#include <SDL2/SDL.h>
#include <stdio.h>
#include "array.h"
#include "tick.h"

const int ZOOM_LEVELS[10] = {1, 2, 3, 5, 8, 12, 20, 30};
const unsigned int MAX_ZOOM_LEVEL = 7;

struct viewport {
	int origin_x;
	int origin_y;
	int zoom_level;
};

void quit(int e_st)
{
	SDL_Quit();
	exit(e_st);
}

int redraw_screen(struct gol_board *state, SDL_Surface *screen, struct viewport viewport);

int handle_mousedown(struct gol_board *state, struct viewport viewport, SDL_Event e);

int main(int argc, char* args[])
{
	struct gol_board state = {
		.live_cells = NULL,
		.n = 0,
		.size = 10,
		.max_x = 0,
		.min_x = 0,
		.max_y = 0,
		.min_y = 0
	};
	SDL_Window *window = NULL;
	SDL_Surface *screen = NULL;

	char finished = 0;
	char tick = 0;
	char redraw = 1;

	// The coordinates of the cell to draw in the bottom left corner of the
	// canvas
	struct viewport viewport = {0, 0, 4};

	SDL_Event e;

	state.live_cells = malloc(10 * sizeof(int_least32_t));
	if (!state.live_cells) {
		return 1;
	}

	gol_vivify(&state, 10, 10);
	
	if (SDL_Init(SDL_INIT_EVERYTHING) < 0) {
		quit(1);
	}

	window = SDL_CreateWindow("SDL Tutorial",
	                          SDL_WINDOWPOS_UNDEFINED,
	                          SDL_WINDOWPOS_UNDEFINED,
	                          640,
	                          480,
	                          SDL_WINDOW_SHOWN);
	if (!window) {
		quit(1);
	}

	screen = SDL_GetWindowSurface(window);
	if (!screen) {
		quit(1);
	}
	SDL_UpdateWindowSurface(window);

	while (!finished) {
		while (SDL_PollEvent(&e) != 0) {
			if (e.type == SDL_QUIT) {
				finished = 1;
			} else if (e.type == SDL_KEYDOWN) {
				switch (e.key.keysym.sym) {
				case SDLK_q:
				case SDLK_x:
					finished = 1;
					break;
				case SDLK_PLUS:
				case SDLK_EQUALS:
					if (viewport.zoom_level != MAX_ZOOM_LEVEL)
						viewport.zoom_level++;
					redraw = 1;
					break;
				case SDLK_MINUS:
				case SDLK_UNDERSCORE:
					if (viewport.zoom_level != 0)
						viewport.zoom_level--;
					redraw = 1;
					break;
				case SDLK_SPACE:
					tick = 1;
				default:
					break;
				}
			} else if (e.type == SDL_MOUSEBUTTONDOWN) {
				handle_mousedown(&state, viewport, e);
				redraw = 1;
			}
		}
		if (tick) {
			tick = 0;
			gol_tick(&state);
			redraw = 1;
		}
		if (redraw) {
			redraw = 0;
			redraw_screen(&state, screen, viewport);
			SDL_UpdateWindowSurface(window);
		}
	}

	SDL_DestroyWindow(window);
	quit(0);
}


int redraw_screen(struct gol_board *state, SDL_Surface *screen,
	struct viewport viewport)
{
	SDL_Rect rect;
	int i, j, ppc;
	char is_live;

	ppc = ZOOM_LEVELS[viewport.zoom_level];

	SDL_FillRect(screen, NULL, SDL_MapRGB(screen->format, 255, 255, 255));

	for (i = viewport.origin_x;
	     i < (screen->w/ppc) + viewport.origin_x;
	     ++i) {
		for (j = viewport.origin_y;
		     j < (screen->h/ppc) + viewport.origin_y;
		     ++j) {
			if (gol_is_live(state, i, j, &is_live) && is_live) {
				rect = (SDL_Rect) {
					((i - viewport.origin_x) * ppc),
					((j - viewport.origin_y) * ppc),
					ppc,
					ppc
				};
				SDL_FillRect(screen, &rect,
					SDL_MapRGB(screen->format, 0, 0, 0));
			}
		}
	}
	return 0;
}

int handle_mousedown(struct gol_board *state, struct viewport viewport, SDL_Event e)
{
	int x, y;
	char is_live;
	x = e.button.x/ZOOM_LEVELS[viewport.zoom_level] - viewport.origin_x;
	y = e.button.y/ZOOM_LEVELS[viewport.zoom_level] - viewport.origin_y;

	gol_is_live(state, x, y, &is_live);
	if (!is_live)
		gol_vivify(state, x, y);

	return 1;
}