/*
 * ====================================================================
 *
 *  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.
 * ====================================================================
 *
 * This software consists of voluntary contributions made by many
 * individuals on behalf of the Apache Software Foundation.  For more
 * information on the Apache Software Foundation, please see
 * <http://www.apache.org/>.
 *
 */

package ch.boye.httpclientandroidlib.impl.client;

import java.security.Principal;

import javax.net.ssl.SSLSession;

import ch.boye.httpclientandroidlib.annotation.Immutable;

import ch.boye.httpclientandroidlib.auth.AuthScheme;
import ch.boye.httpclientandroidlib.auth.AuthState;
import ch.boye.httpclientandroidlib.auth.Credentials;
import ch.boye.httpclientandroidlib.client.UserTokenHandler;
import ch.boye.httpclientandroidlib.client.protocol.ClientContext;
import ch.boye.httpclientandroidlib.conn.HttpRoutedConnection;
import ch.boye.httpclientandroidlib.protocol.ExecutionContext;
import ch.boye.httpclientandroidlib.protocol.HttpContext;

/**
 * Default implementation of {@link UserTokenHandler}. This class will use
 * an instance of {@link Principal} as a state object for HTTP connections,
 * if it can be obtained from the given execution context. This helps ensure
 * persistent connections created with a particular user identity within
 * a particular security context can be reused by the same user only.
 * <p>
 * DefaultUserTokenHandler will use the user principle of connection
 * based authentication schemes such as NTLM or that of the SSL session
 * with the client authentication turned on. If both are unavailable,
 * <code>null</code> token will be returned.
 *
 * @since 4.0
 */
@Immutable
public class DefaultUserTokenHandler implements UserTokenHandler {

    public Object getUserToken(final HttpContext context) {

        Principal userPrincipal = null;

        AuthState targetAuthState = (AuthState) context.getAttribute(
                ClientContext.TARGET_AUTH_STATE);
        if (targetAuthState != null) {
            userPrincipal = getAuthPrincipal(targetAuthState);
            if (userPrincipal == null) {
                AuthState proxyAuthState = (AuthState) context.getAttribute(
                        ClientContext.PROXY_AUTH_STATE);
                userPrincipal = getAuthPrincipal(proxyAuthState);
            }
        }

        if (userPrincipal == null) {
            HttpRoutedConnection conn = (HttpRoutedConnection) context.getAttribute(
                    ExecutionContext.HTTP_CONNECTION);
            if (conn.isOpen()) {
                SSLSession sslsession = conn.getSSLSession();
                if (sslsession != null) {
                    userPrincipal = sslsession.getLocalPrincipal();
                }
            }
        }

        return userPrincipal;
    }

    private static Principal getAuthPrincipal(final AuthState authState) {
        AuthScheme scheme = authState.getAuthScheme();
        if (scheme != null && scheme.isComplete() && scheme.isConnectionBased()) {
            Credentials creds = authState.getCredentials();
            if (creds != null) {
                return creds.getUserPrincipal();
            }
        }
        return null;
    }

}
