/**
 * Logback: the reliable, generic, fast and flexible logging framework.
 * Copyright (C) 2006-2011, QOS.ch. All rights reserved.
 * 
 * This program and the accompanying materials are dual-licensed under
 * either the terms of the Eclipse Public License v1.0 as published by
 * the Eclipse Foundation
 *  
 *   or (per the licensee's choosing)
 *  
 * under the terms of the GNU Lesser General Public License version 2.1
 * as published by the Free Software Foundation.
 */

package examples.access;

import ch.qos.logback.audit.AuditException;
import ch.qos.logback.audit.client.AuditorFacade;
import ch.qos.logback.audit.client.AuditorFactory;

/**
 * A simple application illustrating calls to the logback-audit API.
 * 
 * @author Ceki Gulcu
 */
public class AccessRightsAdministrator {

  static String ACCESS_RIGHTS_ADMIN_APPLICATION_NAME = "AccessRightsAdmin";

  static String ADD_PERMISSION_VERB = "ADD_PERMISSION";
  static String REMOVE_PERMISSION_VERB = "REMOVE_PERMISSION";

  final PermissionMap permissionMap = new PermissionMap();

  /**
   * Add a permission to a user.
   * 
   * @param user
   * @param permission
   * @throws AccessException
   *                 thrown in case of error while adding a permission
   */
  public void addPermission(User user, Permission permission)
      throws AccessException {

    // add the permission
    permissionMap.addPermission(user, permission);

    // let us now audit the code
    
    // The following will create an AuditEvent with a subject equal to the 
    // user's name, a verb equal to ADD_PERMISSION, an the object
    // equal to the name of permission passed as argument
    AuditorFacade auditorFacade = new AuditorFacade(user.getName(),
        ADD_PERMISSION_VERB, permission.getName());
    try {
      // send the AuditEvent through an appender (usually to a server) 
      auditorFacade.audit();
    } catch (AuditException e) {
      // if an AuditException occurs, rethrow it as 
      // an application failure (AccessException)
      throw new AccessException("Audit failure", e);
    }
  }

  /**
   * Remove a permission from a user.
   * 
   * @param user
   * @param permission
   * @throws AccessException
   *                 thrown in case of error while removing a permission
   */
  public void removePermission(User user, Permission permission)
      throws AccessException {
    permissionMap.removePermission(user, permission);

    AuditorFacade auditorFacade = new AuditorFacade(user.getName(),
        REMOVE_PERMISSION_VERB, permission.getName());
    AuditHelper.audit(auditorFacade);

  }

  public static void main(String[] args) throws AuditException, AccessException {
    AuditorFactory.setApplicationName(ACCESS_RIGHTS_ADMIN_APPLICATION_NAME);
    AccessRightsAdministrator ara = new AccessRightsAdministrator();

    // let us simulate a session adding and removing permissions using
    // the AccessRightsAdministration instance just created

    // create 4 users, Alice, Bob, Carol and Dave
    User alice = new User("alice");
    User bob = new User("bob");
    User carol = new User("carol");
    User dave = new User("dave");

    // let us create 5 permission instances
    Permission adminPerm = new Permission("administrator");
    Permission createPerm = new Permission("create");
    Permission commentPerm = new Permission("comment");
    Permission votePerm = new Permission("vote");
    Permission browsePerm = new Permission("browse");

    // grant Alice admin permissions
    ara.addPermission(alice, adminPerm);

    // grant Bob create, comment and voting permissions
    ara.addPermission(bob, createPerm);
    ara.addPermission(bob, commentPerm);
    ara.addPermission(bob, votePerm);

    // grant Carol browsing permissions
    ara.addPermission(carol, browsePerm);

    // grant Dave browsing permissions
    ara.addPermission(dave, browsePerm);

    // remove permissions granted to Bob
    ara.removePermission(bob, createPerm);
    ara.removePermission(bob, commentPerm);
    ara.removePermission(bob, votePerm);
  }

}