docmlet/org.eclipse.statet.docmlet.tex.ui/src/org/eclipse/statet/docmlet/tex/ui/text/LtxDoubleClickStrategy.java

/*=============================================================================#
 # Copyright (c) 2009, 2021 Stephan Wahlbrink and others.
 # 
 # This program and the accompanying materials are made available under the
 # terms of the Eclipse Public License 2.0 which is available at
 # https://www.eclipse.org/legal/epl-2.0, or the Apache License, Version 2.0
 # which is available at https://www.apache.org/licenses/LICENSE-2.0.
 # 
 # SPDX-License-Identifier: EPL-2.0 OR Apache-2.0
 # 
 # Contributors:
 #     Stephan Wahlbrink <sw@wahlbrink.eu> - initial API and implementation
 #=============================================================================*/

package org.eclipse.statet.docmlet.tex.ui.text;

import org.eclipse.jface.text.BadLocationException;
import org.eclipse.jface.text.DefaultTextDoubleClickStrategy;
import org.eclipse.jface.text.IDocument;
import org.eclipse.jface.text.IRegion;
import org.eclipse.jface.text.ITextViewer;
import org.eclipse.jface.text.ITypedRegion;
import org.eclipse.jface.text.TextUtilities;

import org.eclipse.statet.ecommons.text.BasicHeuristicTokenScanner;
import org.eclipse.statet.ecommons.text.PairMatcher;

import org.eclipse.statet.docmlet.tex.core.source.LtxBracketPairMatcher;
import org.eclipse.statet.docmlet.tex.core.source.LtxHeuristicTokenScanner;
import org.eclipse.statet.docmlet.tex.core.source.TexDocumentConstants;


/**
 * If matching pairs found, selection of content inside matching brackets,
 * otherwise default word selection.
 */
public class LtxDoubleClickStrategy extends DefaultTextDoubleClickStrategy {
	
	
	private final String partitioning;
	private final PairMatcher pairMatcher;
	private final BasicHeuristicTokenScanner scanner;
	
	
	public LtxDoubleClickStrategy(final LtxHeuristicTokenScanner scanner) {
		super();
		this.partitioning= scanner.getDocumentPartitioning();
		this.pairMatcher= new LtxBracketPairMatcher(scanner);
		this.scanner= scanner;
	}
	
	
	@Override
	public void doubleClicked(final ITextViewer textViewer) {
		final int offset= textViewer.getSelectedRange().x;
		
		if (offset < 0) {
			return;
		}
		
		final IDocument document= textViewer.getDocument();
		try {
			ITypedRegion partition= TextUtilities.getPartition(document, this.partitioning, offset, true);
			String type= partition.getType();
			
			// Bracket-Pair-Matching in Code-Partitions
			if (type == TexDocumentConstants.LTX_DEFAULT_CONTENT_TYPE) {
				final IRegion region= this.pairMatcher.match(document, offset);
				if (region != null && region.getLength() >= 2) {
					textViewer.setSelectedRange(region.getOffset() + 1, region.getLength() - 2);
					return;
				}
			}
			
			// For other partitions, use prefere new partitions (instead opened)
			partition= TextUtilities.getPartition(document, this.partitioning, offset, false);
			type= partition.getType();
			
			if (type == TexDocumentConstants.LTX_MATH_CONTENT_TYPE) {
				final int partitionOffset= partition.getOffset();
				final int partitionEnd= partitionOffset + partition.getLength();
				if (partitionEnd - partitionOffset >= 4 && (
						offset == partitionOffset || offset == partitionOffset+1
						|| offset == partitionEnd || offset == partitionEnd-1)) {
					final char c0= document.getChar(partitionOffset);
					final char c1= document.getChar(partitionOffset+1);
					int start= -1;
					char[] endPattern= null;
					if (c0 == '$') {
						if (c1 == '$') {
							start= partitionOffset + 2;
							endPattern= "$$".toCharArray();
						}
						else {
							start= partitionOffset + 1;
							endPattern= "$".toCharArray();
						}
					}
					else if (c0 == '\\') {
						if (c1 == '[') {
							start= partitionOffset + 2;
							endPattern= "\\]".toCharArray();
						}
						else if (c1 == '(') {
							start= partitionOffset + 2;
							endPattern= "\\)".toCharArray();
						}
					}
					if (start >= 0) {
						textViewer.setSelectedRange(start, getEndOffset(document, partitionEnd, endPattern) - start);
					}
				}
			}
			if (type == TexDocumentConstants.LTX_DEFAULT_CONTENT_TYPE
					|| type == TexDocumentConstants.LTX_MATH_CONTENT_TYPE ) {
				IRegion region= this.pairMatcher.match(document, offset);
				if (region != null && region.getLength() >= 2) {
					textViewer.setSelectedRange(region.getOffset() + 1, region.getLength() - 2);
					return;
				}
				
				this.scanner.configure(document);
				region= this.scanner.findCommonWord(offset);
				if (region != null) {
					textViewer.setSelectedRange(region.getOffset(), region.getLength());
				}
				else {
					textViewer.setSelectedRange(offset, 0);
				}
				return;
			}
			if (type == TexDocumentConstants.LTX_VERBATIM_CONTENT_TYPE) {
				final int partitionOffset= partition.getOffset();
				final int partitionEnd= partitionOffset + partition.getLength();
				final int start= partitionOffset+6;
				if (partitionEnd - partitionOffset >= 7 && (
						offset == start-1 || offset == start
						|| offset == partitionEnd || offset == partitionEnd-1)) {
					final String text= document.get(partitionOffset, 7);
					if (text.startsWith("\\verb")) {
						textViewer.setSelectedRange(start,
								getEndOffset(document, partitionEnd, new char[] { text.charAt(5) }) - start);
					}
					return;
				}
			}
			// Start in Comment-Partitions
			if (type == TexDocumentConstants.LTX_COMMENT_CONTENT_TYPE
					|| type == TexDocumentConstants.LTX_MATHCOMMENT_CONTENT_TYPE) {
				final int partitionOffset= partition.getOffset();
				if (offset == partitionOffset || offset == partitionOffset+1) {
					final IRegion lineInfo= document.getLineInformationOfOffset(partitionOffset);
					final int end= Math.min(partitionOffset + partition.getLength(),
							lineInfo.getOffset() + lineInfo.getLength() );
					textViewer.setSelectedRange(partitionOffset, end - partitionOffset);
					return;
				}
			}
			
			super.doubleClicked(textViewer);
			return;
		}
		catch (final BadLocationException | NullPointerException e) {
		}
		// else
		textViewer.setSelectedRange(offset, 0);
	}
	
	private int getEndOffset(final IDocument document, int end, final char[] endPattern) throws BadLocationException {
		int i= endPattern.length-1;
		while (--end >= 0 && i >= 0) {
			if (document.getChar(end) != endPattern[i--]) {
				break;
			}
		}
		return end+1;
	}
	
}