declare type TPromoTier = {
  min: number;
  max: number;
  price: number;
};

declare type TPromoCode = {
  _id?: ObjectId;
  code: string;
  description?: string;
  type: "tiered" | "fixed";
  tiers?: TPromoTier[];
  fixed_rate?: number;
  appliesTo?: string; // "subscription" | "order"
  createdAt?: string; // Date of creation
  expiresAt?: string; // Optional expiry
  assignedTo?: string | ObjectId; // Store the only ape who used it
  status?: "active" | "expired" | "disabled";
};
