/*
 *
 * This file is part of the iText (R) project.
    Copyright (c) 1998-2017 iText Group NV
 * Authors: Bruno Lowagie, Paulo Soares, 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 java.io.IOException;
import java.io.OutputStream;
import java.security.PrivateKey;
import java.util.HashMap;

import org.bouncycastle.cms.CMSException;
import org.bouncycastle.cms.Recipient;
import org.bouncycastle.cms.RecipientInformation;
import org.bouncycastle.cms.jcajce.JceKeyTransEnvelopedRecipient;

import com.itextpdf.text.DocumentException;

/** This class takes any PDF and returns exactly the same but
 * encrypted. All the content, links, outlines, etc, are kept.
 * It is also possible to change the info dictionary.
 */
public final class PdfEncryptor {

    private PdfEncryptor(){
    }

    /** Entry point to encrypt a PDF document. The encryption parameters are the same as in
     * <code>PdfWriter</code>. The userPassword and the
     *  ownerPassword can be null or have zero length. In this case the ownerPassword
     *  is replaced by a random string. The open permissions for the document can be
     *  AllowPrinting, AllowModifyContents, AllowCopy, AllowModifyAnnotations,
     *  AllowFillIn, AllowScreenReaders, AllowAssembly and AllowDegradedPrinting.
     *  The permissions can be combined by ORing them.
     * @param reader the read PDF
     * @param os the output destination
     * @param userPassword the user password. Can be null or empty
     * @param ownerPassword the owner password. Can be null or empty
     * @param permissions the user permissions
     * @param strength128Bits <code>true</code> for 128 bit key length, <code>false</code> for 40 bit key length
     * @throws DocumentException on error
     * @throws IOException on error */
    public static void encrypt(PdfReader reader, OutputStream os, byte userPassword[], byte ownerPassword[], int permissions, boolean strength128Bits) throws DocumentException, IOException {
        PdfStamper stamper = new PdfStamper(reader, os);
        stamper.setEncryption(userPassword, ownerPassword, permissions, strength128Bits);
        stamper.close();
    }

    /** Entry point to encrypt a PDF document. The encryption parameters are the same as in
     * <code>PdfWriter</code>. The userPassword and the
     *  ownerPassword can be null or have zero length. In this case the ownerPassword
     *  is replaced by a random string. The open permissions for the document can be
     *  AllowPrinting, AllowModifyContents, AllowCopy, AllowModifyAnnotations,
     *  AllowFillIn, AllowScreenReaders, AllowAssembly and AllowDegradedPrinting.
     *  The permissions can be combined by ORing them.
     * @param reader the read PDF
     * @param os the output destination
     * @param userPassword the user password. Can be null or empty
     * @param ownerPassword the owner password. Can be null or empty
     * @param permissions the user permissions
     * @param strength128Bits <code>true</code> for 128 bit key length, <code>false</code> for 40 bit key length
     * @param newInfo an optional <CODE>String</CODE> map to add or change
     * the info dictionary. Entries with <CODE>null</CODE>
     * values delete the key in the original info dictionary
     * @throws DocumentException on error
     * @throws IOException on error
     * @since 5.0.1 (generic type in signature)
     */
    public static void encrypt(PdfReader reader, OutputStream os, byte userPassword[], byte ownerPassword[], int permissions, boolean strength128Bits, HashMap<String, String> newInfo) throws DocumentException, IOException {
        PdfStamper stamper = new PdfStamper(reader, os);
        stamper.setEncryption(userPassword, ownerPassword, permissions, strength128Bits);
        stamper.setMoreInfo(newInfo);
        stamper.close();
    }

    /** Entry point to encrypt a PDF document. The encryption parameters are the same as in
     * <code>PdfWriter</code>. The userPassword and the
     *  ownerPassword can be null or have zero length. In this case the ownerPassword
     *  is replaced by a random string. The open permissions for the document can be
     *  AllowPrinting, AllowModifyContents, AllowCopy, AllowModifyAnnotations,
     *  AllowFillIn, AllowScreenReaders, AllowAssembly and AllowDegradedPrinting.
     *  The permissions can be combined by ORing them.
     * @param reader the read PDF
     * @param os the output destination
     * @param strength <code>true</code> for 128 bit key length, <code>false</code> for 40 bit key length
     * @param userPassword the user password. Can be null or empty
     * @param ownerPassword the owner password. Can be null or empty
     * @param permissions the user permissions
     * @throws DocumentException on error
     * @throws IOException on error */
    public static void encrypt(PdfReader reader, OutputStream os, boolean strength, String userPassword, String ownerPassword, int permissions) throws DocumentException, IOException {
        PdfStamper stamper = new PdfStamper(reader, os);
        stamper.setEncryption(strength, userPassword, ownerPassword, permissions);
        stamper.close();
    }

    /** Entry point to encrypt a PDF document. The encryption parameters are the same as in
     * <code>PdfWriter</code>. The userPassword and the
     *  ownerPassword can be null or have zero length. In this case the ownerPassword
     *  is replaced by a random string. The open permissions for the document can be
     *  AllowPrinting, AllowModifyContents, AllowCopy, AllowModifyAnnotations,
     *  AllowFillIn, AllowScreenReaders, AllowAssembly and AllowDegradedPrinting.
     *  The permissions can be combined by ORing them.
     * @param reader the read PDF
     * @param os the output destination
     * @param strength <code>true</code> for 128 bit key length, <code>false</code> for 40 bit key length
     * @param userPassword the user password. Can be null or empty
     * @param ownerPassword the owner password. Can be null or empty
     * @param permissions the user permissions
     * @param newInfo an optional <CODE>String</CODE> map to add or change
     * the info dictionary. Entries with <CODE>null</CODE>
     * values delete the key in the original info dictionary
     * @throws DocumentException on error
     * @throws IOException on error
     * @since 5.0.1 (generic type in signature)
     */
    public static void encrypt(PdfReader reader, OutputStream os, boolean strength, String userPassword, String ownerPassword, int permissions, HashMap<String, String> newInfo) throws DocumentException, IOException {
        PdfStamper stamper = new PdfStamper(reader, os);
        stamper.setEncryption(strength, userPassword, ownerPassword, permissions);
        stamper.setMoreInfo(newInfo);
        stamper.close();
    }


    /** Entry point to encrypt a PDF document. The encryption parameters are the same as in
     * <code>PdfWriter</code>. The userPassword and the
     *  ownerPassword can be null or have zero length. In this case the ownerPassword
     *  is replaced by a random string. The open permissions for the document can be
     *  AllowPrinting, AllowModifyContents, AllowCopy, AllowModifyAnnotations,
     *  AllowFillIn, AllowScreenReaders, AllowAssembly and AllowDegradedPrinting.
     *  The permissions can be combined by ORing them.
     * @param reader the read PDF
     * @param os the output destination
     * @param type the type of encryption. It can be one of STANDARD_ENCRYPTION_40, STANDARD_ENCRYPTION_128 or ENCRYPTION_AES128.
     * Optionally DO_NOT_ENCRYPT_METADATA can be ored to output the metadata in cleartext
     * @param userPassword the user password. Can be null or empty
     * @param ownerPassword the owner password. Can be null or empty
     * @param permissions the user permissions
     * @param newInfo an optional <CODE>String</CODE> map to add or change
     * the info dictionary. Entries with <CODE>null</CODE>
     * values delete the key in the original info dictionary
     * @throws DocumentException on error
     * @throws IOException on error
     * @since 5.0.1 (generic type in signature)
     */
    public static void encrypt(PdfReader reader, OutputStream os, int type, String userPassword, String ownerPassword, int permissions, HashMap<String, String> newInfo) throws DocumentException, IOException {
        PdfStamper stamper = new PdfStamper(reader, os);
        stamper.setEncryption(type, userPassword, ownerPassword, permissions);
        stamper.setMoreInfo(newInfo);
        stamper.close();
    }

    /** Entry point to encrypt a PDF document. The encryption parameters are the same as in
     * <code>PdfWriter</code>. The userPassword and the
     *  ownerPassword can be null or have zero length. In this case the ownerPassword
     *  is replaced by a random string. The open permissions for the document can be
     *  AllowPrinting, AllowModifyContents, AllowCopy, AllowModifyAnnotations,
     *  AllowFillIn, AllowScreenReaders, AllowAssembly and AllowDegradedPrinting.
     *  The permissions can be combined by ORing them.
     * @param reader the read PDF
     * @param os the output destination
     * @param type the type of encryption. It can be one of STANDARD_ENCRYPTION_40, STANDARD_ENCRYPTION_128 or ENCRYPTION_AES128.
     * Optionally DO_NOT_ENCRYPT_METADATA can be ored to output the metadata in cleartext
     * @param userPassword the user password. Can be null or empty
     * @param ownerPassword the owner password. Can be null or empty
     * @param permissions the user permissions
     * values delete the key in the original info dictionary
     * @throws DocumentException on error
     * @throws IOException on error
     */
    public static void encrypt(PdfReader reader, OutputStream os, int type, String userPassword, String ownerPassword, int permissions) throws DocumentException, IOException {
        PdfStamper stamper = new PdfStamper(reader, os);
        stamper.setEncryption(type, userPassword, ownerPassword, permissions);
        stamper.close();
    }

    /**
     * Give you a verbose analysis of the permissions.
     * @param permissions the permissions value of a PDF file
     * @return a String that explains the meaning of the permissions value
     */
    public static String getPermissionsVerbose(int permissions) {
    	StringBuffer buf = new StringBuffer("Allowed:");
    	if ((PdfWriter.ALLOW_PRINTING & permissions) == PdfWriter.ALLOW_PRINTING) buf.append(" Printing");
        if ((PdfWriter.ALLOW_MODIFY_CONTENTS & permissions) == PdfWriter.ALLOW_MODIFY_CONTENTS) buf.append(" Modify contents");
        if ((PdfWriter.ALLOW_COPY & permissions) == PdfWriter.ALLOW_COPY) buf.append(" Copy");
        if ((PdfWriter.ALLOW_MODIFY_ANNOTATIONS & permissions) == PdfWriter.ALLOW_MODIFY_ANNOTATIONS) buf.append(" Modify annotations");
        if ((PdfWriter.ALLOW_FILL_IN & permissions) == PdfWriter.ALLOW_FILL_IN) buf.append(" Fill in");
        if ((PdfWriter.ALLOW_SCREENREADERS & permissions) == PdfWriter.ALLOW_SCREENREADERS) buf.append(" Screen readers");
        if ((PdfWriter.ALLOW_ASSEMBLY & permissions) == PdfWriter.ALLOW_ASSEMBLY) buf.append(" Assembly");
        if ((PdfWriter.ALLOW_DEGRADED_PRINTING & permissions) == PdfWriter.ALLOW_DEGRADED_PRINTING) buf.append(" Degraded printing");
        return buf.toString();
    }

    /**
     * Tells you if printing is allowed.
     * @param permissions the permissions value of a PDF file
     * @return	true if printing is allowed
     *
     * @since 2.0.7
     */
    public static boolean isPrintingAllowed(int permissions) {
        return (PdfWriter.ALLOW_PRINTING & permissions) == PdfWriter.ALLOW_PRINTING;
    }

    /**
     * Tells you if modifying content is allowed.
     * @param permissions the permissions value of a PDF file
     * @return	true if modifying content is allowed
     *
     * @since 2.0.7
     */
    public static boolean isModifyContentsAllowed(int permissions) {
        return (PdfWriter.ALLOW_MODIFY_CONTENTS & permissions) == PdfWriter.ALLOW_MODIFY_CONTENTS;
    }

    /**
     * Tells you if copying is allowed.
     * @param permissions the permissions value of a PDF file
     * @return	true if copying is allowed
     *
     * @since 2.0.7
     */
    public static boolean isCopyAllowed(int permissions) {
        return (PdfWriter.ALLOW_COPY & permissions) == PdfWriter.ALLOW_COPY;
    }

    /**
     * Tells you if modifying annotations is allowed.
     * @param permissions the permissions value of a PDF file
     * @return	true if modifying annotations is allowed
     *
     * @since 2.0.7
     */
    public static boolean isModifyAnnotationsAllowed(int permissions) {
        return (PdfWriter.ALLOW_MODIFY_ANNOTATIONS & permissions) == PdfWriter.ALLOW_MODIFY_ANNOTATIONS;
    }

    /**
     * Tells you if filling in fields is allowed.
     * @param permissions the permissions value of a PDF file
     * @return	true if filling in fields is allowed
     *
     * @since 2.0.7
     */
    public static boolean isFillInAllowed(int permissions) {
        return (PdfWriter.ALLOW_FILL_IN & permissions) == PdfWriter.ALLOW_FILL_IN;
    }

    /**
     * Tells you if repurposing for screenreaders is allowed.
     * @param permissions the permissions value of a PDF file
     * @return	true if repurposing for screenreaders is allowed
     *
     * @since 2.0.7
     */
    public static boolean isScreenReadersAllowed(int permissions) {
        return (PdfWriter.ALLOW_SCREENREADERS & permissions) == PdfWriter.ALLOW_SCREENREADERS;
    }

    /**
     * Tells you if document assembly is allowed.
     * @param permissions the permissions value of a PDF file
     * @return	true if document assembly is allowed
     *
     * @since 2.0.7
     */
    public static boolean isAssemblyAllowed(int permissions) {
        return (PdfWriter.ALLOW_ASSEMBLY & permissions) == PdfWriter.ALLOW_ASSEMBLY;
    }

    /**
     * Tells you if degraded printing is allowed.
     * @param permissions the permissions value of a PDF file
     * @return	true if degraded printing is allowed
     *
     * @since 2.0.7
     */
    public static boolean isDegradedPrintingAllowed(int permissions) {
        return (PdfWriter.ALLOW_DEGRADED_PRINTING & permissions) == PdfWriter.ALLOW_DEGRADED_PRINTING;
    }

	/**
	 * Gets the content from a recipient.
	 * @param recipientInfo
	 * @param certificateKey
	 * @param certificateKeyProvider
	 * @return
	 * @throws CMSException
	 */
	public static byte[] getContent(RecipientInformation recipientInfo, PrivateKey certificateKey, String certificateKeyProvider) throws CMSException {
	 	Recipient jceKeyTransRecipient = new JceKeyTransEnvelopedRecipient(certificateKey).setProvider(certificateKeyProvider);
		return recipientInfo.getContent(jceKeyTransRecipient);
	}
}
