import { EventSlot } from "../events/EventSlot";
import { OnBlur, OnFocus, OnMouseDown, OnMouseLeave, OnMouseMove, OnMouseUp, OnTouchCancel, OnTouchEnd, OnTouchMove, OnTouchStart } from "../dom/EventListeners";

export class ActivityAnalyser
{
  readonly onActive = new EventSlot();
  readonly onPassive = new EventSlot();
  private _timeOutDurationMS = 3000;
  private _active = false;
  get active(){ return this._active; }
  
  private _timeOutCallback:any = null;

  start()
  {
    let setActive = ()=>
    {
      this._cancelPassiveState();

      if ( ! this._active )
      {
        this._active = true;
        this.onActive.dispatch( null );
      }
      
      this._reschedulePassiveState();
    }

    let activeEvents = 
    [ 
      OnFocus, OnBlur,
      OnMouseMove, OnMouseDown, OnMouseUp, OnMouseLeave, 
      OnTouchStart, OnTouchMove, OnTouchCancel, OnTouchEnd
    ];

    
    activeEvents.forEach(
      ( onEvent )=>
      {
        onEvent.add( document.body, setActive );
      }
    )
  } 

  private _cancelPassiveState()
  {
    if ( this._timeOutCallback )
    {
      clearTimeout( this._timeOutCallback );
      this._timeOutCallback = null;
    }
  }

  private _reschedulePassiveState()
  {
    this._cancelPassiveState();

    this._timeOutCallback = setTimeout( ()=>{ this._setPassive(); }, this._timeOutDurationMS );
  }

  private _setPassive()
  {
    if ( ! this._active )
    {
      return;
    }

    this._active = false;
    this.onPassive.dispatch( null );
  }

}