/**
    * This file Copyright (c) 2008-2011 Magnolia International
    * Ltd.  (http://www.magnolia-cms.com). All rights reserved.
    *
    *
    * This file is dual-licensed under both the Magnolia
    * Network Agreement and the GNU General Public License.
    * You may elect to use one or the other of these licenses.
    *
   * This file is distributed in the hope that it will be
   * useful, but AS-IS and WITHOUT ANY WARRANTY; without even the
   * implied warranty of MERCHANTABILITY or FITNESS FOR A
   * PARTICULAR PURPOSE, TITLE, or NONINFRINGEMENT.
   * Redistribution, except as permitted by whichever of the GPL
   * or MNA you select, is prohibited.
   *
   * 1. For the GPL license (GPL), you can redistribute and/or
   * modify this file under the terms of the GNU General
   * Public License, Version 3, as published by the Free Software
   * Foundation.  You should have received a copy of the GNU
   * General Public License, Version 3 along with this program;
   * if not, write to the Free Software Foundation, Inc., 51
   * Franklin St, Fifth Floor, Boston, MA 02110-1301 USA.
   *
   * 2. For the Magnolia Network Agreement (MNA), this file
   * and the accompanying materials are made available under the
   * terms of the MNA which accompanies this distribution, and
   * is available at http://www.magnolia-cms.com/mna.html
   *
   * Any modifications to this file must keep this entire header
   * intact.
   *
   */
  package info.magnolia.cms.i18n;
  
  import info.magnolia.cms.core.Content;
  import info.magnolia.cms.core.NodeData;
  import info.magnolia.cms.util.NodeDataUtil;
  import info.magnolia.context.MgnlContext;
  
  import java.util.Collection;
  import java.util.HashSet;
  import java.util.Iterator;
  import java.util.LinkedHashMap;
  import java.util.Locale;
  import java.util.Map;
  import java.util.Set;
  
  import javax.jcr.Node;
  import javax.jcr.RepositoryException;
  
  import org.apache.commons.lang.StringUtils;
  import org.slf4j.Logger;
  import org.slf4j.LoggerFactory;
  
  /**
   * An abstract implementation of {@link I18nContentSupport} which stores the
   * locale specific content in node data having a local suffix:
   * <name>_<locale>.
   *
   * The detection of the current locale, based on the URI for instance, is left to the concrete implementation.
   * @author philipp
   *
   */
  public abstract class AbstractI18nContentSupport implements I18nContentSupport {
  
      private static final Logger log = LoggerFactory.getLogger(AbstractI18nContentSupport.class);
  
      /**
       * The content is served for this locale if the the content is not available for the current locale.
       */
      private Locale fallbackLocale = new Locale("en");
  
      /**
       * If no locale can be determined the default locale will be set. If no default locale is defined the fallback locale is used.
       */
      protected Locale defaultLocale;
  
      private boolean enabled = false;
  
      /**
       * The active locales.
       */
      private Map<String, Locale> locales = new LinkedHashMap<String, Locale>();
  
      @Override
      public Locale getLocale() {
          Locale locale = null;
          if(MgnlContext.getWebContextOrNull() != null){
              locale = MgnlContext.getAggregationState().getLocale();
          }
          if (locale == null) {
              return fallbackLocale;
          }
          return locale;
      }
  
      @Override
      public void setLocale(Locale locale) {
         MgnlContext.getAggregationState().setLocale(locale);
     }
 
     @Override
     public Locale getFallbackLocale() {
         return this.fallbackLocale;
     }
 
     @Override
     public void setFallbackLocale(Locale fallbackLocale) {
         this.fallbackLocale = fallbackLocale;
     }
 
     /**
      * Returns the closest locale for which {@link #isLocaleSupported(Locale)} is true.
      * <ul>
      * <li>If the locale has a country specified (fr_CH) the locale without country (fr) will be returned.</li>
      * <li>If the locale has no country specified (fr) the first locale with the same language but specific country (fr_CH) will be returned.</li>
      * <li>If this fails the fall-back locale is returned</li>
      * </ul>
      * Warning: if you have configured both (fr and fr_CH) this method will jiter between this two values.
      */
     protected Locale getNextLocale(Locale locale) {
         // if this locale defines a country
         if(StringUtils.isNotEmpty(locale.getCountry())){
             // try to use the language only
             Locale langOnlyLocale = new Locale(locale.getLanguage());
             if(isLocaleSupported(langOnlyLocale)){
                 return langOnlyLocale;
             }
         }
         // try to find a locale with the same language (ignore the country)
         for (Iterator<Locale> iter = getLocales().iterator(); iter.hasNext();) {
             Locale otherCountryLocale = iter.next();
             // same lang, but not the same country as well or we end up in the loop
             if(locale.getLanguage().equals(otherCountryLocale.getLanguage()) && !locale.equals(otherCountryLocale)){
                 return otherCountryLocale;
             }
         }
         return getFallbackLocale();
     }
 
     /**
      * Extracts the language from the uri.
      */
     @Override
     public Locale determineLocale() {
         Locale locale;
 
         locale = onDetermineLocale();
 
         // depending on the implementation the returned local can be null (not defined)
         if(locale == null){
             locale = getDefaultLocale();
         }
         // if we have a locale but it is not supported we try to get the closest locale
         if(!isLocaleSupported(locale)){
             locale = getNextLocale(locale);
         }
         // instead of returning the content fallback language
         // we are going to return the default locale which might differ
         if(locale.equals(getFallbackLocale())){
             locale = getDefaultLocale();
         }
         return locale;
     }
 
     protected abstract Locale onDetermineLocale();
 
     protected static Locale determineLocalFromString(String localeStr) {
         if(StringUtils.isNotEmpty(localeStr)){
             String[] localeArr = StringUtils.split(localeStr, "_");
             if(localeArr.length ==1){
                 return new Locale(localeArr[0]);
             }
             else if(localeArr.length == 2){
                 return new Locale(localeArr[0],localeArr[1]);
             }
         }
         return null;
     }
 
     @Override
     public String toI18NURI(String uri) {
         if (!isEnabled()) {
             return uri;
         }
         Locale locale = getLocale();
         if (isLocaleSupported(locale)) {
             return toI18NURI(uri, locale);
         }
         return uri;
     }
 
     protected abstract String toI18NURI(String uri, Locale locale);
 
     /**
      * Removes the prefix.
      */
     @Override
     public String toRawURI(String i18nURI) {
         if (!isEnabled()) {
             return i18nURI;
         }
 
         Locale locale = getLocale();
         if (isLocaleSupported(locale)) {
             return toRawURI(i18nURI, locale);
         }
         return i18nURI;
     }
 
     protected abstract String toRawURI(String i18nURI, Locale locale);
 
     @Override
     public NodeData getNodeData(Content node, String name, Locale locale) throws RepositoryException {
         String nodeDataName = name + "_" + locale;
         if (node.hasNodeData(nodeDataName)) {
             return node.getNodeData(nodeDataName);
         }
         return null;
     }
 
     /**
      * Returns the nodedata with the name &lt;name&gt;_&lt;current language&gt; or &lt;name&gt;_&lt;fallback language&gt
      * otherwise returns &lt;name&gt;.
      */
     @Override
     public NodeData getNodeData(Content node, String name) {
         NodeData nd = null;
 
         if (isEnabled()) {
             try {
                 // test for the current language
                 Locale locale = getLocale();
                 Set<Locale> checkedLocales = new HashSet<Locale>();
 
                 // getNextContentLocale() returns null once the end of the locale chain is reached
                 while(locale != null){
                     nd = getNodeData(node, name, locale);
                     if (!isEmpty(nd)) {
                         return nd;
                     }
                     checkedLocales.add(locale);
                     locale = getNextContentLocale(locale, checkedLocales);
                 }
             }
             catch (RepositoryException e) {
                 log.error("can't read i18n nodeData " + name + " from node " + node, e);
             }
         }
 
         // return the node data
         return node.getNodeData(name);
     }
 
     @Override
     public Node getNode(Node node, String name) throws RepositoryException {
         if (isEnabled()) {
 
             try {
                 // test for the current language
                 Locale locale = getLocale();
                 Set<Locale> checkedLocales = new HashSet<Locale>();
 
                 // getNextContentLocale() returns null once the end of the locale chain is reached
                 while(locale != null){
                     String localeSpecificChildName = name + "_" + locale;
                     if (node.hasNode(localeSpecificChildName))
                         return node.getNode(localeSpecificChildName);
                     checkedLocales.add(locale);
                     locale = getNextContentLocale(locale, checkedLocales);
                 }
             }
             catch (RepositoryException e) {
                 log.error("can't read i18n node " + name + " from node " + node, e);
             }
         }
 
         return node.getNode(name);
     }
 
     /**
      * Uses {@link #getNextLocale(Locale)} to find the next locale. If the returned locale is in the
      * checkedLocales set it falls back to the fall-back locale. If the fall-back locale itself is
      * passed to the method, the method returns null to signal the end of the chain.
      */
     protected Locale getNextContentLocale(Locale locale, Set<Locale> checkedLocales) {
         if(locale.equals(getFallbackLocale())){
             return null;
         }
         Locale candidate = getNextLocale(locale);
         if(!checkedLocales.contains(candidate)){
             return candidate;
         }
         return getFallbackLocale();
     }
 
     @Override
     public boolean isEnabled() {
         return this.enabled;
     }
 
     public void setEnabled(boolean enabled) {
         this.enabled = enabled;
     }
 
     @Override
     public Collection<Locale> getLocales() {
         return this.locales.values();
     }
 
     public void addLocale(LocaleDefinition ld) {
         if (ld.isEnabled()) {
             this.locales.put(ld.getId(), ld.getLocale());
         }
     }
 
     protected boolean isLocaleSupported(Locale locale) {
         return locale != null && locales.containsKey(locale.toString());
     }
 
     /**
      * Checks if the nodedata field is empty.
      */
     protected boolean isEmpty(NodeData nd) {
         if (nd != null && nd.isExist()) {
             // TODO use a better way to find out if it is empty
             return StringUtils.isEmpty(NodeDataUtil.getValueString(nd));
         }
         return true;
     }
 
     public Locale getDefaultLocale() {
         if(this.defaultLocale == null){
             return getFallbackLocale();
         }
         return this.defaultLocale;
     }
 
     public void setDefaultLocale(Locale defaultLocale) {
         this.defaultLocale = defaultLocale;
     }
 }