/*
 * 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.guacamole.auth.header;

import com.google.inject.Inject;
import com.google.inject.Provider;
import javax.servlet.http.HttpServletRequest;
import org.apache.guacamole.GuacamoleException;
import org.apache.guacamole.net.auth.Credentials;
import org.apache.guacamole.net.auth.credentials.CredentialsInfo;
import org.apache.guacamole.net.auth.credentials.GuacamoleInvalidCredentialsException;
import org.apache.guacamole.auth.header.user.AuthenticatedUser;
import java.security.Principal;

/**
 * Service providing convenience functions for the HTTP Header
 * AuthenticationProvider implementation.
 *
 * @author Nick Couchman
 */
public class AuthenticationProviderService {

    /**
     * Service for retrieving header configuration information.
     */
    @Inject
    private ConfigurationService confService;

    /**
     * Provider for AuthenticatedUser objects.
     */
    @Inject
    private Provider<AuthenticatedUser> authenticatedUserProvider;

    /**
     * Returns an AuthenticatedUser representing the user authenticated by the
     * given credentials.
     *
     * @param credentials
     *     The credentials to use for authentication.
     *
     * @return
     *     An AuthenticatedUser representing the user authenticated by the
     *     given credentials.
     *
     * @throws GuacamoleException
     *     If an error occurs while authenticating the user, or if access is
     *     denied.
     */
    public AuthenticatedUser authenticateUser(Credentials credentials)
            throws GuacamoleException {

        // Pull HTTP header from request if present
        HttpServletRequest request = credentials.getRequest();
        if (request != null) {

            // Get the username from the header configured in guacamole.properties
            String username = request.getHeader(confService.getHttpAuthHeader());

            if (username != null) {
                AuthenticatedUser authenticatedUser = authenticatedUserProvider.get();
                authenticatedUser.init(username, credentials);
                return authenticatedUser;
            }

        }

        // Authentication not provided via header, yet, so we request it.
        throw new GuacamoleInvalidCredentialsException("Invalid login.", CredentialsInfo.USERNAME_PASSWORD);

    }

}