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

#define WINDOW_W 1280
#define WINDOW_H 720

SDL_Texture *createTiledTexture(SDL_Renderer *context, const char *filename) {
	SDL_Surface *texture_surface = SDL_LoadBMP(filename);
	SDL_Texture *texture_tile = SDL_CreateTextureFromSurface(context, texture_surface);
	int tile_w = texture_surface->w;
	int tile_h = texture_surface->h;
	SDL_FreeSurface(texture_surface);

	Uint32 pixelformat;
	SDL_QueryTexture(texture_tile, &pixelformat, 0, 0, 0);
	SDL_Texture *texture = SDL_CreateTexture(context, pixelformat, SDL_TEXTUREACCESS_STATIC | SDL_TEXTUREACCESS_TARGET, WINDOW_W, WINDOW_H);
	SDL_SetRenderTarget(context, texture);
	for (int y = 0; y < WINDOW_H; y += tile_h) {
		for (int x = 0; x < WINDOW_W; x += tile_w) {
			SDL_Rect tile_rect = { x, y, tile_w, tile_h };
			SDL_RenderCopy(context, texture_tile, 0, &tile_rect);
		}
	}
	SDL_DestroyTexture(texture_tile);
	SDL_SetRenderTarget(context, 0);
	return texture;
}

int main() {
	SDL_Init(SDL_INIT_VIDEO);

	SDL_Window *window = SDL_CreateWindow("Cannons",
			SDL_WINDOWPOS_UNDEFINED,
			SDL_WINDOWPOS_UNDEFINED,
			WINDOW_W,
			WINDOW_H,
			0);

	SDL_Renderer *context = SDL_CreateRenderer(window, -1, SDL_RENDERER_ACCELERATED);

	SDL_SetRenderDrawColor(context, 40, 40, 40, 255);
	SDL_RenderClear(context);

	SDL_Texture *background = createTiledTexture(context, "background.bmp");
	SDL_Texture *foreground = createTiledTexture(context, "foreground.bmp");

	// TODO:
	// - Map has a mask generated by the game, of where the terrain (foregroud) exists
	float *mask = calloc(WINDOW_W * WINDOW_H, 4);

	int exit = 0;
	while (!exit) {
		SDL_Event event = {0};
		while (SDL_PollEvent(&event)) {
			if (event.type == SDL_QUIT) {
				exit = 1;
			}
		}
		SDL_RenderCopy(context, background, 0, 0);
		SDL_SetRenderTarget(context, foreground);

		// TODO: Get masking right
		SDL_SetTextureBlendMode(mask_texture, SDL_BLENDMODE_MUL);
		SDL_RenderCopy(context, mask_texture, 0, 0);
		SDL_SetRenderTarget(context, 0);

		SDL_RenderPresent(context);
		SDL_Delay(10);
	}

	SDL_DestroyRenderer(context);
	SDL_DestroyWindow(window);
	SDL_Quit();
	return 0;
}