/*
 * Copyright 2007 Future Earth, info@future-earth.eu
 *
 * Licensed under the Apache License, Version 2.0 (the "License"); you may not
 * use this file except in compliance with the License. You may obtain a copy of
 * the License at
 *
 * http://www.apache.org/licenses/LICENSE-2.0
 *
 * Unless required by applicable law or agreed to in writing, software
 * distributed under the License is distributed on an "AS IS" BASIS, WITHOUT
 * WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied. See the
 * License for the specific language governing permissions and limitations under
 * the License.
 */

package eu.future.earth.gwt.server.file;

import java.io.File;
import java.io.IOException;
import java.io.PrintWriter;
import java.util.List;
import java.util.logging.Level;
import java.util.logging.Logger;

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

import org.apache.commons.fileupload.FileItem;
import org.apache.commons.fileupload.FileUploadException;
import org.apache.commons.fileupload.disk.DiskFileItemFactory;
import org.apache.commons.fileupload.servlet.ServletFileUpload;
import org.json.JSONException;
import org.json.JSONObject;

import eu.future.earth.gwt.client.file.FileHolder;

public abstract class FileUploadServlet extends HttpServlet {

	/**
	 * 
	 */
	private static final long serialVersionUID = 1720563248457411214L;

	private static final String CONTENT_TYPE = "text/html";

	private final static Logger LOGGER = Logger.getLogger(FileUploadServlet.class.getName());

	/**
	 * This method will try to display the image. Requested parameters are
	 */
	protected void doGet(HttpServletRequest req, HttpServletResponse response) throws ServletException, IOException {
		// Get All the info for getting the temp file of the sored file
		String name = req.getParameter("name");
		String stored = req.getParameter("stored");
		final FileHolder holder = new FileHolder();
		holder.setName(name);

		FileDataHolder file = null;

		response.setHeader("Expires", "Sat, 6 May 1995 12:00:00 GMT");
		// Set standard HTTP/1.1 no-cache headers.
		response.setHeader("Cache-Control", "no-store, no-cache, must-revalidate");
		// Set IE extended HTTP/1.1 no-cache headers (use addHeader).
		response.addHeader("Cache-Control", "post-check=0, pre-check=0");
		response.setHeader("Pragma", "no-cache");
		response.setContentType("image/jpeg");
		if ("true".equals(stored)) {
			file = getStoredFile(req, holder);
		} else {
			file = getTempFile(req.getSession(), holder);
		}

		if (file != null) {
			response.setContentType(file.getType());
			// response.addHeader("Content-Disposition", "attachment;filename=" + name);
			ServletOutputStream out = response.getOutputStream();
			out.write(file.getData());
			out.close();
		} else {
			// Stream the default type
			response.sendError(HttpServletResponse.SC_FOUND, "Not found " + name + " " + stored);
		}

	}

	public abstract FileDataHolder getStoredFile(HttpServletRequest req, FileHolder holder);

	public abstract int getFileThreshold();

	public abstract File getTempDir();

	public static FileDataHolder getTempFile(HttpSession session, FileHolder holder) {
		return (FileDataHolder) session.getAttribute(holder.getName());
	}

	@SuppressWarnings("unchecked")
	protected void doPost(HttpServletRequest req, HttpServletResponse response) throws ServletException, IOException {
		final JSONObject feedback = new JSONObject();
		final PrintWriter out = response.getWriter();
		try {
			boolean isMultipart = ServletFileUpload.isMultipartContent(req);
			if (isMultipart) {
				final DiskFileItemFactory factory = new DiskFileItemFactory();
				File tempDir = getTempDir();
				if (!tempDir.exists()) {
					tempDir.mkdirs();
				}
				factory.setRepository(tempDir);
				factory.setSizeThreshold(getFileThreshold());
				final ServletFileUpload upload = new ServletFileUpload(factory);
				try {
					final List<FileItem> items = (List<FileItem>) upload.parseRequest(req);
					for (int i = 0; i < items.size(); i++) {
						final FileItem current = items.get(i);
						final HttpSession session = req.getSession();
						final FileDataHolder holder = new FileDataHolder();
						holder.setData(current.get());
						holder.setFileName(current.getName());
						holder.setType(current.getContentType());
						session.setAttribute(holder.getFileName(), holder);
						feedback.put("fileName", holder.getFileName());
						feedback.put("fileType", holder.getType());
						feedback.put("fileSize", String.valueOf(current.getSize()));
					}

					feedback.put("result", "succes");
				} catch (FileUploadException e) {
					LOGGER.log(Level.WARNING, e.getMessage());
					feedback.put("result", "error");
				}

			}
			response.setContentType(CONTENT_TYPE);

		} catch (JSONException e) {
			throw new ServletException(e);
		}
		out.write(feedback.toString());
	}

}