#include <stdio.h>
#include "SDL.h"
#include "SDL_image.h"
#include "Imlib2.h"

enum
{
	IMG_LEFT  = 0,
	IMG_RIGHT = 1,
	IMG_LAST		// should be last
};

typedef struct RGB
{
	Uint8 r,g,b;
} RGB;

typedef struct ARGB
{
	Uint8 a,r,g,b;
} ARGB;

typedef struct BGR
{
	Uint8 b,g,r;
} BGR;

typedef struct BGRA
{
	Uint8 b,g,r,a;
} BGRA;

int main(int argc, char* argv[])
{
	SDL_Surface* pImages[IMG_LAST];
	Imlib_Image  pOut   = NULL;
	DATA32*      pBuf   = NULL;
	Uint32       width  = 0;
	Uint32       height = 0;
	Uint32       bpp    = 0;
	Uint8        r, g, b;
	RGB*         p      = NULL;
	Uint32       offset = 0;

	if (argc < 3)
	{
		printf("Usage: interlace LEFT RIGHT [OUTPUT]\n");
		return -1;
	}

	for (int i = 0; i < IMG_LAST; i++)
	{
		pImages[i] = IMG_Load(argv[i+1]);
		if (!pImages[i])
		{
			printf("IMG_Load: %s\n", IMG_GetError());
			return 1;
		}
		printf("Loaded %dx%dx%d '%s'\n", pImages[i]->w, pImages[i]->h, pImages[i]->format->BitsPerPixel, argv[i+1]);
	}

	if (  (pImages[IMG_LEFT]->w != pImages[IMG_RIGHT]->w)
	   || (pImages[IMG_LEFT]->h != pImages[IMG_RIGHT]->h)
	   || (pImages[IMG_LEFT]->format->BitsPerPixel != pImages[IMG_RIGHT]->format->BitsPerPixel)
	   || (pImages[IMG_LEFT]->format->BitsPerPixel != 24) )
	{
		printf("ERROR: Specified images aren't the same size|bpp or not 24 bpp\n");
		goto cleanup;
	}

	width  = pImages[IMG_RIGHT]->w;
	height = pImages[IMG_RIGHT]->h;
	bpp    = pImages[IMG_RIGHT]->format->BitsPerPixel;

	pOut = imlib_create_image(width, height);
	imlib_context_set_image(pOut);
	pBuf = imlib_image_get_data();
	
	printf("%dx%d\n", imlib_image_get_width(), imlib_image_get_height());

	p = (RGB*)pImages[IMG_LEFT]->pixels;
	for (int y = 0; y < height; y+=2)
		for (int x = 0; x < width; x++)
		{
			offset = y*width + x;
			r = p[offset].r;
			g = p[offset].g;
			b = p[offset].b;
			pBuf[offset] = r << 16 | g << 8 | b;
		}

	p = (RGB*)pImages[IMG_RIGHT]->pixels;
	for (int y = 1; y < height; y+=2)
		for (int x = 0; x < width; x++)
		{
			offset = y*width + x;
			r = p[offset].r;
			g = p[offset].g;
			b = p[offset].b;
			pBuf[offset] = r << 16 | g << 8 | b;
		}

	imlib_image_put_back_data(pBuf);

	if (argc > 3)
		imlib_save_image(argv[3]);
	else
		imlib_save_image("out.jpg");
	imlib_free_image();

cleanup:
	for (int i = 0; i < IMG_LAST; i++)
		SDL_FreeSurface(pImages[i]);

	return 0;
}