/*
 *
 * This file is part of the iText (R) project.
    Copyright (c) 1998-2022 iText Group NV
 * Authors: Pavel Alay, Bruno Lowagie, 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.text.pdf;

import com.itextpdf.text.DocumentException;
import com.itextpdf.text.pdf.security.XmlLocator;
import org.w3c.dom.Document;
import org.xml.sax.SAXException;

import javax.xml.XMLConstants;
import javax.xml.parsers.ParserConfigurationException;
import javax.xml.transform.Transformer;
import javax.xml.transform.TransformerConfigurationException;
import javax.xml.transform.TransformerException;
import javax.xml.transform.TransformerFactory;
import javax.xml.transform.dom.DOMSource;
import javax.xml.transform.stream.StreamResult;
import java.io.ByteArrayOutputStream;
import java.io.IOException;

/**
 * Helps to locate xml stream inside PDF document with Xfa form.
 */
public class XfaXmlLocator implements XmlLocator {

    public XfaXmlLocator(PdfStamper stamper) throws DocumentException, IOException {
        this.stamper = stamper;
        try {
            createXfaForm();
        } catch (ParserConfigurationException e) {
            throw new DocumentException(e);
        } catch (SAXException e) {
            throw new DocumentException(e);
        }
    }

    private PdfStamper stamper;
    private XfaForm xfaForm;
    private String encoding;

    protected void createXfaForm() throws ParserConfigurationException, SAXException, IOException {
        xfaForm = new XfaForm(stamper.getReader());
    }

    /**
     * Gets Document to sign
     */
    public Document getDocument() {
        return xfaForm.getDomDocument();
    }

    /**
     * Save document as single XML stream in AcroForm.
     * @param document signed document
     * @throws IOException
     * @throws DocumentException
     */
    public void setDocument(Document document) throws IOException, DocumentException {

        try {
            ByteArrayOutputStream outputStream = new ByteArrayOutputStream();
            TransformerFactory tf = TransformerFactory.newInstance();

            // preventing XXE in case of using the iText5 with newer versions of java
            try {
                tf.setAttribute("http://javax.xml.XMLConstants/property/accessExternalDTD", "");
            } catch (Exception e) {
            }
            try {
                tf.setAttribute("http://javax.xml.XMLConstants/property/accessExternalStylesheet", "");
            } catch (Exception e) {
            }
            try {
                tf.setFeature(XMLConstants.FEATURE_SECURE_PROCESSING, true);
            } catch (Exception exc) {}

            Transformer trans = tf.newTransformer();

            //Convert Document to byte[] to save to PDF
            trans.transform(new DOMSource(document), new StreamResult(outputStream));
            //Create PdfStream
            PdfIndirectReference iref = stamper.getWriter().
                    addToBody(new PdfStream(outputStream.toByteArray())).getIndirectReference();
            stamper.getReader().getAcroForm().put(PdfName.XFA, iref);
        } catch (TransformerConfigurationException e) {
            throw new DocumentException(e);
        } catch (TransformerException e) {
            throw new DocumentException(e);
        }
    }

    public String getEncoding() {
        return encoding;
    }

    public void setEncoding(String encoding) {
        this.encoding = encoding;
    }
}
