//
   //  ========================================================================
   //  Copyright (c) 1995-2013 Mort Bay Consulting Pty. Ltd.
   //  ------------------------------------------------------------------------
   //  All rights reserved. This program and the accompanying materials
   //  are made available under the terms of the Eclipse Public License v1.0
   //  and Apache License v2.0 which accompanies this distribution.
   //
   //      The Eclipse Public License is available at
  //      http://www.eclipse.org/legal/epl-v10.html
  //
  //      The Apache License v2.0 is available at
  //      http://www.opensource.org/licenses/apache2.0.php
  //
  //  You may elect to redistribute this code under either of these licenses.
  //  ========================================================================
  //
  
  
  package org.eclipse.jetty.spring;
  
  import java.net.URL;
  import java.nio.charset.StandardCharsets;
  import java.util.Arrays;
  import java.util.Map;
  import java.util.ServiceLoader;
  
  import org.eclipse.jetty.util.log.Log;
  import org.eclipse.jetty.util.log.Logger;
  import org.eclipse.jetty.xml.ConfigurationProcessor;
  import org.eclipse.jetty.xml.ConfigurationProcessorFactory;
  import org.eclipse.jetty.xml.XmlConfiguration;
  import org.eclipse.jetty.xml.XmlParser;
  import org.springframework.beans.BeanWrapper;
  import org.springframework.beans.PropertyValues;
  import org.springframework.beans.factory.config.BeanDefinition;
  import org.springframework.beans.factory.support.DefaultListableBeanFactory;
  import org.springframework.beans.factory.xml.XmlBeanDefinitionReader;
  import org.springframework.beans.factory.xml.XmlBeanFactory;
  import org.springframework.core.io.ByteArrayResource;
  import org.springframework.core.io.Resource;
  import org.springframework.core.io.UrlResource;
  
  /**
   * Spring ConfigurationProcessor
   * <p/>
   * A {@link ConfigurationProcessor} that uses a spring XML file to emulate the {@link XmlConfiguration} format.
   * <p/>
   * {@link XmlConfiguration} expects a primary object that is either passed in to a call to {@link #configure(Object)}
   * or that is constructed by a call to {@link #configure()}. This processor looks for a bean definition
   * with an id, name or alias of "Main" as uses that as the primary bean.
   * <p/>
   * The objects mapped by {@link XmlConfiguration#getIdMap()} are set as singletons before any configuration calls
   * and if the spring configuration file contains a definition for the singleton id, the the singleton is updated
   * with a call to {@link XmlBeanFactory#configureBean(Object, String)}.
   * <p/>
   * The property map obtained via {@link XmlConfiguration#getProperties()} is set as a singleton called "properties"
   * and values can be accessed by somewhat verbose
   * usage of {@link org.springframework.beans.factory.config.MethodInvokingFactoryBean}.
   * <p/>
   * This processor is returned by the {@link SpringConfigurationProcessorFactory} for any XML document whos first
   * element is "beans". The factory is discovered by a {@link ServiceLoader} for {@link ConfigurationProcessorFactory}.
   */
  public class SpringConfigurationProcessor implements ConfigurationProcessor
  {
      private static final Logger LOG = Log.getLogger(SpringConfigurationProcessor.class);
  
      private XmlConfiguration _configuration;
      private DefaultListableBeanFactory _beanFactory;
      private String _main;
  
      @Override
      public void init(URL url, XmlParser.Node config, XmlConfiguration configuration)
      {
          try
          {
              _configuration = configuration;
  
              Resource resource = url != null
                      ? new UrlResource(url)
                      : new ByteArrayResource(("" +
                      "<?xml version=\"1.0\" encoding=\"UTF-8\"?>" +
                      "<!DOCTYPE beans PUBLIC \"-//SPRING//DTD BEAN//EN\" \"http://www.springframework.org/dtd/spring-beans.dtd\">" +
                      config).getBytes(StandardCharsets.UTF_8));
  
              _beanFactory = new DefaultListableBeanFactory()
              {
                  @Override
                  protected void applyPropertyValues(String beanName, BeanDefinition mbd, BeanWrapper bw, PropertyValues pvs)
                  {
                      _configuration.initializeDefaults(bw.getWrappedInstance());
                      super.applyPropertyValues(beanName, mbd, bw, pvs);
                  }
              };
  
              new XmlBeanDefinitionReader(_beanFactory).loadBeanDefinitions(resource);
          }
          catch (Exception e)
          {
             throw new RuntimeException(e);
         }
     }
 
     @Override
     public Object configure(Object obj) throws Exception
     {
         doConfigure();
         return _beanFactory.configureBean(obj, _main);
     }
 
     /**
      * Return a configured bean.  If a bean has the id or alias of "Main", then it is returned, otherwise the first bean in the file is returned.
      *
      * @see org.eclipse.jetty.xml.ConfigurationProcessor#configure()
      */
     @Override
     public Object configure() throws Exception
     {
         doConfigure();
         return _beanFactory.getBean(_main);
     }
 
     private void doConfigure()
     {
         _beanFactory.registerSingleton("properties", _configuration.getProperties());
 
         // Look for the main bean;
         for (String bean : _beanFactory.getBeanDefinitionNames())
         {
             LOG.debug("{} - {}", bean, Arrays.asList(_beanFactory.getAliases(bean)));
             String[] aliases = _beanFactory.getAliases(bean);
             if ("Main".equals(bean) || aliases != null && Arrays.asList(aliases).contains("Main"))
             {
                 _main = bean;
                 break;
             }
         }
         if (_main == null)
             _main = _beanFactory.getBeanDefinitionNames()[0];
 
         // Register id beans as singletons
         Map<String, Object> idMap = _configuration.getIdMap();
         LOG.debug("idMap {}", idMap);
         for (String id : idMap.keySet())
         {
             LOG.debug("register {}", id);
             _beanFactory.registerSingleton(id, idMap.get(id));
         }
 
         // Apply configuration to existing singletons
         for (String id : idMap.keySet())
         {
             if (_beanFactory.containsBeanDefinition(id))
             {
                 LOG.debug("reconfigure {}", id);
                 _beanFactory.configureBean(idMap.get(id), id);
             }
         }
 
         // Extract id's for next time.
         for (String id : _beanFactory.getSingletonNames())
             idMap.put(id, _beanFactory.getBean(id));
     }
 }