/*
 * Licensed to Crate.io GmbH ("Crate") under one or more contributor
 * license agreements.  See the NOTICE file distributed with this work for
 * additional information regarding copyright ownership.  Crate 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.
 *
 * However, if you have executed another commercial license agreement
 * with Crate these terms will supersede the license and you may use the
 * software solely pursuant to the terms of the relevant commercial agreement.
 */

package org.elasticsearch.node;

import org.apache.lucene.util.IOUtils;

import java.io.BufferedReader;
import java.io.IOException;
import java.io.InputStream;
import java.io.InputStreamReader;
import java.nio.charset.StandardCharsets;
import java.util.ArrayList;
import java.util.List;
import java.util.concurrent.ThreadLocalRandom;

public final class NodeNames {

    public static String randomNodeName() {
        List<String> names = nodeNames();
        int index = ThreadLocalRandom.current().nextInt(names.size());
        return names.get(index);
    }

    static List<String> nodeNames() {
        InputStream input = NodeNames.class.getResourceAsStream("/config/names.txt");
        try {
            List<String> names = new ArrayList<>();
            try (BufferedReader reader = new BufferedReader(new InputStreamReader(input, StandardCharsets.UTF_8))) {
                String line = reader.readLine();
                while (line != null) {
                    String[] fields = line.split("\t");
                    if (fields.length == 0) {
                        throw new RuntimeException("Failed to parse the names.txt. Malformed record: " + line);
                    }
                    names.add(fields[0]);
                    line = reader.readLine();
                }
            }
            return names;
        } catch (IOException e) {
            throw new RuntimeException("Could not read node names list", e);
        } finally {
            IOUtils.closeWhileHandlingException(input);
        }
    }
}
