import Tone from "../core/Tone";
import "../signal/Signal";
import "../signal/Subtract";
import "../signal/Add";
import "../component/Merge";
import "../core/Gain";
import "../core/AudioNode";

/**
 *  @class Mid/Side processing separates the the 'mid' signal
 *         (which comes out of both the left and the right channel)
 *         and the 'side' (which only comes out of the the side channels).
 *         MidSideMerge merges the mid and side signal after they've been seperated
 *         by Tone.MidSideSplit.<br><br>
 *         <code>
 *         Left = (Mid+Side)/sqrt(2);   // obtain left signal from mid and side<br>
 *         Right = (Mid-Side)/sqrt(2);   // obtain right signal from mid and side<br>
 *         </code>
 *
 *  @extends {Tone.AudioNode}
 *  @constructor
 */
Tone.MidSideMerge = function(){

	Tone.AudioNode.call(this);
	this.createInsOuts(2, 0);

	/**
	 *  The mid signal input. Alias for
	 *  <code>input[0]</code>
	 *  @type  {Tone.Gain}
	 */
	this.mid = this.input[0] = new Tone.Gain();

	/**
	 *  recombine the mid/side into Left
	 *  @type {Tone.Add}
	 *  @private
	 */
	this._left = new Tone.Add();

	/**
	 * Multiply the left by sqrt(1/2)
	 * @type {Tone.Multiply}
	 */
	this._timesTwoLeft = new Tone.Multiply(Math.SQRT1_2);

	/**
	 *  The side signal input. Alias for
	 *  <code>input[1]</code>
	 *  @type  {Tone.Gain}
	 */
	this.side = this.input[1] = new Tone.Gain();

	/**
	 *  recombine the mid/side into Right
	 *  @type {Tone.Subtract}
	 *  @private
	 */
	this._right = new Tone.Subtract(/*"($0 - $1) * $2"*/);

	/**
	 * Multiply the right by sqrt(1/2)
	 * @type {Tone.Multiply}
	 */
	this._timesTwoRight = new Tone.Multiply(Math.SQRT1_2);

	/**
	 *  Merge the left/right signal back into a stereo signal.
	 *  @type {Tone.Merge}
	 *  @private
	 */
	this._merge = this.output = new Tone.Merge();

	this.mid.connect(this._left, 0, 0);
	this.side.connect(this._left, 0, 1);
	this.mid.connect(this._right, 0, 0);
	this.side.connect(this._right, 0, 1);
	this._left.connect(this._timesTwoLeft);
	this._right.connect(this._timesTwoRight);
	this._timesTwoLeft.connect(this._merge, 0, 0);
	this._timesTwoRight.connect(this._merge, 0, 1);
};

Tone.extend(Tone.MidSideMerge, Tone.AudioNode);

/**
 *  clean up
 *  @returns {Tone.MidSideMerge} this
 */
Tone.MidSideMerge.prototype.dispose = function(){
	Tone.AudioNode.prototype.dispose.call(this);
	this.mid.dispose();
	this.mid = null;
	this.side.dispose();
	this.side = null;
	this._left.dispose();
	this._left = null;
	this._timesTwoLeft.dispose();
	this._timesTwoLeft = null;
	this._right.dispose();
	this._right = null;
	this._timesTwoRight.dispose();
	this._timesTwoRight = null;
	this._merge.dispose();
	this._merge = null;
	return this;
};

export default Tone.MidSideMerge;