/*

 * Copyright (c) 2019, Oracle and/or its affiliates. All rights reserved.

 * DO NOT ALTER OR REMOVE COPYRIGHT NOTICES OR THIS FILE HEADER.

 *

 * This code is free software; you can redistribute it and/or modify it

 * under the terms of the GNU General Public License version 2 only, as

 * published by the Free Software Foundation.  Oracle designates this

 * particular file as subject to the "Classpath" exception as provided

 * by Oracle in the LICENSE file that accompanied this code.

 *

 * This code 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 General Public License

 * version 2 for more details (a copy is included in the LICENSE file that

 * accompanied this code).

 *

 * You should have received a copy of the GNU General Public License version

 * 2 along with this work; if not, write to the Free Software Foundation,

 * Inc., 51 Franklin St, Fifth Floor, Boston, MA 02110-1301 USA.

 *

 * Please contact Oracle, 500 Oracle Parkway, Redwood Shores, CA 94065 USA

 * or visit www.oracle.com if you need additional information or have any

 * questions.

 */

package jdk.jpackage.internal;

import java.io.FileInputStream;

import java.io.IOException;

import java.nio.file.Path;

import java.util.List;

import java.util.ArrayList;

import java.util.Map;

import javax.xml.parsers.DocumentBuilder;

import javax.xml.parsers.DocumentBuilderFactory;

import javax.xml.parsers.ParserConfigurationException;

import javax.xml.xpath.XPath;

import javax.xml.xpath.XPathConstants;

import javax.xml.xpath.XPathExpressionException;

import javax.xml.xpath.XPathFactory;

import org.w3c.dom.Document;

import org.w3c.dom.NodeList;

import org.xml.sax.SAXException;

import static jdk.jpackage.internal.StandardBundlerParam.*;

public class AppImageFile {

    // These values will be loaded from AppImage xml file.

    private final String creatorVersion;

    private final String creatorPlatform;

    private final String launcherName;

    private final List<String> addLauncherNames;

    private final static Map<Platform, String> PLATFORM_LABELS = Map.of(

            Platform.LINUX, "linux", Platform.WINDOWS, "windows", Platform.MAC,

            "macOS");

    private AppImageFile() {

        this(null, null, null, null);

    }

    private AppImageFile(String launcherName, List<String> addLauncherNames,

            String creatorVersion, String creatorPlatform) {

        this.launcherName = launcherName;

        this.addLauncherNames = addLauncherNames;

        this.creatorVersion = creatorVersion;

        this.creatorPlatform = creatorPlatform;

    }

    /**

     * Returns list of additional launchers configured for the application.

     * Each item in the list is not null or empty string.

     * Returns empty list for application without additional launchers.

     */

    List<String> getAddLauncherNames() {

        return addLauncherNames;

    }

    /**

     * Returns main application launcher name. Never returns null or empty value.

     */

    String getLauncherName() {

        return launcherName;

    }

    void verifyCompatible() throws ConfigException {

        // Just do nothing for now.

    }

    /**

     * Saves file with application image info in application image.

     * @param appImageDir - path to application image

     * @throws IOException

     */

            throws IOException {

            xml.writeStartElement("jpackage-state");

            xml.writeAttribute("version", getVersion());

            xml.writeAttribute("platform", getPlatform());

            xml.writeStartElement("main-launcher");

            xml.writeCharacters(APP_NAME.fetchFrom(params));

            xml.writeEndElement();

            List<Map<String, ? super Object>> addLaunchers =

                ADD_LAUNCHERS.fetchFrom(params);

            for (int i = 0; i < addLaunchers.size(); i++) {

                Map<String, ? super Object> sl = addLaunchers.get(i);

                xml.writeStartElement("add-launcher");

                xml.writeCharacters(APP_NAME.fetchFrom(sl));

                xml.writeEndElement();

            }

        });

    }

    /**

     * Loads application image info from application image.

     * @param appImageDir - path to application image

     * @return valid info about application image or null

     * @throws IOException

     */

    static AppImageFile load(Path appImageDir) throws IOException {

        try {

            DocumentBuilderFactory dbf =

                    DocumentBuilderFactory.newDefaultInstance();

            dbf.setFeature(

                   "http://apache.org/xml/features/nonvalidating/load-external-dtd",

                    false);

            DocumentBuilder b = dbf.newDocumentBuilder();

            Document doc = b.parse(new FileInputStream(path.toFile()));

            XPath xPath = XPathFactory.newInstance().newXPath();

            String mainLauncher = xpathQueryNullable(xPath,

                    "/jpackage-state/main-launcher/text()", doc);

            if (mainLauncher == null) {

                // No main launcher, this is fatal.

                return new AppImageFile();

            }

            List<String> addLaunchers = new ArrayList<String>();

            String platform = xpathQueryNullable(xPath,

                    "/jpackage-state/@platform", doc);

            String version = xpathQueryNullable(xPath,

                    "/jpackage-state/@version", doc);

            NodeList launcherNameNodes = (NodeList) xPath.evaluate(

                    "/jpackage-state/add-launcher/text()", doc,

                    XPathConstants.NODESET);

            for (int i = 0; i != launcherNameNodes.getLength(); i++) {

                addLaunchers.add(launcherNameNodes.item(i).getNodeValue());

            }

            AppImageFile file = new AppImageFile(

                    mainLauncher, addLaunchers, version, platform);

            if (!file.isValid()) {

                file = new AppImageFile();

            }

            return file;

        } catch (ParserConfigurationException | SAXException ex) {

            // Let caller sort this out

            throw new IOException(ex);

        } catch (XPathExpressionException ex) {

            // This should never happen as XPath expressions should be correct

            throw new RuntimeException(ex);

        }

    }

    /**

     * Returns list of launcher names configured for the application.

     * Following items in the list are names of additional launchers.

     */

    static List<String> getLauncherNames(Path appImageDir,

            Map<String, ? super Object> params) {

        List<String> launchers = new ArrayList<>();

        try {

            AppImageFile appImageInfo = AppImageFile.load(appImageDir);

            if (appImageInfo != null) {

                launchers.add(appImageInfo.getLauncherName());

                launchers.addAll(appImageInfo.getAddLauncherNames());

                return launchers;

            }

        } catch (IOException ioe) {

            Log.verbose(ioe);

        }

        launchers.add(APP_NAME.fetchFrom(params));

        ADD_LAUNCHERS.fetchFrom(params).stream().map(APP_NAME::fetchFrom).forEach(

                launchers::add);

        return launchers;

    }

    private static String xpathQueryNullable(XPath xPath, String xpathExpr,

            Document xml) throws XPathExpressionException {

        NodeList nodes = (NodeList) xPath.evaluate(xpathExpr, xml,

                XPathConstants.NODESET);

        if (nodes != null && nodes.getLength() > 0) {

            return nodes.item(0).getNodeValue();

        }

        return null;

    }

    private static String getVersion() {

        return System.getProperty("java.version");

    }

    private static String getPlatform() {

        return PLATFORM_LABELS.get(Platform.getPlatform());

    }

    private boolean isValid() {

        if (launcherName == null || launcherName.length() == 0 ||

            addLauncherNames.indexOf("") != -1) {

            // Some launchers have empty names. This is invalid.

            return false;

        }

        // Add more validation.

        return true;

    }

}