package org.nzdl.gsdl.GsdlCollageApplet;

import java.awt.*;
import java.io.*;
import java.net.*;
import java.util.*;
import java.awt.image.*;
import java.awt.geom.*;

/** 
 *  @author Katrina Edgar
 *  @author David Bainbridge
 *
 *  Stores images that are downloaded but have not yet been displayed
 *  in the applet. Provides methods to add to and remove from this list
 *  and check it's size. It uses an inner class to store the data for these
 *  images, comprising of three parts: the image itself, it's source url
 *  and the name of the image */
public class DownloadImages {

    /** Data structure to store an image that has been downloaded and is
     *  waiting to be used. */
    public class ImageUrlTriple {

	Image image_;
	String urlString_;
	String name_;
        URL url_;

	/** Constructs a downloaded image structure from the given parameters
	 *  @param image the graphical image
	 *  @param url the source url for this image
	 *  @param name the name of the image file */
	public ImageUrlTriple (Image image, URL url, String urlString, String name)
	{
	    image_ = image;
	    url_ = url;
            urlString_ = urlString; 
	    name_ = name;
	}

	Image image() {
	    return image_;
	}

	String urlString() {
	    return urlString_;
	}

	String name() {
	    return name_;
	}

	URL url(){
	    return url_;
	}

    }

   
    ImageUrlTriple downloaded_image;
    CollageImage collage_image; 

    /** Refers to applet */
    GsdlCollageApplet app_ = null;
    boolean isJava2_;
    int num_of_downloads;
    boolean stopDownload;

  

    /** Initialises an empty vector to store downloaded images in and sets
     *  the verbosity for this class */
    public DownloadImages(GsdlCollageApplet app, int verbosity, boolean isJava2)
    {
	
        app_=app;
        isJava2_= isJava2;
    }


    /** Push a new image into the vector of downloaded images
     *  @param image the graphical image to add
     *  @param url the source url of the image
     *  @param name the name of the image to add */
    public  synchronized int downloadImage(MediaTracker tracker, URL url, String urlString, String name)
    {

	while (downloaded_image != null ){
	    System.out.println(Thread.currentThread().getName() + " wait to download..."); 
	    try{
		wait();
	    }
	    catch(InterruptedException e){
		return 0;
	    }

	}

	    Image image = Toolkit.getDefaultToolkit().getImage(url);

	    tracker.addImage(image,num_of_downloads);

	    try{
	       System.out.println( "   downloading ..."); 
	       tracker.waitForID(num_of_downloads);
                System.out.println(Thread.currentThread().getName() + " get!!!"); 
	       }
	       catch (InterruptedException e){
	        return 0;
	     }
     
	downloaded_image  = new ImageUrlTriple(image,url,urlString,name);
	num_of_downloads++;

	if (num_of_downloads == app_.maxDownloads()){
	    stopDownload = true;
            System.out.println("num_of_downloads "+num_of_downloads);

	}	
	//System.out.println("num_of_downloads "+num_of_downloads +" ");
	notify();
       
	return num_of_downloads ;
    }

    /** Remove the image from the specified position in the array of downloaded images
     *  @return an ImageUrlTriple containing the image, url and image name */
    public synchronized CollageImage getCollageImage()
    {
	if (stopDownload)  return null;   

	while (downloaded_image == null && !stopDownload){
	    System.out.println(Thread.currentThread().getName() + " wait to get Collage image...");
	    try{
		wait();
	    }
	    catch(InterruptedException e){
		//e.printStackTrace();	
		return null;
	    }
	}

	collage_image = process(downloaded_image);
	downloaded_image = null;
       
        notify();
	System.out.println(Thread.currentThread().getName() + " get Collage image!!!");
        return collage_image;

    }

    public void stopDownload(){
        stopDownload = true;
    }

    private CollageImage process(ImageUrlTriple iutriple){
            Image image     = iutriple.image();
	    String from_url = iutriple.urlString();
	    String img_name = iutriple.name();
	    URL url =  iutriple.url();
	    
	    CollageImage collage_image = new CollageImage(image,url,from_url,img_name);

	    image = collage_image.image_;
	    // images x and y dimensions
	    int image_x_dim = image.getWidth(app_);
	    int image_y_dim = image.getHeight(app_);

	    if ((image_x_dim>0) && (image_y_dim>0))
	    {
		collage_image.setDimensions(image_x_dim,image_y_dim);
		
		// places and sizes the image
		MyAffineTransform af = new MyAffineTransform(image_x_dim,image_y_dim);
		
		// sets location & size of collage image
		collage_image.setAffineTransform(af, isJava2_);
		
		 if (isJava2_ ) {
		    collage_image.image_ 
			= restoreAlpha(collage_image.image_, 0, 0, 
				       collage_image.image_x_dim_, collage_image.image_y_dim_); 
		    
		}
			
			
	    }
	 
	    collage_image.fresh = false;
	    return collage_image;
    }

  /** Resets the alpha channel of an image so that it appears solid
     *
     *  @param img the image to restore
     *  @param x the x co-ordinate of the image
     *  @param y the y co-ordinate of the image
     *  @param w the width of the image
     *  @param h the height of the image */
    public Image restoreAlpha(Image img, int x, int y, int w, int h) {
      
	// declare an array to hold the pixels
	int[] pixels = new int[w * h];
	
	// get the pixels of the image into the pixels array
	PixelGrabber pg = new PixelGrabber(img, x, y, w, h, pixels, 0, w);
       
	try {
	    System.err.println("  grab pixels....");
	    pg.grabPixels();
	    System.err.println("  got pixels");
	} catch (InterruptedException e) {
	    System.err.println("interrupted waiting for pixels!");
	    return img;
	}

      
	// check for any failures
	if ((pg.getStatus() & ImageObserver.ABORT) != 0) {
	    System.err.println(" image fetch aborted or errored");
	    return img;
	}

	// loop through every pixel in the picture and handle it
	   for (int j = 0; j < h; j++) {
	       for (int i = 0; i < w; i++) {
		   pixels[j * w + i] |= (255 << 24) & 0xff000000;
	       }
	   }
	   
	   // set the pixels of the whole picture to the pixels array
	   pg.setPixels(0, 0, w, h, pg.getColorModel(), pixels, 0, w);
	   // create the new image and return it
	   return( app_.createImage(new MemoryImageSource(w, h, pixels, 0, w)) );
	  
	
	   
	   
    }


}