#include <SDL2/SDL.h>
#include <SDL2/SDL_events.h>

extern void keydownHandler(SDL_Scancode);

/* Predefined Screen Size */
#define SCREEN_WIDTH 640
#define SCREEN_HEIGHT 480

static float sdlUpdate = 33.f;

/* Video Memory */
static uint32_t videoMemory[SCREEN_WIDTH * SCREEN_HEIGHT];

/* SDL static stuff */
static SDL_Window *window;
static SDL_Renderer *renderer;
static SDL_Texture *texture;
static SDL_Cursor *cursor;
static SDL_Event event;


/* Function to init the SDL Window and dependencies */
void initWindow(){
    if (SDL_Init(SDL_INIT_VIDEO)){
        printf("Could not init SDL: %s\n", SDL_GetError());
        exit(EXIT_FAILURE);
    }
    
    /* When we exit(CODE), then SDL_Quit is ran */
    atexit(SDL_Quit);
    
    /* Init Window */
    window = SDL_CreateWindow("Program", 
                              SDL_WINDOWPOS_UNDEFINED, SDL_WINDOWPOS_UNDEFINED,
                              SCREEN_WIDTH, SCREEN_HEIGHT, 0);
    if (window == NULL){
        printf("Fatal! Could not create SDL Window: %s\n", SDL_GetError());
        exit(EXIT_FAILURE);
    }
    
    /* Init Renderer */
    renderer = SDL_CreateRenderer(window, -1, 2);
    if (renderer == NULL){
        printf("Fatal! Could not create SDL Renderer: %s\n", SDL_GetError());
        exit(EXIT_FAILURE);
    }
    
    /* Init Texture */
    texture = SDL_CreateTexture(renderer, SDL_PIXELFORMAT_ARGB8888,
                                SDL_TEXTUREACCESS_STREAMING,
                                SCREEN_WIDTH, SCREEN_HEIGHT);
    if (texture == NULL){
        printf("Fatal! Could not create SDL Texture: %s\n", SDL_GetError());
        exit(EXIT_FAILURE);
    }
    
    if (SDL_SetTextureBlendMode(texture, SDL_BLENDMODE_NONE)){
        printf("Fatal! Could not set SDL blend mode: %s\n", SDL_GetError());
        exit(EXIT_FAILURE);
    }
    
    /* Init the Cursor */
    cursor = SDL_CreateSystemCursor(0);
    
    if (cursor == NULL){
        printf("Fatal! Could not create SDL cursor: %s\n", SDL_GetError());
        exit(EXIT_FAILURE);
    }
    SDL_SetCursor(cursor);
}

/* Clear the framebuffer with a color */
void clearScreen(uint32_t pixels[], uint32_t color){
    for (uint32_t i = 0; i < SCREEN_WIDTH * SCREEN_HEIGHT; i++) pixels[i] = color;
}

/* Get next events and do sm with it */
void pollEvents(){
    while (SDL_PollEvent(&event)){
        switch(event.type){
            
            /* If Quit, we quit the Application lul */
            case SDL_QUIT:
                printf("Quit at users request\n");
                exit(EXIT_SUCCESS);
                break;
                
            /* Fetch pressed Keys */
            case SDL_KEYDOWN:
                switch (event.key.keysym.scancode){
                    case SDL_SCANCODE_ESCAPE:
                        printf("Quit at users request\n");
                        exit(0);
                        break;
                    
                    default:
                        keydownHandler(event.key.keysym.scancode);
                        break;
                }
                break;
            default:
                break;
        }
    }
}

/* Update SDL Texture and Renderer with framebuffer */
void updateSDL(){
    if (SDL_UpdateTexture(texture, NULL, videoMemory, (sizeof(uint32_t) * SCREEN_WIDTH))) { 
        fprintf(stderr, "Could not update SDL texture: %s.\n", SDL_GetError());
        exit(EXIT_FAILURE);
    }
    if (SDL_RenderCopy(renderer, texture, NULL, NULL)) { 
        fprintf(stderr, "Could not display SDL texture: %s.\n", SDL_GetError());
        exit(EXIT_FAILURE);
    }
}