package com.blue.servlet;

import java.io.BufferedInputStream;
import java.io.ByteArrayOutputStream;
import java.io.File;
import java.io.FileOutputStream;
import java.io.IOException;
import java.io.OutputStream;

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

import org.apache.commons.fileupload.FileItemIterator;
import org.apache.commons.fileupload.FileItemStream;
import org.apache.commons.fileupload.servlet.ServletFileUpload;
import org.apache.commons.fileupload.util.Streams;

import com.blue.beans.ProgressInfo;
import com.blue.util.UploadListener;
import com.blue.util.Util;

public class FileUploadServlet extends HttpServlet {

	private static final long serialVersionUID = 1L;

	private static final String FILE_UPLOAD_JSP = "/jsp/FileUploadForm.jsp";

	private static final long MAX_LENGTH = 10 * 1024 * 1024L; // 10MB

	private static final int HTTP_REDUNDANT_LENGTH = 1024; // 1KB

	protected void doGet(HttpServletRequest request, 
			HttpServletResponse response) throws ServletException, IOException {
		RequestDispatcher rd = request.getRequestDispatcher(FILE_UPLOAD_JSP);
		rd.forward(request, response);

	}

	protected void doPost(HttpServletRequest request,
			HttpServletResponse response) throws ServletException, IOException {

		ProgressInfo pi = new ProgressInfo();
		
		try {
			this.doUpload(request, pi);
		} catch (Exception e) {
			pi.setInProgress(false);
			Util.info("FileUploadServlet", "cancelled or interrupted!");
			e.printStackTrace();
			throw new ServletException(e);
		}
	}

	private String getFileName(String fileName) {
		String name = fileName.substring(fileName.lastIndexOf("\\") + 1);
		return System.getProperty("java.io.tmpdir") + "/" + name;
	}

	private void doUpload(HttpServletRequest request, ProgressInfo pi)
			throws Exception {

		String fldName = "";
		FileItemStream item = null;
		BufferedInputStream stream = null;

		boolean isMultipart = ServletFileUpload.isMultipartContent(request);

		if (isMultipart) {
			int filesSize = request.getContentLength() - HTTP_REDUNDANT_LENGTH;
			if (filesSize >= MAX_LENGTH) {
				String errorMsg = "Error: Current files size is " + filesSize
						/ (1024 * 1024) + "MB which has exceeded max " + "10MB";
				pi.setCompleted(true);
				pi.setErrorMsg(errorMsg);
				throw new Exception(errorMsg);
			}
			ServletFileUpload upload = new ServletFileUpload();
			upload.setHeaderEncoding("UTF-8");
			upload.setFileSizeMax(MAX_LENGTH);
			upload.setSizeMax(MAX_LENGTH);
			UploadListener uploadListener = new UploadListener(pi);
			upload.setProgressListener(uploadListener);
			// Parse the request
			FileItemIterator fIter = upload.getItemIterator(request);
			
			while (fIter.hasNext()) {
				item = fIter.next();
				fldName = item.getFieldName();
				Util.info("FileUploadServlet", fldName + ", "
						+ item.isFormField() + ", " + item.getContentType()
						+ ", " + item.getName() + ", " + item.getHeaders());

				if (!item.isFormField()) {
					fldName = item.getFieldName();
					if (item.getName() == null
							|| "".equals(item.getName().trim())) {
						continue;
					}

					pi.setCurFileName(item.getName());
					pi.setUploadedFiles(pi.getUploadedFiles() + "<b>"
							+ item.getName() + "</b><br/>");
					
					stream = new BufferedInputStream(item.openStream());
					ByteArrayOutputStream bStream = new ByteArrayOutputStream();
					long bStreamLen = Streams.copy(stream, bStream, true);

					Util.info("FileUploadServlet", this.getFileName(item
							.getName()));
					
					File file = new File(this.getFileName(item.getName()));
					if (file.exists()) {
						file.delete();
					}
					OutputStream out = new FileOutputStream(file);
					bStream.writeTo(out);

					Util.info("FileUploadServlet", fldName
							+ " just was uploaded, len " + bStreamLen);
				}

			}
		}

	}

}