import { Vector2 } from 'three'
import SAT from 'sat'
import SATX from './satx.js'

export default class Projectile {
  id = crypto.randomUUID()
  after = null
  height = 50
  memory = {}
  onCollide = null
  owner = null
  position = new Vector2()
  radius = 5
  speed = 1000
  visualRadius = null

  #dest = null
  #homingTarget = null
  #game = null

  get game() { return this.#game }
  set game(value) { this.#game = value }
  set destination(value) { this.#dest = value }
  set homingTarget(value) { this.#homingTarget = value }

  get destination() {
    return this.#dest ?? this.#homingTarget?.position
  }

  constructor(options = {}) {
    Object.entries(options).forEach(([key, value]) => this[key] = value)
    if (this.visualRadius == null) {
      this.visualRadius = this.radius
    }
  }

  checkCollisions(collider) {
    (this.game?.entities ?? []).filter((e) => e.id != this.id).forEach((e) => {
      if (e.id == this.owner?.id) { return }

      if (SATX.collideObject(collider, e.collider())) {
        if (this.onCollide != null) { this.onCollide(this, e) }
      }
    })
  }

  collider() {
    return new SAT.Circle(new SAT.Vector(this.position.x, this.position.y), this.radius)
  }

  despawn() {
    this.game?.despawn(this)
  }

  update() {
    this.#move()
    if (this.onCollide != null) { this.checkCollisions(this.collider()) }
    this.#checkIfArrived()
  }

  #checkIfArrived() {
    if (this.destination == null) { return }
    if (!this.position.equals(this.destination)) { return }

    if (this.after != null) {
      this.after(this, this.#homingTarget)
    }

    this.despawn()
  }

  #move() {
    if (this.destination == null) { return }

    const speed = (this.speed / (this.game?.tickBudget ?? 1000))
    const prevPos = this.position.clone()
    if (this.position.distanceTo(this.destination) < speed) {
      this.position.copy(this.destination)
    }
    else {
      const step = this.destination.clone().sub(this.position).normalize().multiplyScalar(speed)
      this.position.add(step)
    }

    const tunnel = SATX.entityTunnel(prevPos.x, prevPos.y, this.position.x, this.position.y, this.radius)
    if (this.onCollide != null) { this.checkCollisions(tunnel) }
  }
}