/*
 * SPDX-License-Identifier: Apache-2.0
 *
 * The OpenSearch Contributors require contributions made to
 * this file be licensed under the Apache-2.0 license or a
 * compatible open source license.
 */

/*
 * Licensed to Elasticsearch under one or more contributor
 * license agreements. See the NOTICE file distributed with
 * this work for additional information regarding copyright
 * ownership. Elasticsearch 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.
 */
/*
 * Modifications Copyright OpenSearch Contributors. See
 * GitHub history for details.
 */

package fixture.s3;

import com.sun.net.httpserver.HttpHandler;
import org.opensearch.core.rest.RestStatus;

import java.nio.charset.StandardCharsets;
import java.time.ZonedDateTime;
import java.time.format.DateTimeFormatter;
import java.util.Objects;

public class S3HttpFixtureWithEC2 extends S3HttpFixtureWithSessionToken {

    private static final String EC2_PATH = "/latest/meta-data/iam/security-credentials/";
    private static final String EC2_PROFILE = "ec2Profile";

    S3HttpFixtureWithEC2(final String[] args) throws Exception {
        super(args);
    }

    @Override
    protected HttpHandler createHandler(final String[] args) {
        final String ec2AccessKey = Objects.requireNonNull(args[4]);
        final String ec2SessionToken = Objects.requireNonNull(args[5], "session token is missing");
        final HttpHandler delegate = super.createHandler(args);

        return exchange -> {
            final String path = exchange.getRequestURI().getPath();
            // http://docs.aws.amazon.com/AWSEC2/latest/UserGuide/iam-roles-for-amazon-ec2.html
            if ("GET".equals(exchange.getRequestMethod()) && path.startsWith(EC2_PATH)) {
                if (path.equals(EC2_PATH)) {
                    final byte[] response = EC2_PROFILE.getBytes(StandardCharsets.UTF_8);
                    exchange.getResponseHeaders().add("Content-Type", "text/plain");
                    exchange.sendResponseHeaders(RestStatus.OK.getStatus(), response.length);
                    exchange.getResponseBody().write(response);
                    exchange.close();
                    return;

                } else if (path.equals(EC2_PATH + EC2_PROFILE)) {
                    final byte[] response = buildCredentialResponse(ec2AccessKey, ec2SessionToken).getBytes(StandardCharsets.UTF_8);
                    exchange.getResponseHeaders().add("Content-Type", "application/json");
                    exchange.sendResponseHeaders(RestStatus.OK.getStatus(), response.length);
                    exchange.getResponseBody().write(response);
                    exchange.close();
                    return;
                }

                final byte[] response = "unknown profile".getBytes(StandardCharsets.UTF_8);
                exchange.getResponseHeaders().add("Content-Type", "text/plain");
                exchange.sendResponseHeaders(RestStatus.NOT_FOUND.getStatus(), response.length);
                exchange.getResponseBody().write(response);
                exchange.close();
                return;

            }
            delegate.handle(exchange);
        };
    }

    protected String buildCredentialResponse(final String ec2AccessKey, final String ec2SessionToken) {
        return "{"
            + "\"AccessKeyId\": \"" + ec2AccessKey + "\","
            + "\"Expiration\": \"" + ZonedDateTime.now().plusDays(1L).format(DateTimeFormatter.ISO_DATE_TIME) + "\","
            + "\"RoleArn\": \"arn\","
            + "\"SecretAccessKey\": \"secret\","
            + "\"Token\": \"" + ec2SessionToken + "\""
            + "}";
    }

    public static void main(final String[] args) throws Exception {
        if (args == null || args.length < 6) {
            throw new IllegalArgumentException("S3HttpFixtureWithEC2 expects 6 arguments " +
                "[address, port, bucket, base path, ec2 access id, ec2 session token]");
        }
        final S3HttpFixtureWithEC2 fixture = new S3HttpFixtureWithEC2(args);
        fixture.start();
    }
}