/**
    * This file Copyright (c) 2003-2017 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.util.ObservationUtil;
  import info.magnolia.context.SystemContext;
  import info.magnolia.jcr.node2bean.Node2BeanProcessor;
  import info.magnolia.jcr.node2bean.TransformationState;
  import info.magnolia.jcr.node2bean.TypeDescriptor;
  import info.magnolia.jcr.node2bean.TypeMapping;
  import info.magnolia.jcr.node2bean.impl.Node2BeanTransformerImpl;
  import info.magnolia.jcr.util.NodeTypes;
  import info.magnolia.jcr.util.PropertyUtil;
  import info.magnolia.objectfactory.ComponentProvider;
  import info.magnolia.objectfactory.Components;
  import info.magnolia.repository.RepositoryConstants;
  
  import java.util.ArrayList;
  import java.util.Collection;
  import java.util.Collections;
  import java.util.HashMap;
  import java.util.Iterator;
  import java.util.LinkedHashMap;
  import java.util.Locale;
  import java.util.Map;
  
  import javax.inject.Inject;
  import javax.inject.Singleton;
  import javax.jcr.Node;
  import javax.jcr.Session;
  import javax.jcr.observation.EventIterator;
  import javax.jcr.observation.EventListener;
  
  import org.apache.commons.collections4.Transformer;
  import org.apache.commons.collections4.map.LazyMap;
  import org.apache.commons.lang3.StringUtils;
  import org.slf4j.Logger;
  import org.slf4j.LoggerFactory;
  
  
  /**
   * Default MessagesManager implementation.
   */
  @Singleton
  public class DefaultMessagesManager extends MessagesManager {
      private final static Logger log = LoggerFactory.getLogger(DefaultMessagesManager.class);
  
      /**
       * The current locale of the application.
       */
      private Locale applicationLocale;
  
      /**
       * List of the available locales.
       */
      private final Collection<Locale> availableLocales = new ArrayList<>();
  
      /**
       * Map for the messages.
       */
      private Map messages;
  
      private String defaultBasename = DEFAULT_BASENAME;
  
      private final Node2BeanProcessor nodeToBean;
      private final SystemContext systemContext;
  
      @Inject
     public DefaultMessagesManager(Node2BeanProcessor nodeToBean, SystemContext systemContext) {
         this.nodeToBean = nodeToBean;
         this.systemContext = systemContext;
 
         // setting default language (en)
         setDefaultLocale(FALLBACK_LOCALE);
 
         initMap();
     }
 
     /**
      * @deprecated since 5.5.1 - use {@link #DefaultMessagesManager(info.magnolia.jcr.node2bean.Node2BeanProcessor, info.magnolia.context.SystemContext)} instead.
      */
     @Deprecated
     public DefaultMessagesManager() {
         this(Components.getComponent(Node2BeanProcessor.class), Components.getComponent(SystemContext.class));
     }
 
     /**
      * @deprecated since 5.5.1 - use {@link #DefaultMessagesManager(info.magnolia.jcr.node2bean.Node2BeanProcessor, info.magnolia.context.SystemContext)} instead.
      */
     @Deprecated
     public DefaultMessagesManager(Node2BeanProcessor nodeToBean) {
         this(nodeToBean, Components.getComponent(SystemContext.class));
     }
 
     // for tests
     void setDefaultBasename(String defaultBasename) {
         this.defaultBasename = defaultBasename;
     }
 
     /**
      * Called through the initialization process. (startup of the container)
      */
 
     @Override
     public void init() {
         load();
         registerEventListener();
     }
 
     /**
      * The lazy Map creates messages objects with a fall back to the default locale.
      */
     protected void initMap() {
         // LazyMap will instantiate bundles on demand.
         final Map map = LazyMap.lazyMap(new HashMap(), new Transformer() {
 
             // this transformer will wrap the Messages in a MessagesChain which
             // will fall back to a Messages instance for the same bundle with
             // default locale.
             @Override
             public Object transform(Object input) {
                 final MessagesID id = (MessagesID) input;
                 return newMessages(id);
             }
         });
         messages = Collections.synchronizedMap(map);
     }
 
     /**
      * Initializes a new Messages instances for the given MessagesID. By default, we chain to the same bundle with the
      * default Locale. (so untranslated messages show up in the default language)
      */
     protected Messages newMessages(MessagesID messagesID) {
         Messages messages = new DefaultMessagesImpl(messagesID.basename, messagesID.locale);
         if (!getDefaultLocale().equals(messagesID.locale)) {
             messages = new MessagesChain(messages).chain(getMessages(messagesID.basename, getDefaultLocale()));
         }
         return messages;
     }
 
     /**
      * Load i18n configuration.
      */
     protected void load() {
         try {
             // reading the configuration from the repository, no need for context
             final Session session = systemContext.getJCRSession(RepositoryConstants.CONFIG);
 
             log.info("Loading i18n configuration - {}", I18N_CONFIG_PATH);
 
             // checks if node exists
             if (!session.nodeExists(I18N_CONFIG_PATH)) {
                 log.warn("{} does not exist yet; skipping.", I18N_CONFIG_PATH);
                 return;
             }
 
             final Node configNode = session.getNode(I18N_CONFIG_PATH);
 
             setDefaultLocale(PropertyUtil.getString(configNode, FALLBACK_NODEDATA, FALLBACK_LOCALE));
 
             // get the available languages - creates it if it does not exist - necessary to update to 3.5
             final Node languagesNode;
             if (configNode.hasNode(LANGUAGES_NODE_NAME)) {
                 languagesNode = configNode.getNode(LANGUAGES_NODE_NAME);
             } else {
                 languagesNode = configNode.addNode(LANGUAGES_NODE_NAME, NodeTypes.Content.NAME);
             }
 
             final Map<String, LocaleDefinition> localeDefinitions = (Map<String, LocaleDefinition>) nodeToBean.setProperties(new LinkedHashMap<String, LocaleDefinition>(), languagesNode, true, new Node2BeanTransformerImpl() {
                 @Override
                 protected TypeDescriptor onResolveType(TypeMapping typeMapping, TransformationState state, TypeDescriptor resolvedType, ComponentProvider componentProvider) {
                     if (resolvedType == null && state.getLevel() == 2) {
                         return typeMapping.getTypeDescriptor(LocaleDefinition.class);
                     }
                     return resolvedType;
                 }
             }, Components.getComponentProvider());
 
             // clear collection for reload
             availableLocales.clear();
 
             for (LocaleDefinition localeDefinition : localeDefinitions.values()) {
                 if (localeDefinition.isEnabled()) {
                     availableLocales.add(localeDefinition.getLocale());
                 }
             }
         } catch (Exception e) {
             log.error("Failed to load i18n configuration - {}", I18N_CONFIG_PATH, e);
         }
     }
 
     /**
      * Register an event listener: reload configuration when something changes.
      */
     private void registerEventListener() {
         log.info("Registering event listener for i18n");
         ObservationUtil.registerChangeListener(RepositoryConstants.CONFIG, I18N_CONFIG_PATH, new EventListener() {
 
             @Override
             public void onEvent(EventIterator iterator) {
                 // reload everything
                 reload();
             }
         });
     }
 
     /**
      * Reload i18n configuration.
      */
     @Override
     public void reload() {
         try {
             // reload all present
             for (Iterator messagesIterator = messages.values().iterator(); messagesIterator.hasNext(); ) {
                 Messages messages = (Messages) messagesIterator.next();
                 messages.reload();
             }
         } catch (Exception e) {
             log.error("Can't reload i18n messages", e);
         }
         initMap();
         load();
     }
 
     @Override
     public Messages getMessagesInternal(String basename, Locale locale) {
         if (StringUtils.isEmpty(basename)) {
             basename = defaultBasename;
         }
         return (Messages) messages.get(new MessagesID(basename, locale));
     }
 
     @Override
     public Locale getDefaultLocale() {
         return applicationLocale;
     }
 
     /**
      * @param defaultLocale The defaultLocale to set.
      * @deprecated since 4.0 - not used and should not be. Use setLocale() on the SystemContext instead. --note: do not
      *             remove the method, make it private. applicationLocale field is still needed. --and/or remove duplication with
      *             SystemContext.locale
      */
     @Deprecated
     public void setDefaultLocale(String defaultLocale) {
         this.applicationLocale = new Locale(defaultLocale);
     }
 
     @Override
     public Collection getAvailableLocales() {
         return availableLocales;
     }
 
     public void setMessages(Map messages) {
         this.messages = messages;
     }
 
     /**
      * Used as the key in the Map.
      */
     public static class MessagesID {
 
         private final String basename;
 
         private final Locale locale;
 
         public MessagesID(String basename, Locale locale) {
             this.basename = basename;
             this.locale = locale;
         }
 
         // generated equals and hashcode methods
 
         @Override
         public boolean equals(Object o) {
             if (this == o) {
                 return true;
             }
             if (o == null || getClass() != o.getClass()) {
                 return false;
             }
 
             MessagesID that = (MessagesID) o;
 
             if (basename != null ? !basename.equals(that.basename) : that.basename != null) {
                 return false;
             }
             if (locale != null ? !locale.equals(that.locale) : that.locale != null) {
                 return false;
             }
 
             return true;
         }
 
         @Override
         public int hashCode() {
             int result = basename != null ? basename.hashCode() : 0;
             result = 31 * result + (locale != null ? locale.hashCode() : 0);
             return result;
         }
 
         /**
          * Returns the basename.
          *
          * @return the basename
          */
         public String getBasename() {
             return basename;
         }
 
         /**
          * Returns the locale.
          *
          * @return the locale
          */
         public Locale getLocale() {
             return locale;
         }
 
     }
 }