/*
 *
 * 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.security;

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

import com.itextpdf.text.pdf.PdfArray;
import com.itextpdf.text.pdf.PdfDictionary;
import com.itextpdf.text.pdf.PdfName;
import com.itextpdf.text.pdf.PdfNumber;

/**
 * A helper class that tells you more about the type of signature
 * (certification or approval) and the signature's DMP settings.
 */
public class SignaturePermissions {

	/**
	 * Class that contains a field lock action and
	 * an array of the fields that are involved.
	 */
	public class FieldLock {
		/** Can be /All, /Exclude or /Include */
		PdfName action;
		/** An array of PdfString values with fieldnames */
		PdfArray fields;
		/** Creates a FieldLock instance */
		public FieldLock(PdfName action, PdfArray fields) {
			this.action = action;
			this.fields = fields;
		}
		/** Getter for the field lock action. */
		public PdfName getAction() { return action; }
		/** Getter for the fields involved in the lock action. */
		public PdfArray getFields() { return fields; }
		/** toString method */
		public String toString() {
			return action.toString() + (fields == null ? "" : fields.toString());
		}
	}
	
	/** Is the signature a cerification signature (true) or an approval signature (false)? */
	boolean certification = false;
	/** Is form filling allowed by this signature? */
	boolean fillInAllowed = true;
	/** Is adding annotations allowed by this signature? */
	boolean annotationsAllowed = true;
	/** Does this signature lock specific fields? */
	List<FieldLock> fieldLocks = new ArrayList<FieldLock>();

	/**
	 * Creates an object that can inform you about the type of signature
	 * in a signature dictionary as well as some of the permissions
	 * defined by the signature.
	 */
	public SignaturePermissions(PdfDictionary sigDict, SignaturePermissions previous) {
		if (previous != null) {
			annotationsAllowed &= previous.isAnnotationsAllowed();
			fillInAllowed &= previous.isFillInAllowed();
			fieldLocks.addAll(previous.getFieldLocks());
		}
		PdfArray ref = sigDict.getAsArray(PdfName.REFERENCE);
		if (ref != null) {
			for (int i = 0; i < ref.size(); i++) {
				PdfDictionary dict = ref.getAsDict(i);
				PdfDictionary params = dict.getAsDict(PdfName.TRANSFORMPARAMS);
				if (PdfName.DOCMDP.equals(dict.getAsName(PdfName.TRANSFORMMETHOD))) {
					certification = true;
				}
				PdfName action = params.getAsName(PdfName.ACTION);
				if (action != null) {
					fieldLocks.add(new FieldLock(action, params.getAsArray(PdfName.FIELDS)));
				}
				PdfNumber p = params.getAsNumber(PdfName.P);
				if (p == null)
					continue;
				switch (p.intValue()) {
				default:
					break;
				case 1:
					fillInAllowed &= false;
				case 2:
					annotationsAllowed &= false;
				}
			}
		}
	}
	
	/**
	 * Getter to find out if the signature is a certification signature.
	 * @return true if the signature is a certification signature, false for an approval signature.
	 */
	public boolean isCertification() {
		return certification;
	}
	/**
	 * Getter to find out if filling out fields is allowed after signing.
	 * @return true if filling out fields is allowed
	 */
	public boolean isFillInAllowed() {
		return fillInAllowed;
	}
	/**
	 * Getter to find out if adding annotations is allowed after signing.
	 * @return true if adding annotations is allowed
	 */
	public boolean isAnnotationsAllowed() {
		return annotationsAllowed;
	}
	/**
	 * Getter for the field lock actions, and fields that are impacted by the action
	 * @return an Array with field names
	 */
	public List<FieldLock> getFieldLocks() {
		return fieldLocks;
	}	
}