//
   //  ========================================================================
   //  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.annotations;
  
  import java.util.ArrayList;
  import java.util.List;
  
  import javax.servlet.ServletSecurityElement;
  import javax.servlet.annotation.HttpConstraint;
  import javax.servlet.annotation.HttpMethodConstraint;
  import javax.servlet.annotation.ServletSecurity;
  import javax.servlet.annotation.ServletSecurity.EmptyRoleSemantic;
  import javax.servlet.annotation.ServletSecurity.TransportGuarantee;
  
  import org.eclipse.jetty.annotations.AnnotationIntrospector.AbstractIntrospectableAnnotationHandler;
  import org.eclipse.jetty.security.ConstraintAware;
  import org.eclipse.jetty.security.ConstraintMapping;
  import org.eclipse.jetty.security.ConstraintSecurityHandler;
  import org.eclipse.jetty.servlet.ServletHolder;
  import org.eclipse.jetty.servlet.ServletMapping;
  import org.eclipse.jetty.util.log.Log;
  import org.eclipse.jetty.util.log.Logger;
  import org.eclipse.jetty.util.security.Constraint;
  import org.eclipse.jetty.webapp.Origin;
  import org.eclipse.jetty.webapp.WebAppContext;
  
  /**
   * ServletSecurityAnnotationHandler
   *
   * Inspect a class to see if it has an @ServletSecurity annotation on it,
   * setting up the <security-constraint>s.
   * 
   * A servlet can be defined in:
   * <ul>
   * <li>web.xml
   * <li>web-fragment.xml
   * <li>@WebServlet annotation discovered
   * <li>ServletContext.createServlet
   * </ul>
   * 
   * The ServletSecurity annotation for a servlet should only be processed
   * iff metadata-complete == false.
   */
  public class ServletSecurityAnnotationHandler extends AbstractIntrospectableAnnotationHandler
  {
      private static final Logger LOG = Log.getLogger(ServletSecurityAnnotationHandler.class);
  
      private WebAppContext _context;
      
      public ServletSecurityAnnotationHandler(WebAppContext wac)
      {
          super(false);
          _context = wac;
      }
      
      /** 
       * @see org.eclipse.jetty.annotations.AnnotationIntrospector.IntrospectableAnnotationHandler#handle(java.lang.Class)
       */
      public void doHandle(Class clazz)
      {
          if (!(_context.getSecurityHandler() instanceof ConstraintAware))
          {
              LOG.warn("SecurityHandler not ConstraintAware, skipping security annotation processing");
              return;
          }
          
         ServletSecurity servletSecurity = (ServletSecurity)clazz.getAnnotation(ServletSecurity.class);
         if (servletSecurity == null)
             return;
         
         //If there are already constraints defined (ie from web.xml) that match any 
         //of the url patterns defined for this servlet, then skip the security annotation.
        
         List<ServletMapping> servletMappings = getServletMappings(clazz.getCanonicalName());
         List<ConstraintMapping> constraintMappings =  ((ConstraintAware)_context.getSecurityHandler()).getConstraintMappings();
       
         if (constraintsExist(servletMappings, constraintMappings))
         {
             LOG.warn("Constraints already defined for "+clazz.getName()+", skipping ServletSecurity annotation");
             return;
         }
  
         //Make a fresh list
        constraintMappings = new ArrayList<ConstraintMapping>();
        
        ServletSecurityElement securityElement = new ServletSecurityElement(servletSecurity);
        for (ServletMapping sm : servletMappings)
        {
            for (String url : sm.getPathSpecs())
            {
                _context.getMetaData().setOrigin("constraint.url."+url, Origin.Annotation);
                constraintMappings.addAll(ConstraintSecurityHandler.createConstraintsWithMappingsForPath(clazz.getName(), url, securityElement));
            }
        }
 
        //set up the security constraints produced by the annotation
        ConstraintAware securityHandler = (ConstraintAware)_context.getSecurityHandler();
 
        for (ConstraintMapping m:constraintMappings)
            securityHandler.addConstraintMapping(m); 
     }
     
  
     
     /**
      * Make a jetty Constraint object, which represents the <auth-constraint> and
      * <user-data-constraint> elements, based on the security annotation.
      * @param servlet
      * @param rolesAllowed
      * @param permitOrDeny
      * @param transport
      * @return
      */
     protected Constraint makeConstraint (Class servlet, String[] rolesAllowed, EmptyRoleSemantic permitOrDeny, TransportGuarantee transport)
     {  
         return ConstraintSecurityHandler.createConstraint(servlet.getName(), rolesAllowed, permitOrDeny, transport);
     }
     
     
     
     /**
      * Get the ServletMappings for the servlet's class.
      * @param className
      * @return
      */
     protected List<ServletMapping> getServletMappings(String className)
     {
         List<ServletMapping> results = new ArrayList<ServletMapping>();
         ServletMapping[] mappings = _context.getServletHandler().getServletMappings();
         for (ServletMapping mapping : mappings)
         {
             //Check the name of the servlet that this mapping applies to, and then find the ServletHolder for it to find it's class
             ServletHolder holder = _context.getServletHandler().getServlet(mapping.getServletName());
             if (holder.getClassName() != null && holder.getClassName().equals(className))
               results.add(mapping);
         }
         return results;
     }
     
     
     
     /**
      * Check if there are already <security-constraint> elements defined that match the url-patterns for
      * the servlet.
      * @param servletMappings
      * @return
      */
     protected boolean constraintsExist (List<ServletMapping> servletMappings, List<ConstraintMapping> constraintMappings)
     {
         boolean exists = false;
 
         //Check to see if the path spec on each constraint mapping matches a pathSpec in the servlet mappings.
         //If it does, then we should ignore the security annotations.
         for (ServletMapping mapping : servletMappings)
         {  
             //Get its url mappings
             String[] pathSpecs = mapping.getPathSpecs();
             if (pathSpecs == null)
                 continue;
 
             //Check through the constraints to see if there are any whose pathSpecs (url mappings)
             //match the servlet. If so, then we already have constraints defined for this servlet,
             //and we will not be processing the annotation (ie web.xml or programmatic override).
            for (int i=0; constraintMappings != null && i < constraintMappings.size() && !exists; i++)
            {
                for (int j=0; j < pathSpecs.length; j++)
                {
                    //TODO decide if we need to check the origin
                    if (pathSpecs[j].equals(constraintMappings.get(i).getPathSpec()))
                    {
                        exists = true;
                        break;
                    }
                }
            }
         }      
         return exists;
     }
 
 }