/*
 * 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.ranger.solr.krb;

import javax.security.auth.login.LoginException;
import java.security.PrivilegedAction;
import java.security.PrivilegedActionException;
import java.security.PrivilegedExceptionAction;

/**
 * A keytab-based user that can login/logout and perform actions as the given user.
 */
public interface KerberosUser {

    /**
     * Performs a login for the given user.
     *
     * @throws LoginException if the login fails
     */
    void login() throws LoginException;

    /**
     * Performs a logout for the given user.
     *
     * @throws LoginException if the logout fails
     */
    void logout() throws LoginException;

    /**
     * Executes the given action as the given user.
     *
     * @param action the action to execute
     * @param <T> the type of response
     * @return the result of the action
     * @throws IllegalStateException if attempting to execute an action before performing a login
     */
    <T> T doAs(PrivilegedAction<T> action) throws IllegalStateException;

    /**
     * Executes the given action as the given user.
     *
     * @param action the action to execute
     * @param <T> the type of response
     * @return the result of the action
     * @throws IllegalStateException if attempting to execute an action before performing a login
     * @throws PrivilegedActionException if the action itself threw an exception
     */
    <T> T doAs(PrivilegedExceptionAction<T> action)
            throws IllegalStateException, PrivilegedActionException;

    /**
     * Performs a re-login if the TGT is close to expiration.
     *
     * @return true if a re-login was performed, false otherwise
     * @throws LoginException if the re-login fails
     */
    boolean checkTGTAndRelogin() throws LoginException;

    /**
     * @return true if this user is currently logged in, false otherwise
     */
    boolean isLoggedIn();

    /**
     * @return the principal for this user
     */
    String getPrincipal();

}

