/*
 * 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.catalina.cluster.authenticator;


import java.security.Principal;

import org.apache.catalina.Container;
import org.apache.catalina.Cluster;
import org.apache.catalina.Engine;
import org.apache.catalina.Host;
import org.apache.catalina.LifecycleException;
import org.apache.catalina.Manager;
import org.apache.catalina.Session;
import org.apache.catalina.authenticator.SingleSignOn;
import org.apache.catalina.authenticator.SingleSignOnEntry;
import org.apache.catalina.cluster.CatalinaCluster;
import org.apache.catalina.cluster.ClusterManager;
import org.apache.catalina.cluster.ClusterValve;

/**
 * A <strong>Valve</strong> that supports a "single sign on" user experience on
 * each nodes of a cluster, where the security identity of a user who successfully
 * authenticates to one web application is propogated to other web applications and
 * to other nodes cluster in the same security domain.  For successful use, the following
 * requirements must be met:
 * <ul>
 * <li>This Valve must be configured on the Container that represents a
 *     virtual host (typically an implementation of <code>Host</code>).</li>
 * <li>The <code>Realm</code> that contains the shared user and role
 *     information must be configured on the same Container (or a higher
 *     one), and not overridden at the web application level.</li>
 * <li>The web applications themselves must use one of the standard
 *     Authenticators found in the
 *     <code>org.apache.catalina.authenticator</code> package.</li>
 * </ul>
 *
 * @author Fabien Carrion
 * @author Peter Rossbach
 * @version $Revision$ $Date$
 */

public class ClusterSingleSignOn
    extends SingleSignOn implements ClusterValve {

    // ----------------------------------------------------- Instance Variables

    /**
     * Descriptive information about this Valve implementation.
     */
    protected static String info =
        "org.apache.catalina.cluster.authenticator.ClusterSingleSignOn/1.0";

    protected int messageNumber = 0;

    private ClusterSingleSignOnListener clusterSSOListener = null;

    // ------------------------------------------------------------- Properties

    private CatalinaCluster cluster = null;

    /**
     * Return descriptive information about this Valve implementation.
     */
    public String getInfo() {
        return (info);
    }

    public CatalinaCluster getCluster() {
        return cluster;
    }

    public void setCluster(CatalinaCluster cluster) {
        this.cluster = cluster;
    }

    // ------------------------------------------------------ Lifecycle Methods

    /**
     * Prepare for the beginning of active use of the public methods of this
     * component.  This method should be called after <code>configure()</code>,
     * and before any of the public methods of the component are utilized.
     *
     * @exception LifecycleException if this component detects a fatal error
     *  that prevents this component from being used
     */
    public void start() throws LifecycleException {
        super.start();
        clusterSSOListener = new ClusterSingleSignOnListener();
        clusterSSOListener.setClusterSSO(this);
        // Load the cluster component, if any
        try {
            //the channel is already running
            Cluster cluster = getCluster();
            // stop remove cluster binding
            if(cluster == null) {
                Container host = getContainer();
                if(host != null && host instanceof Host) {
                    cluster = host.getCluster();
                    if(cluster != null && cluster instanceof CatalinaCluster) {
                        setCluster((CatalinaCluster) cluster);
                    } else {
                        Container engine = host.getParent();
                        if(engine != null && engine instanceof Engine) {
                            cluster = engine.getCluster();
                            if(cluster != null && cluster instanceof CatalinaCluster) {
                                setCluster((CatalinaCluster) cluster);
                            }
                        } else {
                            cluster = null;
                        }
                    }
                }
            }
            if (cluster == null) {
                throw new LifecycleException
                ("There is no Cluster for ClusterSingleSignOn");
            }
            ((CatalinaCluster)cluster).addClusterListener(clusterSSOListener);
        } catch (Throwable t) {
            throw new LifecycleException
            ("ClusterSingleSignOn exception during clusterLoad " + t);
        }
    }

    /**
     * Gracefully terminate the active use of the public methods of this
     * component.  This method should be the last one called on a given
     * instance of this component.
     *
     * @exception LifecycleException if this component detects a fatal error
     *  that needs to be reported
     */
    public void stop() throws LifecycleException {
        super.stop();
        if (getCluster() != null && getCluster() instanceof CatalinaCluster) {
            getCluster().removeClusterListener(clusterSSOListener);
        }
    }

    // --------------------------------------------------------- Public Methods

    /**
     * Return a String rendering of this object.
     */
    public String toString() {
        StringBuffer sb = new StringBuffer("ClusterSingleSignOn[");
        if (container == null )
            sb.append("Container is null");
        else
            sb.append(container.getName());
        sb.append("]");
        return (sb.toString());
    }

    // ------------------------------------------------------ Protected Methods

    /**
     * Notify the cluster of the addition of a Session to
     * an SSO session and associate the specified single
     * sign on identifier with the specified Session on the
     * local node.
     *
     * @param ssoId Single sign on identifier
     * @param session Session to be associated
     */
    protected void associate(String ssoId, Session session) {
        boolean addSession = true ;
        SingleSignOnEntry entry = lookup(ssoId);
        if (entry != null) {
            addSession = !entry.sessionExists(session);
        }
        if(addSession) {
            sendSSOId(ssoId,session,SingleSignOnMessage.ADD_SESSION) ;
            associateLocal(ssoId, session);
        }
    }

    protected void associateLocal(String ssoId, Session session) {
        super.associate(ssoId, session);
    }

    /**
     * Notify the cluster of the removal of a Session from an
     * SSO session and deregister the specified session. If it is the last
     * session, then also get rid of the single sign on identifier on the
     * local node.
     *
     * @param ssoId Single sign on identifier
     * @param session Session to be deregistered
     */
    protected void deregister(String ssoId, Session session) {
       sendSSOId(ssoId,session,SingleSignOnMessage.DEREGISTER_SESSION) ;
       deregisterLocal(ssoId, session);
    }

    protected void deregisterLocal(String ssoId, Session session) {
        super.deregister(ssoId, session);
    }

    /**
     * Notifies the cluster that a single sign on session
     * has been terminated due to a user logout, deregister
     * the specified single sign on identifier, and invalidate
     * any associated sessions on the local node.
     *
     * @param ssoId Single sign on identifier to deregister
     */
    protected void deregister(String ssoId) {
        sendSSOId(ssoId,null,SingleSignOnMessage.LOGOUT_SESSION) ;
        deregisterLocal(ssoId);
    }

    protected void deregisterLocal(String ssoId) {
        super.deregister(ssoId);
    }

    /**
     * Notifies the cluster of the creation of a new SSO entry
     * and register the specified Principal as being associated
     * with the specified value for the single sign on identifier.
     *
     * @param ssoId Single sign on identifier to register
     * @param principal Associated user principal that is identified
     * @param authType Authentication type used to authenticate this
     *  user principal
     * @param username Username used to authenticate this user
     * @param password Password used to authenticate this user
     */
    protected void register(String ssoId, Principal principal, String authType,
                  String username, String password) {
        sendSSOIdWithAuth(ssoId,
                authType, username, password,
                SingleSignOnMessage.REGISTER_SESSION);
     	registerLocal(ssoId, principal, authType, username, password);
    }

    protected void registerLocal(String ssoId, Principal principal, String authType,
                  String username, String password) {
        super.register(ssoId, principal, authType, username, password);
    }

    /**
     * Notifies the cluster of an update of the security credentials
     * associated with an SSO session. Updates any <code>SingleSignOnEntry</code>
     * found under key <code>ssoId</code> with the given authentication data.
     * <p>
     * The purpose of this method is to allow an SSO entry that was
     * established without a username/password combination (i.e. established
     * following DIGEST or CLIENT-CERT authentication) to be updated with
     * a username and password if one becomes available through a subsequent
     * BASIC or FORM authentication.  The SSO entry will then be usable for
     * reauthentication.
     * <p>
     * <b>NOTE:</b> Only updates the SSO entry if a call to
     * <code>SingleSignOnEntry.getCanReauthenticate()</code> returns
     * <code>false</code>; otherwise, it is assumed that the SSO entry already
     * has sufficient information to allow reauthentication and that no update
     * is needed.
     *
     * @param ssoId     identifier of Single sign to be updated
     * @param principal the <code>Principal</code> returned by the latest
     *                  call to <code>Realm.authenticate</code>.
     * @param authType  the type of authenticator used (BASIC, CLIENT-CERT,
     *                  DIGEST or FORM)
     * @param username  the username (if any) used for the authentication
     * @param password  the password (if any) used for the authentication
     */
    protected void update(String ssoId, Principal principal, String authType,
                          String username, String password) {
        sendSSOIdWithAuth(ssoId,
                authType, username, password,
                SingleSignOnMessage.UPDATE_SESSION);
        updateLocal(ssoId, principal, authType, username, password);
    }

    protected void updateLocal(String ssoId, Principal principal, String authType,
                          String username, String password) {
        super.update(ssoId, principal, authType, username, password);
    }

    /**
     * Remove a single Session from a SingleSignOn and notify the cluster
     * of the removal. Called when a session is timed out and no longer active.
     *
     * @param ssoId Single sign on identifier from which to remove the session.
     * @param session the session to be removed.
     */
    protected void removeSession(String ssoId, Session session) {
        sendSSOId(ssoId,session,SingleSignOnMessage.REMOVE_SESSION) ;
        removeSessionLocal(ssoId, session);
    }

    protected void removeSessionLocal(String ssoId, Session session) {
        super.removeSession(ssoId, session);
    }
    
    
    /**
     * Create SingleSignOnMessage with session informations and send to other domain members.
     * @param ssoId     identifier of Single sign to be updated
     * @param session   the session to be handle or null.
     * @param action    SSO Action type
     */
    protected void sendSSOId(String ssoId, Session session, int action) {
        if (cluster != null) {
            messageNumber++;
            String sessionId = null ;
            if(session != null)
                sessionId = session.getId() ;
            SingleSignOnMessage msg =
                new SingleSignOnMessage(cluster.getLocalMember(),
                        ssoId, sessionId);
            if(session != null) {
                Manager mgr = session.getManager();
                if ((mgr != null) && (mgr instanceof ClusterManager))
                    msg.setContextName(((ClusterManager) mgr).getName());
            }
            send(msg,action);
        }
    }

    /**
     * Create SingleSignOnMessage with auth informations and send to other domain members.
     * @param ssoId     identifier of Single sign to be updated
     * @param authType  the type of authenticator used (BASIC, CLIENT-CERT,
     *                  DIGEST or FORM)
     * @param username  the username (if any) used for the authentication
     * @param password  the password (if any) used for the authentication
     * @param action    SSO Action type
     */
    protected void sendSSOIdWithAuth(String ssoId,String authType,
            String username, String password, int action) {
        if (cluster != null) {
            messageNumber++;
            SingleSignOnMessage msg =
                new SingleSignOnMessage(cluster.getLocalMember(),
                        ssoId, null);
            msg.setAuthType(authType);
            msg.setUsername(username);
            msg.setPassword(password);
            send(msg,action);
        }
    }

    /**
     * Send SingleSignOnMessage to other domain members.
     * @param msg     SingleSignOnMessage
     * @param action  SSO Action type
     */
    protected void send(SingleSignOnMessage msg, int action) {
        msg.setAction(action);
        cluster.sendClusterDomain(msg);
        if (containerLog.isDebugEnabled())
            containerLog.debug("SingleSignOnMessage Send with action "
                + action);
    }

}