/*
  http-cm - File management extensions to jdk.httpserver
  Copyright (C) 2021  Ulrich Hilger

  This program is free software: you can redistribute it and/or modify
  it under the terms of the GNU Affero General Public License as
  published by the Free Software Foundation, either version 3 of the
  License, or (at your option) any later version.

  This program is distributed in the hope that it will be useful,
  but WITHOUT ANY WARRANTY; without even the implied warranty of
  MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
  GNU Affero General Public License for more details.

  You should have received a copy of the GNU Affero General Public License
  along with this program.  If not, see <https://www.gnu.org/licenses/>.
 */
package de.uhilger.httpserver.cm.actor;

import static de.uhilger.httpserver.cm.FileManager.STR_SLASH;
import java.io.File;
import java.io.FileInputStream;
import java.io.FileOutputStream;
import java.io.IOException;
import java.util.zip.Adler32;
import java.util.zip.CheckedOutputStream;
import java.util.zip.ZipEntry;
import java.util.zip.ZipOutputStream;

/**
 * Eine Klasse mit Methoden zum Packen von Dateien
 * #
 * @author Ulrich Hilger, 15. Januar 2024
 */
public class Zipper {

  /* --------------- Ordner packen ----------------- */

  /**
   * Einen Ordner packen.
   * 
   * Als Ziel wird eine neue Datei mit Dateiendung '.zip' erzeugt, die so 
   * heisst wie der Ordner, der gapckt werden soll. Die Datei mit 
   * dem gepackten Ordnerinhalt wird in dem Ordner angelegt, der den zu 
   * packenden Ordner enthaelt.
   * 
   * @param fName  Name des zu packenden Ordners
   * @param relPath  relativer Pfad zum Ordner, der gepackt werden soll  
   * @return die Meldung mit dem Ergebnis. Wenn die Meldung nicht "ok" lautet
   * wurde die ZIP-Datei nicht erzeugt und die Meldung nennt den Grund.
   */
  public String packFolder(String fName, String relPath, String base/*, HttpExchange e*/) {
    if (!relPath.startsWith(".")) {    
      try {        
        //String fName = getFileName(e);
        //logger.fine("fName: " + fName);
        if (fName.endsWith(STR_SLASH)) {
          File dir = new File(base, fName);
          if(dir.isDirectory()) {
            //logger.fine("absPath: " + dir.getAbsolutePath());
            File parentDir = dir.getParentFile();
            StringBuilder fname = new StringBuilder();
            fname.append(dir.getName());
            fname.append(".zip");
            File archiveFile = new File(parentDir, fname.toString());
            pack(dir.getAbsolutePath(), archiveFile.getAbsolutePath());
            return "ok";
          } else {
            return "kein Ordner";
          }
        } else {
          return "kein Ordner";
        }
      } catch(Exception ex) {
        String result = ex.getLocalizedMessage();
        //logger.log(Level.SEVERE, result, ex);
        return result;
      }
    } else {
      return "Falsche relative Pfadangabe";
    }
  }
  
	/**
	 * pack the contents of a given folder into a new ZIP compressed archive
	 * @param folder  absolute path and name of the folder to pack
	 * @param archive  absolute path and name of the archive to create from the given files
	 * @throws Exception
	 */
	private boolean pack(String folder, String archive) throws Exception {
		File file = new File(archive);
		FileOutputStream fos = new FileOutputStream(file);
		CheckedOutputStream checksum = new CheckedOutputStream(fos, new Adler32());
		ZipOutputStream zos = new ZipOutputStream(checksum);
		pack(zos, folder, "");
		zos.flush();
		zos.finish();
		zos.close();
		fos.flush();
		fos.close();
		return true;
	}

	/**
	 * go through the given file structure recursively
	 * @param zipFile  the ZIP file to write to
	 * @param srcDir  the directory to pack during this cycle
	 * @param subDir  the subdirectory to append to names of file entries inside the archive
	 * @throws IOException
	 */
	private void pack(ZipOutputStream zipFile, String srcDir, String subDir) throws IOException {
		File[] files = new File(srcDir).listFiles();
		for(int i = 0; i < files.length; i++) {
			if(files[i].isDirectory()) {
				pack(zipFile, files[i].getAbsolutePath(), subDir + File.separator + files[i].getName());
			}
			else {
				packFile(zipFile, subDir, files[i]);
			}
		}
	}

	/**
	 * pack a given file
	 * @param zipFile  the ZIP archive to pack to
	 * @param dir  the directory name to append to name of file entry inside archive
	 * @param file  the file to pack
	 * @throws IOException
	 */
	private void packFile(ZipOutputStream zipFile, String dir, File file) throws IOException
	{
		FileInputStream fileinputstream = new FileInputStream(file);
		byte buf[] = new byte[fileinputstream.available()];
		fileinputstream.read(buf);
		String dirWithSlashes = dir.replace('\\', '/');
		//System.out.println("zipping " + dirWithSlashes + "/" + file.getName());
		ZipEntry ze = new ZipEntry(dirWithSlashes + "/" + file.getName());
		ze.setMethod(ZipEntry.DEFLATED);
		zipFile.putNextEntry(ze);
		zipFile.write(buf, 0, buf.length);
		zipFile.closeEntry();
		fileinputstream.close();
	}

      
}