// scoring.js — accuracy calculation

const Scoring = (() => {

  /**
   * Calculate score from drawn path points.
   * MVP: fake score based on number of points drawn (effort-based).
   * TODO: replace with real compareShapes() using polygon overlap.
   */
  function calculateScore(drawnPoints) {
    if (!drawnPoints || drawnPoints.length < 10) return 0;

    // Fake scoring: reward effort + randomness so it feels real
    const effort = Math.min(drawnPoints.length / 300, 1); // 0–1
    const base   = 40 + Math.round(effort * 45);          // 40–85
    const jitter = Math.round((Math.random() - 0.5) * 14); // ±7
    const score  = Math.max(0, Math.min(100, base + jitter));
    return score;
  }

  /**
   * Stub for real shape comparison (future).
   * drawnPoints: [{x,y}, ...]
   * referencePolygon: [{x,y}, ...] (normalised 0–1 coords)
   */
  function compareShapes(_drawnPoints, _referencePolygon) {
    // TODO: implement IoU (Intersection over Union) or
    //       Hausdorff distance for polygon comparison.
    return 0;
  }

  function getGrade(score) {
    if (score >= 90) return { label: "S", color: "#f0b429" };
    if (score >= 75) return { label: "A", color: "#41b869" };
    if (score >= 60) return { label: "B", color: "#1a7fc4" };
    if (score >= 40) return { label: "C", color: "#7a9aaa" };
    return           { label: "D", color: "#e05c5c" };
  }

  return { calculateScore, compareShapes, getGrade };
})();