import DeviceDetector from "https://cdn.skypack.dev/[email protected]";

// Usage: testSupport({client?: string, os?: string}[])
// Client and os are regular expressions.
// See: https://cdn.jsdelivr.net/npm/[email protected]/README.md for
// legal values for client and os
testSupport([
  {client: 'Chrome'},
]);

function testSupport(supportedDevices:{client?: string; os?: string;}[]) {
  const deviceDetector = new DeviceDetector();
  const detectedDevice = deviceDetector.parse(navigator.userAgent);

  let isSupported = false;
  for (const device of supportedDevices) {
    if (device.client !== undefined) {
      const re = new RegExp(`^${device.client}$`);
      if (!re.test(detectedDevice.client.name)) {
        continue;
      }
    }
    if (device.os !== undefined) {
      const re = new RegExp(`^${device.os}$`);
      if (!re.test(detectedDevice.os.name)) {
        continue;
      }
    }
    isSupported = true;
    break;
  }
  if (!isSupported) {
    alert(`This demo, running on ${detectedDevice.client.name}/${detectedDevice.os.name}, ` +
          `is not well supported at this time, continue at your own risk.`);
  }
}

/**
 * @fileoverview Demonstrates a minimal use case for MediaPipe face tracking.
 */

const controls = window;
const mpSelfieSegmentation = window;

const examples = {
  images: [],
  // {name: 'name', src: 'https://url.com'},
  videos: [],
};

// Our input frames will come from here.
const videoElement =      
      document.getElementsByClassName('input_video')[0] as HTMLVideoElement;
const canvasElement =
    document.getElementsByClassName('output_canvas')[0] as HTMLCanvasElement;
const controlsElement =
    document.getElementsByClassName('control-panel')[0] as HTMLDivElement;
const canvasCtx = canvasElement.getContext('2d')!;

// We'll add this to our control panel later, but we'll save it here so we can
// call tick() each time the graph runs.
const fpsControl = new controls.FPS();

// Optimization: Turn off animated spinner after its hiding animation is done.
const spinner = document.querySelector('.loading')! as HTMLDivElement;
spinner.ontransitionend = () => {
  spinner.style.display = 'none';
};

let activeEffect = 'mask';
function onResults(results: mpSelfieSegmentation.Results): void {
  // Hide the spinner.
  document.body.classList.add('loaded');

  // Update the frame rate.
  fpsControl.tick();

  // Draw the overlays.
  canvasCtx.save();

  canvasCtx.clearRect(0, 0, canvasElement.width, canvasElement.height);

  canvasCtx.drawImage(
      results.segmentationMask, 0, 0, canvasElement.width,
      canvasElement.height);

  // Only overwrite existing pixels.
    if (activeEffect === 'mask' || activeEffect === 'both') {
      canvasCtx.globalCompositeOperation = 'source-in';
      // This can be a color or a texture or whatever...
      canvasCtx.fillStyle = '#00FF007F';
      canvasCtx.fillRect(0, 0, canvasElement.width, canvasElement.height);
    } else {
      canvasCtx.globalCompositeOperation = 'source-out';
      canvasCtx.fillStyle = '#0000FF7F';
      canvasCtx.fillRect(0, 0, canvasElement.width, canvasElement.height);
    }

    // Only overwrite missing pixels.
    canvasCtx.globalCompositeOperation = 'destination-atop';
    canvasCtx.drawImage(
        results.image, 0, 0, canvasElement.width, canvasElement.height);


  canvasCtx.restore();
}

const selfieSegmentation = new SelfieSegmentation({locateFile: (file) => {
  return `https://cdn.jsdelivr.net/npm/@mediapipe/[email protected]/${file}`;
}});
selfieSegmentation.onResults(onResults);

// Present a control panel through which the user can manipulate the solution
// options.
new controls
    .ControlPanel(controlsElement, {
      selfieMode: true,
      modelSelection: 1,
      effect: 'mask',
    })
    .add([
      new controls.StaticText({title: 'MediaPipe Selfie Segmentation'}),
      fpsControl,
      new controls.Toggle({title: 'Selfie Mode', field: 'selfieMode'}),
      new controls.SourcePicker({
        onSourceChanged: () => {
          selfieSegmentation.reset();
        },
        onFrame:
            async (input: controls.InputImage, size: controls.Rectangle) => {
              const aspect = size.height / size.width;
              let width: number, height: number;
              if (window.innerWidth > window.innerHeight) {
                height = window.innerHeight;
                width = height / aspect;
              } else {
                width = window.innerWidth;
                height = width * aspect;
              }
              canvasElement.width = width;
              canvasElement.height = height;
              await selfieSegmentation.send({image: input});
            },
        examples: examples
      }),
      new controls.Slider({
        title: 'Model Selection',
        field: 'modelSelection',
        discrete: ['General', 'Landscape'],
      }),
      new controls.Slider({
        title: 'Effect',
        field: 'effect',
        discrete: {'background': 'Background', 'mask': 'Foreground'},
      }),
    ])
    .on(x => {
      const options = x as mpSelfieSegmentation.Options;
      videoElement.classList.toggle('selfie', options.selfieMode);
      activeEffect = (x as {[key: string]: string})['effect'];
      selfieSegmentation.setOptions(options);
    });