/*******************************************************************************
 * Copyright (c) 2000, 2005 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
 * Port to the D programming language:
 *     Frank Benoit <benoit@tionex.de>
 *******************************************************************************/
module dwt.internal.image.OS2BMPFileFormat;

import dwt.DWT;
import dwt.graphics.ImageData;
import dwt.graphics.ImageLoader;
import dwt.graphics.PaletteData;
import dwt.graphics.RGB;
import dwt.internal.image.LEDataInputStream;
import dwt.internal.image.FileFormat;
import dwt.dwthelper.ByteArrayOutputStream;
import dwt.dwthelper.utils;

import tango.core.Exception;

final class OS2BMPFileFormat : FileFormat {
    static final int BMPFileHeaderSize = 14;
    static final int BMPHeaderFixedSize = 12;
    int width, height, bitCount;

override bool isFileFormat(LEDataInputStream stream) {
    try {
        byte[] header = new byte[18];
        stream.read(header);
        stream.unread(header);
        int infoHeaderSize = (header[14] & 0xFF) | ((header[15] & 0xFF) << 8) | ((header[16] & 0xFF) << 16) | ((header[17] & 0xFF) << 24);
        return header[0] is 0x42 && header[1] is 0x4D && infoHeaderSize is BMPHeaderFixedSize;
    } catch (Exception e) {
        return false;
    }
}
byte[] loadData(byte[] infoHeader) {
    int stride = (width * bitCount + 7) / 8;
    stride = (stride + 3) / 4 * 4; // Round up to 4 byte multiple
    byte[] data = loadData(infoHeader, stride);
    flipScanLines(data, stride, height);
    return data;
}
byte[] loadData(byte[] infoHeader, int stride) {
    int dataSize = height * stride;
    byte[] data = new byte[dataSize];
    try {
        if (inputStream.read(data) !is dataSize)
            DWT.error(DWT.ERROR_INVALID_IMAGE);
    } catch (IOException e) {
        DWT.error(DWT.ERROR_IO, e);
    }
    return data;
}
int[] loadFileHeader() {
    int[] header = new int[5];
    try {
        header[0] = inputStream.readShort();
        header[1] = inputStream.readInt();
        header[2] = inputStream.readShort();
        header[3] = inputStream.readShort();
        header[4] = inputStream.readInt();
    } catch (IOException e) {
        DWT.error(DWT.ERROR_IO, e);
    }
    if (header[0] !is 0x4D42)
        DWT.error(DWT.ERROR_INVALID_IMAGE);
    return header;
}
override ImageData[] loadFromByteStream() {
    int[] fileHeader = loadFileHeader();
    byte[] infoHeader = new byte[BMPHeaderFixedSize];
    try {
        inputStream.read(infoHeader);
    } catch (Exception e) {
        DWT.error(DWT.ERROR_IO, e);
    }
    width = (infoHeader[4] & 0xFF) | ((infoHeader[5] & 0xFF) << 8);
    height = (infoHeader[6] & 0xFF) | ((infoHeader[7] & 0xFF) << 8);
    bitCount = (infoHeader[10] & 0xFF) | ((infoHeader[11] & 0xFF) << 8);
    PaletteData palette = loadPalette(infoHeader);
    if (inputStream.getPosition() < fileHeader[4]) {
        // Seek to the specified offset
        try {
            inputStream.skip(fileHeader[4] - inputStream.getPosition());
        } catch (IOException e) {
            DWT.error(DWT.ERROR_IO, e);
        }
    }
    byte[] data = loadData(infoHeader);
    int type = DWT.IMAGE_OS2_BMP;
    return [
        ImageData.internal_new(
            width,
            height,
            bitCount,
            palette,
            4,
            data,
            0,
            null,
            null,
            -1,
            -1,
            type,
            0,
            0,
            0,
            0)
    ];
}
PaletteData loadPalette(byte[] infoHeader) {
    if (bitCount <= 8) {
        int numColors = 1 << bitCount;
        byte[] buf = new byte[numColors * 3];
        try {
            if (inputStream.read(buf) !is buf.length)
                DWT.error(DWT.ERROR_INVALID_IMAGE);
        } catch (IOException e) {
            DWT.error(DWT.ERROR_IO, e);
        }
        return paletteFromBytes(buf, numColors);
    }
    if (bitCount is 16) return new PaletteData(0x7C00, 0x3E0, 0x1F);
    if (bitCount is 24) return new PaletteData(0xFF, 0xFF00, 0xFF0000);
    return new PaletteData(0xFF00, 0xFF0000, 0xFF000000);
}
PaletteData paletteFromBytes(byte[] bytes, int numColors) {
    int bytesOffset = 0;
    RGB[] colors = new RGB[numColors];
    for (int i = 0; i < numColors; i++) {
        colors[i] = new RGB(bytes[bytesOffset + 2] & 0xFF,
            bytes[bytesOffset + 1] & 0xFF,
            bytes[bytesOffset] & 0xFF);
        bytesOffset += 3;
    }
    return new PaletteData(colors);
}
/**
 * Answer a byte array containing the BMP representation of
 * the given device independent palette.
 */
static byte[] paletteToBytes(PaletteData pal) {
    int n = pal.colors is null ? 0 : (pal.colors.length < 256 ? pal.colors.length : 256);
    byte[] bytes = new byte[n * 3];
    int offset = 0;
    for (int i = 0; i < n; i++) {
        RGB col = pal.colors[i];
        bytes[offset] = cast(byte)col.blue;
        bytes[offset + 1] = cast(byte)col.green;
        bytes[offset + 2] = cast(byte)col.red;
        offset += 3;
    }
    return bytes;
}
/**
 * Unload the given image's data into the given byte stream.
 * Answer the number of bytes written.
 */
int unloadData(ImageData image, OutputStream ostr) {
    int bmpBpl = 0;
    try {
        int bpl = (image.width * image.depth + 7) / 8;
        bmpBpl = (bpl + 3) / 4 * 4; // BMP pads scanlines to multiples of 4 bytes
        int linesPerBuf = 32678 / bmpBpl;
        byte[] buf = new byte[linesPerBuf * bmpBpl];
        byte[] data = image.data;
        int imageBpl = image.bytesPerLine;
        int dataIndex = imageBpl * (image.height - 1); // Start at last line
        if (image.depth is 16) {
            for (int y = 0; y < image.height; y += linesPerBuf) {
                int count = image.height - y;
                if (linesPerBuf < count) count = linesPerBuf;
                int bufOffset = 0;
                for (int i = 0; i < count; i++) {
                    for (int wIndex = 0; wIndex < bpl; wIndex += 2) {
                        buf[bufOffset + wIndex + 1] = data[dataIndex + wIndex + 1];
                        buf[bufOffset + wIndex] = data[dataIndex + wIndex];
                    }
                    bufOffset += bmpBpl;
                    dataIndex -= imageBpl;
                }
                ostr.write(buf, 0, bufOffset);
            }
        } else {
            for (int y = 0; y < image.height; y += linesPerBuf) {
                int tmp = image.height - y;
                int count = tmp < linesPerBuf ? tmp : linesPerBuf;
                int bufOffset = 0;
                for (int i = 0; i < count; i++) {
                    System.arraycopy(data, dataIndex, buf, bufOffset, bpl);
                    bufOffset += bmpBpl;
                    dataIndex -= imageBpl;
                }
                ostr.write(buf, 0, bufOffset);
            }
        }
    } catch (IOException e) {
        DWT.error(DWT.ERROR_IO, e);
    }
    return bmpBpl * image.height;
}
/**
 * Unload a DeviceIndependentImage using Windows .BMP format into the given
 * byte stream.
 */
override void unloadIntoByteStream(ImageLoader loader) {
    ImageData image = loader.data[0];
    byte[] rgbs;
    int numCols;
    if (!((image.depth is 1) || (image.depth is 4) || (image.depth is 8) ||
          (image.depth is 16) || (image.depth is 24) || (image.depth is 32)))
            DWT.error(DWT.ERROR_UNSUPPORTED_DEPTH);
    PaletteData pal = image.palette;
    if ((image.depth is 16) || (image.depth is 24) || (image.depth is 32)) {
        if (!pal.isDirect)
            DWT.error(DWT.ERROR_INVALID_IMAGE);
        numCols = 0;
        rgbs = null;
    } else {
        if (pal.isDirect)
            DWT.error(DWT.ERROR_INVALID_IMAGE);
        numCols = pal.colors.length;
        rgbs = paletteToBytes(pal);
    }
    // Fill in file header, except for bfsize, which is done later.
    int headersSize = BMPFileHeaderSize + BMPHeaderFixedSize;
    int[] fileHeader = new int[5];
    fileHeader[0] = 0x4D42; // Signature
    fileHeader[1] = 0; // File size - filled in later
    fileHeader[2] = 0; // Reserved 1
    fileHeader[3] = 0; // Reserved 2
    fileHeader[4] = headersSize; // Offset to data
    if (rgbs !is null) {
        fileHeader[4] += rgbs.length;
    }

    // Prepare data. This is done first so we don't have to try to rewind
    // the stream and fill in the details later.
    ByteArrayOutputStream ostr = new ByteArrayOutputStream();
    unloadData(image, ostr);
    byte[] data = ostr.toByteArray();

    // Calculate file size
    fileHeader[1] = fileHeader[4] + data.length;

    // Write the headers
    try {
        outputStream.writeShort(fileHeader[0]);
        outputStream.writeInt(fileHeader[1]);
        outputStream.writeShort(fileHeader[2]);
        outputStream.writeShort(fileHeader[3]);
        outputStream.writeInt(fileHeader[4]);
    } catch (IOException e) {
        DWT.error(DWT.ERROR_IO, e);
    }
    try {
        outputStream.writeInt(BMPHeaderFixedSize);
        outputStream.writeShort(image.width);
        outputStream.writeShort(image.height);
        outputStream.writeShort(1);
        outputStream.writeShort(cast(short)image.depth);
    } catch (IOException e) {
        DWT.error(DWT.ERROR_IO, e);
    }

    // Unload palette
    if (numCols > 0) {
        try {
            outputStream.write(rgbs);
        } catch (IOException e) {
            DWT.error(DWT.ERROR_IO, e);
        }
    }

    // Unload the data
    try {
        outputStream.write(data);
    } catch (IOException e) {
        DWT.error(DWT.ERROR_IO, e);
    }
}
void flipScanLines(byte[] data, int stride, int height) {
    int i1 = 0;
    int i2 = (height - 1) * stride;
    for (int i = 0; i < height / 2; i++) {
        for (int index = 0; index < stride; index++) {
            byte b = data[index + i1];
            data[index + i1] = data[index + i2];
            data[index + i2] = b;
        }
        i1 += stride;
        i2 -= stride;
    }
}

}