frontend/face_features.js

window.WhistleCoach = window.WhistleCoach || {};

window.WhistleCoach.FaceFeatures = (() => {
  const clamp = (value, minimum = 0, maximum = 1) =>
    Math.min(maximum, Math.max(minimum, value));

  function toFeaturePayload(face) {
    return {
      face_visible: Boolean(face?.visible),
      face_centered: Boolean(face?.centered),
      mouth_opening_ratio: Number(face?.openingRatio || 0),
      lip_roundness_score: Number(face?.puckerScore || 0),
      upper_lip_lift_score: Number(face?.upperLipLiftScore || 0),
      jaw_stability_score: Number(face?.jawScore || 0),
      mouth_symmetry_score: Number(face?.symmetry || 0),
      mouth_shape_score: Number(face?.score || 0),
    };
  }

  function classifyMouthShape(features) {
    if (!features.face_visible || !features.face_centered) return "no_face";
    if (features.mouth_opening_ratio > 0.34 || features.jaw_stability_score < 0.45) {
      return "mouth_too_open";
    }
    if (features.lip_roundness_score < 0.52) return "not_rounded";
    if (features.mouth_symmetry_score < 0.58) return "asymmetric_mouth";
    if (features.mouth_shape_score >= 0.62) return "mouth_ready";
    return "adjust_mouth";
  }

  function smoothFeature(previous, next, alpha = 0.28) {
    if (!previous) return next;
    const output = { ...next };
    for (const [key, value] of Object.entries(next)) {
      if (typeof value === "number") {
        output[key] = clamp(previous[key] * (1 - alpha) + value * alpha);
      }
    }
    return output;
  }

  return {
    toFeaturePayload,
    classifyMouthShape,
    smoothFeature,
  };
})();