/*
    * Copyright (c) 2002-2014, Mairie de Paris
    * All rights reserved.
    *
    * Redistribution and use in source and binary forms, with or without
    * modification, are permitted provided that the following conditions
    * are met:
    *
    *  1. Redistributions of source code must retain the above copyright notice
   *     and the following disclaimer.
   *
   *  2. Redistributions in binary form must reproduce the above copyright notice
   *     and the following disclaimer in the documentation and/or other materials
   *     provided with the distribution.
   *
   *  3. Neither the name of 'Mairie de Paris' nor 'Lutece' nor the names of its
   *     contributors may be used to endorse or promote products derived from
   *     this software without specific prior written permission.
   *
   * THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS "AS IS"
   * AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
   * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
   * ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT HOLDERS OR CONTRIBUTORS BE
   * LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR
   * CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF
   * SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS
   * INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN
   * CONTRACT, STRICT LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE)
   * ARISING IN ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE
   * POSSIBILITY OF SUCH DAMAGE.
   *
   * License 1.0
   */
  package fr.paris.lutece.portal.service.security;
  
  import fr.paris.lutece.portal.service.datastore.DatastoreService;
  import fr.paris.lutece.portal.service.init.LuteceInitException;
  import fr.paris.lutece.portal.service.util.AppLogService;
  import fr.paris.lutece.portal.service.util.AppPropertiesService;
  import fr.paris.lutece.util.url.UrlItem;
  
  import java.security.Principal;
  
  import java.util.Collection;
  import java.util.Enumeration;
  
  import javax.security.auth.login.LoginException;
  
  import javax.servlet.http.HttpServletRequest;
  import javax.servlet.http.HttpSession;
  
  
  /**
   * This class provides a security service to register and check user
   * authentication
   */
  public final class SecurityService
  {
      /**
       * Session attribute that stores the LuteceUser object attached to the
       * session
       */
      private static final String ATTRIBUTE_LUTECE_USER = "lutece_user";
      private static final String PROPERTY_AUTHENTICATION_CLASS = "mylutece.authentication.class";
      private static final String PROPERTY_AUTHENTICATION_ENABLE = "mylutece.authentication.enable";
      private static final String PROPERTY_PORTAL_AUTHENTICATION_REQUIRED = "mylutece.portal.authentication.required";
      private static final String URL_INTERROGATIVE = "?";
      private static final String URL_AMPERSAND = "&";
      private static final String URL_EQUAL = "=";
      private static SecurityService _singleton = new SecurityService(  );
      private static LuteceAuthentication _authenticationService;
      private static boolean _bEnable;
  
      /**
       * Private constructor
       */
      private SecurityService(  )
      {
      }
  
      /**
       * Initialize service
       * @throws LuteceInitException if an error occurs
       */
      public static synchronized void init(  ) throws LuteceInitException
      {
          _bEnable = false;
  
          String strEnable = AppPropertiesService.getProperty( PROPERTY_AUTHENTICATION_ENABLE, "false" );
  
          if ( strEnable.equalsIgnoreCase( "true" ) )
          {
              _authenticationService = getPortalAuthentication(  );
  
              if ( _authenticationService != null )
              {
                  _bEnable = true;
              }
          } else
         {
             // in case authentication is disabled after having been enabled
             _authenticationService = null;
         }
     }
 
     /**
      * Get the unique instance of the Security Service
      * @return The instance
      */
     public static SecurityService getInstance(  )
     {
         return _singleton;
     }
 
     /**
      * Returns the authentication's activation : enable or disable
      * @return true if the authentication is active, false otherwise
      */
     public static boolean isAuthenticationEnable(  )
     {
         return _bEnable;
     }
 
     /**
      * Gets the LuteceUser attached to the current Http session
      * @param request The Http request
      * @return A LuteceUser object if found
      * @throws UserNotSignedException If there is no current user
      */
     public LuteceUser getRemoteUser( HttpServletRequest request )
         throws UserNotSignedException
     {
         LuteceUser user = getRegisteredUser( request );
 
         if ( user == null )
         {
             // User is not registered by Lutece, but it may be authenticated by another system
             if ( _authenticationService.isExternalAuthentication(  ) ||
                     _authenticationService.isMultiAuthenticationSupported(  ) )
             {
                 user = _authenticationService.getHttpAuthenticatedUser( request );
 
                 if ( ( user == null ) && isPortalAuthenticationRequired(  ) )
                 {
                     throw new UserNotSignedException(  );
                 }
 
                 registerUser( request, user );
             }
             else
             {
                 throw new UserNotSignedException(  );
             }
         }
 
         return user;
     }
 
     /**
      * Returns the user's principal
      * @param request The HTTP request
      * @return The user's principal
      * @throws UserNotSignedException The UserNotSignedException
      */
     public Principal getUserPrincipal( HttpServletRequest request )
         throws UserNotSignedException
     {
         return getRemoteUser( request );
     }
 
     /**
      * Checks if the user is associated to a given role
      * @param request The Http request
      * @param strRole The Role name
      * @return Returns true if the user is associated to the given role
      */
     public boolean isUserInRole( HttpServletRequest request, String strRole )
     {
         LuteceUser user;
 
         try
         {
             user = getRemoteUser( request );
         }
         catch ( UserNotSignedException e )
         {
             return false;
         }
 
         return _authenticationService.isUserInRole( user, request, strRole );
     }
 
     /**
      * get all roles for this user : - user's roles - user's groups roles
      *
      * @param user The user
      * @return Array of roles
      */
     public String[] getRolesByUser( LuteceUser user )
     {
         return _authenticationService.getRolesByUser( user );
     }
 
     /**
      * Checks user's login with the Authentication service.
      * @param request The Http request
      * @param strUserName The user's login
      * @param strPassword The user's password
      * @throws LoginException The LoginException
      * @throws LoginRedirectException if redirect exception
      */
     public void loginUser( HttpServletRequest request, final String strUserName, final String strPassword )
         throws LoginException, LoginRedirectException
     {
         LuteceUser user = _authenticationService.login( strUserName, strPassword, request );
         _authenticationService.updateDateLastLogin( user, request );
 
         if ( _authenticationService.findResetPassword( request, strUserName ) )
         {
             String redirect = _authenticationService.getResetPasswordPageUrl( request );
             registerUser( request, user );
             throw new LoginRedirectException( redirect );
         }
 
         registerUser( request, user );
     }
 
     /**
      * Logout the user
      * @param request The HTTP request
      */
     public void logoutUser( HttpServletRequest request )
     {
         LuteceUser user;
 
         try
         {
             user = getRemoteUser( request );
         }
         catch ( UserNotSignedException e )
         {
             return;
         }
 
         _authenticationService.logout( user );
         unregisterUser( request );
     }
 
     /**
      * Retrieves the portal authentication service configured in the
      * config.properties
      * @return A PortalAuthentication object
      * @throws LuteceInitException If an error occurred
      */
     private static LuteceAuthentication getPortalAuthentication(  )
         throws LuteceInitException
     {
         String strAuthenticationClass = AppPropertiesService.getProperty( PROPERTY_AUTHENTICATION_CLASS );
         LuteceAuthentication authentication = null;
 
         if ( ( strAuthenticationClass != null ) && !strAuthenticationClass.equals( "" ) )
         {
             try
             {
                 authentication = (LuteceAuthentication) Class.forName( strAuthenticationClass ).newInstance(  );
                 AppLogService.info( "Authentication service loaded : " + authentication.getAuthServiceName(  ) );
             }
             catch ( InstantiationException e )
             {
                 throw new LuteceInitException( "Error instantiating Authentication Class", e );
             }
             catch ( IllegalAccessException e )
             {
                 throw new LuteceInitException( "Error instantiating Authentication Class", e );
             }
             catch ( ClassNotFoundException e )
             {
                 throw new LuteceInitException( "Error instantiating Authentication Class", e );
             }
         }
 
         return authentication;
     }
 
     /**
      * Register the user in the Http session
      * @param request The Http request
      * @param user The current user
      */
     public void registerUser( HttpServletRequest request, LuteceUser user )
     {
         HttpSession session = request.getSession( true );
         session.setAttribute( ATTRIBUTE_LUTECE_USER, user );
     }
 
     /**
      * Unregister the user in the Http session
      * @param request The Http request
      */
     public void unregisterUser( HttpServletRequest request )
     {
         HttpSession session = request.getSession( true );
         session.removeAttribute( ATTRIBUTE_LUTECE_USER );
     }
 
     /**
      * Gets the Lutece user registered in the Http session
      * @param request The HTTP request
      * @return The User registered or null if the user has not been registered
      */
     public LuteceUser getRegisteredUser( HttpServletRequest request )
     {
         HttpSession session = ( request != null ) ? request.getSession( false ) : null;
 
         if ( session != null )
         {
             return (LuteceUser) session.getAttribute( ATTRIBUTE_LUTECE_USER );
         }
 
         return null;
     }
 
     /**
      * Returns the authentication type : External or Lutece portal based
      * @return true if the user is already authenticated or false if it needs to
      *         login.
      */
     public boolean isExternalAuthentication(  )
     {
         return _authenticationService.isExternalAuthentication(  );
     }
 
     /**
      * Returns the Login page URL of the Authentication Service
      * @return The URL
      */
     public String getLoginPageUrl(  )
     {
         return _authenticationService.getLoginPageUrl(  );
     }
 
     /**
      * Returns the DoLogin URL of the Authentication Service
      * @return The URL
      */
     public String getDoLoginUrl(  )
     {
         return _authenticationService.getDoLoginUrl(  );
     }
 
     /**
      * Returns the DoLogout URL of the Authentication Service
      * @return The URL
      */
     public String getDoLogoutUrl(  )
     {
         return _authenticationService.getDoLogoutUrl(  );
     }
 
     /**
      * Returns the new account page URL of the Authentication Service
      * @return The URL
      */
     public String getNewAccountPageUrl(  )
     {
         return _authenticationService.getNewAccountPageUrl(  );
     }
 
     /**
      * Returns the view account page URL of the Authentication Service
      * @return The URL
      */
     public String getViewAccountPageUrl(  )
     {
         return _authenticationService.getViewAccountPageUrl(  );
     }
 
     /**
      * Returns the lost password URL of the Authentication Service
      * @return The URL
      */
     public String getLostPasswordPageUrl(  )
     {
         return _authenticationService.getLostPasswordPageUrl(  );
     }
 
     // Added in v1.3
 
     /**
      * Returns the access denied template
      * @return The template
      */
     public String getAccessDeniedTemplate(  )
     {
         return _authenticationService.getAccessDeniedTemplate(  );
     }
 
     /**
      * Returns the access controled template
      * @return The template
      */
     public String getAccessControledTemplate(  )
     {
         return _authenticationService.getAccessControledTemplate(  );
     }
 
     /**
      * Returns whether or not the portal needs authentication
      * @return true if the access needs authentication, otherwise
      * @since 1.3.1
      */
     public boolean isPortalAuthenticationRequired(  )
     {
         String strAuthenticationRequired = DatastoreService.getDataValue( PROPERTY_PORTAL_AUTHENTICATION_REQUIRED,
                 "false" );
 
         return strAuthenticationRequired.equals( "true" );
     }
 
     /**
      * Checks user's login with the Authentication service. Used during remote
      * authentication validation We don't have to put user informations in
      * session, since it is only used in external
      * applications
      * @param request the request
      * @param strUserName The user's login
      * @param strPassword The user's password
      * @return user's informations
      * @throws LoginException The LoginException
      * @throws LoginRedirectException The redirect exception
      */
     public LuteceUser remoteLoginUser( final HttpServletRequest request, final String strUserName,
         final String strPassword ) throws LoginException, LoginRedirectException
     {
         LuteceUser user = _authenticationService.login( strUserName, strPassword, request );
 
         return user;
     }
 
     /**
      * Return true if the requested url is equal to LoginUrl
      * @param request The Http servlet request
      * @return True if the requested url is equal to LoginUrl, false else.
      */
     public boolean isLoginUrl( HttpServletRequest request )
     {
         if ( ( getLoginPageUrl(  ) == null ) || ( request == null ) )
         {
             return false;
         }
 
         String strRequestUrl = request.getRequestURI(  );
         UrlItem url = new UrlItem( strRequestUrl );
 
         for ( String strParamValueLoginPageUrl : getLoginPageUrl(  )
                                                      .substring( getLoginPageUrl(  ).indexOf( URL_INTERROGATIVE ) + 1 )
                                                      .split( URL_AMPERSAND ) )
         {
             String[] arrayParamValueLoginPageUrl = strParamValueLoginPageUrl.split( URL_EQUAL );
             Enumeration<String> enumParams = request.getParameterNames(  );
 
             while ( enumParams.hasMoreElements(  ) )
             {
                 String strRequestParameter = (String) enumParams.nextElement(  );
 
                 if ( arrayParamValueLoginPageUrl[0].equals( strRequestParameter ) &&
                         arrayParamValueLoginPageUrl[1].equals( request.getParameter( strRequestParameter ) ) )
                 {
                     url.addParameter( strRequestParameter, request.getParameter( strRequestParameter ) );
                 }
             }
         }
 
         if ( url.getUrl(  ).endsWith( getLoginPageUrl(  ) ) && !getLoginPageUrl(  ).equals( "" ) )
         {
             return true;
         }
 
         return false;
     }
 
     /**
      * Tells whether or not the authentication service can provide a list of all
      * its users
      * @return true if the service can return a users list
      */
     boolean isUsersListAvailable(  )
     {
         return _authenticationService.isUsersListAvailable(  );
     }
 
     /**
      * Returns all users managed by the authentication service if this feature
      * is available.
      * @return A collection of Lutece users or null if the service doesn't
      *         provide a users list
      */
     public Collection<LuteceUser> getUsers(  )
     {
         return _authenticationService.getUsers(  );
     }
 
     /**
      * Returns user managed by the authentication service if this feature is
      * available.
      * @param strUserLogin the user login
      * @return A Lutece user or null if the service doesn't provide LuteceUser
      */
     public LuteceUser getUser( String strUserLogin )
     {
         return _authenticationService.getUser( strUserLogin );
     }
 
     /**
      * <b>true</b> when the service provides multi authentication support
      * @return <code>true</code> if multi authentication is supported,
      *         <code>false</code> otherwise.
      */
     public boolean isMultiAuthenticationSupported(  )
     {
         return _authenticationService.isMultiAuthenticationSupported(  );
     }
 
     /**
      * Gets the actual authentication implementation
      * @return {@link LuteceAuthentication} implementation
      */
     public LuteceAuthentication getAuthenticationService(  )
     {
         return _authenticationService;
     }
 }