/*******************************************************************************
 * Copyright (c) 2000, 2011 IBM Corporation and others.
 *
 * This program and the accompanying materials
 * are made available under the terms of the Eclipse Public License 2.0
 * which accompanies this distribution, and is available at
 * https://www.eclipse.org/legal/epl-2.0/
 *
 * SPDX-License-Identifier: EPL-2.0
 *
 * Contributors:
 *     IBM Corporation - initial API and implementation
 *******************************************************************************/
package org.eclipse.compare.internal;

import java.io.IOException;
import java.io.InputStream;
import java.util.ResourceBundle;

import org.eclipse.compare.CompareConfiguration;
import org.eclipse.compare.CompareUI;
import org.eclipse.compare.IStreamContentAccessor;
import org.eclipse.compare.contentmergeviewer.ContentMergeViewer;
import org.eclipse.core.runtime.CoreException;
import org.eclipse.swt.SWT;
import org.eclipse.swt.SWTException;
import org.eclipse.swt.graphics.Image;
import org.eclipse.swt.widgets.Composite;
import org.eclipse.swt.widgets.Display;
import org.eclipse.ui.PlatformUI;

/**
 */
public class ImageMergeViewer extends ContentMergeViewer {
	private static final String BUNDLE_NAME= "org.eclipse.compare.internal.ImageMergeViewerResources"; //$NON-NLS-1$

	private Object fLeftImage;
	private Object fRightImage;

	private ImageCanvas fAncestor;
	private ImageCanvas fLeft;
	private ImageCanvas fRight;

	public ImageMergeViewer(Composite parent, int styles, CompareConfiguration mp) {
		super(styles, ResourceBundle.getBundle(BUNDLE_NAME), mp);

		if (PlatformUI.isWorkbenchRunning()) {
			PlatformUI.getWorkbench().getHelpSystem().setHelp(parent, ICompareContextIds.IMAGE_COMPARE_VIEW);
		}

		buildControl(parent);
		String title= Utilities.getString(getResourceBundle(), "title"); //$NON-NLS-1$
		getControl().setData(CompareUI.COMPARE_VIEWER_TITLE, title);
	}

	@Override
	protected void updateContent(Object ancestor, Object left, Object right) {
		setInput(fAncestor, ancestor);

		fLeftImage= left;
		setInput(fLeft, left);

		fRightImage= right;
		setInput(fRight, right);
	}

	/*
	 * We can't modify the contents of either side we just return null.
	 */
	@Override
	protected byte[] getContents(boolean left) {
		return null;
	}

	@Override
	public void createControls(Composite composite) {
		fAncestor= new ImageCanvas(composite, SWT.NO_FOCUS);
		fLeft= new ImageCanvas(composite, SWT.NO_FOCUS);
		fRight= new ImageCanvas(composite, SWT.NO_FOCUS);
	}

	private static void setInput(ImageCanvas canvas, Object input) {
		if (canvas != null) {
			InputStream stream= null;
			try {
				if (input instanceof IStreamContentAccessor) {
					IStreamContentAccessor sca= (IStreamContentAccessor) input;
					if (sca != null) {
						try {
							stream= sca.getContents();
						} catch (CoreException e) {
							// NeedWork
						}
					}
				}

				Image image= null;
				Display display= canvas.getDisplay();
				if (stream != null) {
					try {
						image= new Image(display, stream);
					} catch (SWTException e) {
						// silently ignored
					}
				}

				if (image != null) {
					Image nonNullImage = image;
					canvas.setImage(nonNullImage);
					canvas.addDisposeListener(e -> nonNullImage.dispose());
					canvas.setBackground(display.getSystemColor(SWT.COLOR_LIST_BACKGROUND));
				} else {
					canvas.setBackground(null);
				}
			} finally {
				if (stream != null) {
					try {
						stream.close();
					} catch (IOException e) {
						// silently ignored
					}
				}
			}
		}
	}

	@Override
	protected void handleResizeAncestor(int x, int y, int width, int height) {
		if (width > 0) {
			fAncestor.setVisible(true);
			fAncestor.setBounds(x, y, width, height);
		} else {
			fAncestor.setVisible(false);
		}
	}

	@Override
	protected void handleResizeLeftRight(int x, int y, int width1, int centerWidth, int width2, int height) {
		fLeft.setBounds(x, y, width1, height);
		fRight.setBounds(x + width1 + centerWidth, y, width2, height);
	}

	@Override
	protected void copy(boolean leftToRight) {
		if (leftToRight) {
			fRightImage= fLeftImage;
			setInput(fRight, fRightImage);
			setRightDirty(true);
		} else {
			fLeftImage= fRightImage;
			setInput(fLeft, fLeftImage);
			setLeftDirty(true);
		}
	}
}
