/**
 * @author mikael emtinger / http://gomo.se/
 * @author alteredq / http://alteredqualia.com/
 */

import { Vector2 } from '../math/Vector2.js';
import { Vector3 } from '../math/Vector3.js';
import { Matrix4 } from '../math/Matrix4.js';
import { Triangle } from '../math/Triangle.js';
import { Object3D } from '../core/Object3D.js';
import { BufferGeometry } from '../core/BufferGeometry.js';
import { InterleavedBuffer } from '../core/InterleavedBuffer.js';
import { InterleavedBufferAttribute } from '../core/InterleavedBufferAttribute.js';
import { SpriteMaterial } from '../materials/SpriteMaterial.js';

var _geometry;

var _intersectPoint = new Vector3();
var _worldScale = new Vector3();
var _mvPosition = new Vector3();

var _alignedPosition = new Vector2();
var _rotatedPosition = new Vector2();
var _viewWorldMatrix = new Matrix4();

var _vA = new Vector3();
var _vB = new Vector3();
var _vC = new Vector3();

var _uvA = new Vector2();
var _uvB = new Vector2();
var _uvC = new Vector2();

function Sprite( material ) {

	Object3D.call( this );

	this.type = 'Sprite';

	if ( _geometry === undefined ) {

		_geometry = new BufferGeometry();

		var float32Array = new Float32Array( [
			- 0.5, - 0.5, 0, 0, 0,
			0.5, - 0.5, 0, 1, 0,
			0.5, 0.5, 0, 1, 1,
			- 0.5, 0.5, 0, 0, 1
		] );

		var interleavedBuffer = new InterleavedBuffer( float32Array, 5 );

		_geometry.setIndex( [ 0, 1, 2,	0, 2, 3 ] );
		_geometry.setAttribute( 'position', new InterleavedBufferAttribute( interleavedBuffer, 3, 0, false ) );
		_geometry.setAttribute( 'uv', new InterleavedBufferAttribute( interleavedBuffer, 2, 3, false ) );

	}

	this.geometry = _geometry;
	this.material = ( material !== undefined ) ? material : new SpriteMaterial();

	this.center = new Vector2( 0.5, 0.5 );

}

Sprite.prototype = Object.assign( Object.create( Object3D.prototype ), {

	constructor: Sprite,

	isSprite: true,

	raycast: function ( raycaster, intersects ) {

		if ( raycaster.camera === null ) {

			console.error( 'THREE.Sprite: "Raycaster.camera" needs to be set in order to raycast against sprites.' );

		}

		_worldScale.setFromMatrixScale( this.matrixWorld );

		_viewWorldMatrix.copy( raycaster.camera.matrixWorld );
		this.modelViewMatrix.multiplyMatrices( raycaster.camera.matrixWorldInverse, this.matrixWorld );

		_mvPosition.setFromMatrixPosition( this.modelViewMatrix );

		if ( raycaster.camera.isPerspectiveCamera && this.material.sizeAttenuation === false ) {

			_worldScale.multiplyScalar( - _mvPosition.z );

		}

		var rotation = this.material.rotation;
		var sin, cos;
		if ( rotation !== 0 ) {

			cos = Math.cos( rotation );
			sin = Math.sin( rotation );

		}

		var center = this.center;

		transformVertex( _vA.set( - 0.5, - 0.5, 0 ), _mvPosition, center, _worldScale, sin, cos );
		transformVertex( _vB.set( 0.5, - 0.5, 0 ), _mvPosition, center, _worldScale, sin, cos );
		transformVertex( _vC.set( 0.5, 0.5, 0 ), _mvPosition, center, _worldScale, sin, cos );

		_uvA.set( 0, 0 );
		_uvB.set( 1, 0 );
		_uvC.set( 1, 1 );

		// check first triangle
		var intersect = raycaster.ray.intersectTriangle( _vA, _vB, _vC, false, _intersectPoint );

		if ( intersect === null ) {

			// check second triangle
			transformVertex( _vB.set( - 0.5, 0.5, 0 ), _mvPosition, center, _worldScale, sin, cos );
			_uvB.set( 0, 1 );

			intersect = raycaster.ray.intersectTriangle( _vA, _vC, _vB, false, _intersectPoint );
			if ( intersect === null ) {

				return;

			}

		}

		var distance = raycaster.ray.origin.distanceTo( _intersectPoint );

		if ( distance < raycaster.near || distance > raycaster.far ) return;

		intersects.push( {

			distance: distance,
			point: _intersectPoint.clone(),
			uv: Triangle.getUV( _intersectPoint, _vA, _vB, _vC, _uvA, _uvB, _uvC, new Vector2() ),
			face: null,
			object: this

		} );

	},

	clone: function () {

		return new this.constructor( this.material ).copy( this );

	},

	copy: function ( source ) {

		Object3D.prototype.copy.call( this, source );

		if ( source.center !== undefined ) this.center.copy( source.center );

		return this;

	}


} );

function transformVertex( vertexPosition, mvPosition, center, scale, sin, cos ) {

	// compute position in camera space
	_alignedPosition.subVectors( vertexPosition, center ).addScalar( 0.5 ).multiply( scale );

	// to check if rotation is not zero
	if ( sin !== undefined ) {

		_rotatedPosition.x = ( cos * _alignedPosition.x ) - ( sin * _alignedPosition.y );
		_rotatedPosition.y = ( sin * _alignedPosition.x ) + ( cos * _alignedPosition.y );

	} else {

		_rotatedPosition.copy( _alignedPosition );

	}


	vertexPosition.copy( mvPosition );
	vertexPosition.x += _rotatedPosition.x;
	vertexPosition.y += _rotatedPosition.y;

	// transform to world space
	vertexPosition.applyMatrix4( _viewWorldMatrix );

}

export { Sprite };