#include <stdio.h>
#include <stdlib.h>
#include <SDL2/SDL.h>
#include <SDL2/SDL_image.h>

static SDL_Texture * * render_texture;
static int render_texture_count = 0;

static SDL_Window   * window;
static SDL_Renderer * renderer;
static SDL_Texture  * font;
static SDL_Texture  * mono;

static void render_clean_up (void) {
	int i;

	for (i = 0; i < render_texture_count; ++i) {
		SDL_DestroyTexture (render_texture [i]);
	}

	free (render_texture);

	SDL_DestroyTexture (font);
	SDL_DestroyTexture (mono);

	SDL_DestroyRenderer (renderer);
	SDL_DestroyWindow   (window);

	SDL_Quit ();
}

extern int signal_x;
extern int signal_y;
extern int cursor_mode;
extern int signal_mode;

extern int engine_active;

extern int window_width  (void);
extern int window_height (void);

extern void render_sprite (int    sprite, int x, int y, int u, int v, int width, int height);
extern void render_string (char * string, int x, int y, int colour, char monospace);

extern void engine_configure   (void);
extern void engine_synchronize (void);

extern int import_sprite (char * path);
extern int sprite_width  (int index);
extern int sprite_height (int index);

int signal_x    = 0;
int signal_y    = 0;
int cursor_mode = 0;
int signal_mode = 0;

int engine_active = 0;

int window_width  (void) { int width  = 0; SDL_GetWindowSize (window, & width, NULL);  return (width);  }
int window_height (void) { int height = 0; SDL_GetWindowSize (window, NULL, & height); return (height); }

void render_sprite (int sprite, int x, int y, int u, int v, int width, int height) {
	SDL_Rect source, destination;

	source.x = u;
	source.y = v;
	source.w = width;
	source.h = height;

	destination.x = x;
	destination.y = y;
	destination.w = (width  < 0) ? -width  : width;
	destination.h = (height < 0) ? -height : height;

	SDL_RenderCopy (renderer, render_texture [sprite], & source, & destination);
}

void render_string (char * string, int x, int y, int colour, char monospace) {
	int i;

	(void) colour;

	for (i = 0; string [i] != '\0'; ++i) {
		SDL_Rect source, destination;

		source.x = (string [i] - 32) / 8 *  9;
		source.y = (string [i] - 32) % 8 * 18;
		source.w =  9;
		source.h = 18;

		destination.x = x + 7 + 9 * i;
		destination.y = y + 7;
		destination.w =  9;
		destination.h = 18;

		SDL_RenderCopy (renderer, (monospace != 0) ? mono : font, & source, & destination);
	}
}

void engine_configure (void) {
	engine_active = 1;

	SDL_Init (SDL_INIT_VIDEO);

	window   = SDL_CreateWindow   ("Chads of Might & Magic", 0, 0, 1800, 900, 0);
	renderer = SDL_CreateRenderer (window, -1, SDL_RENDERER_ACCELERATED);

	font = IMG_LoadTexture (renderer, "sprite/font/font.png");
	mono = IMG_LoadTexture (renderer, "sprite/font/mono.png");

	atexit (render_clean_up);
}

void engine_synchronize (void) {
	SDL_Event event;

	SDL_RenderPresent (renderer);

	SDL_GetMouseState (& signal_x, & signal_y);

	SDL_PollEvent (& event);

	switch (event.type) {
		case SDL_QUIT:
			engine_active = 0;
			break;
		case SDL_MOUSEBUTTONDOWN:
			if (event.button.button == SDL_BUTTON_LEFT)   cursor_mode = 1;
			if (event.button.button == SDL_BUTTON_RIGHT)  cursor_mode = 2;
			if (event.button.button == SDL_BUTTON_MIDDLE) cursor_mode = 3;
			break;
		case SDL_MOUSEBUTTONUP:
			cursor_mode = 0;
			break;
		case SDL_KEYDOWN:
			switch (event.key.keysym.sym) {
				case SDLK_UP:     signal_mode   = 1; break;
				case SDLK_DOWN:   signal_mode   = 2; break;
				case SDLK_LEFT:   signal_mode   = 3; break;
				case SDLK_RIGHT:  signal_mode   = 4; break;
				case SDLK_ESCAPE: engine_active = 0; break;
				default:          signal_mode   = 0; break;
			}
			break;
		case SDL_KEYUP:
			cursor_mode = 0;
			break;
		default:
			break;
	}

	signal_mode = 0;

	SDL_RenderClear (renderer);
}

int import_sprite (char * path) {
	++render_texture_count;

	render_texture = realloc (render_texture, (unsigned long int) render_texture_count * sizeof (* render_texture));

	render_texture [render_texture_count - 1] = IMG_LoadTexture (renderer, path);

	if (render_texture [render_texture_count - 1] == NULL) {
		printf ("\033[1;31m%3i : '%60s';\033[0m\n", render_texture_count - 1, path);
	}

	return (render_texture_count - 1);
}

int sprite_width (int index) {
	int width = 0;
	SDL_QueryTexture (render_texture [index], NULL, NULL, & width, NULL);
	return (width);
}

int sprite_height (int index) {
	int height = 0;
	SDL_QueryTexture (render_texture [index], NULL, NULL, NULL, & height);
	return (height);
}