/*

  * Copyright (c) 2003-2011, Simon Brown

  * All rights reserved.

  *

  * Redistribution and use in source and binary forms, with or without

  * modification, are permitted provided that the following conditions are met:

  *

  *   - Redistributions of source code must retain the above copyright

  *     notice, this list of conditions and the following disclaimer.

  *

  *   - 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.

  *

  *   - Neither the name of Pebble 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 COPYRIGHT OWNER 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.

  */

 package net.sourceforge.pebble.decorator;

 import java.awt.RenderingHints;

 import java.awt.geom.AffineTransform;

 import java.awt.image.AffineTransformOp;

 import java.awt.image.BufferedImage;

 import java.io.File;

 import java.io.IOException;

 import java.util.HashMap;

 import java.util.Iterator;

 import java.util.Map;

 import net.sourceforge.pebble.domain.BlogEntry;

 import net.sourceforge.pebble.domain.StaticPage;

 import net.sourceforge.pebble.api.decorator.ContentDecoratorContext;

 import java.util.regex.Matcher;

 import java.util.regex.Pattern;

 import javax.imageio.IIOImage;

 import javax.imageio.ImageIO;

 import javax.imageio.ImageWriteParam;

 import javax.imageio.ImageWriter;

 import javax.imageio.stream.FileImageOutputStream;

 import net.sourceforge.pebble.PluginProperties;

 import net.sourceforge.pebble.domain.Blog;

 /**

  * Converts <thumbnail> tags into image thumbnails.

  * @author Alan Burlison

  */

 public class ThumbnailDecorator extends ContentDecoratorSupport {

     /**

      * Decorates the specified blog entry.

      *

      * @param context   the context in which the decoration is running

      * @param blogEntry the blog entry to be decorated

      */

     @Override

     public void decorate(ContentDecoratorContext context, BlogEntry blogEntry) {

         Blog blog = blogEntry.getBlog();

         blogEntry.setBody(replaceTags(blogEntry.getBody(), blog));

         blogEntry.setExcerpt(replaceTags(blogEntry.getExcerpt(), blog));

     }

     /**

      * Decorates the specified static page.

      *

      * @param context    the context in which the decoration is running

      * @param staticPage the static page to be decorated

      */

     @Override

     public void decorate(ContentDecoratorContext context,

       StaticPage staticPage) {

         staticPage.setBody(replaceTags(staticPage.getContent(),

           staticPage.getBlog()));

     }

     /**

      * Find all the thumbnail tags and replace them with the equivalent HTML.

      * @param content the page content

      * @param blog the current blog.

      * @return the decorated content.

      */

     private String replaceTags(String content, Blog blog) {

         // Check there is something to do.

         if (content == null || content.length() == 0) {

             return "";

         }

         // Establish default sizes.

         int defaultThumbSize = 200;

         int defaultPopupSize = 640;

         PluginProperties props = blog.getPluginProperties();

         if (props.hasProperty(thumbSizeProp)) {

             try {

                 defaultThumbSize =

                   Integer.parseInt(props.getProperty(thumbSizeProp));

             } catch (NumberFormatException nfe) {

                 // Ignore.

             }

         }

         if (props.hasProperty(popupSizeProp)) {

             try {

                 defaultPopupSize =

                   Integer.parseInt(props.getProperty(popupSizeProp));

             } catch (NumberFormatException nfe) {

                 // Ignore.

             }

         }

         // Find all the thumbnail tags.

         Matcher tagM = tagRE.matcher(content);

         StringBuffer sb = new StringBuffer(content.length());

         while (tagM.find()) {

             StringBuilder repl = new StringBuilder();

             Matcher attrM = attrRE.matcher(tagM.group(1));

             String src = null;

             String alt = "";

             int thumbSize = defaultThumbSize;

             int popupSize = defaultPopupSize;

             // Parse the attributes of the tag.

             while (attrM.find()) {

                 String an = attrM.group(1);

                 String av = attrM.group(2);

                 if (an.equalsIgnoreCase("src")) {

                     src = av;

                 } else if (an.equalsIgnoreCase("alt")) {

                     alt = av;

                 } else if (an.equalsIgnoreCase("thumbSize")) {

                     try {

                         thumbSize = Integer.parseInt(av);

                     } catch (NumberFormatException e) {

                         tagM.appendReplacement(sb, String.format(

                           "<!-- ERROR: invalid thumbnail thumbSize \"%s\" -->",

                           av));

                     }

                 } else if (an.equalsIgnoreCase("popupSize")) {

                     try {

                         popupSize = Integer.parseInt(av);

                     } catch (NumberFormatException e) {

                         tagM.appendReplacement(sb, String.format(

                           "<!-- ERROR: invalid thumbnail popupSize \"%s\" -->",

                           av));

                     }

                 }

             }

             // Replace the tag with the equivalent HTML.

             if (src == null) {

                 tagM.appendReplacement(sb, String.format(

                     "<!-- ERROR: missing thumbnail src -->"));

             } else {

                 tagM.appendReplacement(sb,

                   renderTag(new File(src), thumbSize, popupSize, alt, blog));

             }

         }

         tagM.appendTail(sb);

         return sb.toString();

     }

     /**

      * Render a thumbnail tag into the equivalent HTML, also creating and

      * caching the thumbnail as appropriate.

      * @param src image source.

      * @param thumbSize required thumbmail size, maximum dimension.

      * @param popupSize required popup size, maximum dimension.

      * @param alt alternate text for link.

      * @param blog the current blog.

      * @return the equivalent HTML.

      */

     private String renderTag(File src, int thumbSize, int popupSize,

       String alt, Blog blog) {

         // Check the image exists.

         File img = new File(blog.getRoot(), src.getPath());

         if (! img.isFile()) {

             return String.format(

               "<!-- ERROR: invalid thumbnail src \"%s\" -->", src);

         }

         // Check the thumbnail directory exists.

         File thumbDir = new File(img.getParent(), "thumbnails");

         if (!thumbDir.isDirectory()) {

             if (!thumbDir.mkdir()) {

                 return String.format(

                   "<!-- ERROR: can't create thumbnail directory -->",

                   thumbDir.toString());

             }

         }

         // Check that an up-to-date thumbnail exists.

         File thumb = new File(thumbDir, img.getName());

         if (!thumb.isFile() || thumb.lastModified() < img.lastModified()) {

             if (! createThumbnail(img, thumb, thumbSize)) {

                 return String.format(

                   "<!-- ERROR: can't create thumbnail \"%s\" -->", thumb);

             }

         }

         // Build the replacement HTML & return it.

         File tsrc = new File(new File(src.getParent(), "thumbnails"),

           src.getName());

         return String.format("<a href=\"%1$s\" onclick=\"window.open(" +

           "'%1$s','popup','width=%4$d,height=%4$d,toolbar=no,directories=no," +

           "location=no,menubar=no,status=no'); return false\" " +

           "class=\"thumbnailLink\"><img src=\"%2$s\" alt=\"%3$s\" " +

           "class=\"thumbnailImage\"/></a>",

           src, tsrc, alt, popupSize);

     }

     /**

      * Create a new thumbnail from an image.

      * @param imgFile the image to thumbnail.

      * @param thumbFile the thumbnail to create.

      * @param thumbSize the maximum dimension of the thumbnail.

      * @return true if the thumbnail was created successfully.

      */

     public boolean createThumbnail(File imgFile, File thumbFile,

       int thumbSize) {

         // Work out the image file suffix.

         String suffix = imgFile.getName();

         int dot = suffix.lastIndexOf('.');

         if (dot < 1) {

             return false;

         }

         suffix = suffix.substring(dot + 1);

         try {

             // Read in the image.

             BufferedImage img = ImageIO.read(imgFile);

             if (img == null) {

                 return false;

             }

             // Calcuate the scaling.

             int ih = img.getHeight();

             int iw = img.getWidth();

             int thumbH, thumbW;

             float scale;

             if (iw > ih) {

                 scale = (float) thumbSize / (float) iw;

                 thumbW = thumbSize;

                 thumbH = Math.round(ih * scale);

             } else {

                 scale = (float) thumbSize / (float) ih;

                 thumbH = thumbSize;

                 thumbW = Math.round(iw * scale);

             }

             // Scale the image.

             BufferedImage thumb =

               new BufferedImage(thumbW, thumbH, img.getType());

             AffineTransform at =

               AffineTransform.getScaleInstance(scale, scale);

             AffineTransformOp ato = new AffineTransformOp(at, renderHints);

             ato.filter(img, thumb);

             // Save the image.

             Iterator<ImageWriter> iwi =

               ImageIO.getImageWritersBySuffix(suffix);

             if (! iwi.hasNext()) {

                 return false;

             }

             ImageWriter thumbWriter = iwi.next();

             ImageWriteParam iwp = thumbWriter.getDefaultWriteParam();

             if (iwp.canWriteCompressed()) {

                 String ct[] = iwp.getCompressionTypes();

                 if (ct != null) {

                     iwp.setCompressionMode(ImageWriteParam.MODE_EXPLICIT);

                     iwp.setCompressionType(ct[0]);

                     iwp.setCompressionQuality(0.8F);

                 }

             }

             FileImageOutputStream thumbOut =

               new FileImageOutputStream(thumbFile);

             thumbWriter.setOutput(thumbOut);

             thumbWriter.write(null, new IIOImage(thumb, null, null), iwp);

             thumbWriter.dispose();

             thumbOut.close();

         } catch (IOException ex) {

             return false;

         }

         return true;

     }

     /** Default thumbnail size property name. */

     private static final String thumbSizeProp = "Thumbnail.thumbnailSize";

     /** Default popup window size property name. */

     private static final String popupSizeProp = "Thumbnail.popupSize";

     /** RE for matching thumbnail tags. */

     private static Pattern tagRE = Pattern.compile(

       "<thumbnail\\s+(.+?)\\s*/>",

       Pattern.CASE_INSENSITIVE | Pattern.DOTALL);

     /** RE for matching tag attributes. */

     private static Pattern attrRE = Pattern.compile(

       "([\\w_-]+)\\s*=\\s*\"([^\"]+)\"",

       Pattern.CASE_INSENSITIVE | Pattern.DOTALL);

     /** Image transform hints. */

     private static final RenderingHints renderHints;

     // Initialise rendering hints.

     static {

         Map<RenderingHints.Key, Object> hintMap =

           new HashMap<RenderingHints.Key, Object>();

         hintMap.put(RenderingHints.KEY_ALPHA_INTERPOLATION,

           RenderingHints.VALUE_ALPHA_INTERPOLATION_QUALITY);

         hintMap.put(RenderingHints.KEY_ANTIALIASING,

           RenderingHints.VALUE_ANTIALIAS_ON);

         hintMap.put(RenderingHints.KEY_COLOR_RENDERING,

           RenderingHints.VALUE_COLOR_RENDER_QUALITY);

         hintMap.put(RenderingHints.KEY_DITHERING,

           RenderingHints.VALUE_DITHER_DISABLE);

         hintMap.put(RenderingHints.KEY_INTERPOLATION,

           RenderingHints.VALUE_INTERPOLATION_BILINEAR);

         hintMap.put(RenderingHints.KEY_ALPHA_INTERPOLATION,

           RenderingHints.VALUE_ALPHA_INTERPOLATION_QUALITY);

         hintMap.put(RenderingHints.KEY_COLOR_RENDERING,

           RenderingHints.VALUE_COLOR_RENDER_QUALITY);

         renderHints = new RenderingHints(hintMap);

     }

 }