/*******************************************************************************
 * Breakout Cave Survey Visualizer
 *
 * Copyright (C) 2014 James Edwards
 *
 * jedwards8 at fastmail dot fm
 *
 * This program is free software; you can redistribute it and/or modify it under
 * the terms of the GNU General Public License as published by the Free Software
 * Foundation; either version 2 of the License, or (at your option) any later
 * version.
 *
 * This program is distributed in the hope that it will be useful, but WITHOUT
 * ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or FITNESS
 * FOR A PARTICULAR PURPOSE. See the GNU General Public License for more
 * details.
 *
 * You should have received a copy of the GNU General Public License along with
 * this program; if not, write to the Free Software Foundation, Inc., 51
 * Franklin Street, Fifth Floor, Boston, MA 02110-1301 USA.
 *******************************************************************************/
package org.andork.swing.text;

import java.util.regex.Pattern;

import javax.swing.text.AttributeSet;
import javax.swing.text.BadLocationException;
import javax.swing.text.DocumentFilter;

public class PatternDocumentFilter extends DocumentFilter {
	Pattern pattern;
	boolean enabled = true;

	public PatternDocumentFilter(Pattern pattern) {
		super();
		this.pattern = pattern;
	}

	private String getNewText(FilterBypass fb, String insertText, int offset, int length) {
		try {
			return getNewText(fb.getDocument().getText(0, fb.getDocument().getLength()), insertText, offset, length);
		} catch (BadLocationException e) {
			return null;
		}
	}

	private String getNewText(String inputText, String insertText, int offset, int length) {
		StringBuffer sb = new StringBuffer();
		sb.append(inputText.substring(0, offset));
		if (insertText != null) {
			sb.append(insertText);
		}
		sb.append(inputText.substring(offset + length, inputText.length()));
		return sb.toString();
	}

	public Pattern getPattern() {
		return pattern;
	}

	@Override
	public void insertString(FilterBypass fb, int offset, String string, AttributeSet attr)
			throws BadLocationException {
		String newText = getNewText(fb, string, offset, 0);
		if (!enabled || pattern == null || pattern.matcher(newText).matches()) {
			fb.insertString(offset, string, attr);
		}
	}

	public boolean isEnabled() {
		return enabled;
	}

	@Override
	public void remove(FilterBypass fb, int offset, int length) throws BadLocationException {
		String newText = getNewText(fb, "", offset, length);
		if (!enabled || pattern == null || pattern.matcher(newText).matches()) {
			fb.remove(offset, length);
		}
	}

	@Override
	public void replace(FilterBypass fb, int offset, int length, String text, AttributeSet attrs)
			throws BadLocationException {
		String newText = getNewText(fb, text, offset, length);
		if (!enabled || pattern == null || pattern.matcher(newText).matches()) {
			fb.replace(offset, length, text, attrs);
		}
	}

	public void setEnabled(boolean enabled) {
		this.enabled = enabled;
	}

	public void setPattern(Pattern pattern) {
		this.pattern = pattern;
	}
}