/**
    * This file Copyright (c) 2011-2013 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.rendering.template.registry;
  
  import java.util.ArrayList;
  import java.util.Collection;
  import java.util.Set;
  import javax.inject.Singleton;
  
  import org.slf4j.Logger;
  import org.slf4j.LoggerFactory;
  
  import info.magnolia.registry.RegistrationException;
  import info.magnolia.registry.RegistryMap;
  import info.magnolia.rendering.template.TemplateDefinition;
  
  
  /**
   * The central registry of all {@link TemplateDefinition}s.
   *
   * @version $Id$
   */
  @Singleton
  public class TemplateDefinitionRegistry {
  
      private static final Logger log = LoggerFactory.getLogger(TemplateDefinitionRegistry.class);
  
      private final RegistryMap<String, TemplateDefinitionProvider> registry = new RegistryMap<String, TemplateDefinitionProvider>() {
  
          @Override
          protected String keyFromValue(TemplateDefinitionProvider provider) {
              return provider.getId();
          }
      };
  
      public TemplateDefinition getTemplateDefinition(String id) throws RegistrationException {
  
          TemplateDefinitionProvider templateDefinitionProvider;
          try {
              templateDefinitionProvider = registry.getRequired(id);
          } catch (RegistrationException e) {
              throw new RegistrationException("No template definition registered for id: " + id, e);
          }
  
          return templateDefinitionProvider.getTemplateDefinition();
      }
  
      /**
       * @return all TemplateDefinitions - in case of errors it'll just deliver the ones that are properly registered and logs error's for the others.
       */
      public Collection<TemplateDefinition> getTemplateDefinitions() {
          final Collection<TemplateDefinition> templateDefinitions = new ArrayList<TemplateDefinition>();
          for (TemplateDefinitionProvider provider : registry.values()) {
              try {
                  final TemplateDefinition templateDefinition = provider.getTemplateDefinition();
                  if (templateDefinition == null) {
                      log.error("Provider's TemplateDefinition is null: " + provider);
                  } else {
                      templateDefinitions.add(templateDefinition);
                  }
              } catch (RegistrationException e) {
                  log.error("Failed to read template definition from " + provider + ".", e);
              }
          }
          return templateDefinitions;
      }
  
      public void register(TemplateDefinitionProvider provider) {
         registry.put(provider);
     }
 
     public void unregister(String id) {
         registry.remove(id);
     }
 
     public Set<String> unregisterAndRegister(Collection<String> registeredIds, Collection<TemplateDefinitionProvider> providers) {
         return registry.removeAndPutAll(registeredIds, providers);
     }
 }