/*
    * Copyright (C) 2003-2010 eXo Platform SAS.
    *
    * This program is free software; you can redistribute it and/or
    * modify it under the terms of the GNU Affero 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 Public License for more details.
   *
   * You should have received a copy of the GNU General Public License
   * along with this program; if not, see<http://www.gnu.org/licenses/>.
   */
  package org.exoplatform.social.webui.activity;
  
  import java.util.Hashtable;
  import java.util.Map;
  
  import javax.inject.Provider;
  
  import org.exoplatform.container.PortalContainer;
  import org.exoplatform.container.component.BaseComponentPlugin;
  import org.exoplatform.services.log.ExoLogger;
  import org.exoplatform.services.log.Log;
  import org.exoplatform.social.core.activity.model.ExoSocialActivity;
  import org.exoplatform.webui.core.UIContainer;
  import org.exoplatform.webui.ext.UIExtension;
  import org.exoplatform.webui.ext.UIExtensionManager;
  
  /**
   * UIActivityFactory.java
   *
   * @author    zun
   * @since     Jul 22, 2010
   */
  public class UIActivityFactory extends BaseComponentPlugin {
    
    private static final Log LOG = ExoLogger.getLogger(UIActivityFactory.class);
    
    private Map<String, Provider<BaseUIActivityBuilder>> builders = new Hashtable<String, Provider<BaseUIActivityBuilder>>();
    
    private UIExtensionManager extensionManager;
    
    public UIActivityFactory() {
      extensionManager = (UIExtensionManager) PortalContainer.getInstance().getComponentInstanceOfType(UIExtensionManager.class);
    }
  
    /**
     * Find BaseUIActivity which compatible with Activity's type, and then add UIComponent the parent UI.
     * 
     * @param activity
     * @param parent
     * @return
     * @throws Exception
     */
    public BaseUIActivity addChild(ExoSocialActivity activity, UIContainer parent) throws Exception {
      final String type = activity.getType();
      final String externalId = activity.getExternalId();
      if (type != null) {
        return buildActivity(activity, parent, type);
      } else if (externalId != null) {
        // TODO Need to check if match the provided activity type or not
        return buildActivity(activity, parent, externalId);
      }
      return buildActivity(activity, parent, UIDefaultActivity.ACTIVITY_TYPE);
    }
  
    private BaseUIActivity buildActivity(ExoSocialActivity activity, UIContainer parent, String type) throws Exception {
      
      UIExtension activityExtension = extensionManager.getUIExtension(BaseUIActivity.class.getName(), type);
      if (activityExtension == null) {
        activityExtension = extensionManager.getUIExtension(BaseUIActivity.class.getName(), UIDefaultActivity.ACTIVITY_TYPE);
      }
      BaseUIActivity uiActivity = (BaseUIActivity) extensionManager.addUIExtension(activityExtension, null, parent);
      uiActivity.setId(uiActivity.getId().replace(":","_") + "_" + uiActivity.hashCode());
  
      //populate data for this uiActivity
      registerBuilder((UIActivityExtension) activityExtension);
      BaseUIActivityBuilder builder = getBuilder(type);
      return builder.populateData(uiActivity, activity);
    }
  
    private BaseUIActivityBuilder getBuilder(String activityType) {
      Provider<BaseUIActivityBuilder> providerBuilder = builders.get(activityType);
      if(providerBuilder == null) {
        providerBuilder = builders.get(UIDefaultActivity.ACTIVITY_TYPE);
      }
      return providerBuilder.get();
    }
  
    private void registerBuilder(final UIActivityExtension activityExtension) throws Exception {
      String activityType = activityExtension.getName();
      if (builders.containsKey(activityType) == false) {
        builders.put(activityType, new BuilderProvider<BaseUIActivityBuilder>(activityExtension));
      }
      
   }
   
   /**
    * Lazy creating the BaseUIActivityBuilder
    * @author thanh_vucong
    *
    * @param <T>
    */
   static class BuilderProvider<T extends BaseUIActivityBuilder> implements Provider<T> {
 
     final UIActivityExtension activityExtension;
     T instance = null;
     public BuilderProvider(UIActivityExtension activityExtension) {
       this.activityExtension = activityExtension;
     }
 
     public T get() {
       if (instance != null) {
         return instance;
       }
       
       try {
         Class<T> builderClass = (Class<T>) Thread.currentThread().getContextClassLoader()
                                             .loadClass(this.activityExtension.getActivityBuiderClass());
         instance = (T) builderClass.newInstance();
       } catch (Exception e) {
         LOG.error(e);
       }
 
       return instance;
     }
     
   }
 }