/*
  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 java.io.File;
import java.io.FileOutputStream;
import java.io.IOException;
import java.io.InputStream;
import java.util.Enumeration;
import java.util.zip.ZipEntry;
import java.util.zip.ZipFile;

/**
 * Eine Klasse mit Methoden zum entpacken von Dateien
 * 
 * @author Ulrich Hilger, 15. Januar 2024
 */
public class Unzipper {
  /* --------- ZIP entpacken ---------------- */
  
  public String extractZipfile(String fName, String relPath, String base) {  
    //logger.fine("fName: " + fName + ", relPath: " + relPath);
    String result = null;
    if (!relPath.startsWith(".")) {    
      try {
        //File targetDir = new File(fileBase, relPath);
        //File targetDir = getTargetDir(relPath);
        File archive = new File(base, fName);
        if(extract(archive)) {
          result = "ok";
        } else {
          result = "error while extracting";
        }
      } catch(Exception ex) {
        result = ex.getLocalizedMessage();
        //logger.log(Level.SEVERE, ex.getLocalizedMessage(), ex);
      }
    } else {
      result = "Falsche relative Pfadangabe.";
    }
    return result;
  }
  
  /**
	 * extract a given ZIP archive to the folder respective archive resides in
	 * @param archive  the archive to extract
	 * @throws Exception
	 */
	private boolean extract(File archive) throws Exception {
		ZipFile zipfile = new ZipFile(archive);
		Enumeration en = zipfile.entries();
		while(en.hasMoreElements()) {
			ZipEntry zipentry = (ZipEntry) en.nextElement();
			unzip(zipfile, zipentry, archive.getParent());
		}
		zipfile.close();
		return true;
	}

	/**
	 * unzip a given entry of a given zip file to a given location
	 * @param zipfile  the zip file to read an entry from
	 * @param zipentry  the zip entry to read
	 * @param destPath  the path to the destination location for the extracted content
	 * @throws IOException
	 */
	private void unzip(ZipFile zipfile, ZipEntry zipentry, String destPath) throws IOException {
		byte buf[] = new byte[1024];
		InputStream is = zipfile.getInputStream(zipentry);
		String outFileName = destPath + File.separator + zipentry.getName();
		File file = new File(outFileName);
		if(!zipentry.isDirectory()) {
			file.getParentFile().mkdirs();
			if(!file.exists())
				file.createNewFile();
			FileOutputStream fos = new FileOutputStream(file);
			int i = is.read(buf, 0, 1024);
			while(i > -1) {
				fos.write(buf, 0, i);
				i = is.read(buf, 0, 1024);
			}
			fos.close();
			is.close();
		} else {
			file.mkdirs();
		}
	}

  
}