#include <SDL.h>
#include <SDL_image.h>
#include <stdlib.h>
#include <stdio.h>
#include <stdint.h>
#include <errno.h>
#include <string.h>
#include <assert.h>
#include "kiss.h"

char *title = "SDL 18 - Key States";
SDL_Window *window;
SDL_Renderer *renderer;
SDL_Texture *back;
SDL_Texture *sprite_sheet;
SDL_Rect sprite[] = {
   { 0, 0, 100, 200 },
   { 100, 0, 100, 200 },
   { 200, 0, 100, 200 },
   { 300, 0, 100, 200 },
};

int
init_sdl(void)
{
   int status = -1;
   int x = SDL_WINDOWPOS_UNDEFINED;
   int y = SDL_WINDOWPOS_UNDEFINED;
   int width = 800;
   int height = 600;
   int flags = 0;       // SDL_WINDOW_FULLSCREEN_DESKTOP

   SDL_INIT(SDL_INIT_VIDEO);
   IMG_INIT(IMG_INIT_PNG);
   window = SDL_CREATEWINDOW(title, x, y, width, height, flags);
   renderer = SDL_CREATERENDERER(window, -1, SDL_RENDERER_ACCELERATED | SDL_RENDERER_PRESENTVSYNC);
   status = 0;
error:
   return status;
}

#define INIT_SDL(...) SDL_ZERO(init_sdl, __VA_ARGS__)

SDL_Texture *
load_texture(char *path)
{
   SDL_Texture *ret = NULL;
   SDL_Texture *texture = NULL;
   SDL_Surface *surface = NULL;
   surface = IMG_LOAD(path);
   texture = SDL_CREATETEXTUREFROMSURFACE(renderer, surface);
   SDL_SETTEXTUREBLENDMODE(texture, SDL_BLENDMODE_BLEND);
   ret = texture;
error:
   if (!ret)
     SDL_DestroyTexture(texture);
   SDL_FreeSurface(surface);
   return ret;
}

#define LOAD_TEXTURE(...) SDL_CHK(load_texture, __VA_ARGS__)

int
sprite_draw_ex(SDL_Rect *sprite, int x, int y, double zoom, double angle, SDL_RendererFlip flip, const SDL_Color *c)
{
   int status = -1;
   SDL_Rect target = { x, y, sprite->w * zoom, sprite->h * zoom };
   if (c)
     {
        SDL_SETTEXTURECOLORMOD(sprite_sheet, c->r, c->g, c->b);
        SDL_SETTEXTUREALPHAMOD(sprite_sheet, c->a);
     }
   SDL_RENDERCOPYEX(renderer, sprite_sheet, sprite, &target, angle, NULL, flip);
   if (c)
     {
        SDL_SETTEXTURECOLORMOD(sprite_sheet, 0xFF, 0xFF, 0xFF);
        SDL_SETTEXTUREALPHAMOD(sprite_sheet, 0xFF);
     }
   status = 0;
error:
   return status;
}

#define SPRITE_DRAW_EX(...) SDL_ZERO(sprite_draw_ex, __VA_ARGS__)

void
close_sdl(void)
{
   SDL_DestroyRenderer(renderer);
   SDL_DestroyWindow(window);
   IMG_Quit();
   SDL_Quit();
}

double x = 240;
double y = 240;
double dx = 0;
double dy = 0;
double angle = 0;
SDL_Color tint = { 0xFF, 0xFF, 0xFF, 0xFF };
int flip = 0;

int frame = 0;

int
draw(void)
{
   int status = -1;
   int w, h;
   double zoom = 1;
   SDL_GetWindowSize(window, &w, &h);
   SDL_RendererFlip sdl_flip = 0;

   SDL_RENDERCOPY(renderer, back, NULL, NULL);
   if (dx < 0)
     flip = 1;
   if (dx > 0)
     flip = 0;
   if (flip)
     sdl_flip = SDL_FLIP_HORIZONTAL;
   SPRITE_DRAW_EX(&sprite[(frame / 16) % NELEMS(sprite)], (int)x, (int)y, zoom, angle, sdl_flip, &tint);
   SDL_RenderPresent(renderer);
   double d = hypot(dx, dy);
   if (d > 4)
     {
        dx *= 4 / d;
        dy *= 4 / d;
        d = 4;
     }
   if (dx || dy)
     frame += (int)d;
   x += dx;
   y += dy;
   dx *= 0.98;
   dy *= 0.98;
   status = 0;
error:
   return status;
}

#define DRAW(...)   SDL_ZERO(draw, __VA_ARGS__)

#define K(scancode) (kb[SDL_SCANCODE_ ## scancode])
#define B(button)   (buttons & SDL_BUTTON(SDL_BUTTON_ ## button))

void
input(void)
{
   const uint8_t *kb;
//	int numkeys;
   int mx, my;
   int footx, footy;
   uint32_t buttons;
//	kb = SDL_GetKeyboardState(&numkeys);
   kb = SDL_GetKeyboardState(NULL);
   buttons = SDL_GetMouseState(&mx, &my);

   if (K(LEFT)) dx -= 0.1;
   if (K(RIGHT)) dx += 0.1;
   if (K(UP)) dy -= 0.1;
   if (K(DOWN)) dy += 0.1;
   if (K(Q)) tint.r += 1;
   if (K(W)) tint.g += 1;
   if (K(E)) tint.b += 1;
   if (K(R)) tint.a += 1;
   if (K(A)) tint.r -= 1;
   if (K(S)) tint.g -= 1;
   if (K(D)) tint.b -= 1;
   if (K(F)) tint.a -= 1;
   if (K(T)) angle += 1;
   if (K(G)) angle -= 1;

   footx = x + 50;
   footy = y + 200;

   if (B(LEFT))
     {
        dx = mx - footx;
        dy = my - footy;
     }
   if (B(RIGHT))
     {
        dx = footx - mx;
        dy = footy - my;
     }
}

int
main(void)
{
   int exit_status = EXIT_FAILURE;
   bool quit = 0;
   SDL_Event e;

   INIT_SDL();

   back = LOAD_TEXTURE("back.png");
   sprite_sheet = LOAD_TEXTURE("animation.png");

   while (!quit)
     {
        while (SDL_PollEvent(&e))
          {
             if (e.type == SDL_QUIT)
               quit = 1;
          }
        input();
        DRAW();
     }

   exit_status = EXIT_SUCCESS;
error:
   SDL_DestroyTexture(back);
   SDL_DestroyTexture(sprite_sheet);
   close_sdl();
   exit(exit_status);
}