/*******************************************************************************
 * Copyright (c) 2007, 2009 Red Hat, Inc.
 * 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:
 *    Red Hat - initial API and implementation
 *******************************************************************************/

package org.eclipse.linuxtools.internal.rpm.ui.editor;

import org.eclipse.jface.text.BadLocationException;
import org.eclipse.jface.text.IDocument;
import org.eclipse.jface.text.ITextDoubleClickStrategy;
import org.eclipse.jface.text.ITextViewer;

public class SpecfileDoubleClickStrategy implements ITextDoubleClickStrategy {
	protected ITextViewer fText;
	//lTerminator should be either '\r' or '\n' depending on the OS
	final char lTerminator = System.getProperty("line.separator").charAt(0); //$NON-NLS-1$

	@Override
	public void doubleClicked(ITextViewer part) {
		int pos = part.getSelectedRange().x;

		if (pos < 0) {
			return;
		}

		fText = part;

		if (!selectComment(pos)) {
			selectWord(pos);
		}
	}
	protected boolean selectComment(int caretPos) {
		IDocument doc = fText.getDocument();
		int startPos, endPos;
		try {
			int pos = caretPos;
			char c = ' ';

			while (pos >= 0) {
				c = doc.getChar(pos);
				if (c == '\\') {
					pos -= 2;
					continue;
				}
				if ( c == lTerminator || c == '\"') {
					break;
				}
				--pos;
			}
			if (c != '\"') {
				return false;
			}

			startPos = pos;

			pos = caretPos;
			int length = doc.getLength();
			c = ' ';

			while (pos < length) {
				c = doc.getChar(pos);
				if ( c == lTerminator || c == '\"' ) {
					break;
				}
				++pos;
			}
			if (c != '\"')
				return false;

			endPos = pos;

			int offset = startPos + 1;
			int len = endPos - offset;
			fText.setSelectedRange(offset, len);
			return true;
		} catch (BadLocationException x) {
		}

		return false;
	}
	protected boolean selectWord(int caretPos) {

		IDocument doc = fText.getDocument();
		int startPos, endPos;

		try {

			int pos = caretPos;
			char c;

			while (pos >= 0) {
				c = doc.getChar(pos);
				if (!Character.isJavaIdentifierPart(c)) {
					break;
				}
				--pos;
			}

			startPos = pos;

			pos = caretPos;
			int length = doc.getLength();

			while (pos < length) {
				c = doc.getChar(pos);
				if (!Character.isJavaIdentifierPart(c)) {
					break;
				}
				++pos;
			}

			endPos = pos;
			selectRange(startPos, endPos);
			return true;

		} catch (BadLocationException x) {
		}

		return false;
	}

	private void selectRange(int startPos, int stopPos) {
		int offset = startPos + 1;
		int length = stopPos - offset;
		fText.setSelectedRange(offset, length);
	}
}