/*
 *  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.isis.applib.services.session;

import java.util.Date;

import org.apache.isis.applib.annotation.Programmatic;

/**
 * Similar to the {@link org.apache.isis.applib.services.audit.AuditerService}, this defines an API to track
 * the status of the current sessions (&quot;users logged on&quot;) on the system.
 */
public interface SessionLoggingService {

    public enum Type {
        LOGIN,
        LOGOUT
    }

    public enum CausedBy {
        USER,
        SESSION_EXPIRATION,
        RESTART
    }

    @Programmatic
    void log(Type type, String username, Date date, CausedBy causedBy, String sessionId);


    public static class Stderr implements SessionLoggingService {

        @Override
        public void log(final Type type, final String username, final Date date, final CausedBy causedBy, final String sessionId) {
            final StringBuilder logMessage = new StringBuilder();
            logMessage.append("User '").append(username);
            logMessage.append("' with sessionId '").append(sessionId)
            .append("' has logged ");
            if (type == Type.LOGIN) {
                logMessage.append("in");
            } else {
                logMessage.append("out");
            }
            logMessage.append(" at '").append(date).append("'.");
            if (causedBy == CausedBy.SESSION_EXPIRATION) {
                logMessage.append("Cause: session expiration");
            }
            System.err.println(logMessage);
        }
    }
}
