/* (c) Magnus Auvinen. See licence.txt in the root of the distribution for more information. */
/* If you are missing that file, acquire a complete release at teeworlds.com.                */
#include <base/math.h>
#include <base/system.h>
#include <engine/external/pnglite/pnglite.h>

typedef struct
{
	unsigned char r, g, b, a;
} CPixel;

static void TilesetBorderrem(int w, int h, CPixel *pSrc, CPixel *pDest)
{
	int TileW = w/16;
	int TileH = h/16;

	for(int tx = 0; tx < 16; tx++)
	{
		for(int ty = 0; ty < 16; ty++)
		{
			for(int x = 0; x < TileW - 4; x++)
			{
				for(int y = 0; y < TileH - 4; y++)
				{
					int SourceX = tx * TileW + x + 2;
					int SourceY = ty * TileH + y + 2;
					int DestX = tx * (TileW - 4) + x;
					int DestY = ty * (TileH - 4) + y;

					int SourceI = SourceY * w + SourceX;
					int DestI = DestY * (w - 16 * 4) + DestX;

					pDest[DestI] = pSrc[SourceI];

				}
			}
		}
	}
}


int FixFile(const char *pFileName)
{
	png_t Png;
	CPixel *pBuffer[2] = {0,0};

	png_init(0, 0);
	png_open_file(&Png, pFileName);

	if(Png.color_type != PNG_TRUECOLOR_ALPHA)
	{
		dbg_msg("tileset_borderrem", "%s: not an RGBA image", pFileName);
		return 1;
	}

	int w = Png.width;
	int h = Png.height;

	pBuffer[0] = (CPixel*)mem_alloc(w*h*sizeof(CPixel), 1);
	pBuffer[1] = (CPixel*)mem_alloc((w-16*4)*(h-16*4)*sizeof(CPixel), 1);
	png_get_data(&Png, (unsigned char *)pBuffer[0]);
	png_close_file(&Png);

	TilesetBorderrem(w, h, pBuffer[0], pBuffer[1]);

	// save here
	png_open_file_write(&Png, pFileName);
	png_set_data(&Png, w - 16 * 4, h - 16 * 4, 8, PNG_TRUECOLOR_ALPHA, (unsigned char *)pBuffer[1]);
	png_close_file(&Png);

	return 0;
}

int main(int argc, const char **argv)
{
	dbg_logger_stdout();
	if(argc == 1)
	{
		dbg_msg("usage", "%s FILE1 [ FILE2... ]", argv[0]);
		return -1;
	}

	for(int i = 1; i < argc; i++)
		FixFile(argv[i]);
	return 0;
}