/**
 * Based on http://www.emagix.net/academic/mscs-project/item/camera-sync-with-css3-and-webgl-threejs
 * @author mrdoob / http://mrdoob.com/
 */

THREE.CSS3DObject = function ( element ) {

    THREE.Object3D.call( this );

    this.element = element;
    this.element.style.position = 'absolute';

    this.addEventListener( 'removed', function ( event ) {

        if ( this.element.parentNode !== null ) {

            this.element.parentNode.removeChild( this.element );

            for ( var i = 0, l = this.children.length; i < l; i ++ ) {

                this.children[ i ].dispatchEvent( event );

            }

        }

    } );

};

THREE.CSS3DObject.prototype = Object.create( THREE.Object3D.prototype );

THREE.CSS3DSprite = function ( element ) {

    THREE.CSS3DObject.call( this, element );

};

THREE.CSS3DSprite.prototype = Object.create( THREE.CSS3DObject.prototype );

//

THREE.CSS3DRenderer = function () {

    console.log( 'THREE.CSS3DRenderer', THREE.REVISION );

    var _width, _height;
    var _widthHalf, _heightHalf;

    var matrix = new THREE.Matrix4();

    var domElement = document.createElement( 'div' );
    domElement.style.overflow = 'hidden';

    domElement.style.WebkitTransformStyle = 'preserve-3d';
    domElement.style.MozTransformStyle = 'preserve-3d';
    domElement.style.oTransformStyle = 'preserve-3d';
    domElement.style.transformStyle = 'preserve-3d';

    this.domElement = domElement;

    var cameraElement = document.createElement( 'div' );

    cameraElement.style.WebkitTransformStyle = 'preserve-3d';
    cameraElement.style.MozTransformStyle = 'preserve-3d';
    cameraElement.style.oTransformStyle = 'preserve-3d';
    cameraElement.style.transformStyle = 'preserve-3d';

    domElement.appendChild( cameraElement );

    this.setClearColor = function () {

    };

    this.setSize = function ( width, height ) {

        _width = width;
        _height = height;

        _widthHalf = _width / 2;
        _heightHalf = _height / 2;

        domElement.style.width = width + 'px';
        domElement.style.height = height + 'px';

        cameraElement.style.width = width + 'px';
        cameraElement.style.height = height + 'px';

    };

    var epsilon = function ( value ) {

        return Math.abs( value ) < 0.000001 ? 0 : value;

    };

    var getCameraCSSMatrix = function ( matrix ) {

        var elements = matrix.elements;

        return 'matrix3d(' +
            epsilon( elements[ 0 ] ) + ',' +
            epsilon( - elements[ 1 ] ) + ',' +
            epsilon( elements[ 2 ] ) + ',' +
            epsilon( elements[ 3 ] ) + ',' +
            epsilon( elements[ 4 ] ) + ',' +
            epsilon( - elements[ 5 ] ) + ',' +
            epsilon( elements[ 6 ] ) + ',' +
            epsilon( elements[ 7 ] ) + ',' +
            epsilon( elements[ 8 ] ) + ',' +
            epsilon( - elements[ 9 ] ) + ',' +
            epsilon( elements[ 10 ] ) + ',' +
            epsilon( elements[ 11 ] ) + ',' +
            epsilon( elements[ 12 ] ) + ',' +
            epsilon( - elements[ 13 ] ) + ',' +
            epsilon( elements[ 14 ] ) + ',' +
            epsilon( elements[ 15 ] ) +
            ')';

    };

    var getObjectCSSMatrix = function ( matrix ) {

        var elements = matrix.elements;

        return 'translate3d(-50%,-50%,0) matrix3d(' +
            epsilon( elements[ 0 ] ) + ',' +
            epsilon( elements[ 1 ] ) + ',' +
            epsilon( elements[ 2 ] ) + ',' +
            epsilon( elements[ 3 ] ) + ',' +
            epsilon( - elements[ 4 ] ) + ',' +
            epsilon( - elements[ 5 ] ) + ',' +
            epsilon( - elements[ 6 ] ) + ',' +
            epsilon( - elements[ 7 ] ) + ',' +
            epsilon( elements[ 8 ] ) + ',' +
            epsilon( elements[ 9 ] ) + ',' +
            epsilon( elements[ 10 ] ) + ',' +
            epsilon( elements[ 11 ] ) + ',' +
            epsilon( elements[ 12 ] ) + ',' +
            epsilon( elements[ 13 ] ) + ',' +
            epsilon( elements[ 14 ] ) + ',' +
            epsilon( elements[ 15 ] ) +
            ')';

    };

    var renderObject = function ( object, camera ) {

        if ( object instanceof THREE.CSS3DObject ) {

            var style;

            if ( object instanceof THREE.CSS3DSprite ) {

                // http://swiftcoder.wordpress.com/2008/11/25/constructing-a-billboard-matrix/

                matrix.copy( camera.matrixWorldInverse );
                matrix.transpose();
                matrix.copyPosition( object.matrixWorld );
                matrix.scale( object.scale );

                matrix.elements[ 3 ] = 0;
                matrix.elements[ 7 ] = 0;
                matrix.elements[ 11 ] = 0;
                matrix.elements[ 15 ] = 1;

                style = getObjectCSSMatrix( matrix );

            } else {

                style = getObjectCSSMatrix( object.matrixWorld );

            }

            var element = object.element;

            element.style.WebkitTransform = style;
            element.style.MozTransform = style;
            element.style.oTransform = style;
            element.style.transform = style;

            if ( element.parentNode !== cameraElement ) {

                cameraElement.appendChild( element );

            }

        }

        for ( var i = 0, l = object.children.length; i < l; i ++ ) {

            renderObject( object.children[ i ], camera );

        }

    };

    this.render = function ( scene, camera ) {

        var fov = 0.5 / Math.tan( THREE.Math.degToRad( camera.fov * 0.5 ) ) * _height;

        domElement.style.WebkitPerspective = fov + "px";
        domElement.style.MozPerspective = fov + "px";
        domElement.style.oPerspective = fov + "px";
        domElement.style.perspective = fov + "px";

        scene.updateMatrixWorld();

        if ( camera.parent === undefined ) camera.updateMatrixWorld();

        camera.matrixWorldInverse.getInverse( camera.matrixWorld );

        var style = "translate3d(0,0," + fov + "px)" + getCameraCSSMatrix( camera.matrixWorldInverse ) +
            " translate3d(" + _widthHalf + "px," + _heightHalf + "px, 0)";

        cameraElement.style.WebkitTransform = style;
        cameraElement.style.MozTransform = style;
        cameraElement.style.oTransform = style;
        cameraElement.style.transform = style;

        renderObject( scene, camera );

    };
};