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/*
 * #%L
 * I18n :: Api
 * 
 * $Id$
 * $HeadURL$
 * %%
 * Copyright (C) 2004 - 2010 CodeLutin
 * %%
 * This program is free software: you can redistribute it and/or modify
 * it under the terms of the GNU Lesser General Public License as 
 * published by the Free Software Foundation, either version 3 of the 
 * License, or (at your option) any later version.
 * 
 * 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 General Lesser Public License for more details.
 * 
 * You should have received a copy of the GNU General Lesser Public 
 * License along with this program.  If not, see
 * .
 * #L%
 */

package org.nuiton.i18n.init;

import org.apache.commons.logging.Log;
import org.apache.commons.logging.LogFactory;
import org.nuiton.i18n.I18nUtil;
import org.nuiton.i18n.bundle.I18nBundle;

import java.io.InputStream;
import java.net.URL;
import java.nio.charset.Charset;
import java.util.ArrayList;
import java.util.Arrays;
import java.util.List;
import java.util.Locale;
import java.util.Properties;

/**
 * Default implementation of a {@link I18nInitializer} using the default i18n
 * implementation (one unique bundle with a definition properties file).
 *
 * @author Tony Chemit - [email protected]
 * @since 1.1
 */
public class DefaultI18nInitializer extends I18nInitializer {

    /** Logger. */
    private static final Log log =
            LogFactory.getLog(DefaultI18nInitializer.class);

    public static final String UNIQUE_BUNDLE_DEF = "%1$s-definition.properties";

    public static final String UNIQUE_BUNDLE_ENTRY = "%1$s_%2$s.properties";

    public static final String BUNDLE_DEF_LOCALES = "locales";

    public static final String BUNDLE_DEF_VERSION = "version";

    public static final String BUNDLE_DEF_ENCODING = "encoding";

    public static final String BUNDLES_FOR_LOCALE = "bundles.";

    /** the name of the bundle. */
    protected final String bundleName;

    /** class loader to use (optional). */
    protected ClassLoader loader;

    /** i18n path  where to seek for resources (optional). */
    protected String i18nPath;

    /** location of the definition file. */
    protected URL definitionURL;

    public static final String DEFAULT_I18N_PATH = "META-INF/";

    public DefaultI18nInitializer(String bundleName) throws
            NullPointerException {
        this(bundleName, null, null);
    }

    public DefaultI18nInitializer(String bundleName,
                                  ClassLoader loader) throws
            NullPointerException {
        this(bundleName, loader, null);
    }

    public DefaultI18nInitializer(String bundleName,
                                  ClassLoader loader,
                                  String i18nPath) throws NullPointerException {
        if (bundleName == null) {
            throw new NullPointerException(
                    "parameter 'bundleName' can not be null");
        }
        this.bundleName = bundleName;
        this.loader = loader == null ? getClass().getClassLoader() : loader;
        this.i18nPath = i18nPath == null ? DEFAULT_I18N_PATH : i18nPath;
    }

    public String getBundleName() {
        return bundleName;
    }

    public ClassLoader getLoader() {
        return loader;
    }

    public String getI18nPath() {
        return i18nPath;
    }

    protected void setLoader(ClassLoader loader) {
        this.loader = loader;
    }

    protected void setI18nPath(String i18nPath) {
        this.i18nPath = i18nPath;
    }

    protected URL getResourceURL(String resource) {
        if (log.isDebugEnabled()) {
            log.debug("resource to seek : " + resource);
        }
        URL url = getLoader().getResource(resource);
        return url;
    }

    public String resolvDefinition(Properties properties) throws Exception {

        String filename = String.format(UNIQUE_BUNDLE_DEF, getBundleName());

        URL url = getDefinitionURL();

        if (log.isInfoEnabled()) {
            log.info("definition file to seek : " + url);
        }

        // load definition file
        InputStream stream = url.openStream();
        try {
            properties.load(stream);
            stream.close();
        } finally {
            stream.close();
        }

        // Load encoding from definition file and use it as Charset encoding
        String encoding = properties.getProperty(BUNDLE_DEF_ENCODING);
        Charset charset = Charset.forName(encoding);
        if (log.isInfoEnabled()) {
            log.info("Use encoding " + charset);
        }
        setEncoding(charset);

        String prefix = url.toString();
        prefix = prefix.substring(0, prefix.length() - filename.length());

        return prefix;
    }

    public URL getDefinitionURL() throws NullPointerException {
        if (definitionURL == null) {
            String filename = String.format(UNIQUE_BUNDLE_DEF, getBundleName());

            String path = getI18nPath() + filename;

            definitionURL = getResourceURL(path);

            if (definitionURL == null) {
                throw new NullPointerException(
                        "could not find bundle definition file at " + path);
            }
        }
        return definitionURL;
    }

    public URL[] resolvURLs(String prefixURL,
                            Properties definition) throws Exception {

        // get locales from properties

        String localesAsStr = definition.getProperty(BUNDLE_DEF_LOCALES);

        Locale[] locales = I18nUtil.parseLocales(localesAsStr);

        if (log.isDebugEnabled()) {
            log.debug("Detected locales : " + Arrays.toString(locales));
        }

        List lUrls = new ArrayList(locales.length);

        // for each locale found in definition file, add resource url

        String bundleName = getBundleName();

        for (Locale l : locales) {
            String url = prefixURL +
                         String.format(UNIQUE_BUNDLE_ENTRY, bundleName, l);
            if (log.isInfoEnabled()) {
                log.info("Detected resource for locale " + l + " : " + url);
            }
            URL u = new URL(url);
            //FIXME on devrait tester que la resource est disponible ?

            lUrls.add(u);
        }

        URL[] urls = lUrls.toArray(new URL[lUrls.size()]);
        return urls;
    }

    @Override
    public I18nBundle[] resolvBundles() throws Exception {

        Properties definition = new Properties();

        String prefixURL = resolvDefinition(definition);

        // detect bundles urls
        URL[] urls = resolvURLs(prefixURL, definition);

        // detect bundles
        I18nBundle[] result = resolvBundles(urls);
        return result;
    }

}