Canvas canvas = new Canvas (shell, SWT.NONE);
			canvas.addPaintListener (e -> {
				Point size1 = canvas.getSize ();
				paintImage (e.gc, size1);
			});
			GridData gridData = new GridData (size.x, size.y);
			gridData.horizontalSpan = 2;
			canvas.setLayoutData (gridData);

			createSeparator(shell);

			new Label (shell, SWT.NONE).setText ("2. Painted image\n (default resolution)");
			Image image = trackImage(new Image (display, size.x, size.y));
			GC gc = new GC (image);
			try {
				paintImage (gc, size);
			} finally {
				gc.dispose ();
			}
			Label imageLabel = new Label (shell, SWT.NONE);
			imageLabel.setImage (image);
			imageLabel.setLayoutData (new GridData (SWT.BEGINNING, SWT.BEGINNING, false, false, 2, 1));

			createSeparator(shell);

			new Label (shell, SWT.NONE).setText ("3. Painted image\n(multi-res, unzoomed paint)");
			imageLabel = new Label (shell, SWT.NONE);
			imageLabel.setImage (trackImage(new Image (display, (ImageDataProvider) zoom -> {
				Image temp = new Image (display, size.x * zoom / 100, size.y * zoom / 100);
				GC gc1 = new GC (temp);
				try {
					paintImage (gc1, size);
					return temp.getImageData ();
				} finally {
					gc1.dispose ();
					temp.dispose ();
				}
			})));
			imageLabel.setLayoutData (new GridData (SWT.BEGINNING, SWT.BEGINNING, false, false, 2, 1));

			createSeparator(shell);

			new Label (shell, SWT.NONE).setText ("4. Painted image\n(multi-res, zoomed paint)");
			imageLabel = new Label (shell, SWT.NONE);
			imageLabel.setImage (trackImage(new Image (display, (ImageDataProvider) zoom -> {
				Image temp = new Image (display, size.x * zoom / 100, size.y * zoom / 100);
				GC gc1 = new GC (temp);
				try {
					paintImage2 (gc1, new Point (size.x * zoom / 100, size.y * zoom / 100), zoom / 100);
					return temp.getImageData ();
				} finally {
					gc1.dispose ();
					temp.dispose ();
				}
			})));
			imageLabel.setLayoutData (new GridData (SWT.BEGINNING, SWT.BEGINNING, false, false, 2, 1));

			createSeparator(shell);

			new Label (shell, SWT.NONE).setText ("5. 50x50 box\n(Display#getDPI(): " + display.getDPI().x + ")");
			Label box= new Label (shell, SWT.NONE);
			box.setBackground(display.getSystemColor(SWT.COLOR_WIDGET_DARK_SHADOW));
			box.setLayoutData (new GridData (50, 50));

			shell.pack ();
			shell.open ();

			long end = System.nanoTime ();
			double elapsed = (end - start) / 1000000000.0;

			if (iIter < numWarmupIters)
				System.out.format ("#*** Time=%.2fsec Avg=(warming up)%n", elapsed);
			else {
				totalElapsed += elapsed;
				totalTests++;
				System.out.format ("#%03d Time=%.2fsec Avg=%.2f%n", totalTests, elapsed, totalElapsed / totalTests);
			}

			shell.dispose ();
			disposeAllImages();
			System.gc();
		}

		display.dispose();
	}

	private static ArrayList<Image> trackedImages = new ArrayList<>();
	private static Image trackImage(Image image) {
		trackedImages.add (image);
		return image;
	}

	private static void disposeAllImages() {
		for (Image image : trackedImages) {
			image.dispose ();
		}

		trackedImages.clear ();
	}

	private static void createSeparator(Composite shell) {
		new Label (shell, SWT.SEPARATOR | SWT.HORIZONTAL).setLayoutData (new GridData (SWT.FILL, SWT.FILL, true, false, 3, 1));
	}

	private static void paintImage (GC gc, Point size) {
		gc.setBackground (gc.getDevice ().getSystemColor (SWT.COLOR_WIDGET_BACKGROUND));
		gc.fillRectangle (0, 0, size.x, size.y);

		gc.setBackground (gc.getDevice ().getSystemColor (SWT.COLOR_LIST_SELECTION));
		gc.fillRoundRectangle (0, 0, size.x - 1, size.y - 1, 10, 10);

		gc.setBackground (gc.getDevice ().getSystemColor (SWT.COLOR_WIDGET_BACKGROUND));
		gc.drawRoundRectangle (0, 0, size.x - 1, size.y - 1, 10, 10);
		gc.drawText (gc.getFont ().getFontData ()[0].toString (), 10, 10, true);
	}

	private static void paintImage2 (GC gc, Point size, int f) {
		gc.setBackground (gc.getDevice ().getSystemColor (SWT.COLOR_WIDGET_BACKGROUND));
		gc.fillRectangle (0, 0, size.x, size.y);

		// Scale line width, corner roundness, and font size.
		// Caveat: line width expands in all directions, so the origin also has to move.

		gc.setBackground (gc.getDevice ().getSystemColor (SWT.COLOR_LIST_SELECTION));
		gc.fillRoundRectangle (f/2, f/2, size.x - f, size.y - f, 10*f, 10*f);

		gc.setBackground (gc.getDevice ().getSystemColor (SWT.COLOR_WIDGET_BACKGROUND));
		gc.setLineWidth (f);
		gc.drawRoundRectangle (f/2, f/2, size.x - f, size.y - f, 10*f, 10*f);
		FontData fontData = gc.getFont ().getFontData ()[0];
		fontData.setHeight (fontData.getHeight ()*f);
		Font font = new Font (gc.getDevice (), fontData);
		try {
			gc.setFont (font);
			gc.drawText (fontData.toString (), 10*f, 10*f, true);
		} finally {
			font.dispose ();
		}
	}
}