declare module 'upay-pg-by-kayesfahim' {
    export interface AuthResponse {
      token: string;
      expires_in: number;
    }
  
    export interface PaymentDetails {
      amount: number;
      currency: string;
      merchant_id: string;
      customer_info: {
        name: string;
        email: string;
      };
    }
  
    export interface PaymentResponse {
      transaction_id: string;
      status: string;
      message: string;
    }
  
    export default class Upay {
      constructor(baseUrl?: string);
  
      /**
       * Authenticate with the Upay API using your merchant credentials.
       * @param merchantId - Your merchant ID.
       * @param merchantKey - Your merchant key.
       * @returns A promise that resolves to the authentication response.
       */
      auth(merchantId: string, merchantKey: string): Promise<AuthResponse>;
  
      /**
       * Initiates a payment request with the given details.
       * @param paymentDetails - The details of the payment to be initiated.
       * @returns A promise that resolves to the payment response.
       */
      initiatePayment(paymentDetails: PaymentDetails): Promise<PaymentResponse>;
    }
  }