/*******************************************************************************

 Copyright (c) 2009, Charles McGarvey
 All rights reserved.
 
 Redistribution   and   use  in  source  and  binary  forms,  with  or  without
 modification, are permitted provided that the following conditions are met:
 
   * Redistributions  of  source  code  must retain the above copyright notice,
     this list of conditions and the following disclaimer.
   * Redistributions  in binary form must reproduce the above copyright notice,
     this  list of conditions and the following disclaimer in the documentation
     and/or other materials provided with the distribution.
 
 THIS  SOFTWARE  IS  PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS "AS IS"
 AND  ANY  EXPRESS  OR  IMPLIED  WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
 IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE
 DISCLAIMED.  IN  NO EVENT SHALL THE COPYRIGHT HOLDER OR CONTRIBUTORS BE LIABLE
 FOR  ANY  DIRECT,  INDIRECT,  INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
 DAMAGES  (INCLUDING,  BUT  NOT  LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR
 SERVICES;  LOSS  OF  USE,  DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER
 CAUSED  AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY,
 OR  TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE
 OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.

*******************************************************************************/

#include <cstdio>		// FILE
#include <cstring>		// strncmp

#include <SDL/SDL.h>
#include <png.h>

#include "Image.hh"
#include "Library.hh"
#include "Log.hh"


namespace Mf {


class Image::Impl : public Library<Impl>
{
public:

	explicit Impl(const std::string& name, bool flipped = false) :
		Library<Impl>(name),
		mContext(0),
		mPixels(0)
	{
		init(getName(), flipped);
	}

	~Impl()
	{
		SDL_FreeSurface(mContext);
		delete[] mPixels;
	}


	void flip()
	{
		unsigned char*	pixels = (Uint8*)(mContext->pixels);

		unsigned		pitch = mContext->pitch;
		unsigned char	line[pitch];

		int				yBegin = 0;
		int				yEnd = mContext->h - 1;

		if (SDL_MUSTLOCK(mContext)) SDL_LockSurface(mContext);
		while (yBegin < yEnd)
		{
			memcpy(line,                    pixels + pitch * yBegin, pitch);
			memcpy(pixels + pitch * yBegin,	pixels + pitch * yEnd,   pitch);
			memcpy(pixels + pitch * yEnd,   line,                    pitch);
			yBegin++;
			yEnd--;
		}
		if (SDL_MUSTLOCK(mContext)) SDL_UnlockSurface(mContext);
	}

	void setAsIcon() const
	{
		SDL_WM_SetIcon(mContext, 0);
	}


	SDL_Surface*	mContext;
	char*			mPixels;

	unsigned		mDepth;
	GLuint			mColorMode;

	std::string		mComment;


private:

	bool init(const std::string& filePath, bool flipped)
	{
		logInfo("opening image file...");
		FILE* fp = fopen(filePath.c_str(), "rb");
		if (!fp) return false;

		png_byte	signature[8];
		size_t		bytesRead;

		png_infop	pngInfo = 0;
		png_infop	pngInfoEnd = 0;
		png_structp pngObj = 0;

		int	width;
		int	height;
		int	pitch;
		int bpp;
		int channels;

		png_byte	colors;
		png_bytepp	rows = 0;

		png_textp	texts = 0;
		int			numTexts;

		logInfo("checking signature...");
		bytesRead = fread(signature, 1, sizeof(signature), fp);
		logInfo << "reading " << bytesRead << " bytes of signature" << std::endl;
		if (bytesRead < sizeof(signature) ||
			png_sig_cmp(signature, 0, sizeof(signature)) != 0) goto cleanup;

		logInfo("creating png structures...");
		pngObj = png_create_read_struct(PNG_LIBPNG_VER_STRING, 0, 0, 0);
		if (!pngObj)     goto cleanup;

		pngInfo = png_create_info_struct(pngObj);
		if (!pngInfo)    goto cleanup;

		pngInfoEnd = png_create_info_struct(pngObj);
		if (!pngInfoEnd) goto cleanup;

		logInfo("setting up long jump...");
		if (setjmp(png_jmpbuf(pngObj))) goto cleanup;

		png_init_io(pngObj, fp);
		png_set_sig_bytes(pngObj, sizeof(signature));
		png_read_info(pngObj, pngInfo);

		bpp = png_get_bit_depth(pngObj, pngInfo);
		logInfo << "texture bpp: " << bpp << std::endl;
		colors = png_get_color_type(pngObj, pngInfo);
		switch (colors)
		{
			case PNG_COLOR_TYPE_PALETTE:
				png_set_palette_to_rgb(pngObj);
				break;

			case PNG_COLOR_TYPE_GRAY:
				if (bpp < 8) png_set_gray_1_2_4_to_8(pngObj);
				break;

			case PNG_COLOR_TYPE_GRAY_ALPHA:
				png_set_gray_to_rgb(pngObj);
				break;
		}

		if (bpp == 16) png_set_strip_16(pngObj);

		png_read_update_info(pngObj, pngInfo);

		bpp = png_get_bit_depth(pngObj, pngInfo);
		channels = png_get_channels(pngObj, pngInfo);
		mDepth = bpp * channels;

		logInfo << "texture channels: " << channels << std::endl;
		if (channels == 3) mColorMode = GL_RGB;
		else               mColorMode = GL_RGBA;
		
		// read comments
		png_get_text(pngObj, pngInfo, &texts, &numTexts);
		logInfo << "num texts: " << numTexts << std::endl;
		for (int i = 0; i < numTexts; ++i)
		{
			if (strncmp(texts[i].key, "Comment", 7) == 0)
			{
				mComment = texts[i].text;
				break;
			}
		}

		width  = png_get_image_width(pngObj, pngInfo);
		height = png_get_image_height(pngObj, pngInfo);

		pitch = png_get_rowbytes(pngObj, pngInfo);
		mPixels = new char[width * pitch];

		rows = new png_bytep[height];
		if (flipped)
		{
			for (int i = 0; i < height; ++i)
			{
				rows[height - 1 - i] = (png_bytep)(mPixels + i * channels * width);
			}
		}
		else
		{
			for (int i = 0; i < height; ++i)
			{
				rows[i] = (png_bytep)(mPixels + i * channels * width);
			}
		}

		png_read_image(pngObj, rows);
		png_read_end(pngObj, 0);

		mContext = SDL_CreateRGBSurfaceFrom
		(
			mPixels,
			width,
			height, 
			bpp * channels,
			pitch,
#if SDL_BYTEORDER == SDL_LIL_ENDIAN
			0x000000FF,
			0x0000FF00,
			0x00FF0000,
			0xFF000000
#else
			0xFF000000,
			0x00FF0000,
			0x0000FF00,
			0x000000FF
#endif
		);

	cleanup:

		logInfo("cleaning up...");
		delete[] rows;
		png_destroy_read_struct(pngObj     ? &pngObj     : 0,
								pngInfo    ? &pngInfo    : 0,
								pngInfoEnd ? &pngInfoEnd : 0);
		fclose(fp);

		return mContext;
	}
};


Image::Image(const std::string& name) :
	// pass through
	mImpl(Image::Impl::getInstance(name)) {}


bool Image::isValid() const
{
	return mImpl->mContext;
}

int Image::getWidth() const
{
	return mImpl->mContext->w;
}

int Image::getHeight() const
{
	return mImpl->mContext->h;
}

unsigned Image::getDepth() const
{
	return mImpl->mDepth;
}

unsigned Image::getPitch() const
{
	return mImpl->mContext->pitch;
}

GLuint Image::getColorMode() const
{
	return mImpl->mColorMode;
}

std::string Image::getComment() const
{
	return mImpl->mComment;
}

const char* Image::getPixels() const
{
	return mImpl->mPixels;
}

char* Image::getPixels()
{
	return mImpl->mPixels;
}


void Image::flip()
{
	// pass through
	mImpl->flip();
}

void Image::setAsIcon() const
{
	// pass through
	mImpl->setAsIcon();
}



std::string Image::getPath(const std::string& name)
{
	std::string path = Resource::getPath("images/" + name + ".png");
	return path;
}


} // namespace Mf

/** vim: set ts=4 sw=4 tw=80: *************************************************/