/*
    * Copyright 2006-2011 The Kuali Foundation
    *
    * Licensed under the Educational Community License, Version 2.0 (the "License");
    * you may not use this file except in compliance with the License.
    * You may obtain a copy of the License at
    *
    * http://www.opensource.org/licenses/ecl2.php
    *
   * Unless required by applicable law or agreed to in writing, software
   * distributed under the License is distributed on an "AS IS" BASIS,
   * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
   * See the License for the specific language governing permissions and
   * limitations under the License.
   */
  package org.kuali.rice.ksb.messaging.serviceproxies;
  
  import org.apache.log4j.Logger;
  import org.kuali.rice.core.api.exception.RiceRuntimeException;
  import org.kuali.rice.core.api.util.ClassLoaderUtils;
  import org.kuali.rice.core.api.util.reflect.BaseInvocationHandler;
  import org.kuali.rice.core.api.util.reflect.TargetedInvocationHandler;
  import org.kuali.rice.core.impl.resourceloader.ContextClassLoaderProxy;
  import org.kuali.rice.ksb.api.bus.Endpoint;
  import org.kuali.rice.ksb.api.bus.ServiceConfiguration;
  import org.kuali.rice.ksb.api.messaging.AsynchronousCall;
  import org.kuali.rice.ksb.api.messaging.AsynchronousCallback;
  import org.kuali.rice.ksb.messaging.PersistedMessageBO;
  import org.kuali.rice.ksb.service.KSBServiceLocator;
  import org.kuali.rice.ksb.util.KSBConstants;
  
  import java.io.Serializable;
  import java.lang.reflect.Method;
  import java.lang.reflect.Proxy;
  import java.util.List;
  
  
  /**
   * Standard default proxy used to call services asynchronously. Persists the method call to the db so call is never lost and
   * only sent when transaction is committed.
   * 
   * @author Kuali Rice Team (rice.collab@kuali.org)
   * 
   */
  public class AsynchronousServiceCallProxy extends BaseInvocationHandler implements TargetedInvocationHandler {
      
      private static final Logger LOG = Logger.getLogger(AsynchronousServiceCallProxy.class);
  
      private AsynchronousCallback callback;
  
      private List<Endpoint> endpoints;
  
      private Serializable context;
  
      private String value1;
  
      private String value2;
  
      protected AsynchronousServiceCallProxy(List<Endpoint> endpoints, AsynchronousCallback callback,
  	    Serializable context, String value1, String value2) {
  	this.endpoints = endpoints;
  	this.callback = callback;
  	this.context = context;
  	this.value1 = value1;
  	this.value2 = value2;
      }
  
      public static Object createInstance(List<Endpoint> endpoints, AsynchronousCallback callback,
  	    Serializable context, String value1, String value2) {
  	if (endpoints == null || endpoints.isEmpty()) {
  	    throw new RuntimeException("Cannot create service proxy, no service(s) passed in.");
  	}
  	try {
  	    return Proxy.newProxyInstance(ClassLoaderUtils.getDefaultClassLoader(), ContextClassLoaderProxy
  		    .getInterfacesToProxy(endpoints.get(0).getService()), new AsynchronousServiceCallProxy(
  		    endpoints, callback, context, value1, value2));
  	} catch (Exception e) {
  	    throw new RiceRuntimeException(e);
  	}
      }
  
      @Override
      protected Object invokeInternal(Object proxy, Method method, Object[] arguments) throws Throwable {
  
  	if (LOG.isDebugEnabled()) {
  	    LOG.debug("creating messages for method invocation: " + method.getName());
  	}
  	// there are multiple service calls to make in the case of topics.
  	AsynchronousCall methodCall = null;
  	PersistedMessageBO message = null;
  	synchronized (this) {
  	    // consider moving all this topic invocation stuff to the service
  	    // invoker for speed reasons
  	    for (Endpoint endpoint : this.endpoints) {
  		ServiceConfiguration serviceConfiguration = endpoint.getServiceConfiguration();
  		methodCall = new AsynchronousCall(method.getParameterTypes(), arguments, serviceConfiguration, method.getName(),
  			this.callback, this.context);
  		message = KSBServiceLocator.getMessageQueueService().getMessage(serviceConfiguration, methodCall);
  		message.setValue1(this.value1);
 		message.setValue2(this.value2);
 		saveMessage(message);
 		executeMessage(message);
 		// only do one iteration if this is a queue. The load balancing
 		// will be handled when the service is
 		// fetched by the MessageServiceInvoker through the GRL (and
 		// then through the RemoteResourceServiceLocatorImpl)
 		if (serviceConfiguration.isQueue()) {
 		    break;
 		}
 	    }
 	}
 	if (LOG.isDebugEnabled()) {
 	    LOG.debug("finished creating messages for method invocation: " + method.getName());
 	}
 	return null;
     }
 
     protected void saveMessage(PersistedMessageBO message) {
 	message.setQueueStatus(KSBConstants.ROUTE_QUEUE_ROUTING);
 	KSBServiceLocator.getMessageQueueService().save(message);
     }
 
     protected void executeMessage(PersistedMessageBO message) throws Exception {
 	MessageSender.sendMessage(message);
     }
 
     /**
          * Returns the List<RemotedServiceHolder> of asynchronous services which will be invoked by calls to this proxy.
          * This is a List because, in the case of Topics, there can be more than one service invoked.
          */
     public Object getTarget() {
     	return this.endpoints;
     }
 
     public AsynchronousCallback getCallback() {
 	return this.callback;
     }
 
     public void setCallback(AsynchronousCallback callback) {
 	this.callback = callback;
     }
 
 }