(function () {

    var entityID;
    var overlayID;

    var HALF = 0.5;
    var CREATE_OVERLAY_DIMENSIONS_OFFSET = 0.02;
    var OVERLAY_ALPHA = 1.0;

    function CreateOverlayOverEntity () {

    }

    CreateOverlayOverEntity.prototype = {
        preload: function (id) {
            entityID = id;
            
            var entityProperties = Entities.getEntityProperties(entityID, ["position", "registrationPoint", "dimensions", "rotation"])

            var position = entityProperties.position;
            var registrationPoint = entityProperties.registrationPoint;
            var dimensions = entityProperties.dimensions;
            var rotation = entityProperties.rotation;

            var localOffset = {
                x: -1 * (registrationPoint.x - HALF) * dimensions.x,
                y: -1 * (registrationPoint.y - HALF) * dimensions.y,
                z: -1 * (registrationPoint.z - HALF) * dimensions.z
            };
            
            var worldOffset = Vec3.multiplyQbyV(rotation, localOffset);
            var worldPosition = Vec3.sum(position, worldOffset);

            // create visible cube
            overlayID = Overlays.addOverlay("cube", {
                position: {
                    x: worldPosition.x,
                    y: worldPosition.y,
                    z: worldPosition.z
                },
                rotation: rotation,
                dimensions: {
                    x: dimensions.x + CREATE_OVERLAY_DIMENSIONS_OFFSET,
                    y: dimensions.y + CREATE_OVERLAY_DIMENSIONS_OFFSET,
                    z: dimensions.z + CREATE_OVERLAY_DIMENSIONS_OFFSET
                },
                solid: true,
                alpha: OVERLAY_ALPHA,
                parentID: entityID
            });
        },

        unload: function () {
			/*
            if (overlayID) {
                Overlays.deleteOverlay(overlayID);
                overlayID = null;
            }
			*/
        }
    }

    return new CreateOverlayOverEntity();
});