/*-
 * ============LICENSE_START=======================================================
 *  Copyright (C) 2019 Nordix Foundation.
 *  Modifications Copyright (C) 2020-2021 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.
 *
 * SPDX-License-Identifier: Apache-2.0
 * ============LICENSE_END=========================================================
 */

package org.onap.policy.common.utils.resources;

import java.io.File;
import java.io.IOException;
import java.io.InputStream;
import java.io.InputStreamReader;
import java.io.Reader;
import java.nio.charset.StandardCharsets;
import java.nio.file.Files;
import lombok.AccessLevel;
import lombok.NoArgsConstructor;
import org.apache.commons.io.IOUtils;
import org.slf4j.Logger;
import org.slf4j.LoggerFactory;

/**
 * The Class TextFileUtils is class that provides useful functions for handling text files. Functions to read and write
 * text files to strings and strings are provided.
 *
 * @author Liam Fallon (liam.fallon@est.tech)
 */
@NoArgsConstructor(access = AccessLevel.PRIVATE)
public final class TextFileUtils {
    private static final Logger logger = LoggerFactory.getLogger(TextFileUtils.class);

    /**
     * Method to return the contents of a text file as a string.
     *
     * @param textFilePath The path to the file as a string
     * @return A string containing the contents of the file
     * @throws IOException on errors reading text from the file
     */
    public static String getTextFileAsString(final String textFilePath) throws IOException {
        final var textFile = new File(textFilePath);
        return Files.readString(textFile.toPath());
    }

    /**
     * Method to write contents of a string to a text file.
     *
     * @param outString The string to write
     * @param textFilePath The path to the file as a string
     * @throws IOException on errors reading text from the file
     */
    public static void putStringAsTextFile(final String outString, final String textFilePath) throws IOException {
        final var textFile = new File(textFilePath);
        if (!textFile.getParentFile().exists()) {
            textFile.getParentFile().mkdirs();
        }

        putStringAsFile(outString, textFile);
    }

    /**
     * Method to write contents of a string to a text file.
     *
     * @param outString The string to write
     * @param textFile The file to write the string to
     * @throws IOException on errors reading text from the file
     */
    public static void putStringAsFile(final String outString, final File textFile) throws IOException {
        Files.writeString(textFile.toPath(), outString);
    }

    /**
     * Method to return the contents of a text steam as a string.
     *
     * @param textStream The stream
     * @return A string containing the output of the stream as text
     * @throws IOException on errors reading text from the file
     */
    public static String getStreamAsString(final InputStream textStream) throws IOException {
        return getReaderAsString(new InputStreamReader(textStream, StandardCharsets.UTF_8));
    }

    /**
     * Method to return the contents of a reader steam as a string. This closes the reader after use
     *
     * @param textReader The reader
     * @return A string containing the output of the reader as text
     * @throws IOException on errors reading text from the file
     */
    public static String getReaderAsString(final Reader textReader) throws IOException {
        return IOUtils.toString(textReader);
    }

    /**
     * Creates a temporary file, only accessible by the owner.
     *
     * @param prefix file name prefix
     * @param suffix file name suffix
     * @return a new, temporary file
     * @throws IOException if an error occurs
     */
    public static File createTempFile(String prefix, String suffix) throws IOException {
        /*
         * Disabling sonar, because setDefaultPermissions() will set the permissions of
         * the file.
         */
        var file = File.createTempFile(prefix, suffix); // NOSONAR

        setDefaultPermissions(file);

        return file;
    }

    /**
     * Sets permissions on a file or directory so that only the owner can access it.
     *
     * @param file file or directory on which permissions are to be set
     */
    public static void setDefaultPermissions(File file) {
        if (!file.setReadable(true, true) || !file.setWritable(true, true) || !file.setExecutable(true, true)) {
            logger.warn("cannot set permissions for {}", file);
        }
    }
}