/*
 *
 * This file is part of the iText (R) project.
    Copyright (c) 1998-2020 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;

import java.lang.reflect.Field;
import java.lang.reflect.InvocationTargetException;
import java.lang.reflect.Method;

/**
 * This class contains version information about iText.
 * DO NOT CHANGE THE VERSION INFORMATION WITHOUT PERMISSION OF THE COPYRIGHT HOLDERS OF ITEXT.
 * Changing the version makes it extremely difficult to debug an application.
 * Also, the nature of open source software is that you honor the copyright of the original creators of the software.
 */
public final class Version {

    private static final Object staticLock = new Object();

	// membervariables
    
    /** String that will indicate if the AGPL version is used. */
    public static String AGPL = " (AGPL-version)";
    
	/** The iText version instance. */
	private static volatile Version version = null;
	/**
	 * This String contains the name of the product.
	 * iText is a registered trademark by iText Group NV.
	 * Please don't change this constant.
	 */
	private final String iText = "iText\u00ae";
	/**
	 * This String contains the version number of this iText release.
	 * For debugging purposes, we request you NOT to change this constant.
	 */
	private final String release = "5.5.13.2";
	/**
	 * This String contains the iText version as shown in the producer line.
	 * iText is a product developed by iText Group NV.
	 * iText Group requests that you retain the iText producer line
	 * in every PDF that is created or manipulated using iText.
	 */
	private String iTextVersion = iText + " " + release + " \u00a92000-2020 iText Group NV";
	/**
	 * The license key.
	 */
	private String key = null;

	/**
	 * Gets an instance of the iText version that is currently used.
	 * Note that iText Group requests that you retain the iText producer line
	 * in every PDF that is created or manipulated using iText.
	 */
	public static Version getInstance() {
	    synchronized (staticLock) {
	        if (version != null) {
	            return version;
            }
        }
        Version localVersion = new Version();
        try {
            Class<?> klass = Class.forName("com.itextpdf.licensekey.LicenseKey");
            Class[] cArg  = {String.class};
            Method m = klass.getMethod("getLicenseeInfoForVersion",cArg);
            Object[] args = {localVersion.release};
            String[] info = (String[]) m.invoke(klass.newInstance(),args);
            if (info[3] != null && info[3].trim().length() > 0) {
                localVersion.key = info[3];
            } else {
                localVersion.key = "Trial version ";
                if (info[5] == null) {
                    localVersion.key += "unauthorised";
                } else {
                    localVersion.key += info[5];
                }
            }

            if (info[4] != null && info[4].trim().length() > 0) {
                localVersion.iTextVersion = info[4];
            } else if (info[2] != null && info[2].trim().length() > 0) {
                localVersion.iTextVersion += " (" + info[2];
                if (!localVersion.key.toLowerCase().startsWith("trial")) {
                    localVersion.iTextVersion += "; licensed version)";
                } else {
                    localVersion.iTextVersion += "; " + localVersion.key + ")";
                }
            } else if (info[0] != null && info[0].trim().length() > 0) {
                // fall back to contact name, if company name is unavailable
                localVersion.iTextVersion += " (" + info[0];
                if (!localVersion.key.toLowerCase().startsWith("trial")) {
                    // we shouldn't have a licensed version without company name,
                    // but let's account for it anyway
                    localVersion.iTextVersion += "; licensed version)";
                } else {
                    localVersion.iTextVersion += "; " + localVersion.key + ")";
                }
            } else {
                throw new Exception();
            }
        } catch (Exception e) {
            if (dependsOnTheOldLicense()) {
                throw new RuntimeException("iText License Library 1.0.* has been deprecated. Please, update to the latest version.");
            }
            localVersion.iTextVersion += AGPL;
        }
		return atomicSetVersion(localVersion);
	}

	private static boolean dependsOnTheOldLicense() {
	    try {
            Class<?> klass = Class.forName("com.itextpdf.license.LicenseKey");
            return klass.getField("PRODUCT_NAME") != null;
        } catch (Exception e) {
            return false;
        }
    }

	/**
	 * Gets the product name.
	 * iText Group NV requests that you retain the iText producer line
	 * in every PDF that is created or manipulated using iText.
     * @return the product name
     */
    public String getProduct() {
        return iText;
    }

	/**
	 * Gets the release number.
	 * iText Group NV requests that you retain the iText producer line
	 * in every PDF that is created or manipulated using iText.
     * @return the release number
     */
    public String getRelease() {
        return release;
    }

	/**
	 * Returns the iText version as shown in the producer line.
	 * iText is a product developed by iText Group NV.
	 * iText Group requests that you retain the iText producer line
	 * in every PDF that is created or manipulated using iText.
     * @return iText version
     */
    public String getVersion() {
        return iTextVersion;
    }

    /**
     * Returns a license key if one was provided, or null if not.
     * @return a license key.
     */
    public String getKey() {
    	return key;
    }
    
    /**
     * Checks if the AGPL version is used.
     * @return returns true if the AGPL version is used.
     */
    public static boolean isAGPLVersion() {
        return getInstance().getVersion().indexOf(AGPL) > 0;
    }

    private static Version atomicSetVersion(Version newVersion) {
        synchronized (staticLock) {
            version = newVersion;
            return version;
        }
    }
}
