/// Represents the hierarchical echelon levels in U.S. Army doctrine.
///
/// Ordered from highest (Brigade) to lowest (Team) echelon.
enum Echelon {
  brigade,
  battalion,
  company,
  platoon,
  section,
  squad,
  team;

  /// Returns a human-readable display name for this echelon.
  String get displayName {
    switch (this) {
      case Echelon.brigade:
        return 'Brigade';
      case Echelon.battalion:
        return 'Battalion';
      case Echelon.company:
        return 'Company';
      case Echelon.platoon:
        return 'Platoon';
      case Echelon.section:
        return 'Section';
      case Echelon.squad:
        return 'Squad';
      case Echelon.team:
        return 'Team';
    }
  }

  /// Returns the numeric level (lower = higher echelon).
  int get level {
    switch (this) {
      case Echelon.brigade:
        return 1;
      case Echelon.battalion:
        return 2;
      case Echelon.company:
        return 3;
      case Echelon.platoon:
        return 4;
      case Echelon.section:
        return 5;
      case Echelon.squad:
        return 6;
      case Echelon.team:
        return 7;
    }
  }

  /// Returns true if [other] is a valid parent echelon for this echelon.
  ///
  /// A valid parent must be exactly one level higher (lower level number).
  bool isValidParent(Echelon other) {
    return other.level == level - 1;
  }

  /// Returns true if [other] is a valid child echelon for this echelon.
  bool isValidChild(Echelon other) {
    return other.level == level + 1;
  }
}