/*
 * DSI utilities
 *
 * Copyright (C) 2005-2020 Sebastiano Vigna
 *
 *  This library is free software; you can redistribute it and/or modify it
 *  under the terms of the GNU Lesser General Public License as published by the Free
 *  Software Foundation; either version 3 of the License, or (at your option)
 *  any later version.
 *
 *  This library 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 Lesser General Public License
 *  for more details.
 *
 *  You should have received a copy of the GNU Lesser General Public License
 *  along with this program; if not, see <http://www.gnu.org/licenses/>.
 *
 */

package it.unimi.dsi.parser.callback;

import java.util.Map;

import it.unimi.dsi.lang.MutableString;
import it.unimi.dsi.parser.Attribute;
import it.unimi.dsi.parser.BulletParser;
import it.unimi.dsi.parser.Element;

/** A callback extracting text and titles.
 *
 * <P>This callbacks extracts all text in the page, and the title.
 * The resulting
 * text is available through {@link #text}, and the title through {@link #title}.
 *
 * <P>Note that {@link #text} and {@link #title} are never trimmed.
 */


public class TextExtractor extends DefaultCallback {

	/** The text resulting from the parsing process. */
	public final MutableString text = new MutableString();
	/** The title resulting from the parsing process. */
	public final MutableString title = new MutableString();
	/** True if we are in the middle of the title. */
	private boolean inTitle;

	/**
	 * Configure the parser to parse text.
	 */

	@Override
	public void configure(final BulletParser parser) {
		parser.parseText(true);
		// To get the title.
		parser.parseTags(true);
	}

	@Override
	public void startDocument() {
		text.length(0);
		title.length(0);
		inTitle = false;
	}

	@Override
	public boolean characters(final char[] characters, final int offset, final int length, final boolean flowBroken) {
		text.append(characters, offset, length);
		if (inTitle) title.append(characters, offset, length);
		return true;
	}

	@Override
	public boolean endElement(final Element element) {
		// No element is allowed inside a title.
		inTitle = false;
		if (element.breaksFlow) {
			if (inTitle) title.append(' ');
			text.append(' ');
		}
		return true;
	}

	@Override
	public boolean startElement(final Element element, final Map<Attribute,MutableString> attrMapUnused) {
		// No element is allowed inside a title.
		inTitle = element == Element.TITLE;
		if (element.breaksFlow) {
			if (inTitle) title.append(' ');
			text.append(' ');
		}
		return true;
	}

}
