import {getTimer}					from "../utils/getTimer";

export class RequestAnimationFrame
{
	private _callback:Function;
	private _callbackContext:Object;
	private _active:boolean = false;
	private _rafUpdateFunction:any;
	private _prevTime:number;
	private _dt:number;
	private _currentTime:number;
	private _argsArray:Array<any> = new Array();
	private _getTimer:Function;

	constructor(callback:Function, callbackContext:Object)
	{
		this._getTimer = getTimer;

		this.setCallback(callback, callbackContext);

		this._rafUpdateFunction = () => {
			if (this._active)
				this._tick();
		}

		this._argsArray.push(this._dt);
	}

	// Public

	/**
	 *
	 * @param callback
	 * @param callbackContext
	 */
	public setCallback(callback:Function, callbackContext:Object):void
	{
		this._callback = callback;
		this._callbackContext = callbackContext;
	}

	/**
	 *
	 */
	public start():void
	{
		this._prevTime = this._getTimer();
		this._active = true;

		if(window) {
			if (window.requestAnimationFrame) {
				window.requestAnimationFrame(this._rafUpdateFunction);
			} else {
				if (window['mozRequestAnimationFrame'])
					window.requestAnimationFrame = window['mozRequestAnimationFrame'];
				else if (window['webkitRequestAnimationFrame'])
					window.requestAnimationFrame = window['webkitRequestAnimationFrame'];
				else if (window['oRequestAnimationFrame'])
					window.requestAnimationFrame = window['oRequestAnimationFrame'];
			}
		}
	}

	/**
	 *
	 */
	public stop():void
	{
		this._active = false;
	}

	// Get / Set

	/**
	 *
	 * @returns {boolean}
	 */
	public get active():boolean
	{
		return this._active;
	}

	// Private

	/**
	 *
	 * @private
	 */
	private _tick():void
	{
		this._currentTime = this._getTimer();
		this._dt = this._currentTime - this._prevTime;
		this._argsArray[0] = this._dt;
		this._callback.apply(this._callbackContext, this._argsArray);

		window.requestAnimationFrame(this._rafUpdateFunction);

		this._prevTime = this._currentTime;
	}


}