/*
 * 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.awt.image.BufferedImage;
import java.io.*;
import java.nio.file.Path;
import java.util.*;
import java.util.stream.Collectors;
import java.util.stream.Stream;
import javax.imageio.ImageIO;
import javax.xml.stream.XMLOutputFactory;
import javax.xml.stream.XMLStreamException;
import javax.xml.stream.XMLStreamWriter;
import static jdk.jpackage.internal.LinuxAppBundler.ICON_PNG;
import static jdk.jpackage.internal.LinuxAppImageBuilder.DEFAULT_ICON;
import static jdk.jpackage.internal.OverridableResource.createResource;
import static jdk.jpackage.internal.StandardBundlerParam.*;

/**
 * Helper to create files for desktop integration.
 */
final class DesktopIntegration {

    static final String DESKTOP_COMMANDS_INSTALL = "DESKTOP_COMMANDS_INSTALL";
    static final String DESKTOP_COMMANDS_UNINSTALL = "DESKTOP_COMMANDS_UNINSTALL";
    static final String UTILITY_SCRIPTS = "UTILITY_SCRIPTS";

    DesktopIntegration(PlatformPackage thePackage,
            Map<String, ? super Object> params) {

        associations = FILE_ASSOCIATIONS.fetchFrom(params).stream().filter(
                a -> {
                    if (a == null) {
                        return false;
                    }
                    List<String> mimes = FA_CONTENT_TYPE.fetchFrom(a);
                    return (mimes != null && !mimes.isEmpty());
                }).collect(Collectors.toUnmodifiableList());

        launchers = ADD_LAUNCHERS.fetchFrom(params);

        this.thePackage = thePackage;

        final File customIconFile = ICON_PNG.fetchFrom(params);

        iconResource = createResource(DEFAULT_ICON, params)
                .setCategory(I18N.getString("resource.menu-icon"))
                .setExternal(customIconFile);
        desktopFileResource = createResource("template.desktop", params)
                .setCategory(I18N.getString("resource.menu-shortcut-descriptor"));

        // XDG recommends to use vendor prefix in desktop file names as xdg
        // commands copy files to system directories.
        // Package name should be a good prefix.
        final String desktopFileName = String.format("%s-%s.desktop",
                    thePackage.name(), APP_NAME.fetchFrom(params));
        final String mimeInfoFileName = String.format("%s-%s-MimeInfo.xml",
                    thePackage.name(), APP_NAME.fetchFrom(params));

        mimeInfoFile = new DesktopFile(mimeInfoFileName);

        if (!associations.isEmpty() || SHORTCUT_HINT.fetchFrom(params) || customIconFile != null) {
            //
            // Create primary .desktop file if one of conditions is met:
            // - there are file associations configured
            // - user explicitely requested to create a shortcut
            // - custom icon specified
            //
            desktopFile = new DesktopFile(desktopFileName);
            iconFile = new DesktopFile(String.format("%s.png",
                    APP_NAME.fetchFrom(params)));
        } else {
            desktopFile = null;
            iconFile = null;
        }

        desktopFileData = Collections.unmodifiableMap(
                createDataForDesktopFile(params));

        nestedIntegrations = launchers.stream().map(
                launcherParams -> new DesktopIntegration(thePackage,
                        launcherParams)).collect(Collectors.toList());
    }

    List<String> requiredPackages() {
        return Stream.of(List.of(this), nestedIntegrations).flatMap(
                List::stream).map(DesktopIntegration::requiredPackagesSelf).flatMap(
                List::stream).distinct().collect(Collectors.toList());
    }

    Map<String, String> create() throws IOException {
        if (iconFile != null) {
            // Create application icon file.
            iconResource.saveToFile(iconFile.srcPath());
        }

        Map<String, String> data = new HashMap<>(desktopFileData);

        final ShellCommands shellCommands;
        if (desktopFile != null) {
            // Create application desktop description file.
            createDesktopFile(data);

            // Shell commands will be created only if desktop file
            // should be installed.
            shellCommands = new ShellCommands();
        } else {
            shellCommands = null;
        }

        if (!associations.isEmpty()) {
            // Create XML file with mime types corresponding to file associations.
            createFileAssociationsMimeInfoFile();

            shellCommands.setFileAssociations();

            // Create icon files corresponding to file associations
            Map<String, Path> mimeTypeWithIconFile = createFileAssociationIconFiles();
            mimeTypeWithIconFile.forEach((k, v) -> {
                shellCommands.addIcon(k, v);
            });
        }

        // Create shell commands to install/uninstall integration with desktop of the app.
        if (shellCommands != null) {
            shellCommands.applyTo(data);
        }

        boolean needCleanupScripts = !associations.isEmpty();

        // Take care of additional launchers if there are any.
        // Process every additional launcher as the main application launcher.
        // Collect shell commands to install/uninstall integration with desktop
        // of the additional launchers and append them to the corresponding
        // commands of the main launcher.
        List<String> installShellCmds = new ArrayList<>(Arrays.asList(
                data.get(DESKTOP_COMMANDS_INSTALL)));
        List<String> uninstallShellCmds = new ArrayList<>(Arrays.asList(
                data.get(DESKTOP_COMMANDS_UNINSTALL)));
        for (var integration: nestedIntegrations) {
            if (!integration.associations.isEmpty()) {
                needCleanupScripts = true;
            }

            Map<String, String> launcherData = integration.create();

            installShellCmds.add(launcherData.get(DESKTOP_COMMANDS_INSTALL));
            uninstallShellCmds.add(launcherData.get(
                    DESKTOP_COMMANDS_UNINSTALL));
        }

        data.put(DESKTOP_COMMANDS_INSTALL, stringifyShellCommands(
                installShellCmds));
        data.put(DESKTOP_COMMANDS_UNINSTALL, stringifyShellCommands(
                uninstallShellCmds));

        if (needCleanupScripts) {
            // Pull in utils.sh scrips library.
            try (InputStream is = OverridableResource.readDefault("utils.sh");
                    InputStreamReader isr = new InputStreamReader(is);
                    BufferedReader reader = new BufferedReader(isr)) {
                data.put(UTILITY_SCRIPTS, reader.lines().collect(
                        Collectors.joining(System.lineSeparator())));
            }
        } else {
            data.put(UTILITY_SCRIPTS, "");
        }

        return data;
    }

    private List<String> requiredPackagesSelf() {
        if (desktopFile != null) {
            return List.of("xdg-utils");
        }
        return Collections.emptyList();
    }

    private Map<String, String> createDataForDesktopFile(
            Map<String, ? super Object> params) {
        Map<String, String> data = new HashMap<>();
        data.put("APPLICATION_NAME", APP_NAME.fetchFrom(params));
        data.put("APPLICATION_DESCRIPTION", DESCRIPTION.fetchFrom(params));
        data.put("APPLICATION_ICON",
                iconFile != null ? iconFile.installPath().toString() : null);
        data.put("DEPLOY_BUNDLE_CATEGORY", MENU_GROUP.fetchFrom(params));
        data.put("APPLICATION_LAUNCHER",
                thePackage.installedApplicationLayout().launchersDirectory().resolve(
                        LinuxAppImageBuilder.getLauncherName(params)).toString());

        return data;
    }

    /**
     * Shell commands to integrate something with desktop.
     */
    private class ShellCommands {

        ShellCommands() {
            registerIconCmds = new ArrayList<>();
            unregisterIconCmds = new ArrayList<>();

            registerDesktopFileCmd = String.join(" ", "xdg-desktop-menu",
                    "install", desktopFile.installPath().toString());
            unregisterDesktopFileCmd = String.join(" ", "xdg-desktop-menu",
                    "uninstall", desktopFile.installPath().toString());
        }

        void setFileAssociations() {
            registerFileAssociationsCmd = String.join(" ", "xdg-mime",
                    "install",
                    mimeInfoFile.installPath().toString());
            unregisterFileAssociationsCmd = String.join(" ", "xdg-mime",
                    "uninstall", mimeInfoFile.installPath().toString());

            //
            // Add manual cleanup of system files to get rid of
            // the default mime type handlers.
            //
            // Even after mime type is unregisterd with `xdg-mime uninstall`
            // command and desktop file deleted with `xdg-desktop-menu uninstall`
            // command, records in
            // `/usr/share/applications/defaults.list` (Ubuntu 16) or
            // `/usr/local/share/applications/defaults.list` (OracleLinux 7)
            // files remain referencing deleted mime time and deleted
            // desktop file which makes `xdg-mime query default` output name
            // of non-existing desktop file.
            //
            String cleanUpCommand = String.join(" ",
                    "uninstall_default_mime_handler",
                    desktopFile.installPath().getFileName().toString(),
                    String.join(" ", getMimeTypeNamesFromFileAssociations()));

            unregisterFileAssociationsCmd = stringifyShellCommands(
                    unregisterFileAssociationsCmd, cleanUpCommand);
        }

        void addIcon(String mimeType, Path iconFile) {
            final int imgSize = getSquareSizeOfImage(iconFile.toFile());
            final String dashMime = mimeType.replace('/', '-');
            registerIconCmds.add(String.join(" ", "xdg-icon-resource",
                    "install", "--context", "mimetypes", "--size ",
                    Integer.toString(imgSize), iconFile.toString(), dashMime));
            unregisterIconCmds.add(String.join(" ", "xdg-icon-resource",
                    "uninstall", dashMime));
        }

        void applyTo(Map<String, String> data) {
            List<String> cmds = new ArrayList<>();

            cmds.add(registerDesktopFileCmd);
            cmds.add(registerFileAssociationsCmd);
            cmds.addAll(registerIconCmds);
            data.put(DESKTOP_COMMANDS_INSTALL, stringifyShellCommands(cmds));

            cmds.clear();
            cmds.add(unregisterDesktopFileCmd);
            cmds.add(unregisterFileAssociationsCmd);
            cmds.addAll(unregisterIconCmds);
            data.put(DESKTOP_COMMANDS_UNINSTALL, stringifyShellCommands(cmds));
        }

        private String registerDesktopFileCmd;
        private String unregisterDesktopFileCmd;

        private String registerFileAssociationsCmd;
        private String unregisterFileAssociationsCmd;

        private List<String> registerIconCmds;
        private List<String> unregisterIconCmds;
    }

    /**
     * Desktop integration file. xml, icon, etc.
     * Resides somewhere in application installation tree.
     * Has two paths:
     *  - path where it should be placed at package build time;
     *  - path where it should be installed by package manager;
     */
    private class DesktopFile {

        DesktopFile(String fileName) {
            installPath = thePackage
                    .installedApplicationLayout()
                    .destktopIntegrationDirectory().resolve(fileName);
            srcPath = thePackage
                    .sourceApplicationLayout()
                    .destktopIntegrationDirectory().resolve(fileName);
        }

        private final Path installPath;
        private final Path srcPath;

        Path installPath() {
            return installPath;
        }

        Path srcPath() {
            return srcPath;
        }
    }

    private void appendFileAssociation(XMLStreamWriter xml,
            Map<String, ? super Object> assoc) throws XMLStreamException {

        xml.writeStartElement("mime-type");
        final String thisMime = FA_CONTENT_TYPE.fetchFrom(assoc).get(0);
        xml.writeAttribute("type", thisMime);

        final String description = FA_DESCRIPTION.fetchFrom(assoc);
        if (description != null && !description.isEmpty()) {
            xml.writeStartElement("comment");
            xml.writeCharacters(description);
            xml.writeEndElement();
        }

        final List<String> extensions = FA_EXTENSIONS.fetchFrom(assoc);
        if (extensions == null) {
            Log.error(I18N.getString(
                    "message.creating-association-with-null-extension"));
        } else {
            for (String ext : extensions) {
                xml.writeStartElement("glob");
                xml.writeAttribute("pattern", "*." + ext);
                xml.writeEndElement();
            }
        }

        xml.writeEndElement();
    }

    private void createFileAssociationsMimeInfoFile() throws IOException {
        XMLOutputFactory xmlFactory = XMLOutputFactory.newInstance();

        try (Writer w = new BufferedWriter(new FileWriter(
                mimeInfoFile.srcPath().toFile()))) {
            XMLStreamWriter xml = xmlFactory.createXMLStreamWriter(w);

            xml.writeStartDocument();
            xml.writeStartElement("mime-info");
            xml.writeNamespace("xmlns",
                    "http://www.freedesktop.org/standards/shared-mime-info");

            for (var assoc : associations) {
                appendFileAssociation(xml, assoc);
            }

            xml.writeEndElement();
            xml.writeEndDocument();
            xml.flush();
            xml.close();

        } catch (XMLStreamException ex) {
            Log.verbose(ex);
            throw new IOException(ex);
        }
    }

    private Map<String, Path> createFileAssociationIconFiles() throws
            IOException {
        Map<String, Path> mimeTypeWithIconFile = new HashMap<>();
        for (var assoc : associations) {
            File customFaIcon = FA_ICON.fetchFrom(assoc);
            if (customFaIcon == null || !customFaIcon.exists() || getSquareSizeOfImage(
                    customFaIcon) == 0) {
                continue;
            }

            String fname = iconFile.srcPath().getFileName().toString();
            if (fname.indexOf(".") > 0) {
                fname = fname.substring(0, fname.lastIndexOf("."));
            }

            DesktopFile faIconFile = new DesktopFile(
                    fname + "_fa_" + customFaIcon.getName());

            IOUtils.copyFile(customFaIcon, faIconFile.srcPath().toFile());

            mimeTypeWithIconFile.put(FA_CONTENT_TYPE.fetchFrom(assoc).get(0),
                    faIconFile.installPath());
        }
        return mimeTypeWithIconFile;
    }

    private void createDesktopFile(Map<String, String> data) throws IOException {
        List<String> mimeTypes = getMimeTypeNamesFromFileAssociations();
        data.put("DESKTOP_MIMES", "MimeType=" + String.join(";", mimeTypes));

        // prepare desktop shortcut
        desktopFileResource
                .setSubstitutionData(data)
                .saveToFile(desktopFile.srcPath());
    }

    private List<String> getMimeTypeNamesFromFileAssociations() {
        return associations.stream().map(
                a -> FA_CONTENT_TYPE.fetchFrom(a).get(0)).collect(
                        Collectors.toUnmodifiableList());
    }

    private static int getSquareSizeOfImage(File f) {
        try {
            BufferedImage bi = ImageIO.read(f);
            if (bi.getWidth() == bi.getHeight()) {
                return bi.getWidth();
            }
        } catch (IOException e) {
            Log.verbose(e);
        }
        return 0;
    }

    private static String stringifyShellCommands(String... commands) {
        return stringifyShellCommands(Arrays.asList(commands));
    }

    private static String stringifyShellCommands(List<String> commands) {
        return String.join(System.lineSeparator(), commands.stream().filter(
                s -> s != null && !s.isEmpty()).collect(Collectors.toList()));
    }

    private final PlatformPackage thePackage;

    private final List<Map<String, ? super Object>> associations;

    private final List<Map<String, ? super Object>> launchers;

    private final OverridableResource iconResource;
    private final OverridableResource desktopFileResource;

    private final DesktopFile mimeInfoFile;
    private final DesktopFile desktopFile;
    private final DesktopFile iconFile;

    private final List<DesktopIntegration> nestedIntegrations;

    private final Map<String, String> desktopFileData;

    private static final BundlerParamInfo<String> MENU_GROUP =
        new StandardBundlerParam<>(
                Arguments.CLIOptions.LINUX_MENU_GROUP.getId(),
                String.class,
                params -> I18N.getString("param.menu-group.default"),
                (s, p) -> s
        );

    private static final StandardBundlerParam<Boolean> SHORTCUT_HINT =
        new StandardBundlerParam<>(
                Arguments.CLIOptions.LINUX_SHORTCUT_HINT.getId(),
                Boolean.class,
                params -> false,
                (s, p) -> (s == null || "null".equalsIgnoreCase(s))
                        ? false : Boolean.valueOf(s)
        );
}