/*******************************************************************************
 * Copyright (c) 2001, 2007 IBM Corporation and others.
 * All rights reserved. This program and the accompanying materials
 * are made available under the terms of the Eclipse Public License v1.0
 * which accompanies this distribution, and is available at
 * http://www.eclipse.org/legal/epl-v10.html
 * 
 * Contributors:
 *     IBM Corporation - initial API and implementation
 *     Jens Lukowski/Innoopract - initial renaming/restructuring
 *     
 *******************************************************************************/
package org.eclipse.wst.sse.ui;

import java.util.ArrayList;
import java.util.List;

import org.eclipse.jface.preference.IPreferenceStore;
import org.eclipse.jface.preference.PreferenceConverter;
import org.eclipse.jface.text.DefaultInformationControl;
import org.eclipse.jface.text.IAutoEditStrategy;
import org.eclipse.jface.text.IDocument;
import org.eclipse.jface.text.IDocumentExtension3;
import org.eclipse.jface.text.IDocumentPartitioner;
import org.eclipse.jface.text.IInformationControl;
import org.eclipse.jface.text.IInformationControlCreator;
import org.eclipse.jface.text.ITextDoubleClickStrategy;
import org.eclipse.jface.text.ITextHover;
import org.eclipse.jface.text.IUndoManager;
import org.eclipse.jface.text.contentassist.IContentAssistProcessor;
import org.eclipse.jface.text.contentassist.IContentAssistant;
import org.eclipse.jface.text.formatter.IContentFormatter;
import org.eclipse.jface.text.hyperlink.IHyperlinkPresenter;
import org.eclipse.jface.text.information.IInformationPresenter;
import org.eclipse.jface.text.information.IInformationProvider;
import org.eclipse.jface.text.information.InformationPresenter;
import org.eclipse.jface.text.presentation.IPresentationReconciler;
import org.eclipse.jface.text.quickassist.IQuickAssistAssistant;
import org.eclipse.jface.text.quickassist.QuickAssistAssistant;
import org.eclipse.jface.text.reconciler.IReconciler;
import org.eclipse.jface.text.source.IAnnotationHover;
import org.eclipse.jface.text.source.ISourceViewer;
import org.eclipse.jface.viewers.ILabelProvider;
import org.eclipse.swt.SWT;
import org.eclipse.swt.graphics.Color;
import org.eclipse.swt.graphics.RGB;
import org.eclipse.swt.widgets.Shell;
import org.eclipse.ui.editors.text.EditorsUI;
import org.eclipse.ui.editors.text.TextSourceViewerConfiguration;
import org.eclipse.ui.texteditor.ChainedPreferenceStore;
import org.eclipse.wst.sse.core.internal.provisional.text.IStructuredPartitioning;
import org.eclipse.wst.sse.core.internal.text.rules.StructuredTextPartitioner;
import org.eclipse.wst.sse.ui.internal.ExtendedConfigurationBuilder;
import org.eclipse.wst.sse.ui.internal.SSEUIPlugin;
import org.eclipse.wst.sse.ui.internal.StructuredTextAnnotationHover;
import org.eclipse.wst.sse.ui.internal.contentassist.StructuredContentAssistant;
import org.eclipse.wst.sse.ui.internal.correction.CompoundQuickAssistProcessor;
import org.eclipse.wst.sse.ui.internal.derived.HTMLTextPresenter;
import org.eclipse.wst.sse.ui.internal.hyperlink.HighlighterHyperlinkPresenter;
import org.eclipse.wst.sse.ui.internal.preferences.EditorPreferenceNames;
import org.eclipse.wst.sse.ui.internal.provisional.preferences.CommonEditorPreferenceNames;
import org.eclipse.wst.sse.ui.internal.provisional.style.LineStyleProvider;
import org.eclipse.wst.sse.ui.internal.reconcile.StructuredRegionProcessor;
import org.eclipse.wst.sse.ui.internal.taginfo.AnnotationHoverProcessor;
import org.eclipse.wst.sse.ui.internal.taginfo.BestMatchHover;
import org.eclipse.wst.sse.ui.internal.taginfo.ProblemAnnotationHoverProcessor;
import org.eclipse.wst.sse.ui.internal.taginfo.TextHoverManager;
import org.eclipse.wst.sse.ui.internal.util.EditorUtility;


/**
 * Configuration for the source viewer used by StructuredTextEditor.<br />
 * Note: While ISourceViewer is passed in for each get configuration, clients
 * should create a new viewer configuration instance for each instance of
 * source viewer as some methods return the same instance of an object,
 * regardless of the sourceviewer.
 * <p>
 * Clients should subclass and override just those methods which must be
 * specific to their needs.
 * </p>
 * 
 * @see org.eclipse.wst.sse.ui.StructuredTextEditor
 * @see org.eclipse.wst.sse.ui.internal.StructuredTextViewer
 * @since 1.0
 */
public class StructuredTextViewerConfiguration extends TextSourceViewerConfiguration {
	/*
	 * One instance per configuration because creating a second assistant that
	 * is added to a viewer can cause odd key-eating by the wrong one.
	 */
	private StructuredContentAssistant fContentAssistant = null;
	/*
	 * One instance per configuration because it's just like content assistant
	 */
	private IQuickAssistAssistant fQuickAssistant = null;
	/*
	 * One instance per configuration
	 */
	private IReconciler fReconciler;
	/**
	 * Extended configuration provisionalConfiguration type to contribute
	 * additional auto edit strategies
	 */
	private final String AUTOEDITSTRATEGY = "autoeditstrategy";


	/**
	 * Creates a structured text viewer configuration.
	 */
	public StructuredTextViewerConfiguration() {
		super();
		// initialize fPreferenceStore with same preference store used in
		// StructuredTextEditor
		fPreferenceStore = createCombinedPreferenceStore();
	}

	/**
	 * Create a preference store that combines the source editor preferences
	 * with the base editor's preferences.
	 * 
	 * @return IPreferenceStore
	 */
	private IPreferenceStore createCombinedPreferenceStore() {
		IPreferenceStore sseEditorPrefs = SSEUIPlugin.getDefault().getPreferenceStore();
		IPreferenceStore baseEditorPrefs = EditorsUI.getPreferenceStore();
		return new ChainedPreferenceStore(new IPreferenceStore[]{sseEditorPrefs, baseEditorPrefs});
	}

	/**
	 * Returns the annotation hover which will provide the information to be
	 * shown in a hover popup window when requested for the given source
	 * viewer.<br />
	 * Note: Clients cannot override this method because this method returns a
	 * specially configured Annotation Hover for the StructuredTextViewer.
	 * 
	 * @param sourceViewer
	 *            the source viewer to be configured by this configuration
	 * @return an annotation hover specially configured for
	 *         StructuredTextViewer
	 */
	final public IAnnotationHover getAnnotationHover(ISourceViewer sourceViewer) {
		/*
		 * This implmentation returns an annotation hover that works with
		 * StructuredTextViewer and breakpoints. Important! must remember to
		 * release it when done with it (during viewer.unconfigure)
		 */
		return new StructuredTextAnnotationHover();
	}

	/**
	 * Get color for the preference key. Assumes fPreferenceStore is not null.
	 * 
	 * @param key
	 * @return Color for preference key or null if none found
	 */
	private Color getColor(String key) {
		RGB rgb = PreferenceConverter.getColor(fPreferenceStore, key);
		return EditorUtility.getColor(rgb);
	}

	public IAutoEditStrategy[] getAutoEditStrategies(ISourceViewer sourceViewer, String contentType) {
		List allStrategies = new ArrayList(0);

		IAutoEditStrategy[] superStrategies = super.getAutoEditStrategies(sourceViewer, contentType);
		for (int i = 0; i < superStrategies.length; i++) {
			allStrategies.add(superStrategies[i]);
		}

		// add auto edit strategies contributed by clients
		List extendedAutoEdits = ExtendedConfigurationBuilder.getInstance().getConfigurations(AUTOEDITSTRATEGY, contentType);
		if (!extendedAutoEdits.isEmpty()) {
			allStrategies.addAll(extendedAutoEdits);
		}

		return (IAutoEditStrategy[]) allStrategies.toArray(new IAutoEditStrategy[allStrategies.size()]);
	}

	/**
	 * Returns the configured partitioning for the given source viewer. The
	 * partitioning is used when the querying content types from the source
	 * viewer's input document.<br />
	 * Note: Clients cannot override this method at this time.
	 * 
	 * @param sourceViewer
	 *            the source viewer to be configured by this configuration
	 * @return the configured partitioning
	 * @see #getConfiguredContentTypes(ISourceViewer)
	 */
	final public String getConfiguredDocumentPartitioning(ISourceViewer sourceViewer) {
		/*
		 * This implementation returns default structured text partitioning
		 */
		return IStructuredPartitioning.DEFAULT_STRUCTURED_PARTITIONING;
	}

	public int[] getConfiguredTextHoverStateMasks(ISourceViewer sourceViewer, String contentType) {
		/*
		 * This implementation returns configured text hover state masks for
		 * StructuredTextViewers
		 */
		TextHoverManager.TextHoverDescriptor[] hoverDescs = SSEUIPlugin.getDefault().getTextHoverManager().getTextHovers();
		int stateMasks[] = new int[hoverDescs.length];
		int stateMasksLength = 0;
		for (int i = 0; i < hoverDescs.length; i++) {
			if (hoverDescs[i].isEnabled()) {
				int j = 0;
				int stateMask = computeStateMask(hoverDescs[i].getModifierString());
				while (j < stateMasksLength) {
					if (stateMasks[j] == stateMask)
						break;
					j++;
				}
				if (j == stateMasksLength)
					stateMasks[stateMasksLength++] = stateMask;
			}
		}
		if (stateMasksLength == hoverDescs.length)
			return stateMasks;

		int[] shortenedStateMasks = new int[stateMasksLength];
		System.arraycopy(stateMasks, 0, shortenedStateMasks, 0, stateMasksLength);
		return shortenedStateMasks;
	}

	/**
	 * Returns the content assistant ready to be used with the given source
	 * viewer.<br />
	 * Note: The same instance of IContentAssistant is returned regardless of
	 * the source viewer passed in.
	 * <p>
	 * Clients should generally not override this method. Instead, clients
	 * wanting to add their own processors should override
	 * <code>getContentAssistProcessors(ISourceViewer, String)</code>
	 * </p>
	 * 
	 * @param sourceViewer
	 *            the source viewer to be configured by this configuration
	 * @return a content assistant
	 * @see #getContentAssistProcessors(ISourceViewer, String)
	 */
	public IContentAssistant getContentAssistant(ISourceViewer sourceViewer) {
		/*
		 * Note: This method was made final so that StructuredContentAssist is
		 * always used and content assist extension point always works.
		 */
		if (fContentAssistant == null) {
			fContentAssistant = new StructuredContentAssistant();

			// content assistant configurations
			fContentAssistant.setDocumentPartitioning(getConfiguredDocumentPartitioning(sourceViewer));
			fContentAssistant.enableAutoActivation(true);
			fContentAssistant.setProposalPopupOrientation(IContentAssistant.PROPOSAL_OVERLAY);
			fContentAssistant.setContextInformationPopupOrientation(IContentAssistant.CONTEXT_INFO_ABOVE);
			fContentAssistant.setInformationControlCreator(getInformationControlCreator(sourceViewer));

			// set content assist preferences
			if (fPreferenceStore != null) {
				int delay = fPreferenceStore.getInt(EditorPreferenceNames.CODEASSIST_AUTOACTIVATION_DELAY);
				fContentAssistant.setAutoActivationDelay(delay);

				Color color = getColor(EditorPreferenceNames.CODEASSIST_PROPOSALS_BACKGROUND);
				fContentAssistant.setProposalSelectorBackground(color);

				color = getColor(EditorPreferenceNames.CODEASSIST_PROPOSALS_FOREGROUND);
				fContentAssistant.setProposalSelectorForeground(color);

				color = getColor(EditorPreferenceNames.CODEASSIST_PARAMETERS_BACKGROUND);
				fContentAssistant.setContextInformationPopupBackground(color);
				fContentAssistant.setContextSelectorBackground(color);

				color = getColor(EditorPreferenceNames.CODEASSIST_PARAMETERS_FOREGROUND);
				fContentAssistant.setContextInformationPopupForeground(color);
				fContentAssistant.setContextSelectorForeground(color);
			}
		}

		if (!fContentAssistant.isInitialized()) {
			// add content assist processors for each partition type
			String[] types = getConfiguredContentTypes(sourceViewer);
			for (int i = 0; i < types.length; i++) {
				String type = types[i];

				// add all content assist processors for current partiton type
				IContentAssistProcessor[] processors = getContentAssistProcessors(sourceViewer, type);
				if (processors != null) {
					for (int j = 0; j < processors.length; j++) {
						fContentAssistant.setContentAssistProcessor(processors[j], type);
					}
				}
			}
		}
		return fContentAssistant;
	}

	/**
	 * Returns the content assist processors that will be used for content
	 * assist in the given source viewer and for the given partition type.
	 * 
	 * @param sourceViewer
	 *            the source viewer to be configured by this configuration
	 * @param partitionType
	 *            the partition type for which the content assist processors
	 *            are applicable
	 * @return IContentAssistProcessors or null if should not be supported
	 */
	protected IContentAssistProcessor[] getContentAssistProcessors(ISourceViewer sourceViewer, String partitionType) {
		return null;
	}

	/**
	 * Returns the content formatter ready to be used with the given source
	 * viewer.
	 * <p>
	 * It is not recommended that clients override this method as it may
	 * become <code>final</code> in the future and replaced by an extensible
	 * framework.
	 * </p>
	 * 
	 * @param sourceViewer
	 *            the source viewer to be configured by this configuration
	 * @return a content formatter or <code>null</code> if formatting should
	 *         not be supported
	 */
	public IContentFormatter getContentFormatter(ISourceViewer sourceViewer) {
		// try to use the StructuredTextMultiPassContentFormatter so that it
		// picks up any additional formatting strategies contributed via the
		// editorConfiguration extension point
		IContentFormatter formatter = null;
		if (sourceViewer != null) {
			IDocument document = sourceViewer.getDocument();
			if (document instanceof IDocumentExtension3) {
				String partitioning = getConfiguredDocumentPartitioning(sourceViewer);
				IDocumentPartitioner partitioner = ((IDocumentExtension3) document).getDocumentPartitioner(partitioning);
				if (partitioner instanceof StructuredTextPartitioner) {
					String defaultPartitionType = ((StructuredTextPartitioner) partitioner).getDefaultPartitionType();
					formatter = new StructuredTextMultiPassContentFormatter(partitioning, defaultPartitionType);
				}
			}
		}

		return formatter;
	}

	/**
	 * Returns the double-click strategy ready to be used in this viewer when
	 * double clicking onto text of the given content type. Note that if
	 * clients want to contribute their own doubleclick strategy, they should
	 * use <code>org.eclipse.wst.sse.ui.editorConfiguration</code> extension
	 * point's <code>doubleClickStrategy</code> element instead of
	 * overriding this method. If clients do override this method, please
	 * remember to call <code>super.getDoubleClickStrategy()</code>.
	 * 
	 * @param sourceViewer
	 *            the source viewer to be configured by this configuration
	 * @param contentType
	 *            the content type for which the strategy is applicable
	 * @return a double-click strategy or <code>null</code> if double
	 *         clicking should not be supported
	 */
	public ITextDoubleClickStrategy getDoubleClickStrategy(ISourceViewer sourceViewer, String contentType) {
		ITextDoubleClickStrategy strategy = null;
		Object extendedStrategy = ExtendedConfigurationBuilder.getInstance().getConfiguration(ExtendedConfigurationBuilder.DOUBLECLICKSTRATEGY, contentType);
		if (extendedStrategy instanceof ITextDoubleClickStrategy) {
			strategy = (ITextDoubleClickStrategy) extendedStrategy;
		}
		else {
			strategy = super.getDoubleClickStrategy(sourceViewer, contentType);
		}
		return strategy;
	}

	/**
	 * Returns the hyperlink presenter for the given source viewer.<br />
	 * Note: Clients cannot override this method because this method returns a
	 * specially configured hyperlink presenter for the StructuredTextViewer.
	 * 
	 * @param sourceViewer
	 *            the source viewer to be configured by this configuration
	 * @return a hyperlink presenter specially configured for
	 *         StructuredTextViewer
	 */
	final public IHyperlinkPresenter getHyperlinkPresenter(ISourceViewer sourceViewer) {
		/*
		 * This implementation returns a hyperlink presenter that uses
		 * Highlither instead of PresentationReconciler
		 */
		if (fPreferenceStore == null) {
			return super.getHyperlinkPresenter(sourceViewer);
		}
		return new HighlighterHyperlinkPresenter(fPreferenceStore);
	}

	/**
	 * Returns the information control creator. The creator is a factory
	 * creating information controls for the given source viewer.<br />
	 * Note: Clients cannot override this method at this time.
	 * 
	 * @param sourceViewer
	 *            the source viewer to be configured by this configuration
	 * @return the information control creator
	 */
	final public IInformationControlCreator getInformationControlCreator(ISourceViewer sourceViewer) {
		// used by hover help
		return new IInformationControlCreator() {
			public IInformationControl createInformationControl(Shell parent) {
				return new DefaultInformationControl(parent, SWT.NONE, new HTMLTextPresenter(true));
			}
		};
	}

	/**
	 * Returns the information presenter ready to be used with the given
	 * source viewer.
	 * <p>
	 * Clients cannot override this method. Instead, clients wanting to add
	 * their own information providers should override
	 * <code>getInformationProvider(ISourceViewer, String)</code>
	 * </p>
	 * 
	 * @param sourceViewer
	 *            the source viewer to be configured by this configuration
	 * @return a content assistant
	 * @see #getInformationProvider(ISourceViewer, String)
	 */
	final public IInformationPresenter getInformationPresenter(ISourceViewer sourceViewer) {
		InformationPresenter presenter = new InformationPresenter(getInformationPresenterControlCreator(sourceViewer));

		// information presenter configurations
		presenter.setSizeConstraints(60, 10, true, true);
		presenter.setDocumentPartitioning(getConfiguredDocumentPartitioning(sourceViewer));

		// add information providers for each partition type
		String[] types = getConfiguredContentTypes(sourceViewer);
		for (int i = 0; i < types.length; i++) {
			String type = types[i];

			IInformationProvider provider = getInformationProvider(sourceViewer, type);
			if (provider != null) {
				presenter.setInformationProvider(provider, type);
			}
		}

		return presenter;
	}

	/**
	 * Returns the information provider that will be used for information
	 * presentation in the given source viewer and for the given partition
	 * type.
	 * 
	 * @param sourceViewer
	 *            the source viewer to be configured by this configuration
	 * @param partitionType
	 *            the partition type for which the information provider is
	 *            applicable
	 * @return IInformationProvider or null if should not be supported
	 * @deprecated instead of overriding this method to provide documentation
	 *             information, adopters should use the
	 *             <code>documentationTextHover</code> element in the
	 *             <code>org.eclipse.wst.sse.ui.editorConfiguration</code>
	 *             extension point
	 */
	protected IInformationProvider getInformationProvider(ISourceViewer sourceViewer, String partitionType) {
		ITextHover bestMatchHover = new BestMatchHover(createDocumentationHover(partitionType));
		return new TextHoverInformationProvider(bestMatchHover);
	}

	/**
	 * Returns the information presenter control creator. The creator is a
	 * factory creating the presenter controls for the given source viewer.
	 * 
	 * @param sourceViewer
	 *            the source viewer to be configured by this configuration
	 * @return an information control creator
	 */
	private IInformationControlCreator getInformationPresenterControlCreator(ISourceViewer sourceViewer) {
		return new IInformationControlCreator() {
			public IInformationControl createInformationControl(Shell parent) {
				int shellStyle = SWT.RESIZE | SWT.TOOL;
				int style = SWT.V_SCROLL | SWT.H_SCROLL;
				return new DefaultInformationControl(parent, shellStyle, style, new HTMLTextPresenter(false));
			}
		};
	}

	/**
	 * Returns the line style providers that will be used for syntax
	 * highlighting in the given source viewer.
	 * <p>
	 * Not fully API since return type LineStyleProvider is not API.
	 * </p>
	 * 
	 * @param sourceViewer
	 *            the source viewer to be configured by this configuration
	 * @param partitionType
	 *            the partition type for which the lineStyleProviders are
	 *            applicable
	 * @return LineStyleProvders or null if should not be supported
	 */
	public LineStyleProvider[] getLineStyleProviders(ISourceViewer sourceViewer, String partitionType) {
		return null;
	}

	/**
	 * StructuredTextViewer currently does not support presentation
	 * reconciler, so clients cannot override this method to provide their own
	 * presentation reconciler. <br />
	 * See <code>getLineStyleProviders(ISourceViewer, String)</code> for
	 * alternative way to provide highlighting information.
	 * 
	 * @param sourceViewer
	 *            the source viewer to be configured by this configuration
	 * @return always returns null
	 * @see #getLineStyleProviders(ISourceViewer, String)
	 */
	final public IPresentationReconciler getPresentationReconciler(ISourceViewer sourceViewer) {
		/*
		 * This implementation returns null because StructuredTextViewer does
		 * not use presentation reconciler
		 */
		return null;
	}

	/*
	 * @see org.eclipse.jface.text.source.SourceViewerConfiguration#getQuickAssistAssistant(org.eclipse.jface.text.source.ISourceViewer)
	 */
	public IQuickAssistAssistant getQuickAssistAssistant(ISourceViewer sourceViewer) {
		if (fQuickAssistant == null) {
			IQuickAssistAssistant assistant = new QuickAssistAssistant();
			assistant.setQuickAssistProcessor(new CompoundQuickAssistProcessor());
			assistant.setInformationControlCreator(getQuickAssistAssistantInformationControlCreator());

			// Waiting for color preferences, see:
			// https://bugs.eclipse.org/bugs/show_bug.cgi?id=133731
			// set content assist preferences
			if (fPreferenceStore != null) {
				Color color = getColor(EditorPreferenceNames.CODEASSIST_PROPOSALS_BACKGROUND);
				assistant.setProposalSelectorBackground(color);

				color = getColor(EditorPreferenceNames.CODEASSIST_PROPOSALS_FOREGROUND);
				assistant.setProposalSelectorForeground(color);
			}
			fQuickAssistant = assistant;
		}
		return fQuickAssistant;
	}

	/**
	 * Returns the information control creator for the quick assist assistant.
	 * 
	 * @return the information control creator
	 */
	private IInformationControlCreator getQuickAssistAssistantInformationControlCreator() {
		return new IInformationControlCreator() {
			public IInformationControl createInformationControl(Shell parent) {
				return new DefaultInformationControl(parent, SWT.NONE, new HTMLTextPresenter(true));
			}
		};
	}

	/**
	 * Returns the reconciler ready to be used with the given source viewer.<br />
	 * Note: The same instance of IReconciler is returned regardless of the
	 * source viewer passed in.
	 * <p>
	 * Clients cannot override this method. Instead, clients wanting to add
	 * their own reconciling strategy should use the
	 * <code>org.eclipse.wst.sse.ui.extensions.sourcevalidation</code>
	 * extension point.
	 * </p>
	 * 
	 * @param sourceViewer
	 *            the source viewer to be configured by this configuration
	 * @return a reconciler
	 */
	final public IReconciler getReconciler(ISourceViewer sourceViewer) {
		boolean reconcilingEnabled = fPreferenceStore.getBoolean(CommonEditorPreferenceNames.EVALUATE_TEMPORARY_PROBLEMS);
		if (sourceViewer == null || !reconcilingEnabled)
			return null;

		/*
		 * Only create reconciler if sourceviewer is present
		 */
		if (fReconciler == null && sourceViewer != null) {
			StructuredRegionProcessor reconciler = new StructuredRegionProcessor();

			// reconciler configurations
			reconciler.setDocumentPartitioning(getConfiguredDocumentPartitioning(sourceViewer));

			fReconciler = reconciler;
		}
		return fReconciler;
	}

	/**
	 * @since 2.0
	 * @param treeViewer
	 * @return a label provider providing the status line contents
	 */
	public ILabelProvider getStatusLineLabelProvider(ISourceViewer sourceViewer) {
		return null;
	}

	/**
	 * Create a documentation hover based on hovers contributed via
	 * <code>org.eclipse.wst.sse.ui.editorConfiguration</code> extension
	 * point
	 * 
	 * @param partitionType
	 * @return
	 */
	private ITextHover createDocumentationHover(String partitionType) {
		ITextHover textHover = null;
		Object extendedTextHover = ExtendedConfigurationBuilder.getInstance().getConfiguration(ExtendedConfigurationBuilder.DOCUMENTATIONTEXTHOVER, partitionType);
		if (extendedTextHover instanceof ITextHover) {
			textHover = (ITextHover) extendedTextHover;
		}
		return textHover;
	}

	public ITextHover getTextHover(ISourceViewer sourceViewer, String contentType, int stateMask) {
		ITextHover textHover = null;

		/*
		 * Returns a default problem, annotation, and best match hover
		 * depending on stateMask
		 */
		TextHoverManager.TextHoverDescriptor[] hoverDescs = SSEUIPlugin.getDefault().getTextHoverManager().getTextHovers();
		int i = 0;
		while (i < hoverDescs.length && textHover == null) {
			if (hoverDescs[i].isEnabled() && computeStateMask(hoverDescs[i].getModifierString()) == stateMask) {
				String hoverType = hoverDescs[i].getId();
				if (TextHoverManager.PROBLEM_HOVER.equalsIgnoreCase(hoverType))
					textHover = new ProblemAnnotationHoverProcessor();
				else if (TextHoverManager.ANNOTATION_HOVER.equalsIgnoreCase(hoverType))
					textHover = new AnnotationHoverProcessor();
				else if (TextHoverManager.COMBINATION_HOVER.equalsIgnoreCase(hoverType))
					textHover = new BestMatchHover(createDocumentationHover(contentType));
				else if (TextHoverManager.DOCUMENTATION_HOVER.equalsIgnoreCase(hoverType)) {
					textHover = createDocumentationHover(contentType);
				}
			}
			i++;
		}
		return textHover;
	}

	/**
	 * Returns the undo manager for the given source viewer.<br />
	 * Note: Clients cannot override this method because this method returns a
	 * specially configured undo manager for the StructuredTextViewer.
	 * 
	 * @param sourceViewer
	 *            the source viewer to be configured by this configuration
	 * @return an undo manager specially configured for StructuredTextViewer
	 */
	final public IUndoManager getUndoManager(ISourceViewer sourceViewer) {
		/*
		 * This implementation returns an UndoManager that is used exclusively
		 * in StructuredTextViewer
		 */
		return new StructuredTextViewerUndoManager();
	}
}