/*
 * Licensed to the Apache Software Foundation (ASF) under one or more
 * contributor license agreements.  See the NOTICE file distributed with
 * this work for additional information regarding copyright ownership.
 * The ASF licenses this file to You under the Apache License, Version 2.0
 * (the "License"); you may not use this file except in compliance with
 * the License.  You may obtain a copy of the License at
 *
 *      http://www.apache.org/licenses/LICENSE-2.0
 *
 * Unless required by applicable law or agreed to in writing, software
 * distributed under the License is distributed on an "AS IS" BASIS,
 * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
 * See the License for the specific language governing permissions and
 * limitations under the License.
 */
package org.apache.commons.vfs2.util;

import java.io.IOException;
import java.net.URL;
import java.util.Enumeration;
import java.util.Locale;
import java.util.Properties;
import java.util.ResourceBundle;

/**
 * @since 2.0
 */
public class CombinedResources extends ResourceBundle {

    // locale.getLanguage()
    // locale.getCountry()
    // locale.getVariant()

    private final String resourceName;
    private boolean inited;
    private final Properties properties = new Properties();

    public CombinedResources(final String resourceName) {
        this.resourceName = resourceName;
    }

    protected void init() {
        if (inited) {
            return;
        }

        loadResources(getResourceName());
        loadResources(Locale.getDefault());
        loadResources(getLocale());
        inited = true;
    }

    protected void loadResources(final Locale locale) {
        if (locale == null) {
            return;
        }
        final String[] parts = new String[] { locale.getLanguage(), locale.getCountry(), locale.getVariant() };
        final StringBuilder sb = new StringBuilder();
        for (int i = 0; i < 3; i++) {
            sb.append(getResourceName());
            for (int j = 0; j < i; j++) {
                sb.append('_').append(parts[j]);
            }
            if (parts[i].length() != 0) {
                sb.append('_').append(parts[i]);
                loadResources(sb.toString());
            }
            sb.setLength(0);
        }
    }

    protected void loadResources(String resourceName) {
        ClassLoader loader = getClass().getClassLoader();
        if (loader == null) {
            loader = ClassLoader.getSystemClassLoader();
        }
        if (loader != null) {
            resourceName = resourceName.replace('.', '/') + ".properties";
            try {
                final Enumeration<URL> resources = loader.getResources(resourceName);
                while (resources.hasMoreElements()) {
                    final URL resource = resources.nextElement();
                    try {
                        properties.load(resource.openConnection().getInputStream());
                    } catch (final IOException ignored) {
                        // Ignore
                    }
                }
            } catch (final IOException ignored) {
                // Ignore
            }
        }
    }

    public String getResourceName() {
        return resourceName;
    }

    @Override
    public Enumeration<String> getKeys() {
        if (!inited) {
            init();
        }
        return new Enumeration<String>() {
            @Override
            public boolean hasMoreElements() {
                return properties.keys().hasMoreElements();
            }

            @Override
            public String nextElement() {
                // We know that our properties will only ever contain Strings
                return (String) properties.keys().nextElement();
            }

        };
    }

    @Override
    protected Object handleGetObject(final String key) {
        if (!inited) {
            init();
        }
        return properties.get(key);
    }
}
