package org.expeditee.gio;

import java.io.File;
import java.io.IOException;
import java.net.HttpURLConnection;
import java.net.URL;
import java.util.Random;

import org.expeditee.core.Colour;
import org.expeditee.core.Dimension;
import org.expeditee.core.Image;

import com.sun.pdfview.PDFPage;

/**
 * Manager in charge of creating and working with images in memory. Maintains a mapping
 * from org.expeditee.core.Image handles to the underlying images, and provides methods
 * for manipulating the underlying images through those handles.
 * 
 * @author cts16
 */
public abstract class ImageManager {
	
	/*
	 * 
	 *  Image-creation functions
	 *  
	 */
	
	/**
	 * Creates an image of the given size in either main or video RAM.
	 * 
	 * @param hintUseAcceleratedMemory
	 * 			True to use video RAM, false for main memory.
	 */
	public Image createImage(Dimension size, boolean hintUseAcceleratedMemory)
	{
		if (size == null) return null;
		
		return createImage(size.width, size.height, hintUseAcceleratedMemory);
	}

	/** Creates an image in main memory with the given size. */
	public Image createImage(Dimension size)
	{
		return createImage(size, false);
	}

	/** Creates an image in main memory with the given width and height. */
	public Image createImage(int width, int height)	{
		return createImage(width, height, false);
	}
		
	/**
	 * Creates an image of the given width and height in either main or video RAM.
	 * 
	 * @param hintUseAcceleratedMemory
	 * 			True to use video RAM, false for main memory.
	 */
	public abstract Image createImage(int width, int height, boolean hintUseAcceleratedMemory);
	
	/** Creates an image from packed 32-bit ARGB data in an array. */
	public abstract Image createImage(int width, int height, int[] pixelData);
	
	/** Creates an image of a PDF page. */
	public abstract Image createImage(int width, int height, PDFPage page);
	
	/** Creates an image from the raw byte data read from a file.  Must be in a format recognised by the implementing Ecosystem. **/
	public abstract Image createImage(byte[] rawImageData);
	
	/** Creates a new image which is a cropped section of another image. */
	public abstract Image createImageAsCroppedCopy(Image orig, int x, int y, int width, int height);
	
	/** Gets image data from a URL. */
	public abstract Image getImage(URL url);
	
	/** Gets image data from a file. */
	public abstract Image getImage(String filename);
	
	//public abstract Image getItem(byte[] imageData);
	
	/** Gets an image that is just noise */
	public Image getNoise() {
		int width = 100;
		int height = 100;
		int[] pixelData = new int[width * height];
		Random rand = new Random();
		
		for (int i = 0; i < pixelData.length; i++) {
			int alpha = rand.nextInt(256) << 24;
			int red = rand.nextInt(256) << 16;
			int green = rand.nextInt(256) << 8;
			int blue = rand.nextInt(256);
			pixelData[i] = alpha | red | green | blue;
		} 
		
		return createImage(width, height, pixelData);
	}
	
	/** Gets image data from a HTTP connection. */
	public abstract Image getImage(HttpURLConnection connection) throws IOException;
	
	/*
	 * 
	 *  Image-destruction functions
	 *  
	 */
	
	/** Tells the image manager that the given image is no longer needed. */
	public abstract void releaseImage(Image image);
	
	/*
	 * 
	 *  Image info getters
	 *  
	 */
	
	/** Checks if the given handle corresponds to a real image in the image manager. */
	public abstract boolean isImageValid(Image image);
	
	/** Gets the width of the given image. */
	public abstract int getWidth(Image image);
	
	/** Gets the height of the given image. */
	public abstract int getHeight(Image image);
	
	/** Gets the colours of an area of pixels from the image. */
	public abstract Colour[] getPixels(Image image, int x, int y, int width, int height);
	
	/** Gets the colour of a single pixel in the image. */
	public Colour getPixel(Image image, int x, int y)
	{
		Colour[] pixels = getPixels(image, x, y, 1, 1);
		
		if (pixels == null) return null;
		
		return pixels[0];
	}
	
	/*
	 * 
	 *  Image-manipulation functions
	 *  
	 */
	
	/** Sets the colour of a single pixel in the image. */
	public abstract void setPixel(Image image, int x, int y, Colour c);
	
	/** Writes the image data to disk. Format should be png, bmp, etc. */
	public abstract boolean writeImageToDisk(Image image, String format, File file) throws IOException;	
}