import {
  Animation,
  AnimationGroup,
} from '../anvil'

export class AnimationQueue {

  public queue: (Animation | AnimationGroup)[]

  public callback: Function = function(): void { }

  public isAnimating: boolean = false

  constructor() {
    this.queue = new Array
  }

  public enqueue(animation: Animation | AnimationGroup): AnimationQueue {
    this.queue.push(animation)
    return this
  }

  public dequeue() {
    return this
  }

  public clear(): AnimationQueue {
    this.queue = new Array
    return this
  }

  public play(): AnimationQueue {
    this.isAnimating = true
    this.queue[0].callback = this.next.bind(this)
    this.queue[0].play()
    return this
  }

  public stop(): AnimationQueue {
    if (this.queue.length > 0) {
      for (let animation of this.queue) {
        animation.stop()
      }
    }
    if (this.isAnimating === true) {
      this.isAnimating = false
    }
    this.callback()
    return this
  }

  private next(): void {
    this.queue[0].callback = undefined
    this.queue.splice(0, 1)
    if (this.queue.length > 0) {
      this.play()
    } else {
      this.stop()
    }
  }

}