/*
 * 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.jackrabbit.oak.plugins.index.elastic.util;

import org.slf4j.Logger;
import org.slf4j.LoggerFactory;

public class EnvironmentVariableProcessorUtil {
    private static final Logger LOG = LoggerFactory.getLogger(EnvironmentVariableProcessorUtil.class);

    public static String getEnvironmentVariable(String variableName) {
        String value = System.getenv(variableName);
        if (value == null) {
            throw new IllegalArgumentException("Environment variable " + variableName + " not found");
        }
        return value;
    }

    public static String processEnvironmentVariable(String envVariablePrefix, String variableNameIncludingPrefix, String defaultValue) {
        String value = null;
        if (variableNameIncludingPrefix.startsWith(envVariablePrefix)) {
            String variableName = variableNameIncludingPrefix.substring(envVariablePrefix.length());
            value = System.getenv(variableName);
        } else {
            value = variableNameIncludingPrefix;
        }
        if (value == null) {
            LOG.warn("EnvironmentVariable {} used in inference header is not set", variableNameIncludingPrefix);
            return defaultValue;
        }
        return value;
    }

    public static String processEnvironmentVariable(String envVariablePrefix, String variableNameIncludingPrefix) {
        return processEnvironmentVariable(envVariablePrefix, variableNameIncludingPrefix, null);
    }

}
