/*
 * Creation date: 21 Oct 2007
 * Author: ZaidaZadkiel
 * Purpose: None, really. I think it looks pretty.
 */

#include "SDL/SDL.h"
#include "SDL/SDL_gfxPrimitives.h"
#include <stdio.h>

#define UPDATES 10

typedef enum
{
    true = 1,
    false = 0
} boxes_boolean_t;

typedef struct
{
    SDL_Surface *screen;
    int xtimes, ytimes;
    int seed;
    boxes_boolean_t print;
    Uint8 colors[30*30];
    Uint8 newcolors[30*30];
    Sint8 deltas[30*30];
} boxes_data_t;

int do_events(boxes_data_t *data){
	SDL_Event e;
	SDLKey k;
	while(SDL_PollEvent(&e)){
		switch(e.type){
			case SDL_KEYDOWN:
				k = e.key.keysym.sym;
				if(k == SDLK_ESCAPE){
					printf("escape pressed\n");
					return 1;
				}/*if*/
				data.print   = (k == SDLK_p);
				if(k == SDLK_RIGHT   ) data->xtimes += (data->xtimes < 30);
				if(k == SDLK_LEFT    ) data->xtimes -= (data->xtimes > 1);
				if(k == SDLK_UP      ) data->ytimes -= (data->ytimes > 1);
				if(k == SDLK_DOWN    ) data->ytimes += (data->ytimes < 30);
				if(k == SDLK_HOME    ) {data->seed   =  5000; srand(data->seed);}
				if(k == SDLK_END     ) {data->seed   = 10000; srand(data->seed);}
				if(k == SDLK_PAGEDOWN) {data->seed  += (data->seed < 10000) * 100; srand(data->seed);}
				if(k == SDLK_PAGEUP) {data->seed  -= (data->seed >  5000) * 100; srand(data->seed);}
				break;
			default:
				break;
		}/*switch*/
	}/*if*/

	return 0;
}

Uint32 get_color(int i, int len){
/*	Uint8 d = ((float)i/(float)len)*255.0;
*/

	Uint8 *c, *nc;
	Sint8 *d;

	c  = &colors[i];
	nc = &newcolors[i];
	d  = &deltas[i];

	if(*c > (*nc - *d)){// && *c < (*nc + *d)){
		if(i == 3)
			printf(">> c %3d, nc %3d, d %3d\n", *c, *nc, *d);
	}else{
	//	printf("oldcolor: c=%3d, nc=%3d\n", *c, *nc);
		*nc = rand() % 256;
		//*d  = (*nc - *c) / UPDATES;
		if(*c > *nc){
			*d = (*nc - *c) / UPDATES;
		}else{
			*d = (*c - *nc) / UPDATES;
		}
		if(*d == 0) *d = (*c > *nc ? -1 : 1);
		//printf("nc %3d, c %3d, d %3d\n", *nc, *c, *d);

	//	printf("newcolor: i=%3d, c=%3d, nc=%3d, d=%3d\n", i, *c, *nc, *d);		
	}

	*c += *d;

//	Uint8 d = rand() % 256; //((double)rand() / (double)RAND_MAX+(double)1) * 512;


	return SDL_MapRGB(
		screen->format,
		*c, 0, 0
	);

}

void paint_boxes(int nw, int nh){
	SDL_Rect r;
	int boxlen;
	float cx, cy; /*correction x and y*/

	r.x = 0;
	r.y = 0;
	r.w = screen->w / nw+1;
	r.h = screen->h / nh+1;
	cx = 1-(float)(r.w * nw) / screen->w;
	cy = 1-(float)(r.h * nh) / screen->h;

	boxlen = nw*nh;

	if(print){
		print = false;
		printf("-------\n");
		printf("seed = %d\n", seed);
		printf("xtimes = %2d ytimes = %2d\n", nw, nh);
		printf("r = {%3d,%3d,%3d,%3d}\n", 
			r.x, r.y, r.w, r.h
		);
		printf("boxlen = %3d\n", boxlen);
		printf("cx = %3f cy = %3f\n", cx, cy);
		printf("test %d : %f\n", 
			((boxlen/2) % nw) * r.w,
			(((boxlen/2) % nw) * r.w) +
			((((boxlen/2) % nw) * r.w) * cx)
		);
	}/*if(print)*/

	int i;

	for(i = 1; i <= boxlen; i++){
		SDL_FillRect(screen, &r, get_color(i, boxlen));
		
		r.x  = (i % nw) * r.w;
		r.y  = (i / nw) * r.h;
		r.x += (r.x * cx);
		r.y += r.y * cy;
	}
}

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

putenv("SDL_VIDEO_WINDOW_POS");
putenv("SDL_VIDEO_CENTERED=1");

	atexit(SDL_Quit);

	/* Initialize the SDL library */
	if( SDL_Init(SDL_INIT_VIDEO) < 0 ) {
		fprintf(stderr,"Couldn't initialize SDL: %s\n", SDL_GetError());
		exit(1);
	}

	screen = SDL_SetVideoMode(800, 600, 16, SDL_DOUBLEBUF | SDL_SWSURFACE | SDL_NOFRAME );
	if ( screen == NULL ) {
		fprintf(stderr, "Couldn't set 640x480x8 video mode: %s\n",
			SDL_GetError());
		exit(1);
	}

	xtimes = 30;
	ytimes = 30;

	int i;
	for(i = 0; i != 30*30; i++){
		colors[i] = 0;
		newcolors[i] = 255;
		deltas[i] = 255/UPDATES;
	}

	while(do_events() == false){
		SDL_FillRect(screen, NULL, 0);
		paint_boxes(xtimes,ytimes);
		SDL_Flip(screen);
		SDL_Delay(1000/UPDATES);
	}

	return 0;
}