define(["Tone/core/Tone", "Tone/signal/Add", "Tone/signal/Negate", "Tone/signal/SignalBase"], function(Tone){

	"use strict";

	/**
	 *  @class Subtract a signal and a number or two signals. 
	 *         input 0 : minuend.
	 *         input 1 : subtrahend
	 *
	 *  @extends {Tone.SignalBase}
	 *  @constructor
	 *  @param {number=} value value to subtract from the incoming signal. If the value
	 *                         is omitted, it will subtract the second signal from the first
	 */
	Tone.Subtract = function(value){

		Tone.call(this, 2, 0);

		/**
		 *  the adder node
		 *  @type {Tone.Add}
		 *  @private
		 */
		this._adder = this.input[0] = this.output = new Tone.Add(-value);

		/**
		 *  the negate node
		 *  @type {Tone.Negate}
		 *  @private
		 */
		this._neg = this.input[1] = new Tone.Negate();

		//connect it up
		this._neg.connect(this._adder, 0, 1);
	};

	Tone.extend(Tone.Subtract, Tone.SignalBase);

	/**
	 * The value being subtracted from the incoming signal. 
	 * @memberOf Tone.Subtract#
	 * @type {number}
	 * @name value
	 */
	Object.defineProperty(Tone.Subtract.prototype, "value", {
		get : function(){
			return -this._adder.value;
		},
		set : function(value){
			this._adder.value = -value;
		}
	});

	/**
	 *  clean up
	 *  @returns {Tone.SignalBase} `this`
	 */
	Tone.Subtract.prototype.dispose = function(){
		Tone.prototype.dispose.call(this);
		this._neg.dispose();
		this._neg = null;
		this._adder.dispose();
		this._adder = null;
		return this;
	};

	return Tone.Subtract;
});