/**
 * The contents of this file are subject to the license and copyright
 * detailed in the LICENSE and NOTICE files at the root of the source
 * tree and available online at
 *
 * http://www.dspace.org/license/
 */
package org.dspace.app.mediafilter;

import java.io.File;
import java.io.FileOutputStream;
import java.io.IOException;
import java.io.InputStream;
import java.util.regex.Pattern;
import java.util.regex.PatternSyntaxException;

import javax.imageio.ImageIO;

import org.dspace.content.Bitstream;
import org.dspace.content.Bundle;
import org.dspace.content.Item;
import org.dspace.content.factory.ContentServiceFactory;
import org.dspace.content.service.ItemService;
import org.dspace.core.Context;
import org.im4java.core.ConvertCmd;
import org.im4java.core.IM4JavaException;
import org.im4java.core.IMOperation;
import org.im4java.process.ProcessStarter;

import org.dspace.core.ConfigurationManager;

/**
 * Filter image bitstreams, scaling the image to be within the bounds of
 * thumbnail.maxwidth, thumbnail.maxheight, the size we want our thumbnail to be
 * no bigger than. Creates only JPEGs.
 */
public abstract class ImageMagickThumbnailFilter extends MediaFilter
{
	protected static int width = 180;
    protected static int height = 120;
	private static boolean flatten = true;
	static String bitstreamDescription = "IM Thumbnail";
	static final String defaultPattern = "Generated Thumbnail";
	static Pattern replaceRegex = Pattern.compile(defaultPattern);
    protected final ItemService itemService = ContentServiceFactory.getInstance().getItemService();
	
	static {
		String pre = ImageMagickThumbnailFilter.class.getName();
		String s = ConfigurationManager.getProperty(pre + ".ProcessStarter");
		ProcessStarter.setGlobalSearchPath(s);
		width = ConfigurationManager.getIntProperty("thumbnail.maxwidth", width);
		height = ConfigurationManager.getIntProperty("thumbnail.maxheight", height);
                flatten = ConfigurationManager.getBooleanProperty(pre + ".flatten", flatten);
		String description = ConfigurationManager.getProperty(pre + ".bitstreamDescription");
		if (description != null) {
			bitstreamDescription = description;
		}
		try {
			String patt = ConfigurationManager.getProperty(pre + ".replaceRegex");
		    replaceRegex = Pattern.compile(patt == null ? defaultPattern : patt);
		} catch(PatternSyntaxException e) {
			System.err.println("Invalid thumbnail replacement pattern: "+e.getMessage());
		}
	}
	
	public ImageMagickThumbnailFilter() {
	}
	
	
    @Override
    public String getFilteredName(String oldFilename)
    {
        return oldFilename + ".jpg";
    }

    /**
     * @return String bundle name
     *  
     */
    @Override
    public String getBundleName()
    {
        return "THUMBNAIL";
    }

    /**
     * @return String bitstreamformat
     */
    @Override
    public String getFormatString()
    {
        return "JPEG";
    }

    /**
     * @return String bitstreamDescription
     */
    @Override
    public String getDescription()
    {
        return bitstreamDescription;
    }

    public File inputStreamToTempFile(InputStream source, String prefix, String suffix) throws IOException {
		File f = File.createTempFile(prefix, suffix);
		f.deleteOnExit();
    	FileOutputStream fos = new FileOutputStream(f);
    	
    	byte[] buffer = new byte[1024];
    	int len = source.read(buffer);
    	while (len != -1) {
    		fos.write(buffer, 0, len);
    		len = source.read(buffer);
    	}
    	fos.close();
		return f;
    }
    
    public File getThumbnailFile(File f, boolean verbose) throws IOException, InterruptedException, IM4JavaException {
    	File f2 = new File(f.getParentFile(), f.getName() + ".jpg");
    	f2.deleteOnExit();
    	ConvertCmd cmd = new ConvertCmd();
		IMOperation op = new IMOperation();
		op.addImage(f.getAbsolutePath());
		op.thumbnail(width, height);
		op.addImage(f2.getAbsolutePath());
        if (verbose) {
		    System.out.println("IM Thumbnail Param: "+op);
        }
		cmd.run(op);
		return f2;
    }
    
    public File getImageFile(File f, int page, boolean verbose) throws IOException, InterruptedException, IM4JavaException {
    	File f2 = new File(f.getParentFile(), f.getName() + ".jpg");
    	f2.deleteOnExit();
    	ConvertCmd cmd = new ConvertCmd();
		IMOperation op = new IMOperation();
		String s = "[" + page + "]";
		op.addImage(f.getAbsolutePath()+s);
                if (flatten)
                {
                    op.flatten();
                }
		op.addImage(f2.getAbsolutePath());
        if (verbose) {
		    System.out.println("IM Image Param: "+op);
        }
		cmd.run(op);
		return f2;
    }
    
    @Override
    public boolean preProcessBitstream(Context c, Item item, Bitstream source, boolean verbose)
            throws Exception
    {
    	String nsrc = source.getName();
    	for(Bundle b: itemService.getBundles(item, "THUMBNAIL")) {
    		for(Bitstream bit: b.getBitstreams()) {
                String n = bit.getName();
    			if (n != null) {
    				if (nsrc != null) {
    					if (!n.startsWith(nsrc)) continue;
    				}
    			}
     	    	String description = bit.getDescription();
    	    	//If anything other than a generated thumbnail is found, halt processing
    	    	if (description != null) {
        	    	if (replaceRegex.matcher(description).matches()) {
        	            if (verbose) {
        	    		    System.out.println(description + " " + nsrc + " matches pattern and is replacable.");
        	            }
        	    		continue;
        	    	}
        	    	if (description.equals(bitstreamDescription)) {
        	            if (verbose) {
        	    		    System.out.println(bitstreamDescription + " " + nsrc + " is replacable.");
        	            }
        	    		continue;    	    		
        	    	}
    	    	}
    			System.out.println("Custom Thumbnail exists for " + nsrc + " for item " + item.getHandle() + ".  Thumbnail will not be generated. ");
    			return false;
    		}
    	}
    	
    	
        return true; //assume that the thumbnail is a custom one
    }

}