import { cls, print, spr, use_texture } from "./graphics";
import { load_texture } from "./assets";
import { since_start } from "./time";
import { btn, Button } from "./input";
import { new_v2, vadd, vmul, vnorm } from "./vector";

let bot_sprite: number | undefined = undefined;

export function init() {
  print("Hello world!");

  // Start this load, but then...
  load_texture("./bot.png").then((n) => {
    print("Bot loaded at", since_start());
    bot_sprite = n;
  });
}

const friction = 0.6;
let robo_vel = new_v2(0);
let robo_pos = new_v2(10);

export function update() {
  // Acceleration from input
  let a = new_v2(0);
  if (btn(Button.Up)) {
    a.y -= 1;
  }
  if (btn(Button.Down)) {
    a.y += 1;
  }
  if (btn(Button.Left)) {
    a.x -= 1;
  }
  if (btn(Button.Right)) {
    a.x += 1;
  }
  vnorm(a);

  // Friction
  let v = vmul(robo_vel, friction);
  v = vadd(v, a);

  // Motion
  let np = vadd(robo_pos, v);

  // TODO: Collide.

  robo_pos = np;
  robo_vel = v;
}

export function draw() {
  cls(0.1, 0.2, 0.3);
  if (bot_sprite != undefined) {
    // ...it gets resolved here?
    use_texture(bot_sprite);

    spr(robo_pos.x, robo_pos.y, 32, 32, 0, 0);
  }
  // print("FRAME TIME:", since_last_frame());
}