import os
  import time
  from fastapi import FastAPI, HTTPException
  from pydantic import BaseModel
  from mmg import MmgCheckoutUtil
  from mmg.types import CheckoutTokenPayload
  app = FastAPI()
  checkout_util = MmgCheckoutUtil(
      environment="Live",  # or "Sandbox"
      public_key=os.getenv("MMG_PUBLIC_KEY"),
      private_key=os.getenv("MMG_PRIVATE_KEY"),
  )
  class CheckoutResponse(BaseModel):
      redirectUrl: str
  @app.post("/api/checkout", response_model=CheckoutResponse)
  async def create_checkout():
      try:
          merchant_txn_id = f"ORD-{int(time.time() * 1000)}"
          payload = CheckoutTokenPayload(
              secret_key=os.getenv("MMG_SECRET_KEY"),
              merchant_id=os.getenv("MMG_MERCHANT_ID"),
              amount="3000",  # GYD
              merchant_transaction_id=merchant_txn_id,
              merchant_name="My Ecommerce Store",
              product_description="Shopping Cart Checkout",
              request_initiation_time=str(int(time.time() * 1000)),
          )
          redirect_url = checkout_util.generate_redirect_url(
              payload=payload,
              client_id=os.getenv("MMG_CLIENT_ID"),
          )
          return {"redirectUrl": redirect_url}
      except Exception as e:
          print(f"Failed to generate checkout URL: {e}")
          raise HTTPException(status_code=500, detail="Internal Server Error")