/*
 *
 * This file is part of the iText (R) project.
    Copyright (c) 1998-2019 iText Group NV
 * Authors: Balder Van Camp, Emiel Ackermann, et al.
 *
 * This program is free software; you can redistribute it and/or modify
 * it under the terms of the GNU Affero General Public License version 3
 * as published by the Free Software Foundation with the addition of the
 * following permission added to Section 15 as permitted in Section 7(a):
 * FOR ANY PART OF THE COVERED WORK IN WHICH THE COPYRIGHT IS OWNED BY
 * ITEXT GROUP. ITEXT GROUP DISCLAIMS THE WARRANTY OF NON INFRINGEMENT
 * OF THIRD PARTY RIGHTS
 *
 * 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 Affero General Public License for more details.
 * You should have received a copy of the GNU Affero General Public License
 * along with this program; if not, see http://www.gnu.org/licenses or write to
 * the Free Software Foundation, Inc., 51 Franklin Street, Fifth Floor,
 * Boston, MA, 02110-1301 USA, or download the license from the following URL:
 * http://itextpdf.com/terms-of-use/
 *
 * The interactive user interfaces in modified source and object code versions
 * of this program must display Appropriate Legal Notices, as required under
 * Section 5 of the GNU Affero General Public License.
 *
 * In accordance with Section 7(b) of the GNU Affero General Public License,
 * a covered work must retain the producer line in every PDF that is created
 * or manipulated using iText.
 *
 * You can be released from the requirements of the license by purchasing
 * a commercial license. Buying such a license is mandatory as soon as you
 * develop commercial activities involving the iText software without
 * disclosing the source code of your own applications.
 * These activities include: offering paid services to customers as an ASP,
 * serving PDFs on the fly in a web application, shipping iText with a closed
 * source product.
 *
 * For more information, please contact iText Software Corp. at this
 * address: sales@itextpdf.com
 */
package com.itextpdf.tool.xml.html.head;

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

import com.itextpdf.text.Element;
import com.itextpdf.text.log.Level;
import com.itextpdf.text.log.Logger;
import com.itextpdf.text.log.LoggerFactory;
import com.itextpdf.tool.xml.NoCustomContextException;
import com.itextpdf.tool.xml.Tag;
import com.itextpdf.tool.xml.WorkerContext;
import com.itextpdf.tool.xml.exceptions.CssResolverException;
import com.itextpdf.tool.xml.exceptions.LocaleMessages;
import com.itextpdf.tool.xml.html.AbstractTagProcessor;
import com.itextpdf.tool.xml.html.HTML;
import com.itextpdf.tool.xml.pipeline.css.CssResolverPipeline;

/**
 * The Link TagProcessor will try to add the content of a &lt;link&gt; that has the attribute type set to "text/css" to the
 * {@link CssResolverPipeline} CSS. If the content cannot be parsed, an error is logged.
 * @author redlab_b
 *
 */
public class Link extends AbstractTagProcessor {

	private static final Logger LOG = LoggerFactory.getLogger(Link.class);
	/* (non-Javadoc)
	 * @see com.itextpdf.tool.xml.TagProcessor#startElement(com.itextpdf.tool.xml.Tag)
	 */
	@Override
	public List<Element> start(final WorkerContext ctx, final Tag tag) {
		if (HTML.Attribute.Value.TEXTCSS.equalsIgnoreCase(tag.getAttributes().get(HTML.Attribute.TYPE))) {
			String href = tag.getAttributes().get(HTML.Attribute.HREF);
			if (null != href) {
				try {
					getCSSResolver(ctx).addCssFile(href, false);
				} catch (CssResolverException e) {
					if (LOG.isLogging(Level.ERROR)) {
						LOG.error(String.format(LocaleMessages.getInstance().getMessage(LocaleMessages.LINK_404), href), e);
					}
				} catch (NoCustomContextException e) {
					if (LOG.isLogging(Level.WARN)) {
						LOG.warn(String.format(LocaleMessages.getInstance().getMessage(LocaleMessages.CUSTOMCONTEXT_404_CONTINUE), CssResolverPipeline.class.getName()));
					}
				}
			}
		}
		return new ArrayList<Element>(0);
	}

}
