/*
 * Licensed to the Apache Software Foundation (ASF) under one
 * or more contributor license agreements.  See the NOTICE file
 * distributed with this work for additional information
 * regarding copyright ownership.  The ASF licenses this file
 * to you 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 org.apache.tuscany.sca.domain.manager.impl;

import java.io.File;
import java.io.FileNotFoundException;
import java.io.IOException;
import java.io.InputStream;
import java.net.URI;
import java.net.URLConnection;
import java.net.URLDecoder;
import java.util.List;
import java.util.logging.Logger;

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

import org.apache.commons.fileupload.FileItem;
import org.apache.commons.fileupload.disk.DiskFileItemFactory;
import org.apache.commons.fileupload.servlet.ServletFileUpload;
import org.osoa.sca.annotations.Init;
import org.osoa.sca.annotations.Property;
import org.osoa.sca.annotations.Reference;
import org.osoa.sca.annotations.Scope;
import org.osoa.sca.annotations.Service;

/**
 * Implementation of a servlet component supporting file upload/download.
 *
 * @version $Rev$ $Date$
 */
@Scope("COMPOSITE")
@Service(Servlet.class)
public class FileServiceImpl extends HttpServlet {
    private static final long serialVersionUID = -4560385595481971616L;
    
    private static final Logger logger = Logger.getLogger(FileServiceImpl.class.getName());

    @Property
    public String directoryName;
    
    @Reference
    public DomainManagerConfiguration domainManagerConfiguration;
    
    private ServletFileUpload upload;
    
    /**
     * Initialize the component.
     */
    @Init
    public void initialize() throws IOException {
        upload = new ServletFileUpload(new DiskFileItemFactory());
    }
    
    @Override
    public void doPost(HttpServletRequest request, HttpServletResponse response) throws IOException {

        // Upload files
        String rootDirectory = domainManagerConfiguration.getRootDirectory();
        try {
            for (FileItem item: (List<FileItem>)upload.parseRequest(request)) {
                if (!item.isFormField()) {
                    File directory = new File(rootDirectory + "/" + directoryName);
                    if (!directory.exists()) {
                        directory.mkdirs();
                    }
                    logger.fine("post " + item.getName());
                    item.write(new File(directory, item.getName()));
                }
            }
            
            // Redirect to the admin page
            response.sendRedirect("/ui/files");
        }
        catch (Exception e) {
            throw new IOException(e.toString());
        }
    }
    
    @Override
    protected void doGet(HttpServletRequest request, HttpServletResponse response) throws ServletException, IOException {
        
        // Download a file
        String requestURI = URLDecoder.decode(request.getRequestURI(), "UTF-8");
        String path = requestURI.substring(request.getServletPath().length());
        if (path.startsWith("/")) {
            path = path.substring(1);
        }
        logger.fine("get " + path);
        
        try {
            
            // Analyze the given path
            URI uri = URI.create(path);
            String scheme = uri.getScheme();
            if (scheme == null) {

                // If no scheme is specified then the path identifies file
                // inside our directory
                String rootDirectory = domainManagerConfiguration.getRootDirectory();
                uri = new File(rootDirectory + "/" + directoryName, path).toURI();
                
            } else if (!scheme.equals("file")) {
                
                // If the scheme does not identify a local file, just redirect to the server
                // hosting the file
                response.sendRedirect(path);
            }
            
            // Read the file and write to response 
            URLConnection connection = uri.toURL().openConnection();
            connection.setUseCaches(false);
            connection.connect();
            InputStream is = connection.getInputStream();
            ServletOutputStream os = response.getOutputStream();
            byte[] buffer = new byte[4096];
            for (;;) {
                int n = is.read(buffer);
                if (n < 0) {
                    break;
                }
                os.write(buffer, 0, n);
            }
            is.close();
            os.flush();
            
      } catch (FileNotFoundException e) {
          response.sendError(HttpServletResponse.SC_NOT_FOUND);
      }
    }
    
}