define( [

  	"../core",
  	"../css"
  ], function( jQuery ) {

  "use strict";

  function Tween( elem, options, prop, end, easing ) {
  	return new Tween.prototype.init( elem, options, prop, end, easing );
  }
  jQuery.Tween = Tween;
  
  Tween.prototype = {
  	constructor: Tween,
  	init: function( elem, options, prop, end, easing, unit ) {
  		this.elem = elem;
  		this.prop = prop;

  		this.easing = easing || jQuery.easing._default;

  		this.options = options;
  		this.start = this.now = this.cur();
  		this.end = end;
  		this.unit = unit || ( jQuery.cssNumber[ prop ] ? "" : "px" );
  	},
  	cur: function() {
  		var hooks = Tween.propHooks[ this.prop ];
  
  		return hooks && hooks.get ?
  			hooks.get( this ) :
  			Tween.propHooks._default.get( this );
  	},
  	run: function( percent ) {
  		var eased,
  			hooks = Tween.propHooks[ this.prop ];
  
  		if ( this.options.duration ) {
  			this.pos = eased = jQuery.easing[ this.easing ](
  				percent, this.options.duration * percent, 0, 1, this.options.duration
  			);
  		} else {
  			this.pos = eased = percent;
  		}
  		this.now = ( this.end - this.start ) * eased + this.start;
  
  		if ( this.options.step ) {
  			this.options.step.call( this.elem, this.now, this );
  		}
  
  		if ( hooks && hooks.set ) {
  			hooks.set( this );
  		} else {
  			Tween.propHooks._default.set( this );
  		}
  		return this;
  	}
  };
  
  Tween.prototype.init.prototype = Tween.prototype;
  
  Tween.propHooks = {
  	_default: {
  		get: function( tween ) {
  			var result;

  			// Use a property on the element directly when it is not a DOM element,
  			// or when there is no matching style property that exists.
  			if ( tween.elem.nodeType !== 1 ||
  				tween.elem[ tween.prop ] != null && tween.elem.style[ tween.prop ] == null ) {

  				return tween.elem[ tween.prop ];
  			}

  			// Passing an empty string as a 3rd parameter to .css will automatically
  			// attempt a parseFloat and fallback to a string if the parse fails.
  			// Simple values such as "10px" are parsed to Float;
  			// complex values such as "rotate(1rad)" are returned as-is.

  			result = jQuery.css( tween.elem, tween.prop, "" );

  			// Empty strings, null, undefined and "auto" are converted to 0.
  			return !result || result === "auto" ? 0 : result;
  		},
  		set: function( tween ) {

  
  			// Use step hook for back compat.
  			// Use cssHook if its there.
  			// Use .style if available and use plain properties where available.

  			if ( jQuery.fx.step[ tween.prop ] ) {
  				jQuery.fx.step[ tween.prop ]( tween );

  			} else if ( tween.elem.nodeType === 1 &&
  				( tween.elem.style[ jQuery.cssProps[ tween.prop ] ] != null ||
  					jQuery.cssHooks[ tween.prop ] ) ) {

  				jQuery.style( tween.elem, tween.prop, tween.now + tween.unit );
  			} else {
  				tween.elem[ tween.prop ] = tween.now;
  			}
  		}
  	}
  };

  // Support: IE <=9 only

  // Panic based approach to setting things on disconnected nodes

  Tween.propHooks.scrollTop = Tween.propHooks.scrollLeft = {
  	set: function( tween ) {
  		if ( tween.elem.nodeType && tween.elem.parentNode ) {
  			tween.elem[ tween.prop ] = tween.now;
  		}
  	}
  };
  
  jQuery.easing = {
  	linear: function( p ) {
  		return p;
  	},
  	swing: function( p ) {
  		return 0.5 - Math.cos( p * Math.PI ) / 2;

  	},
  	_default: "swing"

  };
  
  jQuery.fx = Tween.prototype.init;

  // Back compat <1.8 extension point

  jQuery.fx.step = {};

  } );