/*
    * Licensed to the Apache Software Foundation (ASF) under one
    * or more contributor license agreements.  See the NOTICE file
    * distributed with this work for additional information
    * regarding copyright ownership. The ASF licenses this file
    * to you under the Apache 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.apache.org/licenses/LICENSE-2.0
   * 
   * 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.apache.river.tool;
  
  import java.io.BufferedWriter;
  import java.io.File;
  import java.io.FileWriter;
  import java.io.IOException;
  import java.io.PrintWriter;
  import java.net.URISyntaxException;
  import java.security.KeyStore;
  import java.security.Permission;
  import java.util.ArrayList;
  import java.util.Collection;
  import java.util.Iterator;
  import java.util.TreeSet;
  import org.apache.river.api.security.DefaultPolicyParser;
  import org.apache.river.api.security.PermissionComparator;
  import org.apache.river.api.security.PermissionGrant;
  import org.apache.river.api.security.PermissionGrantBuilder;
  import org.apache.river.api.security.PolicyParser;
  
  /**
   * This PolicyCondenser can be used to consolidate and condense permission
   * grants in policy files.
   * 
   * The condenser will replace properties in grant files passed in using -Dprop=value
   * 
   * java -cp policy-condenser-3.0-SNAPSHOT.jar;%RIVER.HOME%\lib\* 
   * org.apache.river.tool.PolicyCondenser security.policy
   * 
   * @see KeyStore
   * @author Peter Firmstone
   * @since 3.0.0
   */
  public class PolicyCondenser {
      
      public static void main(String [] args) throws Exception{
  	PolicyCondenser condenser = new PolicyCondenser();
  	for (int i = 0, l = args.length; i < l; i++){
  	    condenser.condense(args[i]);
  	}
      }
  
      private PolicyCondenser() 
      {
          super();
      } 
      
      private static File policyFile(String filename) throws URISyntaxException{
         
  	File policyFile = new File(filename);
  	if (!policyFile.exists()){
  	    try {
  		policyFile.createNewFile();
  	    } catch (IOException ex) {
  		throw new RuntimeException("Unable to create a policy file: " + filename, ex);
  	    }
  	}
          return policyFile;
      }
  
      private void condense(String arg) throws Exception {
  	File policy = policyFile(arg);
  	File condensedPolicy = policyFile(arg + ".con");
  	PolicyParser parser = new DefaultPolicyParser();
  	Collection<PermissionGrant> grantsCol = parser.parse(policy.toURI().toURL(), System.getProperties());
  	PermissionGrant [] grants = grantsCol.toArray(new PermissionGrant[grantsCol.size()]);
  	int length = grants.length;
  	Collection<PermissionGrantBuilder> builders = new ArrayList<PermissionGrantBuilder>(length);
  	for (int i = 0; i < length; i++){
  	    if (grants[i] == null) continue;
  	    PermissionGrantBuilder builder = grants[i].getBuilderTemplate();
  	    Collection<Permission> permissions = new TreeSet<Permission>(new PermissionComparator());
  	    permissions.addAll(grants[i].getPermissions());
  	    for (int j = 0; j < length; j++){
  		if (i == j || grants[j] == null) continue;
  		if (grants[i].impliesEquivalent(grants[j])){
  		    permissions.addAll(grants[j].getPermissions());
  		    grants[j] = null;
  		}
  	    }
  	    builder.permissions(permissions.toArray(new Permission[permissions.size()]));
 	    builders.add(builder);
 	    grants[i] = null;
 	}
 	PrintWriter pw = new PrintWriter(new BufferedWriter(new FileWriter(condensedPolicy, true)));
 	Iterator<PermissionGrantBuilder> builderIt = builders.iterator();
 	while(builderIt.hasNext()){
 	    pw.print("grant ");
 	    pw.print(builderIt.next().build().toString());
 	}
 	pw.flush();
 	pw.close();
     }
 
 }