/*
 * 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.sshd.server.jaas;

import javax.security.auth.Subject;
import javax.security.auth.callback.Callback;
import javax.security.auth.callback.NameCallback;
import javax.security.auth.callback.PasswordCallback;
import javax.security.auth.callback.UnsupportedCallbackException;
import javax.security.auth.login.LoginContext;

import org.apache.sshd.common.util.logging.AbstractLoggingBean;
import org.apache.sshd.server.auth.password.PasswordAuthenticator;
import org.apache.sshd.server.session.ServerSession;

/**
 * TODO Add javadoc
 *
 * @author <a href="mailto:dev@mina.apache.org">Apache MINA SSHD Project</a>
 */
public class JaasPasswordAuthenticator extends AbstractLoggingBean implements PasswordAuthenticator {

    private String domain;

    public JaasPasswordAuthenticator() {
        this(null);
    }

    public JaasPasswordAuthenticator(String domain) {
        this.domain = domain;
    }

    public String getDomain() {
        return domain;
    }

    public void setDomain(String domain) {
        this.domain = domain;
    }

    @Override
    public boolean authenticate(String username, String password, ServerSession session) {
        return authenticate(username, password);
    }

    public boolean authenticate(final String username, final String password) {
        try {
            Subject subject = new Subject();
            LoginContext loginContext = new LoginContext(domain, subject, callbacks -> {
                for (Callback callback : callbacks) {
                    if (callback instanceof NameCallback) {
                        ((NameCallback) callback).setName(username);
                    } else if (callback instanceof PasswordCallback) {
                        ((PasswordCallback) callback).setPassword(password.toCharArray());
                    } else {
                        throw new UnsupportedCallbackException(callback);
                    }
                }
            });
            loginContext.login();
            loginContext.logout();
            return true;
        } catch (Exception e) {
            log.error("Authentication failed with error", e);
            return false;
        }
    }

}
