/*
 * Copyright (c) 2008-2014 MongoDB, Inc.
 *
 * Licensed 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 com.mongodb.connection;

import com.mongodb.MongoCredential;
import com.mongodb.MongoSecurityException;
import com.mongodb.ServerAddress;

import javax.security.auth.callback.Callback;
import javax.security.auth.callback.CallbackHandler;
import javax.security.auth.callback.NameCallback;
import javax.security.auth.callback.PasswordCallback;
import javax.security.auth.callback.UnsupportedCallbackException;
import javax.security.sasl.Sasl;
import javax.security.sasl.SaslClient;
import javax.security.sasl.SaslException;
import java.io.IOException;

import static com.mongodb.AuthenticationMechanism.PLAIN;
import static com.mongodb.assertions.Assertions.isTrue;

class PlainAuthenticator extends SaslAuthenticator {
    private static final String DEFAULT_PROTOCOL = "mongodb";

    PlainAuthenticator(final MongoCredential credential) {
        super(credential);
    }

    @Override
    public String getMechanismName() {
        return PLAIN.getMechanismName();
    }

    @Override
    protected SaslClient createSaslClient(final ServerAddress serverAddress) {
        final MongoCredential credential = getCredential();
        isTrue("mechanism is PLAIN", credential.getAuthenticationMechanism() == PLAIN);
        try {
            return Sasl.createSaslClient(new String[]{PLAIN.getMechanismName()},
                                         credential.getUserName(),
                                         DEFAULT_PROTOCOL,
                                         serverAddress.getHost(),
                                         null,
                                         new CallbackHandler() {
                                             @Override
                                             public void handle(final Callback[] callbacks)
                                                 throws IOException, UnsupportedCallbackException {
                                                 for (final Callback callback : callbacks) {
                                                     if (callback instanceof PasswordCallback) {
                                                         ((PasswordCallback) callback).setPassword(credential.getPassword());
                                                     } else if (callback instanceof NameCallback) {
                                                         ((NameCallback) callback).setName(credential.getUserName());
                                                     }
                                                 }
                                             }
                                         });
        } catch (SaslException e) {
            throw new MongoSecurityException(credential, "Exception initializing SASL client", e);
        }
    }
}