/*
    * Copyright 2007-2012 the original author or authors.
    *
    * 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 org.springbyexample.web.servlet.image;
  
  import java.io.File;
  import java.util.ArrayList;
  import java.util.List;
  
  import javax.servlet.http.HttpServletRequest;
  import javax.servlet.http.HttpServletResponse;
  
  import org.slf4j.Logger;
  import org.slf4j.LoggerFactory;
  import org.springbyexample.util.image.ImageProcessor;
  import org.springframework.util.StringUtils;
  import org.springframework.web.servlet.ModelAndView;
  import org.springframework.web.servlet.handler.HandlerInterceptorAdapter;
  
  /**
   * Intercepts a request and if the path to the view matches 
   * a directory in the image directory, a list of images will be 
   * created and thumbnails can optionally be generated.
   * 
   * @author David Winterfeldt
   */
  public class ImageInterceptor extends HandlerInterceptorAdapter {
  
  	final Logger logger = LoggerFactory.getLogger(ImageInterceptor.class);
  	
  	protected ImageProcessor imageProcessor = null;
  	protected String rootImagePath = null;
  	protected String imagesPath = "/images";
  	protected String thumbnailSuffix = "-thumbnail";
  	protected String fileSuffix = ".jpg";
  	protected String imageViewName = null;	
  	protected int rowWidth = 5;
  	
  	/**
       * Sets image processor.
       */
      public void setImageProcessor(ImageProcessor imageProcessor) {
          this.imageProcessor = imageProcessor;
      }
  
  	/**
  	 * Sets root image path.
  	 */
  	public void setRootImagePath(String rootImagePath) {
  		this.rootImagePath = rootImagePath;
  	}
  
  	/**
  	 * Sets relative image path under root.
  	 */
  	public void setImagesPath(String imagesPath) {
  		this.imagesPath = imagesPath;
  	}
  
  	/**
  	 * Sets thumbnail suffix.
  	 */
  	public void setThumbnailSuffix(String thumbnailSuffix) {
  		this.thumbnailSuffix = thumbnailSuffix;
  	}
  
  	/**
  	 * A default image display view to have the interceptor 
  	 * redirect to if an images directory is found 
  	 * that matches the request.
  	 */
      public void setImageViewName(String imageViewName) {
          this.imageViewName = imageViewName;
      }
  
  	/**
  	 * Sets file suffice.
  	 */
  	public void setFileSuffix(String fileSuffix) {
  		this.fileSuffix = fileSuffix;
  	}
  
  	/**
  	 * Row width to expose to view for displaying image list.
  	 */
  	public void setRowWidth(int rowWidth) {
         this.rowWidth = rowWidth;
     }
 
 	/**
 	 * Intercepts before request.
 	 */
 	@Override
 	public void postHandle(HttpServletRequest request, HttpServletResponse response, 
 						   Object handler, ModelAndView modelAndView)
 			throws Exception {
 		List<ThumbnailBean> lResults = new ArrayList<ThumbnailBean>();
 
 		if (!StringUtils.hasText(rootImagePath)) {
 			rootImagePath = request.getSession().getServletContext().getRealPath("/");
 		}
     	
     	String path = request.getServletPath();
     	path = StringUtils.stripFilenameExtension(path);
 		
     	String imagePath = imagesPath + path;
     	String absoluteImagePath = StringUtils.cleanPath(rootImagePath + "/" + imagePath);
     	
     	//logger.debug("imagePath={}", absoluteImagePath);
     	
     	File dir = new File(absoluteImagePath);
     	
 		if (dir.isDirectory()) {
 			File fileList[] = dir.listFiles();
 			
 			for (int i = 0; i < fileList.length; i++) {
 				File file = fileList[i];
 				
 				if (file.exists() && !file.isDirectory() && 
 			        !file.getName().endsWith(thumbnailSuffix + fileSuffix)) {
 					String name = StringUtils.stripFilenameExtension(file.getName());
 					
 					String thumbnailName = name + thumbnailSuffix + fileSuffix;
 					
 					String mainImagePath = imagePath + "/" + name + fileSuffix;
 					String thumbnailPath = imagePath + "/" + thumbnailName;
 					
 					File newFile = new File(dir, thumbnailName);
 					
 					// if thumbnail file doesn't exist, create
 					if  (!newFile.exists()) {
 						imageProcessor.scaleImage(file, newFile);
 					}
 					
 					lResults.add(new ThumbnailBean(mainImagePath, thumbnailPath));
 				}
 			}
 
 			modelAndView.setViewName(imageViewName);
 		}
 		
 		modelAndView.addObject("rowWidth", rowWidth);
     	modelAndView.addObject("imageList", lResults);
     }
     	   
 }