/*
 * Copyright (c) 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.
 */
package org.akraino.validation.ui.common;

import java.io.IOException;
import java.io.InputStream;
import java.util.Properties;

import org.akraino.validation.ui.config.AppConfig;
import org.apache.log4j.Logger;

public class PropertyUtil {
    private static final Logger LOGGER = Logger.getLogger(PropertyUtil.class);
    private static final String PROP_FILENAME = "app.properties";
    private static PropertyUtil instance;

    private Properties appProps;

    /**
     * Return the single instance of this object in the app.
     *
     * @return the singleton
     */
    public static synchronized PropertyUtil getInstance() {
        if (instance == null) {
            instance = new PropertyUtil();
        }
        return instance;
    }

    private PropertyUtil() {
        InputStream input = AppConfig.class.getClassLoader().getResourceAsStream(PROP_FILENAME);
        appProps = new Properties();
        try {
            appProps.load(input);
        } catch (IOException e) {
            LOGGER.error("Error loading properties file: " + PROP_FILENAME);
        } finally {
            try {
                input.close();
            } catch (IOException e) {
                // ignore
            }
        }
    }

    /**
     * Get a property from the PropertyUtil object. If the environment variable $IP is set, then any URL's referring to
     * localhost will be rewritten to use this IP address instead.
     *
     * @param key the key to use to find the property
     * @return the value
     */
    public String getProperty(String key) {
        String property = appProps.getProperty(key);
        if (property != null && property.indexOf("://localhost:") > 0) {
            String ipAddr = System.getenv().get("IP");
            if (ipAddr != null && !"".contentEquals(ipAddr)) {
                property = property.replaceAll("://localhost:", "://" + ipAddr + ":");
            }
        }
        return property;
    }
}