// emcc source.cpp -s USE_SDL=2 -s FULL_ES2=1 --preload-file res/img -o publish\emsripten\index.html -O2 -s ALLOW_MEMORY_GROWTH=1

#include <SDL.h>
#include <stdio.h>
#include <string>
#ifdef __EMSCRIPTEN__
#include <emscripten.h>
#endif

const int SCREEN_WIDTH = 640;
const int SCREEN_HEIGHT = 480;

enum KeyPressSurfaces
{
	KEY_PRESS_SURFACE_DEFAULT,
	KEY_PRESS_SURFACE_UP,
	KEY_PRESS_SURFACE_DOWN,
	KEY_PRESS_SURFACE_LEFT,
	KEY_PRESS_SURFACE_RIGHT,
	KEY_PRESS_SURFACE_TOTAL
};

bool init();
bool loadMedia();
void close();
SDL_Surface* loadSurface(std::string path);

SDL_Window* gWindow = NULL;
SDL_Surface* gScreenSurface = NULL;
//SDL_Surface* gXOut = NULL;
SDL_Surface* gKeyPressSurfaces[KEY_PRESS_SURFACE_TOTAL];
SDL_Surface* gCurrentSurface = NULL;
SDL_Event e;
bool quit = false;

SDL_Surface* loadSurface(std::string path)
{
	//Load image at specified path
	SDL_Surface* loadedSurface = SDL_LoadBMP(path.c_str());
	if (loadedSurface == NULL)
	{
		printf("Unable to load image %s! SDL Error: %s\n", path.c_str(), SDL_GetError());
	}

	return loadedSurface;
}

bool init()
{
	//Initialization flag
	bool success = true;

	//Initialize SDL
	if (SDL_Init(SDL_INIT_VIDEO) < 0)
	{
		printf("SDL could not initialize! SDL_Error: %s\n", SDL_GetError());
		success = false;
	}
	else
	{
		//Create window
		gWindow = SDL_CreateWindow("SDL Tutorial", SDL_WINDOWPOS_UNDEFINED, SDL_WINDOWPOS_UNDEFINED, SCREEN_WIDTH, SCREEN_HEIGHT, SDL_WINDOW_SHOWN);
		if (gWindow == NULL)
		{
			printf("Window could not be created! SDL_Error: %s\n", SDL_GetError());
			success = false;
		}
		else
		{
			//Get window surface
			gScreenSurface = SDL_GetWindowSurface(gWindow);
		}
	}

	return success;
}


bool loadMedia()
{
	//Loading success flag
	bool success = true;

	//Load default surface
	gKeyPressSurfaces[KEY_PRESS_SURFACE_DEFAULT] = loadSurface("./res/img/press.bmp");
	if (gKeyPressSurfaces[KEY_PRESS_SURFACE_DEFAULT] == NULL)
	{
		printf("Failed to load default image!\n");
		success = false;
	}

	//Load up surface
	gKeyPressSurfaces[KEY_PRESS_SURFACE_UP] = loadSurface("./res/img/up.bmp");
	if (gKeyPressSurfaces[KEY_PRESS_SURFACE_UP] == NULL)
	{
		printf("Failed to load up image!\n");
		success = false;
	}

	//Load down surface
	gKeyPressSurfaces[KEY_PRESS_SURFACE_DOWN] = loadSurface("./res/img/down.bmp");
	if (gKeyPressSurfaces[KEY_PRESS_SURFACE_DOWN] == NULL)
	{
		printf("Failed to load down image!\n");
		success = false;
	}

	//Load left surface
	gKeyPressSurfaces[KEY_PRESS_SURFACE_LEFT] = loadSurface("./res/img/left.bmp");
	if (gKeyPressSurfaces[KEY_PRESS_SURFACE_LEFT] == NULL)
	{
		printf("Failed to load left image!\n");
		success = false;
	}

	//Load right surface
	gKeyPressSurfaces[KEY_PRESS_SURFACE_RIGHT] = loadSurface("./res/img/right.bmp");
	if (gKeyPressSurfaces[KEY_PRESS_SURFACE_RIGHT] == NULL)
	{
		printf("Failed to load right image!\n");
		success = false;
	}

	gCurrentSurface = gKeyPressSurfaces[KEY_PRESS_SURFACE_DEFAULT];

	return success;
}

void close()
{
	//Deallocate surfaces
	for (int i = 0; i < KEY_PRESS_SURFACE_TOTAL; ++i)
	{
		SDL_FreeSurface(gKeyPressSurfaces[i]);
		gKeyPressSurfaces[i] = NULL;
	}

	//Destroy window
	SDL_DestroyWindow(gWindow);
	gWindow = NULL;

	//Quit SDL subsystems
	SDL_Quit();
}


void main_loop()
{
	//Handle events on queue
	while (SDL_PollEvent(&e) != 0)
	{
		//User requests quit
		if (e.type == SDL_QUIT)
		{
			quit = true;
		}
		//User presses a key
		else if (e.type == SDL_KEYDOWN)
		{
			//Select surfaces based on key press
			switch (e.key.keysym.sym)
			{
			case SDLK_UP:
				gCurrentSurface = gKeyPressSurfaces[KEY_PRESS_SURFACE_UP];
				break;

			case SDLK_DOWN:
				gCurrentSurface = gKeyPressSurfaces[KEY_PRESS_SURFACE_DOWN];
				break;

			case SDLK_LEFT:
				gCurrentSurface = gKeyPressSurfaces[KEY_PRESS_SURFACE_LEFT];
				break;

			case SDLK_RIGHT:
				gCurrentSurface = gKeyPressSurfaces[KEY_PRESS_SURFACE_RIGHT];
				break;

			default:
				gCurrentSurface = gKeyPressSurfaces[KEY_PRESS_SURFACE_DEFAULT];
				break;
			}
		}
	}

		//Apply the image
		SDL_BlitSurface(gCurrentSurface, NULL, gScreenSurface, NULL);

		//Update the surface
		SDL_UpdateWindowSurface(gWindow);

}

int main(int argc, char* args[])
{
	//Start up SDL and create window
	if (!init())
	{
		printf("Failed to initialize!\n");
	}
	else
	{
		//Load media
		if (!loadMedia())
		{
			printf("Failed to load media!\n");
		}
		else
		{
#ifdef __EMSCRIPTEN__
			emscripten_set_main_loop(main_loop, 0, 1);
#else

			//While application is running
			while (!quit)
			{
				main_loop();
			}
			SDL_Delay(100);
#endif
		}
	}

	//Free resources and close SDL
	close();

	return 0;
}