#include <iostream>
#include <SDL.h>
#include <stdio.h>


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



// returns false if initializing SDL fails or if creating windows fails
bool init(SDL_Window* p_gWindow, SDL_Surface* p_gScreenSurface)
{
    //Initialization flag
    bool success = true;

    //Initialize SDL
    //checks if SDL_Init returns -1
    if (SDL_Init(SDL_INIT_VIDEO) < 0)
    {
        printf("SDL could not initialize! SDL_Error: %s\n", SDL_GetError());
        success = false;
    }
    else
    {
        //Create window
        p_gWindow = SDL_CreateWindow("SDL Tutorial", SDL_WINDOWPOS_UNDEFINED, SDL_WINDOWPOS_UNDEFINED,
            SCREEN_WIDTH, SCREEN_HEIGHT, SDL_WINDOW_SHOWN);
        //checks if SDL_CreateWindow returned null meaning that they couldn't make a window
        if (p_gWindow == NULL)
        {
            printf("Window could not be created! SDL_Error: %s\n", SDL_GetError());
            success = false;
        }
        else
        {
            //Get window surface
            p_gScreenSurface = SDL_GetWindowSurface(p_gWindow);
        }
    }

    return success;
}

// return false if SDL_LoadBMP FAILED. Else it will return true
bool loadMedia(SDL_Surface* gImage)
{
    //Loading success flag
    bool success = true;


    //Load splash image
    gImage = SDL_LoadBMP("background.bmp");
    if (gImage == NULL)
    {
        printf("Unable to load image! SDL Error: %s\n", SDL_GetError());
        success = false;
    }

    return success;
}

void close(SDL_Surface* p_gimage, SDL_Window* p_gWindow)
{
    //Deallocate surface
    SDL_FreeSurface(p_gimage);
    p_gimage = NULL;

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

    //Quit SDL subsystems
    SDL_Quit();
}

//main
int main(int argc, char* args[])
{
    //The window we'll be rendering to
    SDL_Window* gWindow = NULL;

    //The surface contained by the window
    SDL_Surface* gScreenSurface = NULL;

    //The image we will load and show on the screen
    SDL_Surface* gImage = NULL;



    //Start up SDL and create window
    if (!init(gWindow, gScreenSurface))
    {
        printf("Failed to initialize!\n");
    }
    else
    {
        //Load media
        if (!loadMedia(gImage))
        {
            printf("Failed to load media!\n");
        }
        else
        {
            //Main loop flag
            bool quit = false;

            //Event handler
            SDL_Event e;

            while (!quit) {
                while (SDL_PollEvent(&e) != 0)
                {
                    if (e.type == SDL_QUIT)
                    {
                        quit = true;
                    }
                }

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

                //Update the surface
                SDL_UpdateWindowSurface(gWindow);
            }
        }
    }

    //Free resources and close SDL
    close(gImage, gWindow);

    return 0;
}