/*
    * This file is part of ***  M y C o R e  ***
    * See http://www.mycore.de/ for details.
    *
    * MyCoRe is free software: you can redistribute it and/or modify
    * it under the terms of the GNU General Public License as published by
    * the Free Software Foundation, either version 3 of the License, or
    * (at your option) any later version.
    *
   * MyCoRe 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 General Public License for more details.
   *
   * You should have received a copy of the GNU General Public License
   * along with MyCoRe.  If not, see <http://www.gnu.org/licenses/>.
   */
  
  package org.mycore.frontend.servlets;
  
  import java.io.FileNotFoundException;
  import java.io.IOException;
  import java.nio.file.NoSuchFileException;
  import java.util.Locale;
  import java.util.Objects;
  
  import org.apache.logging.log4j.LogManager;
  import org.apache.logging.log4j.Logger;
  import org.apache.logging.log4j.util.Supplier;
  import org.mycore.common.content.MCRContent;
  import org.mycore.common.content.util.MCRServletContentHelper;
  
  import jakarta.servlet.ServletException;
  import jakarta.servlet.http.HttpServletRequest;
  import jakarta.servlet.http.HttpServletResponse;
  
  /**
   * @author Thomas Scheffler (yagee)
   *
   */
  public abstract class MCRContentServlet extends MCRServlet {
      private static final long serialVersionUID = 1L;
  
      private static Logger LOGGER = LogManager.getLogger(MCRContentServlet.class);
  
      private MCRServletContentHelper.Config config;
  
      /**
       * Returns MCRContent matching current request.
       */
      public abstract MCRContent getContent(HttpServletRequest req, HttpServletResponse resp) throws IOException;
  
      @Override
      public void init() throws ServletException {
          super.init();
          this.config = MCRServletContentHelper.buildConfig(getServletConfig());
      }
  
      /**
       * Handles a HEAD request for the specified content.
       */
      @Override
      protected void doHead(final HttpServletRequest request, final HttpServletResponse response) throws IOException,
          ServletException {
  
          request.setAttribute(MCRServletContentHelper.ATT_SERVE_CONTENT, Boolean.FALSE);
          super.doGet(request, response);
      }
  
      @Override
      protected void doOptions(final HttpServletRequest req, final HttpServletResponse resp) throws ServletException,
          IOException {
          resp.setHeader("Allow", "GET, HEAD, POST, OPTIONS");
      }
  
      @Override
      protected void render(final MCRServletJob job, final Exception ex) throws Exception {
          if (ex != null) {
              throw ex;
          }
          final HttpServletRequest request = job.getRequest();
          final HttpServletResponse response = job.getResponse();
          final MCRContent content = getContent(request, response);
          boolean serveContent = MCRServletContentHelper.isServeContent(request);
          try {
              MCRServletContentHelper.serveContent(content, request, response, getServletContext(), getConfig(),
                  serveContent);
          } catch (NoSuchFileException | FileNotFoundException e) {
              LOGGER.info("Catched {}:", e.getClass().getSimpleName(), e);
              response.sendError(HttpServletResponse.SC_NOT_FOUND, e.getMessage());
              return;
          }
  
          final Supplier<Object> getResourceName = () -> {
              String id = "";
              if (Objects.nonNull(content.getSystemId())) {
                  id = content.getSystemId();
              } else if (Objects.nonNull(content.getName())) {
                  id = content.getName();
             }
             return String.format(Locale.ROOT, "Finished serving resource:%s", id);
         };
         LOGGER.debug(getResourceName);
     }
 
     public MCRServletContentHelper.Config getConfig() {
         return config;
     }
 
 }