/*******************************************************************************
 * Copyright (c) 2000, 2006 IBM Corporation and others.
 * All rights reserved. This program and the accompanying materials
 * are made available under the terms of the Eclipse Public License v1.0
 * which accompanies this distribution, and is available at
 * http://www.eclipse.org/legal/epl-v10.html
 *
 * Contributors:
 *     IBM Corporation - initial API and implementation
 *******************************************************************************/
module dwt.internal.image.PngEncoder;

import dwt.internal.image.LEDataOutputStream;
import dwt.internal.image.PngDeflater;
import dwt.dwthelper.ByteArrayOutputStream;
import dwt.SWT;
import dwt.graphics.ImageData;
import dwt.graphics.ImageLoader;
import dwt.graphics.RGB;
import dwt.internal.image.PngChunk;

import tango.core.Exception;

final class PngEncoder {

	static const byte SIGNATURE[] = [cast(byte) '\211', cast(byte) 'P', cast(byte) 'N', cast(byte) 'G', cast(byte) '\r', cast(byte) '\n', cast(byte) '\032', cast(byte) '\n'];
	static const byte TAG_IHDR[] = [cast(byte) 'I', cast(byte) 'H', cast(byte) 'D', cast(byte) 'R'];
	static const byte TAG_PLTE[] = [cast(byte) 'P', cast(byte) 'L', cast(byte) 'T', cast(byte) 'E'];
	static const byte TAG_TRNS[] = [cast(byte) 't', cast(byte) 'R', cast(byte) 'N', cast(byte) 'S'];
	static const byte TAG_IDAT[] = [cast(byte) 'I', cast(byte) 'D', cast(byte) 'A', cast(byte) 'T'];
	static const byte TAG_IEND[] = [cast(byte) 'I', cast(byte) 'E', cast(byte) 'N', cast(byte) 'D'];

	ByteArrayOutputStream bytes;
	PngChunk chunk;

	ImageLoader loader;
	ImageData data;
	int transparencyType;

	int width, height, bitDepth, colorType;

	int compressionMethod = 0;
	int filterMethod = 0;
	int interlaceMethod = 0;

public this(ImageLoader loader) {
    this.bytes = new ByteArrayOutputStream(1024);
	this.loader = loader;
	this.data = loader.data[0];
	this.transparencyType = data.getTransparencyType();

	this.width = data.width;
	this.height = data.height;

	this.bitDepth = 8;

	this.colorType = 2;

	if (data.palette.isDirect) {
		if (transparencyType == SWT.TRANSPARENCY_ALPHA) {
			this.colorType = 6;
		}
	}
	else {
		this.colorType = 3;
	}

	if (!(colorType == 2 || colorType == 3 || colorType == 6)) SWT.error(SWT.ERROR_INVALID_IMAGE);

}

void writeShort(ByteArrayOutputStream baos, int theShort) {

	byte byte1 = cast(byte) ((theShort >> 8) & 0xff);
	byte byte2 = cast(byte) (theShort & 0xff);
	byte[] temp = [byte1, byte2];
	baos.write(temp, 0, 2);

}

void writeInt(ByteArrayOutputStream baos, int theInt) {

	byte byte1 = cast(byte) ((theInt >> 24) & 0xff);
	byte byte2 = cast(byte) ((theInt >> 16) & 0xff);
	byte byte3 = cast(byte) ((theInt >> 8) & 0xff);
	byte byte4 = cast(byte) (theInt & 0xff);
	byte[] temp = [byte1, byte2, byte3, byte4];
	baos.write(temp, 0, 4);

}

void writeChunk(byte[] tag, byte[] buffer) {

	int bufferLength = (buffer != null) ? buffer.length : 0;

	chunk = new PngChunk(bufferLength);

	writeInt(bytes, bufferLength);
	bytes.write(tag, 0, 4);
	chunk.setType(tag);
	if (bufferLength != 0) {
		bytes.write(buffer, 0, bufferLength);
		chunk.setData(buffer);
	}
	else {
		chunk.setCRC(chunk.computeCRC());
	}
	writeInt(bytes, chunk.getCRC());

}

void writeSignature() {

	bytes.write(SIGNATURE, 0, 8);

}

void writeHeader() {

	ByteArrayOutputStream baos = new ByteArrayOutputStream(13);

	writeInt(baos, width);
	writeInt(baos, height);
	baos.write(bitDepth);
	baos.write(colorType);
	baos.write(compressionMethod);
	baos.write(filterMethod);
	baos.write(interlaceMethod);

	writeChunk(TAG_IHDR, baos.toByteArray());

}

void writePalette() {

	RGB[] RGBs = data.palette.getRGBs();

	if (RGBs.length > 256) SWT.error(SWT.ERROR_INVALID_IMAGE);

	ByteArrayOutputStream baos = new ByteArrayOutputStream(RGBs.length);

	for (int i = 0; i < RGBs.length; i++) {

		baos.write(cast(byte) RGBs[i].red);
		baos.write(cast(byte) RGBs[i].green);
		baos.write(cast(byte) RGBs[i].blue);

	}

	writeChunk(TAG_PLTE, baos.toByteArray());

}

void writeTransparency() {

	ByteArrayOutputStream baos = new ByteArrayOutputStream();

	switch (transparencyType) {

		case SWT.TRANSPARENCY_ALPHA:

			int pixelValue, alphaValue;

			byte[] alphas = new byte[data.palette.getRGBs().length];

			for (int y = 0; y < height; y++) {

				for (int x = 0; x < width; x++) {

					pixelValue = data.getPixel(x, y);
					alphaValue = data.getAlpha(x, y);

					alphas[pixelValue] = cast(byte) alphaValue;

				}

			}

			baos.write(alphas, 0, alphas.length);

			break;

		case SWT.TRANSPARENCY_PIXEL:

			int pixel = data.transparentPixel;

			if (colorType == 2) {

				int redMask = data.palette.redMask;
				int redShift = data.palette.redShift;
				int greenMask = data.palette.greenMask;
				int greenShift = data.palette.greenShift;
				int blueShift = data.palette.blueShift;
				int blueMask = data.palette.blueMask;

				int r = pixel & redMask;
				r = (redShift < 0) ? r >>> -redShift : r << redShift;
				int g = pixel & greenMask;
				g = (greenShift < 0) ? g >>> -greenShift : g << greenShift;
				int b = pixel & blueMask;
				b = (blueShift < 0) ? b >>> -blueShift : b << blueShift;

				writeShort(baos, r);
				writeShort(baos, g);
				writeShort(baos, b);

			}

			if (colorType == 3) {

				byte[] padding = new byte[pixel + 1];

				for (int i = 0; i < pixel; i++) {

					padding[i] = cast(byte) 255;

				}

				padding[pixel] = cast(byte) 0;

				baos.write(padding, 0, padding.length);

			}

			break;

	}

	writeChunk(TAG_TRNS, baos.toByteArray());

}

void writeImageData() {

	ByteArrayOutputStream baos = new ByteArrayOutputStream(1024);

	if (colorType == 3) {

		int[] lineData = new int[width];

		for (int y = 0; y < height; y++) {

			byte filter[] = [0];
			baos.write(filter, 0, 1);

			data.getPixels(0, y, width, lineData, 0);

			for (int x = 0; x < lineData.length; x++) {

				baos.write(cast(byte) lineData[x]);

			}

		}

	}

	else {

		int[] lineData = new int[width];
		byte[] alphaData = new byte[width];

		int redMask = data.palette.redMask;
		int redShift = data.palette.redShift;
		int greenMask = data.palette.greenMask;
		int greenShift = data.palette.greenShift;
		int blueShift = data.palette.blueShift;
		int blueMask = data.palette.blueMask;

		for (int y = 0; y < height; y++) {

			byte filter[] = [0];
			baos.write(filter, 0, 1);

			data.getPixels(0, y, width, lineData, 0);

			if (colorType == 6) {
				data.getAlphas(0, y, width, alphaData, 0);
			}

			for (int x = 0; x < lineData.length; x++) {

				int pixel = lineData[x];

				int r = pixel & redMask;
				r = (redShift < 0) ? r >>> -redShift : r << redShift;
				int g = pixel & greenMask;
				g = (greenShift < 0) ? g >>> -greenShift : g << greenShift;
				int b = pixel & blueMask;
				b = (blueShift < 0) ? b >>> -blueShift : b << blueShift;

				byte pixels[] = [cast(byte) r, cast(byte) g, cast(byte) b];
				baos.write(pixels, 0, 3);

				if (colorType == 6) {

					byte alpha[] = [alphaData[x]];
					baos.write(alpha, 0, 1);

				}

			}

		}

	}

	PngDeflater deflater = new PngDeflater();
	byte[] compressed = deflater.deflate(baos.toByteArray());

	writeChunk(TAG_IDAT, compressed);

}

void writeEnd() {

	writeChunk(TAG_IEND, null);

}

public void encode(LEDataOutputStream outputStream) {

	try {

		writeSignature();
		writeHeader();

		if (colorType == 3) {
			writePalette();
		}

		bool transparencyAlpha = (transparencyType == SWT.TRANSPARENCY_ALPHA);
		bool transparencyPixel = (transparencyType == SWT.TRANSPARENCY_PIXEL);
		bool type2Transparency = (colorType == 2 && transparencyPixel);
		bool type3Transparency = (colorType == 3 && (transparencyAlpha || transparencyPixel));

		if (type2Transparency || type3Transparency) {
			writeTransparency();
		}

		writeImageData();
		writeEnd();

		outputStream.write(bytes.toByteArray());

	}

	catch (IOException e) {

		SWT.error(SWT.ERROR_IO, e);

	}

}

}