document.addEventListener('DOMContentLoaded', function () {
  const video = document.querySelector('#video')

  Promise.all([
    faceapi.nets.tinyFaceDetector.loadFromUri('/models'),
    faceapi.nets.faceLandmark68Net.loadFromUri('/models'),
    faceapi.nets.faceRecognitionNet.loadFromUri('/models'),
    faceapi.nets.faceExpressionNet.loadFromUri('/models')
  ]).then(startVideo)
  
  function startVideo() {
    navigator.mediaDevices.getUserMedia({ video: {} }).then(function (stream) {
      video.srcObject = stream
    })
  }
  
  video.addEventListener('play', () => {
    const canvas = faceapi.createCanvasFromMedia(video)
    document.body.append(canvas)
    const displaySize = { width: video.width, height: video.height }
    faceapi.matchDimensions(canvas, displaySize)
    setInterval(async () => {
      const detections = await faceapi.detectAllFaces(video, new faceapi.TinyFaceDetectorOptions()).withFaceLandmarks().withFaceExpressions()
      const resizedDetections = faceapi.resizeResults(detections, displaySize)
      canvas.getContext('2d').clearRect(0, 0, canvas.width, canvas.height)
      faceapi.draw.drawDetections(canvas, resizedDetections)
      faceapi.draw.drawFaceLandmarks(canvas, resizedDetections)
      faceapi.draw.drawFaceExpressions(canvas, resizedDetections)
    }, 100)
  })
})