/*******************************************************************************
 * Copyright (c) 2002, 2013 Innoopract Informationssysteme GmbH and others.
 * All rights reserved. This program and the accompanying materials
 * are made available under the terms of the Eclipse Public License v1.0
 * which accompanies this distribution, and is available at
 * http://www.eclipse.org/legal/epl-v10.html
 *
 * Contributors:
 *    Innoopract Informationssysteme GmbH - initial API and implementation
 *    EclipseSource - ongoing implementation
 ******************************************************************************/
package org.eclipse.rap.rwt.internal.service;

import javax.servlet.http.HttpServletRequest;
import javax.servlet.http.HttpServletResponse;

import org.eclipse.rap.rwt.internal.application.ApplicationContextImpl;
import org.eclipse.rap.rwt.internal.protocol.ProtocolMessageWriter;
import org.eclipse.rap.rwt.internal.util.ParamCheck;
import org.eclipse.rap.rwt.service.UISession;


/**
 * Encapsulates access to the currently processed request, response and other status information.
 * After a request's lifecycle has expired the corresponding ServiceContext will be disposed and
 * throws IllegalStateException when accessed.
 */
public final class ServiceContext {

  private HttpServletRequest request;
  private HttpServletResponse response;
  private ServiceStore serviceStore;
  private boolean disposed;
  private UISession uiSession;
  private ApplicationContextImpl applicationContext;
  private ProtocolMessageWriter protocolWriter;

  public ServiceContext( HttpServletRequest request,
                         HttpServletResponse response,
                         ApplicationContextImpl applicationContext )
  {
    this.request = request;
    this.response = response;
    this.applicationContext = applicationContext;
  }

  public ServiceContext( HttpServletRequest request,
                         HttpServletResponse response,
                         UISession uiSession )
  {
    this.request = request;
    this.response = response;
    this.uiSession = uiSession;
    this.applicationContext = ( ApplicationContextImpl )uiSession.getApplicationContext();
  }

  public HttpServletRequest getRequest() {
    checkState();
    return request;
  }

  public void setRequest( HttpServletRequest request ) {
    this.request = request;
  }

  public HttpServletResponse getResponse() {
    checkState();
    return response;
  }

  public ServiceStore getServiceStore() {
    checkState();
    return serviceStore;
  }

  public void setServiceStore( ServiceStore serviceStore ) {
    checkState();
    ParamCheck.notNull( serviceStore, "serviceStore" );
    if( this.serviceStore != null ) {
      String msg = "ServiceStore is already set and must not be replaced.";
      throw new IllegalStateException( msg );
    }
    this.serviceStore = serviceStore;
  }

  public ProtocolMessageWriter getProtocolWriter() {
    checkState();
    if( protocolWriter == null ) {
      protocolWriter = new ProtocolMessageWriter();
    }
    return protocolWriter;
  }

  public void resetProtocolWriter() {
    protocolWriter = new ProtocolMessageWriter();
  }

  public UISession getUISession() {
    checkState();
    if( uiSession != null && !uiSession.isBound() ) {
      uiSession = null;
    }
    return uiSession;
  }

  public void setUISession( UISession uiSession ) {
    this.uiSession = uiSession;
  }

  public ApplicationContextImpl getApplicationContext() {
    checkState();
    if( applicationContext != null && applicationContext.isActive() ) {
      return applicationContext;
    }
    return null;
  }

  public void dispose() {
    checkState();
    request = null;
    response = null;
    serviceStore = null;
    uiSession = null;
    applicationContext = null;
    disposed = true;
  }

  public boolean isDisposed() {
    return disposed;
  }

  private void checkState() {
    if( disposed ) {
      throw new IllegalStateException( "The context has been disposed." );
    }
  }

}