import {
	Loader
} from 'three';
import { GLTFLoader } from '../loaders/GLTFLoader.js';

// VRM Specification: https://dwango.github.io/vrm/vrm_spec/
//
// VRM is based on glTF 2.0 and VRM extension is defined
// in top-level json.extensions.VRM

class VRMLoader extends Loader {

	constructor( manager ) {

		if ( GLTFLoader === undefined ) {

			throw new Error( 'THREE.VRMLoader: Import GLTFLoader.' );

		}

		super( manager );

		this.gltfLoader = new GLTFLoader( manager );

	}

	load( url, onLoad, onProgress, onError ) {

		const scope = this;

		this.gltfLoader.load( url, function ( gltf ) {

			try {

				scope.parse( gltf, onLoad );

			} catch ( e ) {

				if ( onError ) {

					onError( e );

				} else {

					console.error( e );

				}

				scope.manager.itemError( url );

			}

		}, onProgress, onError );

	}

	setDRACOLoader( dracoLoader ) {

		this.gltfLoader.setDRACOLoader( dracoLoader );
		return this;

	}

	parse( gltf, onLoad ) {

		// const gltfParser = gltf.parser;
		// const gltfExtensions = gltf.userData.gltfExtensions || {};
		// const vrmExtension = gltfExtensions.VRM || {};

		// handle VRM Extension here

		onLoad( gltf );

	}

}

export { VRMLoader };