#include "screen.h"

#include <stdio.h>
#include <stdlib.h>
#include <string.h>
#include <time.h>

void init_screen(Screen* screen, const char* title, uint16_t width, uint16_t height) {
    screen->width = width;
    screen->height = height;
    size_t pixel_count = screen->width * screen->height;
    screen->pixels = malloc(pixel_count * sizeof(uint32_t));
    memset(screen->pixels, 0, pixel_count * sizeof(uint32_t));

	SDL_Init(SDL_INIT_VIDEO);

    screen->window =
        SDL_CreateWindow(
            title,
            SDL_WINDOWPOS_CENTERED_DISPLAY(0),
            SDL_WINDOWPOS_CENTERED_DISPLAY(0),
            screen->width,
            screen->height,
            0
        );

    if (!screen->window) {
		printf("fatal: failed to create sdl window\n");
        exit(EXIT_FAILURE);
	}

    screen->renderer = 
        SDL_CreateRenderer(
            screen->window,
            -1,
            SDL_RENDERER_ACCELERATED
            | SDL_RENDERER_PRESENTVSYNC
        );

    if (!screen->renderer) {
        printf("fatal: failed to create sdl renderer\n");
        exit(EXIT_FAILURE);
    }

    screen->texture =
        SDL_CreateTexture(
            screen->renderer,
            SDL_PIXELFORMAT_RGBA8888,
            SDL_TEXTUREACCESS_STREAMING,
            screen->width,
            screen->height
        );
    
    if (!screen->texture) {
        printf("fatal: failed to create window texture\n");
        exit(EXIT_FAILURE);
    }

    screen->open = true;
    screen->delta = 0;
}

static long last = 0;
void poll_screen(Screen* screen) {
    struct timespec spec;
    clock_gettime(CLOCK_MONOTONIC, &spec);
    long now = round(spec.tv_nsec / 1.0e6) + spec.tv_sec * 1000;
    if (last == 0) {
        screen->delta = 0;
    } else {
        screen->delta = (now - last) / 1000.0;
    }
    last = now;
    
    SDL_Event ev;
    while (SDL_PollEvent(&ev)) {
        switch (ev.type) {
            case SDL_QUIT:
                screen->open = false;
                break;
            default:
                break;
        }
    }

    screen->key_state = SDL_GetKeyboardState(NULL);
}

void draw_screen(Screen* screen) {
    void *px;
    int pitch;
    SDL_LockTexture(screen->texture, NULL, &px, &pitch);
    {
        for (uint16_t y = 0; y < screen->height; y++) {
            memcpy(
                &((uint8_t*) px)[y * pitch],
                &screen->pixels[y * screen->width],
                screen->width * sizeof(uint32_t)
            );
        }
    }
    SDL_UnlockTexture(screen->texture);

    SDL_SetRenderTarget(screen->renderer, NULL);
    SDL_SetRenderDrawColor(screen->renderer, 0, 0, 0, 0xFF);
    SDL_SetRenderDrawBlendMode(screen->renderer, SDL_BLENDMODE_NONE);

    SDL_RenderClear(screen->renderer);
    SDL_RenderCopyEx(
        screen->renderer,
        screen->texture,
        NULL,
        NULL,
        0.0,
        NULL,
        SDL_FLIP_VERTICAL);

    SDL_RenderCopy(screen->renderer, NULL, NULL, &((SDL_Rect) { 0, 0, 512, 512 }));
    SDL_RenderPresent(screen->renderer);
}

void free_screen(Screen* screen) {
    SDL_DestroyTexture(screen->texture);
    SDL_DestroyRenderer(screen->renderer);
	SDL_DestroyWindow(screen->window);
}

bool key_pressed(Screen* screen, SDL_Scancode code) {
    return screen->key_state[code & 0xFFFF];    
}