/*-
 * ============LICENSE_START=======================================================
 * ONAP - SO
 * ================================================================================
 * Copyright (C) 2017 - 2018 AT&T Intellectual Property. All rights reserved.
 * ================================================================================
 * Modifications Copyright (c) 2019 Samsung
 * ================================================================================
 * 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.so.adapters.sdnc;

import org.slf4j.Logger;
import org.slf4j.LoggerFactory;
import java.io.IOException;
import java.io.InputStream;

/**
 * file utility class
 */
public class FileUtil {

    private static final Logger logger = LoggerFactory.getLogger(FileUtil.class);

    /**
     * Read the specified resource file and return the contents as a String.
     *
     * @param fileName Name of the resource file
     * @return the contents of the resource file as a String
     * @throws IOException if there is a problem reading the file
     */
    public static String readResourceFile(String fileName) {
        InputStream stream;
        try {
            stream = getResourceAsStream(fileName);
            byte[] bytes;
            bytes = new byte[stream.available()];
            if (stream.read(bytes) > 0) {
                stream.close();
                return new String(bytes);
            } else {
                stream.close();
                return "";
            }
        } catch (IOException e) {
            logger.debug("Exception:", e);
            return "";
        }
    }

    /**
     * Get an InputStream for the resource specified.
     *
     * @param resourceName Name of resource for which to get InputStream.
     * @return an InputStream for the resource specified.
     * @throws IOException If we can't get the InputStream for whatever reason.
     */
    private static InputStream getResourceAsStream(String resourceName) throws IOException {
        InputStream stream = FileUtil.class.getClassLoader().getResourceAsStream(resourceName);
        if (stream == null) {
            throw new IOException("Can't access resource '" + resourceName + "'");
        }
        return stream;
    }
}