/**
 * Copyright 2016 SmartBear Software
 * <p>
 * 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
 * <p>
 * http://www.apache.org/licenses/LICENSE-2.0
 * <p>
 * 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 io.swagger.generator.util;

import java.io.BufferedInputStream;
import java.io.File;
import java.io.FileInputStream;
import java.io.FileNotFoundException;
import java.io.FileOutputStream;
import java.io.IOException;
import java.util.List;
import java.util.zip.ZipEntry;
import java.util.zip.ZipOutputStream;

/**
 * This utility compresses a list of files to standard ZIP format file.
 * It is able to compresses all sub files and sub directories, recursively.
 * @author Ha Minh Nam
 *
 */
public class ZipUtil {
    /**
     * A constants for buffer size used to read/write data
     */
    private static final int BUFFER_SIZE = 4096;

    /**
     * Compresses a collection of files to a destination zip file
     * @param listFiles A collection of files and directories
     * @param destZipFile The path of the destination zip file
     * @throws FileNotFoundException
     * @throws IOException
     */
    public void compressFiles(List<File> listFiles, String destZipFile) throws FileNotFoundException, IOException {

        ZipOutputStream zos = new ZipOutputStream(new FileOutputStream(destZipFile));

        for (File file : listFiles) {
            if (file.isDirectory()) {
                addFolderToZip(file, file.getName(), zos);
            } else {
                addFileToZip(file, zos);
            }
        }

        zos.flush();
        zos.close();
    }

    /**
     * Adds a directory to the current zip output stream
     * @param folder the directory to be  added
     * @param parentFolder the path of parent directory
     * @param zos the current zip output stream
     * @throws FileNotFoundException
     * @throws IOException
     */
    private void addFolderToZip(File folder, String parentFolder,
                                ZipOutputStream zos) throws FileNotFoundException, IOException {
        for (File file : folder.listFiles()) {
            if (file.isDirectory()) {
                addFolderToZip(file, parentFolder + "/" + file.getName(), zos);
                continue;
            }

            zos.putNextEntry(new ZipEntry(parentFolder + "/" + file.getName()));

            BufferedInputStream bis = new BufferedInputStream(
                    new FileInputStream(file));

            long bytesRead = 0;
            byte[] bytesIn = new byte[BUFFER_SIZE];
            int read = 0;

            while ((read = bis.read(bytesIn)) != -1) {
                zos.write(bytesIn, 0, read);
                bytesRead += read;
            }

            zos.closeEntry();

        }
    }

    /**
     * Adds a file to the current zip output stream
     * @param file the file to be added
     * @param zos the current zip output stream
     * @throws FileNotFoundException
     * @throws IOException
     */
    private void addFileToZip(File file, ZipOutputStream zos)
            throws FileNotFoundException, IOException {
        zos.putNextEntry(new ZipEntry(file.getName()));

        BufferedInputStream bis = new BufferedInputStream(new FileInputStream(
                file));

        long bytesRead = 0;
        byte[] bytesIn = new byte[BUFFER_SIZE];
        int read = 0;

        while ((read = bis.read(bytesIn)) != -1) {
            zos.write(bytesIn, 0, read);
            bytesRead += read;
        }

        zos.closeEntry();
    }
}