/**
 * Copyright (c) 2007-2014 Kaazing Corporation. All rights reserved.
 * 
 * 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.kaazing.net.impl.auth;


import java.net.PasswordAuthentication;
import java.util.Map;
import java.util.concurrent.ConcurrentHashMap;
import java.util.logging.Logger;

import org.kaazing.gateway.client.util.auth.LoginHandlerProvider;
import org.kaazing.net.auth.BasicChallengeHandler;
import org.kaazing.net.auth.ChallengeRequest;
import org.kaazing.net.auth.ChallengeResponse;
import org.kaazing.net.auth.LoginHandler;

/**
 * Challenge handler for Basic authentication. See RFC 2617.
 */
public class DefaultBasicChallengeHandler extends BasicChallengeHandler implements LoginHandlerProvider {

// ------------------------------ FIELDS ------------------------------

    private static final String CLASS_NAME = DefaultBasicChallengeHandler.class.getName();
    private static final Logger LOG = Logger.getLogger(CLASS_NAME);

    private Map<String, LoginHandler> loginHandlersByRealm = new ConcurrentHashMap<String,LoginHandler>();

    @Override
    public void setRealmLoginHandler(String realm, LoginHandler loginHandler) {
        if ( realm == null) {
            throw new NullPointerException("realm");
        }
        if ( loginHandler == null ) {
            throw new NullPointerException("loginHandler");
        }

        loginHandlersByRealm.put(realm, loginHandler);
    }

    /**
     * If specified, this login handler is responsible for assisting in the
     * production of challenge responses.
     */
    private LoginHandler loginHandler;

    /**
     * Provide a login handler to be used in association with this challenge handler.
     * The login handler is used to assist in obtaining credentials to respond to challenge requests.
     *
     * @param loginHandler a login handler for credentials.
     */
    public BasicChallengeHandler setLoginHandler(LoginHandler loginHandler) {
        this.loginHandler = loginHandler;
        return this;
    }

    /**
     * Get the login handler associated with this challenge handler.
     * A login handler is used to assist in obtaining credentials to respond to challenge requests.
     *
     * @return a login handler to assist in providing credentials, or {@code null} if none has been established yet.
     */
    public LoginHandler getLoginHandler() {
        return loginHandler;
    }

    @Override
    public boolean canHandle(ChallengeRequest challengeRequest) {
        return challengeRequest != null &&
                "Basic".equals(challengeRequest.getAuthenticationScheme());
    }

    @Override
    public ChallengeResponse handle(ChallengeRequest challengeRequest) {

        LOG.entering(CLASS_NAME, "handle", new String[]{challengeRequest.getLocation(),
                                                        challengeRequest.getAuthenticationParameters()});

        if (challengeRequest.getLocation() != null) {



            // Start by using this generic Basic handler
            LoginHandler loginHandler = getLoginHandler();

            // Try to delegate to a realm-specific login handler if we can
            String realm = RealmUtils.getRealm(challengeRequest);
            if ( realm != null && loginHandlersByRealm.get(realm) != null) {
                loginHandler = loginHandlersByRealm.get(realm);
            }
            LOG.finest("BasicChallengeHandler.getResponse: login handler = " + loginHandler);
            if (loginHandler != null) {
                PasswordAuthentication creds = loginHandler.getCredentials();
                if (creds != null && creds.getUserName() != null && creds.getPassword() != null) {
                    return BasicChallengeResponseFactory.create(creds, this);
                }
            }
        }
        return null;
    }

}