import { Animator } from './Animator'
import { createSystem, SystemSettings } from '../system/snowSystem'

export function runSnow(canvas: HTMLCanvasElement, settings: SystemSettings){
  const context = canvas.getContext('2d') as CanvasRenderingContext2D
  let viewportWidth = window.innerWidth
  let viewportHeight = window.innerHeight
  const dpr = window.devicePixelRatio || 1
  const system = createSystem(context, () => viewportWidth, () => viewportHeight, settings)
  function resize(){
    viewportWidth = window.innerWidth
    viewportHeight = window.innerHeight
    canvas.style.width = `${viewportWidth}px`
    canvas.style.height = `${viewportHeight}px`
    canvas.width = Math.floor(viewportWidth * dpr)
    canvas.height = Math.floor(viewportHeight * dpr)
    context.setTransform(dpr, 0, 0, dpr, 0, 0)
    system.setViewport(viewportWidth, viewportHeight)
    system.recomputeTarget()
  }
  resize()
  const animator = new Animator(
    (dt) => { system.updateSystem(dt); system.renderSystem() },
    () => system.shouldStop(),
    () => { context.clearRect(0, 0, viewportWidth, viewportHeight); canvas.style.display = 'none' }
  )
  function onResize(){ resize() }
  window.addEventListener('resize', onResize)
  animator.init()
  animator.update()
  return { stop(){ animator.stop(); window.removeEventListener('resize', onResize) } }
}