/*

 * Copyright (c) 2015, 2016, 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 sun.util.locale.provider;

import java.io.IOException;

import java.io.InputStream;

import java.io.UncheckedIOException;

import java.lang.reflect.Constructor;

import java.lang.reflect.InvocationTargetException;

import java.lang.reflect.Modifier;

import java.lang.reflect.Module;

import java.security.AccessController;

import java.security.PrivilegedAction;

import java.util.PropertyResourceBundle;

import java.util.ResourceBundle;

/**

 * ResourceBundleProviderSupport provides convenience methods for loading

 * resource bundles.

 */

public class ResourceBundleProviderSupport {

    /**

     * Loads a {@code ResourceBundle} of the given {@code bundleName} local to

     * the given {@code module}.

     *

     * @apiNote

     * {@link Class#forName(Module, String)} does a stack-based permission check.

     * Caller of this method is responsible for doing an appropriate permission

     * on behalf of the caller before calling this method.

     *

     * @param module     the module from which the {@code ResourceBundle} is loaded

     * @param bundleName the bundle name for the {@code ResourceBundle} class,

     *                   such as "com.example.app.MyResources_fr"

     * @return the {@code ResourceBundle}, or null if no {@code ResourceBundle} is found

     * @throws SecurityException

     *         if a security manager exists, it denies loading the class given by

     *         {@code bundleName} from the given {@code module}.

     *         If the given module is "java.base", this method will not do security check.

     * @throws NullPointerException

     *         if {@code module} or {@code bundleName) is null

     * @see Class#forName(Module, String)

     */

    public static ResourceBundle loadResourceBundle(Module module, String bundleName)

    {

        Class<?> c = Class.forName(module, bundleName);

        if (c != null && ResourceBundle.class.isAssignableFrom(c)) {

            try {

                @SuppressWarnings("unchecked")

                Class<ResourceBundle> bundleClass = (Class<ResourceBundle>) c;

                Constructor<ResourceBundle> ctor = bundleClass.getConstructor();

                if (!Modifier.isPublic(ctor.getModifiers())) {

                    return null;

                }

                // java.base may not be able to read the bundleClass's module.

                PrivilegedAction<Void> pa1 = () -> { ctor.setAccessible(true); return null; };

                AccessController.doPrivileged(pa1);

                try {

                    return ctor.newInstance((Object[]) null);

                } catch (InvocationTargetException e) {

                    uncheckedThrow(e);

                } catch (InstantiationException | IllegalAccessException e) {

                    throw new InternalError(e);

                }

            } catch (NoSuchMethodException e) {

            }

        }

        return null;

    }

    @SuppressWarnings("unchecked")

    private static <T extends Throwable> void uncheckedThrow(Throwable t) throws T {

       if (t != null)

            throw (T)t;

       else

            throw new Error("Unknown Exception");

    }

    /**

     * Loads properties of the given {@code bundleName} local to the given

     * {@code module} and returns a {@code ResourceBundle} produced from the

     * loaded properties.

     *

     * @apiNote This method is intended for internal use.  Need to refactor.

     *

     * @param module     the module from which the properties are loaded

     * @param bundleName the bundle name of the properties,

     *                   such as "com.example.app.MyResources_de"

     * @return the {@code ResourceBundle} produced from the loaded properties,

     *         or null if no properties are found

     * @see PropertyResourceBundle

     */

    public static ResourceBundle loadPropertyResourceBundle(Module module, String bundleName)

            throws IOException

    {

        String resourceName = toResourceName(bundleName, "properties");

        if (resourceName == null) {

            return null;

        }

        PrivilegedAction<InputStream> pa = () -> {

            try {

                return module.getResourceAsStream(resourceName);

            } catch (IOException e) {

                throw new UncheckedIOException(e);

            }

        };

        try (InputStream stream = AccessController.doPrivileged(pa)) {

            if (stream != null) {

                return new PropertyResourceBundle(stream);

            } else {

                return null;

            }

        } catch (UncheckedIOException e) {

            throw e.getCause();

        }

    }

    private static String toResourceName(String bundleName, String suffix) {

        if (bundleName.contains("://")) {

            return null;

        }

        StringBuilder sb = new StringBuilder(bundleName.length() + 1 + suffix.length());

        sb.append(bundleName.replace('.', '/')).append('.').append(suffix);

        return sb.toString();

    }

}