//
   //  ========================================================================
   //  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.policy.entry;
  
  import java.net.URI;
  import java.net.URL;
  import java.security.CodeSource;
  import java.security.KeyStore;
  import java.security.KeyStoreException;
  import java.security.PermissionCollection;
  import java.security.Permissions;
  import java.security.Principal;
  import java.security.cert.Certificate;
  import java.util.Collection;
  import java.util.HashSet;
  import java.util.Iterator;
  import java.util.Set;
  import java.util.StringTokenizer;
  
  import org.eclipse.jetty.policy.PolicyContext;
  import org.eclipse.jetty.policy.PolicyException;
  
  public class GrantEntry extends AbstractEntry
  {
  
      /**
       * The signers part of grant clause. This is a comma-separated list of certificate aliases.
       */
      private String signers;
  
      /**
       * The codebase part of grant clause. This is an URL from which code originates.
       */
      private String codebase;
  
      /**
       * Collection of PrincipalEntries of grant clause.
       */
      private Collection<PrincipalEntry> principalNodes;
  
      /**
       * Collection of PermissionEntries of grant clause.
       */
      private Collection<PermissionEntry> permissionNodes;
  
      // cached permissions
      private PermissionCollection permissions;
      private Certificate[] signerArray;
      private CodeSource codesource;
      private Principal[] principals;
      
      /**
       * Adds specified element to the <code>principals</code> collection. If collection does not exist yet, creates a
       * new one.
       */
      public void addPrincipal( PrincipalEntry pe )
      {
          if ( principalNodes == null )
          {
              principalNodes = new HashSet<PrincipalEntry>();
          }
          principalNodes.add( pe );
      }
  
      public void expand( PolicyContext context ) throws PolicyException
      {
          if ( signers != null )
          {
              signerArray = resolveToCertificates( context.getKeystore(), signers );  // TODO alter to support self:: etc
          }
          codebase = context.evaluate( codebase );
          
          if ( principalNodes != null )
          {
              Set<Principal> principalSet = new HashSet<Principal>();
              for ( Iterator<PrincipalEntry> i = principalNodes.iterator(); i.hasNext(); )
              {
                  PrincipalEntry node = i.next();
                  node.expand( context );
                  principalSet.add( node.toPrincipal( context ) );
              }
              principals = principalSet.toArray( new Principal[principalSet.size()] );
          }
         
         context.setPrincipals( principals );
         permissions = new Permissions();
         for ( Iterator<PermissionEntry> i = permissionNodes.iterator(); i.hasNext(); )
         {
             PermissionEntry node = i.next();
             node.expand( context );
             permissions.add( node.toPermission() );
         }
         context.setPrincipals( null );
         
         setExpanded( true );
     }    
     
     public PermissionCollection getPermissions() throws PolicyException
     {
         return permissions;
     }    
     
     public Principal[] getPrincipals() throws PolicyException
     {
         return principals;
     }
     
     public CodeSource getCodeSource() throws PolicyException
     {
         if ( !isExpanded() )
         {
             throw new PolicyException("GrantNode needs to be expanded.");
         }
         
         try
         {
             if ( codesource == null && codebase != null )
             {
                 URL url = new URI( codebase ).toURL();
                 codesource = new CodeSource( url, signerArray );
             }
 
             return codesource;
         }
         catch ( Exception e )
         {
             throw new PolicyException( e );
         }
     }
     
     /**
      * resolve signers into an array of certificates using a given keystore
      * 
      * @param keyStore
      * @param signers
      * @return
      * @throws Exception
      */
     private Certificate[] resolveToCertificates( KeyStore keyStore, String signers ) throws PolicyException
     {               
         if ( keyStore == null )
         {
             Certificate[] certs = null;
             return certs;
         }
                 
         Set<Certificate> certificateSet = new HashSet<Certificate>();       
         StringTokenizer strTok = new StringTokenizer( signers, ",");
         
         for ( int i = 0; strTok.hasMoreTokens(); ++i )
         {
             try
             {               
                 Certificate certificate = keyStore.getCertificate( strTok.nextToken().trim() );
                 
                 if ( certificate != null )
                 {
                     certificateSet.add( certificate );
                 }               
             }
             catch ( KeyStoreException kse )
             {
                 throw new PolicyException( kse );
             }
         }
         
         return certificateSet.toArray( new Certificate[certificateSet.size()] );
     }
     
 
     public void setSigners( String signers )
     {
         this.signers = signers;
     }
 
     public void setCodebase( String codebase )
     {
         this.codebase = codebase;
     }
 
     public void setPrincipals( Collection<PrincipalEntry> principals )
     {
         this.principalNodes = principals;
     }
 
     public void setPermissions( Collection<PermissionEntry> permissions )
     {
         this.permissionNodes = permissions;
     }
 
     
     
 }