package org.hwo.image.tiff;

import java.awt.image.BufferedImage;
import java.io.File;
import java.io.FileInputStream;
import java.lang.reflect.Array;
import java.nio.ByteBuffer;
import java.nio.ByteOrder;
import java.nio.ShortBuffer;
import java.util.Arrays;
import java.util.LinkedList;
import java.util.List;

import org.hwo.image.ImageFile;
import org.hwo.image.UnsupportedFormatException;

public class TiffFile implements ImageFile {

	ByteBuffer	sourceBuffer;
	
	boolean	bigEndian;
	LinkedList<IFD> ifds;
	List<BufferedImage> pages;
	
	
	public TiffFile()
	{
		reset();
	}
	
	@Override
	public ImageFile newInstance() {
		return new TiffFile();
	}

	@Override
	public void reset() {
		bigEndian = false;
		ifds = new LinkedList<IFD>();
		
		pages = new LinkedList<BufferedImage>();
		sourceBuffer = null;
	}

	@Override
	public void load(File imageFile) {
		
		if (!identify(imageFile))
			throw new UnsupportedFormatException();
		
		Integer firstIFD = sourceBuffer.getInt(0x0004);
		sourceBuffer.position(firstIFD);
		
		ifds.add(0, new IFD(this));
		
		reorderPages();
		
	}
		
	private void reorderPages()
	{
		System.err.println("Testing Page Order");
		
		if (ifds.size() == 0)	// Keine Seiten vorhanden
			return;
		
		if (ifds.get(0).getPageNumber() == -1)	// Keine Seitenzahlen angegeben
			return;
		
		System.err.println("Reorder...");
		
		IFD[] ifdsOrdered = new IFD[ ifds.size() ];
		
		for (int n=0; n<ifdsOrdered.length; n++)
			ifdsOrdered[ ifds.get(n).getPageNumber() ] = ifds.get(n);
		
		ifds.clear();
		ifds.addAll(Arrays.asList(ifdsOrdered));
	}
	

	@Override
	public void save(File imageFile) {

		
	}

	@Override
	public Integer getNumPages() {
		return ifds.size();
	}

	@Override
	public BufferedImage getPage(Integer pageNo) {
		if (pageNo < ifds.size())
		{
			return ifds.get(pageNo).getBufferedImage();
		}
		return null;
	}

	@Override
	public void addPage(BufferedImage image) {
		ifds.add(new IFD(this, image));
	}
	
	@Override
	public Boolean identify(File imageFile) {
		
		reset();
		
		if (!imageFile.exists())
			if (imageFile.getName().endsWith(".tiff"))
				return true;
			else
				return false;
		
		byte[] buffer = new byte[ (int)imageFile.length() ];

		try
		{
			FileInputStream input = new FileInputStream(imageFile);
			input.read(buffer);
			input.close();
			
			sourceBuffer = ByteBuffer.wrap(buffer);
			
			if (sourceBuffer.getShort(0) == 0x4D4D)
				bigEndian = true;
			else if (sourceBuffer.getShort(0) == 0x4949)
				bigEndian = false;
			else			
				return false;
			
			if (bigEndian)
				sourceBuffer.order(ByteOrder.BIG_ENDIAN);
			else
				sourceBuffer.order(ByteOrder.LITTLE_ENDIAN);
			
			
			if (sourceBuffer.getShort(0x0002) != 42)
				return false;
		} catch (Exception e)
		{
			e.printStackTrace();
			return false;
		}
		return true;
	}	
	
	
}