/**
 * @author Mugen87 / http://github.com/Mugen87
 */

import { BufferGeometry } from '../core/BufferGeometry.js';
import { BufferAttribute } from '../core/BufferAttribute.js';
import { LineBasicMaterial } from '../materials/LineBasicMaterial.js';
import { Line } from '../objects/Line.js';
import { _Math } from '../math/Math.js';

function PositionalAudioHelper( audio, range, divisionsInnerAngle, divisionsOuterAngle ) {

	this.audio = audio;
	this.range = range || 1;
	this.divisionsInnerAngle = divisionsInnerAngle || 16;
	this.divisionsOuterAngle = divisionsOuterAngle || 2;

	var geometry = new BufferGeometry();
	var divisions = this.divisionsInnerAngle + this.divisionsOuterAngle * 2;
	var positions = new Float32Array( ( divisions * 3 + 3 ) * 3 );
	geometry.setAttribute( 'position', new BufferAttribute( positions, 3 ) );

	var materialInnerAngle = new LineBasicMaterial( { color: 0x00ff00 } );
	var materialOuterAngle = new LineBasicMaterial( { color: 0xffff00 } );

	Line.call( this, geometry, [ materialOuterAngle, materialInnerAngle ] );

	this.update();

}

PositionalAudioHelper.prototype = Object.create( Line.prototype );
PositionalAudioHelper.prototype.constructor = PositionalAudioHelper;

PositionalAudioHelper.prototype.update = function () {

	var audio = this.audio;
	var range = this.range;
	var divisionsInnerAngle = this.divisionsInnerAngle;
	var divisionsOuterAngle = this.divisionsOuterAngle;

	var coneInnerAngle = _Math.degToRad( audio.panner.coneInnerAngle );
	var coneOuterAngle = _Math.degToRad( audio.panner.coneOuterAngle );

	var halfConeInnerAngle = coneInnerAngle / 2;
	var halfConeOuterAngle = coneOuterAngle / 2;

	var start = 0;
	var count = 0;
	var i, stride;

	var geometry = this.geometry;
	var positionAttribute = geometry.attributes.position;

	geometry.clearGroups();

	//

	function generateSegment( from, to, divisions, materialIndex ) {

		var step = ( to - from ) / divisions;

		positionAttribute.setXYZ( start, 0, 0, 0 );
		count ++;

		for ( i = from; i < to; i += step ) {

			stride = start + count;

			positionAttribute.setXYZ( stride, Math.sin( i ) * range, 0, Math.cos( i ) * range );
			positionAttribute.setXYZ( stride + 1, Math.sin( Math.min( i + step, to ) ) * range, 0, Math.cos( Math.min( i + step, to ) ) * range );
			positionAttribute.setXYZ( stride + 2, 0, 0, 0 );

			count += 3;

		}

		geometry.addGroup( start, count, materialIndex );

		start += count;
		count = 0;

	}

	//

	generateSegment( - halfConeOuterAngle, - halfConeInnerAngle, divisionsOuterAngle, 0 );
	generateSegment( - halfConeInnerAngle, halfConeInnerAngle, divisionsInnerAngle, 1 );
	generateSegment( halfConeInnerAngle, halfConeOuterAngle, divisionsOuterAngle, 0 );

	//

	positionAttribute.needsUpdate = true;

	if ( coneInnerAngle === coneOuterAngle ) this.material[ 0 ].visible = false;

};

PositionalAudioHelper.prototype.dispose = function () {

	this.geometry.dispose();
	this.material[ 0 ].dispose();
	this.material[ 1 ].dispose();

};


export { PositionalAudioHelper };
