import ObjectLoader from '@speckle/objectloader'
import Converter from './Converter'

/**
 * Helper wrapper around the ObjectLoader class, with some built in assumptions.
 */

export default class ViewerObjectLoader {


  constructor( parent, objectUrl, authToken ) {
    this.objectUrl = objectUrl
    this.viewer = parent
    this.token = null
    try {
      this.token = authToken || localStorage.getItem( 'AuthToken' )
    } catch ( error ) {
        // Accessing localStorage may throw when executing on sandboxed document, ignore.
    }

    if ( !this.token ) {
      console.warn( 'Viewer: no auth token present. Requests to non-public stream objects will fail.' )
    }

    // example url: `https://staging.speckle.dev/streams/a75ab4f10f/objects/f33645dc9a702de8af0af16bd5f655b0`
    let url = new URL( objectUrl )

    let segments = url.pathname.split( '/' )
    if ( segments.length < 5 || url.pathname.indexOf( 'streams' ) === -1 || url.pathname.indexOf( 'objects' ) === -1 ) {
      throw new Error( 'Unexpected object url format.' )
    }

    this.serverUrl = url.origin
    this.streamId = segments[2]
    this.objectId = segments[4]

    this.loader = new ObjectLoader( {
      serverUrl: this.serverUrl,
      token: this.token,
      streamId: this.streamId,
      objectId: this.objectId
    } )

    this.converter = new Converter( this.loader )

    this.lastAsyncPause = Date.now()
    this.existingAsyncPause = null
  }

  async asyncPause() {
    // while ( this.existingAsyncPause ) {
    //   await this.existingAsyncPause
    // }
    // Don't freeze the UI
    if ( Date.now() - this.lastAsyncPause >= 100 ) {
      this.lastAsyncPause = Date.now()
      this.existingAsyncPause = new Promise( resolve => setTimeout( resolve, 0 ) )
      await this.existingAsyncPause
      this.existingAsyncPause = null
      if (Date.now() - this.lastAsyncPause > 500) console.log("VObjLoader Event loop lag: ", Date.now() - this.lastAsyncPause)
    }
  }

  async load( ) {
    let first = true
    let current = 0
    let total = 0
    let viewerLoads = 0
    let firstObjectPromise = null
    for await ( let obj of this.loader.getObjectIterator() ) {
      await this.converter.asyncPause()
      if ( first ) {
        firstObjectPromise = this.converter.traverseAndConvert( obj, async ( objectWrapper ) => {
          await this.converter.asyncPause()
          objectWrapper.meta.__importedUrl = this.objectUrl
          this.viewer.sceneManager.addObject( objectWrapper )
          viewerLoads++
        } )
        first = false
        total = obj.totalChildrenCount
      }
      current++
      this.viewer.emit( 'load-progress', { progress: current / ( total + 1 ), id: this.objectId } )
    }

    if ( firstObjectPromise ) {
      await firstObjectPromise
    }

    await this.viewer.sceneManager.postLoad()

    if ( viewerLoads === 0 ) {
      console.warn( `Viewer: no 3d objects found in object ${this.objectId}` )
      this.viewer.emit( 'load-warning', { message: `No displayable objects found in object ${this.objectId}.` } )
    }
  }

  async unload( ) {
    await this.viewer.sceneManager.removeImportedObject( this.objectUrl )
  }
}