export function isGradeThreeSource(source) {
  return /\bGrade 3\b/i.test(source.title ?? '') || /(?:^|[_-])G3(?:[_-]|$)/i.test(source.filename ?? '');
}

export function classifyUnit(filename) {
  const name = String(filename);
  if (/CKMath/i.test(name)) return 'Math';
  if (/CKSci/i.test(name)) return 'Science';
  if (/CKLA/i.test(name)) return 'Language Arts';
  if (/CKHG|CKIYS|LABB_CKHG/i.test(name)) return 'History & Geography';
  if (/CKMusic|CKVA/i.test(name)) return 'Arts';
  return 'Other';
}

export function roleForPdf(filename) {
  const name = String(filename);
  if (/(?:^|[_-])(TG|TeacherGuide|Teacher[_ -]?Guide)(?:[_-]|\.)/i.test(name)) return 'Teacher Guide';
  if (/(?:^|[_-])(SR|StudentReader|Student[_ -]?Reader|ActivityBook)(?:[_-]|\.)/i.test(name)) return 'Student Reader';
  return 'Reference';
}