checkDatasetHealth function exported ✓ 100.0%

export function checkDatasetHealth(minSamplesPerType = 3): DatasetHealthReport {
  const dist = getTrainingDistribution();

  const underrepresentedTypes = Object.entries(dist)
    .filter(([, count]) => count < minSamplesPerType)
    .map(([type]) => type);

  const coveredTypes = new Set(Object.keys(dist));
  const missingTypes = KNOWN_TYPES.filter((t) => !coveredTypes.has(t));

  // Check for data leakage (exact signal match between splits)
  const trainSignals = new Set(
    TRAINING_SAMPLES.map((s) => toTrainingSignalText(s)),
  );
  const leakedSignals: string[] = [];

  for (const vs of VALIDATION_SAMPLES) {
    if (trainSignals.has(vs.signals)) leakedSignals.push(vs.signals);
  }
  for (const ts of TEST_SAMPLES) {
    if (trainSignals.has(ts.signals)) leakedSignals.push(ts.signals);
  }

  return {
    totalSamples:
      TRAINING_SAMPLES.length + VALIDATION_SAMPLES.length + TEST_SAMPLES.length,
    typeCounts: dist,
    underrepresentedTypes,
    missingTypes,
    hasLeakage: leakedSignals.length > 0,
    leakedSignals,
  };
}