#include <stdio.h>
#include <stddef.h>
#include <stdint.h>
#include <limits.h>
#include <SDL2/SDL.h>
#include <SDL2/SDL_image.h>


#include "joey.h"


#pragma GCC diagnostic push
#pragma GCC diagnostic ignored "-Wcast-align"

Uint32 getPixel(SDL_Surface *surface, int x, int y) {

	int bpp = surface->format->BytesPerPixel;
	Uint8 *p = (Uint8 *)surface->pixels + y * surface->pitch + x * bpp;

	switch(bpp) {
		case 1:
			return *p;
			break;

		case 2:
			// Generates cast increases required alignment of target type [-Wcast-align] warning.  Harmless on x86.
			return *(Uint16 *)p;
			break;

		case 3:
			if (SDL_BYTEORDER == SDL_BIG_ENDIAN)
				return (Uint32)(p[0] << 16 | p[1] << 8 | p[2]);
			else
				return (Uint32)(p[0] | p[1] << 8 | p[2] << 16);
			break;

		case 4:
			// Generates cast increases required alignment of target type [-Wcast-align] warning.  Harmless on x86.
			return *(Uint32 *)p;
			break;

		default:
			return 0;
	}
}

#pragma GCC diagnostic pop


int main(int argc, char *argv[]) {

	if (argc < 3) {
		printf("Usage:  %s [infile] [outfile] {anyting}\n", argv[0]);
		printf("(If {anything} is provided, image will be displayed as converted until keypress.)\n");
		return 1;
	}

	jlUtilStartup("STA Converter");

	int imageFlags = IMG_INIT_JPG | IMG_INIT_PNG | IMG_INIT_TIF;
	int imageResult = IMG_Init(imageFlags);
	if ((imageResult & imageFlags) != imageFlags) {
		printf("Failed to initialize SDL2_Image:  %s\n", IMG_GetError());
		jlUtilShutdown();
	}

	SDL_Surface *image = IMG_Load(argv[1]);
	int colors = INT_MAX;
	SDL_Color *c = NULL;

	if (image->format->palette != NULL) {
		colors = image->format->palette->ncolors;
		if (colors > 16) {
			colors = 16;
			printf("Source palette has more than 16 colors.  Only the first 16 will be used.\n");
		}
		c = image->format->palette->colors;
	}

	printf("%s = %dx%d, %d bits per pixel, %d colors\n", argv[1], image->w, image->h, image->format->BitsPerPixel, colors);

	if (image->w != 320 || image->h != 200 || image->format->BitsPerPixel != 8 || colors > 16) {
		printf("Image must be 320x200 pixels, 8 bits per pixel, with 16 or fewer colors.\n");
		free(image);
		IMG_Quit();
		jlUtilShutdown();
	}

	jlStaT *sta = NULL;
	jlStaCreate(sta);

	for (int x=0; x<colors; x++) {
		sta->palette[x].r = c[x].r / 16;
		sta->palette[x].g = c[x].g / 16;
		sta->palette[x].b = c[x].b / 16;
		printf("Palette %03d = R%03d G%03d B%03d\n", x, sta->palette[x].r, sta->palette[x].g, sta->palette[x].b);
	}

	if (colors < 16) {
		for (int x=colors; x<16; x++) {
			sta->palette[x].r = 0;
			sta->palette[x].g = 0;
			sta->palette[x].b = 0;
			printf("Palette %03d = R000 G000 B000 (added)\n", x);
		}
	}

	int p = 0;
	for (int y=0; y<image->h; y++) {
		for (int x=0; x<image->w; x+=2) {
			//printf("%02X %02X ", getPixel(image, x, y), getPixel(image, x + 1, y));
			// These are backwards - no idea why yet.
			sta->pixels[p].r = (unsigned char)getPixel(image, x, y);
			sta->pixels[p++].l = (unsigned char)getPixel(image, x + 1, y);
		}
	}

	jlStaSave(sta, argv[2]);

	SDL_FreeSurface(image);

	if (argc > 3) {
		jlStaDisplay(sta);
		jlDisplayPresent();
		jlKeyWaitForAny();
	}

	IMG_Quit();
	jlUtilShutdown();
}