/* ScummVM - Graphic Adventure Engine
 *
 * ScummVM is the legal property of its developers, whose names
 * are too numerous to list here. Please refer to the COPYRIGHT
 * file distributed with this source distribution.
 *
 * This program is free software; you can redistribute it and/or
 * modify it under the terms of the GNU General Public License
 * as published by the Free Software Foundation; either version 2
 * of the License, or (at your option) any later version.
 *
 * This program is distributed in the hope that it will be useful,
 * but WITHOUT ANY WARRANTY; without even the implied warranty of
 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
 * GNU General Public License for more details.
 *
 * You should have received a copy of the GNU General Public License
 * along with this program; if not, write to the Free Software
 * Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301, USA.
 *
 */

// libjpeg uses forbidden symbols in its header. Thus, we need to allow them
// here.
#define FORBIDDEN_SYMBOL_ALLOW_ALL

#include "image/jpeg.h"

#include "common/debug.h"
#include "common/endian.h"
#include "common/stream.h"
#include "common/textconsole.h"
#include "common/util.h"
#include "graphics/pixelformat.h"

#ifdef USE_JPEG
// The original release of libjpeg v6b did not contain any extern "C" in case
// its header files are included in a C++ environment. To avoid any linking
// issues we need to add it on our own.
extern "C" {
#include <jpeglib.h>
#include <jerror.h>
}
#endif

namespace Image {

JPEGDecoder::JPEGDecoder() :
		_surface(),
		_colorSpace(kColorSpaceRGB),
		_requestedPixelFormat(getByteOrderRgbPixelFormat()) {
}

JPEGDecoder::~JPEGDecoder() {
	destroy();
}

Graphics::PixelFormat JPEGDecoder::getByteOrderRgbPixelFormat() const {
#ifdef SCUMM_BIG_ENDIAN
	return Graphics::PixelFormat(3, 8, 8, 8, 0, 16, 8, 0, 0);
#else
	return Graphics::PixelFormat(3, 8, 8, 8, 0, 0, 8, 16, 0);
#endif
}

const Graphics::Surface *JPEGDecoder::getSurface() const {
	return &_surface;
}

void JPEGDecoder::destroy() {
	_surface.free();
}

const Graphics::Surface *JPEGDecoder::decodeFrame(Common::SeekableReadStream &stream) {
	if (!loadStream(stream))
		return 0;

	return getSurface();
}

Graphics::PixelFormat JPEGDecoder::getPixelFormat() const {
	return _surface.format;
}

#ifdef USE_JPEG
namespace {

#define JPEG_BUFFER_SIZE 4096

struct StreamSource : public jpeg_source_mgr {
	Common::SeekableReadStream *stream;
	bool startOfFile;
	JOCTET buffer[JPEG_BUFFER_SIZE];
};

void initSource(j_decompress_ptr cinfo) {
	StreamSource *source = (StreamSource *)cinfo->src;
	source->startOfFile = true;
}

boolean fillInputBuffer(j_decompress_ptr cinfo) {
	StreamSource *source = (StreamSource *)cinfo->src;

	uint32 bufferSize = source->stream->read((byte *)source->buffer, sizeof(source->buffer));
	if (bufferSize == 0) {
		if (source->startOfFile) {
			// An empty file is a fatal error
			ERREXIT(cinfo, JERR_INPUT_EMPTY);
		} else {
			// Otherwise we insert an EOF marker
			WARNMS(cinfo, JWRN_JPEG_EOF);
			source->buffer[0] = (JOCTET)0xFF;
			source->buffer[1] = (JOCTET)JPEG_EOI;
			bufferSize = 2;
		}
	}

	source->next_input_byte = source->buffer;
	source->bytes_in_buffer = bufferSize;
	source->startOfFile = false;

	return TRUE;
}

void skipInputData(j_decompress_ptr cinfo, long numBytes) {
	StreamSource *source = (StreamSource *)cinfo->src;

	if (numBytes > 0) {
		if (numBytes > (long)source->bytes_in_buffer) {
			// In case we need to skip more bytes than there are in the buffer
			// we will skip the remaining data and fill the buffer again
			numBytes -= (long)source->bytes_in_buffer;

			// Skip the remaining bytes
			source->stream->skip(numBytes);

			// Fill up the buffer again
			(*source->fill_input_buffer)(cinfo);
		} else {
			source->next_input_byte += (size_t)numBytes;
			source->bytes_in_buffer -= (size_t)numBytes;
		}

	}
}

void termSource(j_decompress_ptr cinfo) {
}

void jpeg_scummvm_src(j_decompress_ptr cinfo, Common::SeekableReadStream *stream) {
	StreamSource *source;

	// Initialize the source in case it has not been done yet.
	if (cinfo->src == NULL) {
		cinfo->src = (jpeg_source_mgr *)(*cinfo->mem->alloc_small)((j_common_ptr)cinfo, JPOOL_PERMANENT, sizeof(StreamSource));
	}

	source = (StreamSource *)cinfo->src;
	source->init_source       = &initSource;
	source->fill_input_buffer = &fillInputBuffer;
	source->skip_input_data   = &skipInputData;
	source->resync_to_restart = &jpeg_resync_to_restart;
	source->term_source       = &termSource;
	source->bytes_in_buffer   = 0;
	source->next_input_byte   = NULL;

	source->stream = stream;
}

void errorExit(j_common_ptr cinfo) {
	char buffer[JMSG_LENGTH_MAX];
	(*cinfo->err->format_message)(cinfo, buffer);
	// This function is not allowed to return to the caller, thus we simply
	// error out with our error handling here.
	error("%s", buffer);
}

void outputMessage(j_common_ptr cinfo) {
	char buffer[JMSG_LENGTH_MAX];
	(*cinfo->err->format_message)(cinfo, buffer);
	// Is using debug here a good idea? Or do we want to ignore all libjpeg
	// messages?
	debug(3, "libjpeg: %s", buffer);
}

J_COLOR_SPACE fromScummvmPixelFormat(const Graphics::PixelFormat &format) {
#if defined(JCS_EXTENSIONS) || defined(JCS_ALPHA_EXTENSIONS)
	struct PixelFormatMapping {
		Graphics::PixelFormat pixelFormat;
		J_COLOR_SPACE bigEndianColorSpace;
		J_COLOR_SPACE littleEndianColorSpace;
	};

	static const PixelFormatMapping mappings[] = {
#ifdef JCS_EXTENSIONS
		{ Graphics::PixelFormat(4, 8, 8, 8, 0, 24, 16,  8,  0), JCS_EXT_RGBX, JCS_EXT_XBGR },
		{ Graphics::PixelFormat(4, 8, 8, 8, 0,  0,  8, 16, 24), JCS_EXT_XBGR, JCS_EXT_RGBX },
		{ Graphics::PixelFormat(4, 8, 8, 8, 0, 16,  8,  0, 24), JCS_EXT_XRGB, JCS_EXT_BGRX },
		{ Graphics::PixelFormat(4, 8, 8, 8, 0,  8, 16, 24,  0), JCS_EXT_BGRX, JCS_EXT_XRGB },
		{ Graphics::PixelFormat(3, 8, 8, 8, 0, 16,  8,  0,  0), JCS_EXT_RGB,  JCS_EXT_BGR  },
		{ Graphics::PixelFormat(3, 8, 8, 8, 0,  0,  8, 16,  0), JCS_EXT_BGR,  JCS_EXT_RGB  }
#endif
#if defined(JCS_EXTENSIONS) && defined(JCS_ALPHA_EXTENSIONS)
		,
#endif
#ifdef JCS_ALPHA_EXTENSIONS
		{ Graphics::PixelFormat(4, 8, 8, 8, 8, 24, 16,  8,  0), JCS_EXT_RGBA, JCS_EXT_ABGR },
		{ Graphics::PixelFormat(4, 8, 8, 8, 8,  0,  8, 16, 24), JCS_EXT_ABGR, JCS_EXT_RGBA },
		{ Graphics::PixelFormat(4, 8, 8, 8, 8, 16,  8,  0, 24), JCS_EXT_ARGB, JCS_EXT_BGRA },
		{ Graphics::PixelFormat(4, 8, 8, 8, 8,  8, 16, 24,  0), JCS_EXT_BGRA, JCS_EXT_ARGB }
#endif
	};

	for (uint i = 0; i < ARRAYSIZE(mappings); i++) {
		if (mappings[i].pixelFormat == format) {
#ifdef SCUMM_BIG_ENDIAN
			return mappings[i].bigEndianColorSpace;
#else
			return mappings[i].littleEndianColorSpace;
#endif
		}
	}
#endif

	return JCS_UNKNOWN;
}

} // End of anonymous namespace
#endif

bool JPEGDecoder::loadStream(Common::SeekableReadStream &stream) {
#ifdef USE_JPEG
	// Reset member variables from previous decodings
	destroy();

	jpeg_decompress_struct cinfo;
	jpeg_error_mgr jerr;

	// Initialize error handling callbacks
	cinfo.err = jpeg_std_error(&jerr);
	cinfo.err->error_exit = &errorExit;
	cinfo.err->output_message = &outputMessage;

	// Initialize the decompression structure
	jpeg_create_decompress(&cinfo);

	// Initialize our buffer handling
	jpeg_scummvm_src(&cinfo, &stream);

	// Read the file header
	jpeg_read_header(&cinfo, TRUE);

	// We can request YUV output because Groovie requires it
	switch (_colorSpace) {
	case kColorSpaceRGB: {
		J_COLOR_SPACE colorSpace = fromScummvmPixelFormat(_requestedPixelFormat);

		if (colorSpace == JCS_UNKNOWN) {
			// When libjpeg-turbo is not available or an unhandled pixel
			// format was requested, ask libjpeg to decode to byte order RGB
			// as it's always available.
			colorSpace = JCS_RGB;
		}

		cinfo.out_color_space = colorSpace;
		break;
	}
	case kColorSpaceYUV:
		cinfo.out_color_space = JCS_YCbCr;
		break;
	}

	// Actually start decompressing the image
	jpeg_start_decompress(&cinfo);

	// Allocate buffers for the output data
	switch (_colorSpace) {
	case kColorSpaceRGB: {
		Graphics::PixelFormat outputPixelFormat;
		if (cinfo.out_color_space == JCS_RGB) {
			outputPixelFormat = getByteOrderRgbPixelFormat();
		} else {
			outputPixelFormat = _requestedPixelFormat;
		}
		_surface.create(cinfo.output_width, cinfo.output_height, outputPixelFormat);
		break;
	}
	case kColorSpaceYUV:
		// We use YUV with 3 bytes per pixel otherwise.
		// This is pretty ugly since our PixelFormat cannot express YUV...
		_surface.create(cinfo.output_width, cinfo.output_height, Graphics::PixelFormat(3, 0, 0, 0, 0, 0, 0, 0, 0));
		break;
	}

	// Allocate buffer for one scanline
	JDIMENSION pitch = cinfo.output_width * _surface.format.bytesPerPixel;
	assert(_surface.pitch >= pitch);
	JSAMPARRAY buffer = (*cinfo.mem->alloc_sarray)((j_common_ptr)&cinfo, JPOOL_IMAGE, pitch, 1);

	// Go through the image data scanline by scanline
	while (cinfo.output_scanline < cinfo.output_height) {
		byte *dst = (byte *)_surface.getBasePtr(0, cinfo.output_scanline);

		jpeg_read_scanlines(&cinfo, buffer, 1);

		memcpy(dst, buffer[0], pitch);
	}

	// We are done with decompressing, thus free all the data
	jpeg_finish_decompress(&cinfo);
	jpeg_destroy_decompress(&cinfo);

	if (_colorSpace == kColorSpaceRGB && _surface.format != _requestedPixelFormat) {
		_surface.convertToInPlace(_requestedPixelFormat); // Slow path
	}

	return true;
#else
	return false;
#endif
}

} // End of Graphics namespace
