/*
 * Copyright (C) 2005-2011 Alfresco Software Limited.
 *
 * This file is part of Alfresco
 *
 * Alfresco is free software: you can redistribute it and/or modify
 * it under the terms of the GNU Lesser General Public License as published by
 * the Free Software Foundation, either version 3 of the License, or
 * (at your option) any later version.
 *
 * Alfresco 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 Lesser General Public License for more details.
 *
 * You should have received a copy of the GNU Lesser General Public License
 * along with Alfresco. If not, see <http://www.gnu.org/licenses/>.
 */
package org.alfresco.repo.rendition.executer;

import java.io.Serializable;
import java.util.List;
import java.util.Map;

import org.alfresco.model.ContentModel;
import org.alfresco.repo.action.ParameterDefinitionImpl;
import org.alfresco.repo.action.executer.ActionExecuter;
import org.alfresco.repo.action.executer.ActionExecuterAbstractBase;
import org.alfresco.repo.policy.BehaviourFilter;
import org.alfresco.repo.rendition.RenditionedAspect;
import org.alfresco.repo.security.authentication.AuthenticationUtil;
import org.alfresco.repo.security.authentication.AuthenticationUtil.RunAsWork;
import org.alfresco.repo.thumbnail.AddFailedThumbnailActionExecuter;
import org.alfresco.service.cmr.action.Action;
import org.alfresco.service.cmr.action.ParameterDefinition;
import org.alfresco.service.cmr.dictionary.DataTypeDefinition;
import org.alfresco.service.cmr.rendition.RenditionService;
import org.alfresco.service.cmr.repository.ChildAssociationRef;
import org.alfresco.service.cmr.repository.NodeRef;
import org.alfresco.service.cmr.repository.NodeService;
import org.alfresco.service.namespace.QName;
import org.apache.commons.logging.Log;
import org.apache.commons.logging.LogFactory;

/**
 * This {@link ActionExecuter} implementation is used internally to delete rendition nodes when a rendition update has failed.
 * The scenario is as follows: a content node exists in the repository and has a number of rendition nodes associated with it.
 * When the content node is given new content, each of the rendition nodes must be updated to reflect the new source content.
 * But if one or more of those re-renditions fail, then the old rendition nodes now refer to out of date content and should be deleted.
 * <p/>
 * This class executes the deletion of the specified rendition node.
 * 
 * @author Neil Mc Erlean
 * @since 3.4.2
 * 
 * @see RenditionedAspect
 * @see AddFailedThumbnailActionExecuter
 */
public class DeleteRenditionActionExecuter extends ActionExecuterAbstractBase
{
    private static Log log = LogFactory.getLog(DeleteRenditionActionExecuter.class);
    
    /**
     * The action bean name.
     */
    public static final String NAME = "delete-rendition";
    
    /**
     * The name of the rendition definition to delete e.g. cm:doclib.
     */
    public static final String PARAM_RENDITION_DEFINITION_NAME = "rendition-definition-name";
    
    private NodeService nodeService;
    private RenditionService renditionService;
    private BehaviourFilter behaviourFilter;
    
    public void setNodeService(NodeService nodeService) 
    {
        this.nodeService = nodeService;
    }
    
    public void setRenditionService(RenditionService renditionService) 
    {
        this.renditionService = renditionService;
    }
    
    public void setBehaviourFilter(BehaviourFilter behaviourFilter)
    {
        this.behaviourFilter = behaviourFilter;
    }

	/**
     * @see org.alfresco.repo.action.executer.ActionExecuter#execute(org.alfresco.service.cmr.repository.NodeRef, NodeRef)
     */
    public void executeImpl(final Action action, final NodeRef actionedUponNodeRef)
    {
        // It is possible that the user who triggered the thumbnail update does not have delete permissions on the node
        // but does have write permissions. e.g. if a SiteCollaborator updates a node which they do not own, any failure
        // to update renditions would trigger this DeleteRendition action and they would not have permissions to delete.
        //
        // For that reason this action is run as the system user.
        final NodeService finalNodeService = nodeService;
        
        AuthenticationUtil.runAsSystem(new RunAsWork<Void>()
        {
            @Override public Void doWork() throws Exception
            {
                final boolean nodeExists = finalNodeService.exists(actionedUponNodeRef);
                if (nodeExists)
                {
                    Map<String, Serializable> paramValues = action.getParameterValues();
                    final QName renditionDefName = (QName)paramValues.get(PARAM_RENDITION_DEFINITION_NAME);
                    
                    ChildAssociationRef existingRendition = renditionService.getRenditionByName(actionedUponNodeRef, renditionDefName);
                    
                    if (existingRendition != null)
                    {
                        if (log.isDebugEnabled())
                        {
                            StringBuilder msg = new StringBuilder();
                            msg.append("Deleting rendition node: ").append(existingRendition);
                            log.debug(msg.toString());
                        }
                        
                        behaviourFilter.disableBehaviour(actionedUponNodeRef, ContentModel.ASPECT_AUDITABLE);
                        try
                        {
                            nodeService.deleteNode(existingRendition.getChildRef());
                        }
                        finally
                        {
                            behaviourFilter.enableBehaviour(actionedUponNodeRef, ContentModel.ASPECT_AUDITABLE);
                        }
                    }
                }
                return null;
            }
        });
    }

    /**
     * @see org.alfresco.repo.action.ParameterizedItemAbstractBase#addParameterDefinitions(java.util.List)
     */
    @Override
    protected void addParameterDefinitions(List<ParameterDefinition> paramList) 
    {
        paramList.add(new ParameterDefinitionImpl(PARAM_RENDITION_DEFINITION_NAME, DataTypeDefinition.QNAME, true, getParamDisplayLabel(PARAM_RENDITION_DEFINITION_NAME), false));
    }
}