/*
    WebBox - Dein Server.
    Copyright (C) 2017 Ulrich Hilger, http://uhilger.de

    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 <http://www.gnu.org/licenses/>.
 */
package de.uhilger.wbx.web;

import java.io.File;
import java.io.IOException;
import java.io.UnsupportedEncodingException;
import java.net.URLDecoder;
import java.util.logging.Logger;
import javax.servlet.ServletException;
import javax.servlet.http.HttpServletRequest;
import javax.servlet.http.HttpServletResponse;
import net.coobird.thumbnailator.Thumbnails;
import org.apache.catalina.servlets.DefaultServlet;

/**
 * Mit dem TNServlet kann f&uuml;r eine Bilddatei eine 
 * Miniaturansicht erzeugt werden, wie sie im Dateimanager 
 * der WebBox verwendet wird.
 * 
 * Unterstuetzt werden die Varianten
 * 120 (_tn), 240 (_kl), 500 (_dd), 700 (_mt), 1200 (_gr)
 */
public class TNServlet extends DefaultServlet {
  
  private static final Logger logger = Logger.getLogger(TNServlet.class.getName());
  
  /**
   * Diese String-Konstanten noetigenfalls in eine 
   * Konfigurationsdatei auslagern
   */
  public static final String TN = "_tn"; // 120
  public static final String KL = "_kl"; // 240
  public static final String SM = "_sm"; // 500
  public static final String MT = "_mt"; // 700
  public static final String GR = "_gr"; // 1200
  
  public static final String JPG = ".jpg";
  public static final String JPEG = ".jpeg";
  public static final String PNG = ".png";
  
  /**
   * Handles the HTTP <code>GET</code> method.
   *
   * @param request servlet request
   * @param response servlet response
   * @throws ServletException if a servlet-specific error occurs
   * @throws IOException if an I/O error occurs
   */
  @Override
  protected void doGet(HttpServletRequest request, HttpServletResponse response)
          throws ServletException, IOException {
    
    String uriStr = request.getRequestURI();
    String relname = uriStr.substring(request.getContextPath().length());
    
    // --- Logausgabe Start
    /*
    File logurifile = new File(uriStr);
    String loguriStr = uriStr.substring(request.getContextPath().length());
    File logdir = new File(request.getServletContext().getRealPath("/"));
    File imgfile = new File(logdir, loguriStr);    
    StringBuffer buf = new StringBuffer();
    buf.append("contextPath: ");
    buf.append(request.getContextPath());
    buf.append("\n");
    buf.append("realpath of /: ");
    buf.append(request.getServletContext().getRealPath("/"));
    buf.append("\n");
    buf.append("urifile: ");
    buf.append(logurifile.getAbsolutePath());
    buf.append("\n");
    buf.append("imgfile: ");
    buf.append(imgfile.getAbsolutePath());
    logger.fine(buf.toString());
    //System.out.println("TNServlet uri parts " + buf.toString());
    */
    // --- Logausgabe Ende
        
    if(uriStr.endsWith(JPG) || uriStr.endsWith(JPEG) || uriStr.endsWith(PNG)) {
      File dir = new File(request.getServletContext().getRealPath("/"));
      String suburiStr = uriStr.substring(request.getContextPath().length());
      File imgfile = new File(dir, suburiStr);    
      if(uriStr.contains(TN)) {
        bildErzeugen(dir, relname, TN, 120, imgfile);
      } else if(uriStr.contains(KL)) {
        bildErzeugen(dir, relname, KL, 240, imgfile);
      } else if(uriStr.contains(SM)) {
        bildErzeugen(dir, relname, SM, 500, imgfile);
      } else if(uriStr.contains(MT)) {
        bildErzeugen(dir, relname, MT, 700, imgfile);
      } else if(uriStr.contains(GR)) {
        bildErzeugen(dir, relname, GR, 1200, imgfile);
      }      
    }
    super.doGet(request, response);
  }
  
  private void bildErzeugen(File dir, String relname, String indicator, int gr, File tnfile) 
          throws UnsupportedEncodingException, IOException {
    //File dir = new File(request.getServletContext().getRealPath("/"));
    // System.out.println("TNServlet dir: " + dir);
    relname = relname.replace(indicator, "");
    // System.out.println("TNServlet bildAusgeben relname: " + relname);
    // relname: /test/img/IMG_0524.png
    File imgfile = new File(dir, URLDecoder.decode(relname, "utf-8"));
    
    // 120, 240, 500, 700, 1200

    /*Thumbnails.of(imgfile)
            .size(gr, gr)
            .keepAspectRatio(true)
            .outputQuality(0.7)
            .toOutputStream(response.getOutputStream());*/
    if(!tnfile.exists()) {
      Thumbnails.of(imgfile)
              .size(gr, gr)
              .keepAspectRatio(true)
              .outputQuality(0.7)
              .toFile(tnfile);
    }
  }  
}