/*
    * Copyright 2013 smartics, Kronseder & Reiner GmbH
    *
    * Licensed 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 de.smartics.resteasy.hypermedia.renderer.i18n;
  
  import static de.smartics.resteasy.hypermedia.renderer.i18n.LinkMetadataKeys.ACCESS_KEY;
  import static de.smartics.resteasy.hypermedia.renderer.i18n.LinkMetadataKeys.CONTEXT_MENU;
  import static de.smartics.resteasy.hypermedia.renderer.i18n.LinkMetadataKeys.CSS_CLASS;
  import static de.smartics.resteasy.hypermedia.renderer.i18n.LinkMetadataKeys.DIR;
  import static de.smartics.resteasy.hypermedia.renderer.i18n.LinkMetadataKeys.HELP;
  import static de.smartics.resteasy.hypermedia.renderer.i18n.LinkMetadataKeys.HIDDEN;
  import static de.smartics.resteasy.hypermedia.renderer.i18n.LinkMetadataKeys.ID;
  import static de.smartics.resteasy.hypermedia.renderer.i18n.LinkMetadataKeys.LABEL;
  import static de.smartics.resteasy.hypermedia.renderer.i18n.LinkMetadataKeys.MEDIA;
  import static de.smartics.resteasy.hypermedia.renderer.i18n.LinkMetadataKeys.SHORT_LABEL;
  import static de.smartics.resteasy.hypermedia.renderer.i18n.LinkMetadataKeys.TAB_INDEX;
  import static de.smartics.resteasy.hypermedia.renderer.i18n.LinkMetadataKeys.TARGET;
  import static de.smartics.resteasy.hypermedia.renderer.i18n.LinkMetadataKeys.TITLE;
  
  import java.util.Locale;
  import java.util.MissingResourceException;
  import java.util.ResourceBundle;
  
  import javax.enterprise.context.ApplicationScoped;
  
  import de.smartics.resteasy.hypermedia.renderer.I18nProvider;
  import de.smartics.resteasy.hypermedia.renderer.LinkMetadata;
  import de.smartics.resteasy.hypermedia.renderer.LocalizationProvider;
  
  /**
   * A provider based on resource bundles.
   */
  @ApplicationScoped
  public class ResourceBundleI18nProvider implements I18nProvider
  {
    // ********************************* Fields *********************************
  
    // --- constants ------------------------------------------------------------
  
    /**
     * The key the provider looks up the location to search for link resource
     * information.
     * <p>
     * The value of this constant is {@value}.
     * </p>
     */
    public static final String SYSTEM_KEY = "de.smartics.hypermedia.link";
  
    /**
     * The default location to search for link resource information.
     * <p>
     * The value of this constant is {@value}.
     * </p>
     */
    public static final String DEFAULT_LOCATION = "de/smartics/hypermedia/link";
  
    // --- members --------------------------------------------------------------
  
    // ****************************** Initializer *******************************
  
    // ****************************** Constructors ******************************
  
    // ****************************** Inner Classes *****************************
  
    /**
     * A provider of localized information for links based on resource bundles.
     */
    private static final class ResourceBundleLocalizationProvider implements
        LocalizationProvider
    {
      // ******************************** Fields ********************************
  
      // --- constants ----------------------------------------------------------
  
      // --- members ------------------------------------------------------------
  
      /**
       * The locale the provider provides resources for.
       */
      private final Locale locale;
  
      // ***************************** Initializer ******************************
  
      // ***************************** Constructors *****************************
  
      /**
       * Default constructor.
      *
      * @param locale the locale the provider provides resources for.
      */
     private ResourceBundleLocalizationProvider(final Locale locale)
     {
       this.locale = locale;
     }
 
     // ***************************** Inner Classes ****************************
 
     // ******************************** Methods *******************************
 
     // --- init ---------------------------------------------------------------
 
     // --- get&set ------------------------------------------------------------
 
     /**
      * Returns the locale the provider provides resources for.
      *
      * @return the locale the provider provides resources for.
      */
     @Override
     public Locale getLocale()
     {
       return locale;
     }
 
     // --- business -----------------------------------------------------------
 
     @Override
     public LinkMetadata getLinkMetadata(final String id)
     {
       final BundleAccessor accessor = new BundleAccessor(locale, id);
       final LinkMetadata metadata = accessor.getLinkMetadata();
       return metadata;
     }
 
     // --- object basics ------------------------------------------------------
 
   }
 
   /**
    * Helper to access the resources within a resource bundle.
    */
   private static final class BundleAccessor
   {
     // ******************************** Fields ********************************
 
     // --- constants ----------------------------------------------------------
 
     // --- members ------------------------------------------------------------
 
     /**
      * The selected bundle.
      */
     private final ResourceBundle bundle;
 
     // ***************************** Initializer ******************************
 
     // ***************************** Constructors *****************************
 
     /**
      * Default constructor.
      *
      * @param locale the locale the provider provides resources for.
      * @param id the identifier of the link to fetch metadata.
      */
     private BundleAccessor(final Locale locale, final String id)
     {
       final String baseName = calcBaseName(id);
       this.bundle = ResourceBundle.getBundle(baseName, locale);
     }
 
     // ***************************** Inner Classes ****************************
 
     // ******************************** Methods *******************************
 
     // --- init ---------------------------------------------------------------
 
     private static String calcBaseName(final String id)
     {
       final String prefix = System.getProperty(SYSTEM_KEY, DEFAULT_LOCATION);
       final String baseName = prefix + '/' + id;
       return baseName;
     }
 
     // --- get&set ------------------------------------------------------------
 
     // --- business -----------------------------------------------------------
 
     private LinkMetadata getLinkMetadata()
     {
       final LinkMetadata metadata = new LinkMetadata();
 
       metadata.setAccessKey(getValue(ACCESS_KEY));
       metadata.setContextMenu(getValue(CONTEXT_MENU));
       metadata.setCssClass(getValue(CSS_CLASS));
       metadata.setDir(getValue(DIR));
       metadata.setHelp(getValue(HELP));
       metadata.setHidden(getValueAsBoolean(HIDDEN));
       metadata.setId(getValue(ID));
       metadata.setLabel(getValue(LABEL));
       metadata.setMedia(getValue(MEDIA));
       metadata.setShortLabel(getValue(SHORT_LABEL));
       metadata.setTabIndex(getValueAsInt(TAB_INDEX));
       metadata.setTarget(getValue(TARGET));
       metadata.setTitle(getValue(TITLE));
 
       return metadata;
     }
 
     private Integer getValueAsInt(final String key)
     {
       try
       {
         final String string = bundle.getString(key);
         final Integer value = Integer.parseInt(string);
         return value;
       }
       catch (final MissingResourceException e)
       {
         return null;
       }
     }
 
     private Boolean getValueAsBoolean(final String key)
     {
       try
       {
         final String string = bundle.getString(key);
         final boolean value = Boolean.parseBoolean(string);
         return value;
       }
       catch (final MissingResourceException e)
       {
         return null;
       }
     }
 
     private String getValue(final String key)
     {
       try
       {
         final String value = bundle.getString(key);
         return value;
       }
       catch (final MissingResourceException e)
       {
         return null;
       }
     }
 
     // --- object basics ------------------------------------------------------
   }
 
   // ********************************* Methods ********************************
 
   // --- init -----------------------------------------------------------------
 
   // --- get&set --------------------------------------------------------------
 
   @Override
   public LocalizationProvider getProvider(final Locale locale)
     throws NullPointerException
   {
     final ResourceBundleLocalizationProvider provider =
         new ResourceBundleLocalizationProvider(locale);
     return provider;
   }
 
   // --- business -------------------------------------------------------------
 
   // --- object basics --------------------------------------------------------
 
 }