xrf.frag   = {}
xrf.model  = {}
xrf.mixers = []

xrf.init = ((init) => function(opts){
  let scene = new opts.THREE.Group()
  opts.scene.add(scene)
  opts.scene = scene
  init(opts)
  if( opts.loaders ) Object.values(opts.loaders).map( xrf.patchLoader )

  xrf.patchRenderer(opts)
  xrf.navigator.init()
  // return xrfragment lib as 'xrf' query functor (like jquery)
  for ( let i in xrf ) xrf.query[i] = xrf[i] 
  return xrf.query
})(xrf.init)

xrf.patchRenderer = function(opts){
  let {renderer,camera} = opts
  renderer.xr.addEventListener( 'sessionstart', () => xrf.baseReferenceSpace = renderer.xr.getReferenceSpace() );
  renderer.xr.enabled = true;
  xrf.clock = new xrf.THREE.Clock()
  renderer.render = ((render) => function(scene,camera){
    // update clock
    let time = xrf.clock.getDelta()
    // allow entities to do stuff during render (onBeforeRender and onAfterRender don't always fire)
    xrf.emit('render',{scene,camera,time}) // allow fragments to do something at renderframe
    render(scene,camera)
  })(renderer.render.bind(renderer))

}

xrf.patchLoader = function(loader){
  if( loader.prototype.load.xrf_patched ) return // prevent patching aliased loaders twice
  loader.prototype.load = ((load) => function(url, onLoad, onProgress, onError){
    load.call(  this,
                url,
                (model) => { 
                  onLoad(model); 
                  xrf.parseModel(model,url) 
                },
                onProgress,
                onError)
  })(loader.prototype.load)
  loader.prototype.load.xrf_patched = true
}

xrf.getFile = (url) => url.split("/").pop().replace(/#.*/,'')

xrf.parseModel = function(model,url){
  let file               = xrf.getFile(url)
  model.file             = file
  // eval embedded XR fragments
  model.scene.traverse( (mesh) => {
    mesh.renderOrder = 2 // render after stencil buffers
    xrf.hashbus.pub.mesh(mesh,model) 
  })
  model.animations.map( (a) => console.log("anim: "+a.name) )
  xrf.emit('parseModel',{model,url,file})
}

xrf.getLastModel = ()           => xrf.model.last 

xrf.reset = () => {
  const disposeObject = (obj) => {
    if (obj.children.length > 0) obj.children.forEach((child) => disposeObject(child));
    if (obj.geometry) obj.geometry.dispose();
    if (obj.material) {
      if (obj.material.map) obj.material.map.dispose();
      obj.material.dispose();
    }
    obj.clear()
    obj.removeFromParent() 
    return true
  };
  let nodes = []
  xrf.scene.traverse( (n)     => n.audio ? n.audio.remove() : false )
  xrf.scene.traverse( (child) => child.isXRF ? nodes.push(child) : false )
  nodes.map( disposeObject ) // leave non-XRF objects intact
  xrf.interactive = xrf.InteractiveGroup( xrf.THREE, xrf.renderer, xrf.camera)
  xrf.add( xrf.interactive )
  xrf.layers = 0
  xrf.emit('reset',{})
  // remove mixers
  xrf.mixers.map( (m) => {
    m.stop()
    delete m
  })
  xrf.mixers = []
}

xrf.parseUrl = (url) => {
  const urlObj = new URL( url.match(/:\/\//) ? url : String(`https://fake.com/${url}`).replace(/\/\//,'/') )
  let   dir  = url.substring(0, url.lastIndexOf('/') + 1)
  const file = urlObj.pathname.substring(urlObj.pathname.lastIndexOf('/') + 1);
  const hash = url.match(/#/) ? url.replace(/.*#/,'') : ''
  const ext  = file.split('.').pop()
  return {urlObj,dir,file,hash,ext}
}

xrf.add = (object) => {
  object.isXRF = true // mark for easy deletion when replacing scene
  xrf.scene.add(object)
}