/*******************************************************************************
 * Copyright (c) 2000, 2018 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.jdt.internal.junit.ui;

import java.io.ByteArrayInputStream;
import java.io.InputStream;
import java.nio.charset.StandardCharsets;

import org.eclipse.swt.SWT;
import org.eclipse.swt.custom.StyleRange;
import org.eclipse.swt.graphics.Image;
import org.eclipse.swt.layout.GridData;
import org.eclipse.swt.layout.GridLayout;
import org.eclipse.swt.widgets.Composite;
import org.eclipse.swt.widgets.Control;
import org.eclipse.swt.widgets.Display;
import org.eclipse.swt.widgets.Shell;

import org.eclipse.core.runtime.CoreException;

import org.eclipse.jface.dialogs.IDialogConstants;
import org.eclipse.jface.dialogs.IDialogSettings;
import org.eclipse.jface.dialogs.TrayDialog;

import org.eclipse.jface.text.DocumentEvent;
import org.eclipse.jface.text.IDocument;
import org.eclipse.jface.text.IRegion;
import org.eclipse.jface.text.ITypedRegion;
import org.eclipse.jface.text.Region;
import org.eclipse.jface.text.TextAttribute;
import org.eclipse.jface.text.TextPresentation;
import org.eclipse.jface.text.TextViewer;
import org.eclipse.jface.text.presentation.IPresentationDamager;
import org.eclipse.jface.text.presentation.IPresentationReconciler;
import org.eclipse.jface.text.presentation.IPresentationRepairer;
import org.eclipse.jface.text.presentation.PresentationReconciler;
import org.eclipse.jface.text.source.ISourceViewer;
import org.eclipse.jface.text.source.SourceViewer;
import org.eclipse.jface.text.source.SourceViewerConfiguration;

import org.eclipse.ui.PlatformUI;

import org.eclipse.compare.CompareConfiguration;
import org.eclipse.compare.CompareViewerPane;
import org.eclipse.compare.IEncodedStreamContentAccessor;
import org.eclipse.compare.ITypedElement;
import org.eclipse.compare.contentmergeviewer.TextMergeViewer;
import org.eclipse.compare.structuremergeviewer.DiffNode;

import org.eclipse.jdt.internal.junit.model.TestElement;


public class CompareResultDialog extends TrayDialog {
    private static final String PREFIX_SUFFIX_PROPERTY= "org.eclipse.jdt.internal.junit.ui.CompareResultDialog.prefixSuffix"; //$NON-NLS-1$

	private static class CompareResultMergeViewer extends TextMergeViewer {
         private CompareResultMergeViewer(Composite parent, int style, CompareConfiguration configuration) {
             super(parent, style, configuration);
         }

     	@Override
		protected void createControls(Composite composite) {
     		super.createControls(composite);
    		PlatformUI.getWorkbench().getHelpSystem().setHelp(composite, IJUnitHelpContextIds.RESULT_COMPARE_DIALOG);
     	}

//        protected void createToolItems(ToolBarManager tbm) {
//    		ResourceBundle bundle= CompareUI.getResourceBundle();
//    		tbm.add(new IgnoreWhiteSpaceAction(bundle, getCompareConfiguration()));
//    		super.createToolItems(tbm);
//        }

        @Override
		protected void configureTextViewer(TextViewer textViewer) {
            if (textViewer instanceof SourceViewer) {
                int[] prefixSuffixOffsets= (int[]) getCompareConfiguration().getProperty(PREFIX_SUFFIX_PROPERTY);
				((SourceViewer)textViewer).configure(new CompareResultViewerConfiguration(prefixSuffixOffsets));
            }
        }
    }

    private static class CompareResultViewerConfiguration extends SourceViewerConfiguration {
    	private static class SimpleDamagerRepairer implements IPresentationDamager, IPresentationRepairer {
            private IDocument fDocument;
			private final int[] fPrefixSuffixOffsets2;

			public SimpleDamagerRepairer(int[] prefixSuffixOffsets) {
				fPrefixSuffixOffsets2= prefixSuffixOffsets;
			}

			@Override
			public void setDocument(IDocument document) {
                fDocument= document;
            }

            @Override
			public IRegion getDamageRegion(ITypedRegion partition, DocumentEvent event, boolean changed) {
                return new Region(0, fDocument.getLength());
            }

            @Override
			public void createPresentation(TextPresentation presentation, ITypedRegion damage) {
            	presentation.setDefaultStyleRange(new StyleRange(0, fDocument.getLength(), null, null));
            	int prefix= fPrefixSuffixOffsets2[0];
                int suffix= fPrefixSuffixOffsets2[1];
                TextAttribute attr= new TextAttribute(Display.getDefault().getSystemColor(SWT.COLOR_RED));
                presentation.addStyleRange(new StyleRange(prefix, fDocument.getLength()-suffix-prefix, attr.getForeground(), attr.getBackground(), attr.getStyle()));
            }
        }

		private final int[] fPrefixSuffixOffsets;

		public CompareResultViewerConfiguration(int[] prefixSuffixOffsets) {
			fPrefixSuffixOffsets= prefixSuffixOffsets;
		}

		@Override
		public IPresentationReconciler getPresentationReconciler(ISourceViewer sourceViewer) {
            PresentationReconciler reconciler= new PresentationReconciler();
            SimpleDamagerRepairer dr= new SimpleDamagerRepairer(fPrefixSuffixOffsets);
            reconciler.setDamager(dr, IDocument.DEFAULT_CONTENT_TYPE);
            reconciler.setRepairer(dr, IDocument.DEFAULT_CONTENT_TYPE);
            return reconciler;
        }
    }

	private static class CompareElement implements ITypedElement, IEncodedStreamContentAccessor {
	    private String fContent;

	    public CompareElement(String content) {
	        fContent= content;
	    }
	    @Override
		public String getName() {
	        return "<no name>"; //$NON-NLS-1$
	    }
	    @Override
		public Image getImage() {
	        return null;
	    }
	    @Override
		public String getType() {
	        return "txt"; //$NON-NLS-1$
	    }
	    @Override
		public InputStream getContents() {
		    return new ByteArrayInputStream(fContent.getBytes(StandardCharsets.UTF_8));
	    }
        @Override
		public String getCharset() throws CoreException {
            return "UTF-8"; //$NON-NLS-1$
        }
	}

    private TextMergeViewer fViewer;
    private String fExpected;
    private String fActual;
    private String fTestName;

    /**
     * Lengths of common prefix and suffix.
     * Note: this array is passed to the DamagerRepairer and
     * the lengths are updated on content change.
     */
    private final int[] fPrefixSuffix= new int[2];

	private CompareViewerPane fCompareViewerPane;

	public CompareResultDialog(Shell parentShell, TestElement element) {
		super(parentShell);
		setShellStyle((getShellStyle() & ~SWT.APPLICATION_MODAL) | SWT.TOOL);
		setFailedTest(element);
	}

	@Override
	protected boolean isResizable() {
		return true;
	}

	private void setFailedTest(TestElement failedTest) {
		fTestName= failedTest.getTestName();
		fExpected= failedTest.getExpected();
		fActual= failedTest.getActual();
		computePrefixSuffix();
	}

	@Override
	protected IDialogSettings getDialogBoundsSettings() {
		return JUnitPlugin.getDefault().getDialogSettingsSection(getClass().getName());
	}

	private void computePrefixSuffix() {
		int end= Math.min(fExpected.length(), fActual.length());
		int i= 0;
		for(; i < end; i++)
			if (fExpected.charAt(i) != fActual.charAt(i))
				break;
		fPrefixSuffix[0]= i;

		int j= fExpected.length()-1;
		int k= fActual.length()-1;
		int l= 0;
		for (; k >= i && j >= i; k--,j--) {
			if (fExpected.charAt(j) != fActual.charAt(k))
				break;
			l++;
		}
		fPrefixSuffix[1]= l;
	}

    @Override
	protected void configureShell(Shell newShell) {
		super.configureShell(newShell);
		newShell.setText(JUnitMessages.CompareResultDialog_title);
		PlatformUI.getWorkbench().getHelpSystem().setHelp(newShell, IJUnitHelpContextIds.RESULT_COMPARE_DIALOG);
	}

	@Override
	protected void createButtonsForButtonBar(Composite parent) {
		createButton(parent, IDialogConstants.OK_ID, JUnitMessages.CompareResultDialog_labelOK, true);
	}

	@Override
	protected Control createDialogArea(Composite parent) {
		Composite composite = (Composite)super.createDialogArea(parent);
		GridLayout layout= new GridLayout();
		layout.numColumns= 1;
		composite.setLayout(layout);

		fCompareViewerPane= new CompareViewerPane(composite, SWT.BORDER | SWT.FLAT);
		GridData data= new GridData(GridData.FILL_HORIZONTAL | GridData.FILL_VERTICAL);
		data.widthHint= convertWidthInCharsToPixels(120);
		data.heightHint= convertHeightInCharsToPixels(13);
		fCompareViewerPane.setLayoutData(data);

		Control previewer= createPreviewer(fCompareViewerPane);
		fCompareViewerPane.setContent(previewer);
		GridData gd= new GridData(GridData.FILL_BOTH);
		previewer.setLayoutData(gd);
		applyDialogFont(parent);
		return composite;
	}

	private Control createPreviewer(Composite parent) {
	    final CompareConfiguration compareConfiguration= new CompareConfiguration();
	    compareConfiguration.setLeftLabel(JUnitMessages.CompareResultDialog_expectedLabel);
	    compareConfiguration.setLeftEditable(false);
	    compareConfiguration.setRightLabel(JUnitMessages.CompareResultDialog_actualLabel);
	    compareConfiguration.setRightEditable(false);
	    compareConfiguration.setProperty(CompareConfiguration.IGNORE_WHITESPACE, Boolean.FALSE);
	    compareConfiguration.setProperty(PREFIX_SUFFIX_PROPERTY, fPrefixSuffix);

	    fViewer= new CompareResultMergeViewer(parent, SWT.NONE, compareConfiguration);
	    setCompareViewerInput();

	    Control control= fViewer.getControl();
	    control.addDisposeListener(e -> compareConfiguration.dispose());
	    return control;
	}

	private void setCompareViewerInput() {
		if (!fViewer.getControl().isDisposed()) {
			fViewer.setInput(new DiffNode(new CompareElement(fExpected), new CompareElement(fActual)));
			fCompareViewerPane.setText(fTestName);
		}
	}

	public void setInput(TestElement failedTest) {
		setFailedTest(failedTest);
		setCompareViewerInput();
	}
}
