/**
 * Copyright (c) 2010, Sebastian Sdorra
 * All rights reserved.
 *
 * Redistribution and use in source and binary forms, with or without
 * modification, are permitted provided that the following conditions are met:
 *
 * 1. Redistributions of source code must retain the above copyright notice,
 *    this list of conditions and the following disclaimer.
 * 2. Redistributions in binary form must reproduce the above copyright notice,
 *    this list of conditions and the following disclaimer in the documentation
 *    and/or other materials provided with the distribution.
 * 3. Neither the name of SCM-Manager; nor the names of its
 *    contributors may be used to endorse or promote products derived from this
 *    software without specific prior written permission.
 *
 * THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS "AS IS"
 * AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
 * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE
 * DISCLAIMED.  IN NO EVENT SHALL THE REGENTS OR CONTRIBUTORS BE LIABLE FOR ANY
 * DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES
 * (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES;
 * LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON
 * ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
 * (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF THIS
 * SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
 *
 * http://bitbucket.org/sdorra/scm-manager
 *
 */


package sonia.scm.resources;

//~--- non-JDK imports --------------------------------------------------------

import org.slf4j.Logger;
import org.slf4j.LoggerFactory;

import sonia.scm.util.HttpUtil;
import sonia.scm.util.IOUtil;

//~--- JDK imports ------------------------------------------------------------

import java.io.IOException;
import java.io.OutputStream;

import javax.servlet.ServletException;
import javax.servlet.http.HttpServlet;
import javax.servlet.http.HttpServletRequest;
import javax.servlet.http.HttpServletResponse;

/**
 *
 * @author Sebastian Sdorra
 */
public abstract class AbstractResourceServlet extends HttpServlet
{

  /** Field description */
  private static final long serialVersionUID = -1774434741744054387L;

  /**
   * the logger for AbstractResourceServlet
   */
  private static final Logger logger =
    LoggerFactory.getLogger(AbstractResourceServlet.class);

  //~--- constructors ---------------------------------------------------------

  /**
   * Constructs ...
   *
   *
   * @param resourceManager
   */
  public AbstractResourceServlet(ResourceManager resourceManager)
  {
    this.resourceManager = resourceManager;
  }

  //~--- get methods ----------------------------------------------------------

  /**
   * Method description
   *
   *
   * @return
   */
  protected abstract ResourceType getType();

  //~--- methods --------------------------------------------------------------

  /**
   * Method description
   *
   *
   * @param request
   * @param response
   *
   * @throws IOException
   * @throws ServletException
   */
  @Override
  protected void doGet(HttpServletRequest request, HttpServletResponse response)
          throws ServletException, IOException
  {
    String uri = HttpUtil.getStrippedURI(request);
    ResourceType type = getType();
    String nameSeparator = HttpUtil.SEPARATOR_PATH.concat(
                               type.getExtension()).concat(
                               HttpUtil.SEPARATOR_PATH);
    int index = uri.indexOf(nameSeparator);

    if (index > 0)
    {
      String name = uri.substring(index + nameSeparator.length());
      Resource resource = resourceManager.getResource(type, name);

      if (resource != null)
      {
        printResource(response, resource);
      }
      else
      {
        if (logger.isWarnEnabled())
        {
          logger.warn("no resource with type {} and name {} found", type, name);
        }

        response.sendError(HttpServletResponse.SC_NOT_FOUND);
      }
    }
    else
    {
      response.sendError(HttpServletResponse.SC_NOT_FOUND);
    }
  }

  /**
   * Method description
   *
   *
   * @param response
   * @param resource
   *
   * @throws IOException
   */
  private void printResource(HttpServletResponse response, Resource resource)
          throws IOException
  {
    response.setContentType(resource.getType().getContentType());

    OutputStream output = null;

    try
    {
      output = response.getOutputStream();
      resource.copyTo(output);
    }
    finally
    {
      IOUtil.close(output);
    }
  }

  //~--- fields ---------------------------------------------------------------

  /** Field description */
  private ResourceManager resourceManager;
}
