/*
 * JBoss, Home of Professional Open Source.
 * Copyright 2007, Red Hat Middleware LLC, and individual contributors
 * as indicated by the @author tags. See the copyright.txt file in the
 * distribution for a full listing of individual contributors.
 *
 * This 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 2.1 of
 * the License, or (at your option) any later version.
 *
 * This software 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 this software; if not, write to the Free
 * Software Foundation, Inc., 51 Franklin St, Fifth Floor, Boston, MA
 * 02110-1301 USA, or see the FSF site: http://www.fsf.org.
 */
package org.jboss.deployers.structure.spi.helpers;

import java.lang.reflect.Field;
import java.util.Comparator;
import java.util.List;

import org.jboss.deployers.client.spi.Deployment;
import org.jboss.deployers.spi.DeploymentException;
import org.jboss.deployers.spi.DeploymentState;
import org.jboss.deployers.spi.attachments.Attachments;
import org.jboss.deployers.spi.structure.ContextInfo;
import org.jboss.deployers.spi.structure.StructureMetaData;
import org.jboss.deployers.spi.structure.StructureMetaDataFactory;
import org.jboss.deployers.structure.spi.DeploymentContext;
import org.jboss.deployers.structure.spi.StructureBuilder;
import org.jboss.deployers.structure.spi.StructureProcessor;
import org.jboss.logging.Logger;

/**
 * AbstractStructureBuilder.
 * 
 * @author <a href="adrian@jboss.org">Adrian Brock</a>
 * @author <a href="ales.justin@jboss.org">Ales Justin</a>
 * @version $Revision: 1.1 $
 */
public class AbstractStructureBuilder implements StructureBuilder
{
   /** The log */
   private final Logger log = Logger.getLogger(getClass());

   /** The structure processor */
   private StructureProcessor structureProcessor;

   public DeploymentContext populateContext(Deployment deployment, StructureMetaData metaData) throws DeploymentException
   {
      if (deployment == null)
         throw new IllegalArgumentException("Null deployment");
      if (metaData == null)
         throw new IllegalArgumentException("Null metaData");

      boolean trace = log.isTraceEnabled();
      if (trace)
         log.trace("Populating deployment " + deployment.getName() + " metaData=" + metaData);
      
      DeploymentContext result;
      try
      {
         prepareStructureMetaData(deployment, metaData);

         result = createRootDeploymentContext(deployment, metaData);
         if (result == null)
            throw new IllegalStateException("Root deployment context is null");
         result.setDeployment(deployment);

         ContextInfo contextInfo = metaData.getContext("");
         if (contextInfo == null)
            contextInfo = StructureMetaDataFactory.createContextInfo("", null);

         applyStructureMetaData(result, metaData);
         contextInfo.setPredeterminedManagedObjects(deployment.getPredeterminedManagedObjects());
         applyContextInfo(result, contextInfo);
      }
      catch (Throwable t)
      {
         throw DeploymentException.rethrowAsDeploymentException("Error populating deployment " + deployment.getName(), t);
      }
      
      try
      {
         result.getTransientManagedObjects().addAttachment(StructureMetaData.class, metaData);
         populateContext(result, metaData);
      }
      catch (Throwable t)
      {
         result.setProblem(t);
         result.setState(DeploymentState.ERROR);
         log.warn("Error populating deployment " + deployment.getName(), t);
      }
      return result;
   }

   /**
    * Populate the child deployment contexts
    * 
    * @param context the context
    * @param metaData the metadata
    * @throws Exception for any error
    */
   protected void populateContext(DeploymentContext context, StructureMetaData metaData) throws Exception
   {
      if (context == null)
         throw new IllegalArgumentException("Null context");
      if (metaData == null)
         throw new IllegalArgumentException("Null metaData");
      
      boolean trace = log.isTraceEnabled();
      if (trace)
         log.trace("Populating Context " + context.getName() + " metaData=" + metaData);
      
      List<ContextInfo> contexts = metaData.getContexts();
      if (contexts == null)
         return;
      
      try
      {
         for (ContextInfo child : contexts)
         {
            // Only process the child contexts
            if ("".equals(child.getPath()) == false)
            {
               prepareContextInfo(context, child);

               DeploymentContext childContext = createChildDeploymentContext(context, child);
               if (childContext == null)
                  throw new IllegalStateException("Child deployment context is null");

               childContext.setParent(context);
               applyContextInfo(childContext, child);
               
               // Child must be added after context info is applied for correct sorting
               context.addChild(childContext);

               Attachments attachments = child.getPredeterminedManagedObjects(); 
               if (attachments != null)
               {
                  StructureMetaData childStructure = attachments.getAttachment(StructureMetaData.class);
                  if (childStructure != null)
                     populateContext(childContext, childStructure);
               }
            }
         }
      }
      catch (Throwable t)
      {
         throw DeploymentException.rethrowAsDeploymentException("Error populating context " + context.getName(), t);
      }
   }

   /**
    * Prepare the structure metadata.
    *
    * @param deploymentContext the deployment
    * @param structureMetaData the structure metadata
    */
   protected void prepareStructureMetaData(Deployment deploymentContext, StructureMetaData structureMetaData)
   {
      if (structureProcessor != null)
         structureProcessor.prepareStructureMetaData(deploymentContext, structureMetaData);
   }

   /**
    * Prepare the structure metadata.
    *
    * @param parentDeploymentContext the parent deployment context
    * @param contextInfo the context info
    */
   protected void prepareContextInfo(DeploymentContext parentDeploymentContext, ContextInfo contextInfo)
   {
      if (structureProcessor != null)
         structureProcessor.prepareContextInfo(parentDeploymentContext, contextInfo);
   }

   /**
    * Apply the structure metadata.
    *
    * @param deploymentContext the parent deployment context
    * @param structureMetaData the structure metadata
    */
   protected void applyStructureMetaData(DeploymentContext deploymentContext, StructureMetaData structureMetaData)
   {
      if (structureProcessor != null)
         structureProcessor.applyStructureMetaData(deploymentContext, structureMetaData);
   }

   /**
    * Apply the context info. This transfers the PredeterminedManagedObjects
    * and TransientManagedObjects and other information from the ContextInfo to the DeploymentContext.
    * 
    * @param context the context
    * @param contextInfo the contextInfo
    * @throws Exception for any error
    */
   protected void applyContextInfo(DeploymentContext context, ContextInfo contextInfo) throws Exception
   {
      Attachments attachments = contextInfo.getPredeterminedManagedObjects();
      if (attachments != null)
         context.setPredeterminedManagedObjects(attachments);

      context.setRelativeOrder(contextInfo.getRelativeOrder());
      applyComparator(context, contextInfo);

      if (structureProcessor != null)
         structureProcessor.applyContextInfo(context, contextInfo);
   }

   /**
    * Try to apply the comparator
    * 
    * @param context the context
    * @param contextInfo the contextInfo
    * @throws Exception for any error
    */
   @SuppressWarnings("unchecked")
   protected void applyComparator(DeploymentContext context, ContextInfo contextInfo) throws Exception
   {
      String className = contextInfo.getComparatorClassName();
      if (className == null)
         return;
      Object o = null;
      try
      {
         Class clazz = Thread.currentThread().getContextClassLoader().loadClass(className);
         try
         {
            Field field = clazz.getField("INSTANCE");
            o = field.get(null);
         }
         catch (NoSuchFieldException ignored)
         {
         }
         if (o == null)
            o = clazz.newInstance();
         Comparator comparator = Comparator.class.cast(o);
         context.setComparator(comparator);
      }
      catch (Throwable t)
      {
         log.warn("Unable to load/set comparator: " + className);
      }
   }

   /**
    * Create the root deployment context
    * 
    * @param deployment the deployment
    * @param metaData the structure meta data
    * @return the deployment context
    * @throws Exception for any error
    */
   protected DeploymentContext createRootDeploymentContext(Deployment deployment, StructureMetaData metaData) throws Exception
   {
      return createRootDeploymentContext(deployment);
   }

   /**
    * Create the root deployment context
    *
    * @param deployment the deployment
    * @return the deployment context
    * @throws Exception for any error
    */
   protected DeploymentContext createRootDeploymentContext(Deployment deployment) throws Exception
   {
      return new AbstractDeploymentContext(deployment.getName(), "");
   }
   
   /**
    * Create a child deployment context
    * 
    * @param parent the parent deployment context
    * @param child the child context
    * @return the deployment context
    * @throws Exception for any error
    */
   protected DeploymentContext createChildDeploymentContext(DeploymentContext parent, ContextInfo child) throws Exception
   {
      String path = child.getPath();
      String name = parent.getName() + "/" + path;
      return new AbstractDeploymentContext(name, path); 
   }

   /**
    * Set structure processor.
    *
    * @param structureProcessor the context info processor
    */
   public void setStructureProcessor(StructureProcessor structureProcessor)
   {
      this.structureProcessor = structureProcessor;
   }

   /**
    * Get the context info processor.
    *
    * @return the structure processor
    */
   protected StructureProcessor getStructureProcessor()
   {
      return structureProcessor;
   }
}
