import { load_texture } from "./assets";
import { btn, Button } from "./input";
import { Vec2, new_v2, vadd, vsub, vnorm, vmul } from "./vector";
import { spr, use_texture, Texture } from "./graphics";

export interface ActorProps {
  position: Vec2;
  velocity: Vec2;
  friction: number;
  id: string;
}

export function new_actor_props(id: string, position: Vec2): ActorProps {
  return {
    velocity: new_v2(0),
    friction: 0.6,
    id,
    position,
  };
}

export class Actor {
  type: ActorType;
  props: ActorProps;

  constructor(type: ActorType, props: ActorProps) {
    this.type = type;
    this.props = props;
  }

  update() {}

  update_physics() {
    const velocity = vmul(this.props.velocity, this.props.friction);
    // Zero if we're smaller than some epsilon.
    if (Math.abs(velocity.x) < 0.01) {
      velocity.x = 0;
    }
    if (Math.abs(velocity.y) < 0.01) {
      velocity.y = 0;
    }

    const new_position = vadd(this.props.position, velocity);

    // TODO: Collision detection
    // const { w, h } = this.bounds;

    this.props.velocity = velocity;
    this.props.position = new_position;
  }

  draw(_clock: number) {}

  bonk(_other: Actor) {}
}

const robo_info = {
  anchor: new_v2(16, 24), // Distance from upper-left of sprite.
  bounds: new_v2(32), // Width/height of sprite.
  sprite: "./bot.png",
  animations: [
    { start: 0, length: 1, speed: 20 },
    { start: 1, length: 4, speed: 8 },
  ],
};

export class Robo extends Actor {
  bot_sprite: Texture | undefined = undefined;

  constructor(props: ActorProps) {
    super("robo", props);
    load_texture(robo_info.sprite).then((texture) => {
      this.bot_sprite = texture;
    });
  }

  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);
    this.props.velocity = vadd(this.props.velocity, vmul(a, 1.5));
  }

  draw(clock: number) {
    if (this.bot_sprite != undefined) {
      use_texture(this.bot_sprite);

      const vel = this.props.velocity;
      const moving = vel.x != 0 || vel.y != 0;
      const anim = robo_info.animations[moving ? 1 : 0];

      const { x: w, y: h } = robo_info.bounds;
      const { x, y } = vsub(this.props.position, robo_info.anchor);

      const frame = (anim.start + ((clock / anim.speed) % anim.length)) >> 0;
      spr(x, y, w, h, frame * w, 0, 32, 32);
    }
  }
}

const ACTOR_TABLE = {
  robo: (s: ActorProps) => new Robo(s),
};

export type ActorType = keyof typeof ACTOR_TABLE;

export function is_actor_type(type: string): type is ActorType {
  return ACTOR_TABLE.hasOwnProperty(type);
}

export function spawn_actor(type: ActorType, props: ActorProps): Actor {
  return ACTOR_TABLE[type](props);
}