/*-
 * ============LICENSE_START=======================================================
 * ONAP-PAP-REST
 * ================================================================================
 * Copyright (C) 2017-2019 AT&T Intellectual Property. All rights reserved.
 * ================================================================================
 * 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.
 * ============LICENSE_END=========================================================
 */

package org.onap.policy.pap.xacml.restAuth;

import com.att.research.xacml.util.XACMLProperties;
import java.nio.charset.StandardCharsets;
import java.util.Base64;
import java.util.StringTokenizer;
import org.onap.policy.common.logging.eelf.MessageCodes;
import org.onap.policy.common.logging.eelf.PolicyLogger;
import org.onap.policy.rest.XACMLRestProperties;
import org.onap.policy.utils.PeCryptoUtils;

public class AuthenticationService {
    private String papId = XACMLProperties.getProperty(XACMLRestProperties.PROP_PAP_USERID);
    private String papPass = null;

    /**
     * Authenticate.
     *
     * @param authCredentials the auth credentials
     * @return true, if successful
     */
    public boolean authenticate(String authCredentials) {

        if (null == authCredentials) {
            return false;
        }
        // header value format will be "Basic encodedstring" for Basic authentication.
        final String encodedUserPassword = authCredentials.replaceFirst("Basic" + " ", "");
        String usernameAndPassword = null;

        try {
            String secretKey = XACMLProperties.getProperty(XACMLRestProperties.PROP_AES_KEY);
            PeCryptoUtils.initAesKey(secretKey);
            papPass = PeCryptoUtils.decrypt(XACMLProperties.getProperty(XACMLRestProperties.PROP_PAP_PASS));
        } catch (Exception e) {
            PolicyLogger.error(e);
        }

        try {
            byte[] decodedBytes = Base64.getDecoder().decode(encodedUserPassword);
            usernameAndPassword = new String(decodedBytes, StandardCharsets.UTF_8);
        } catch (Exception e) {
            PolicyLogger.error(MessageCodes.ERROR_SYSTEM_ERROR, e, "AuthenticationService",
                    "Exception decoding username and password");
            return false;
        }
        try {
            final StringTokenizer tokenizer = new StringTokenizer(usernameAndPassword, ":");
            final String username = tokenizer.nextToken();
            final String password = tokenizer.nextToken();

            return papId.equals(username) && papPass.equals(password);
        } catch (Exception e) {
            PolicyLogger.error(MessageCodes.ERROR_SYSTEM_ERROR, e, "AuthenticationService",
                    "Exception authenticating user");
            return false;
        }
    }

}