from typing import Optional, Dict, Any
from pydantic import BaseModel

class IncomingOrderInfo(BaseModel):
    cash_resp_desc: Optional[str] = None
    ref_amt: Optional[float] = None

class IncomingPayload(BaseModel):
    remark: Optional[str] = None
    event_define_no: Optional[str] = None
    trans_amt: Optional[float] = None
    settlement_amt: Optional[float] = None
    out_trans_id: Optional[str] = None
    hf_seq_id: Optional[str] = None
    namespace: Optional[str] = None
    trans_order_info: Optional[IncomingOrderInfo] = None
    extra: Optional[Dict[str, Any]] = None

    def idempotent_key(self) -> Optional[str]:
        return self.out_trans_id or self.hf_seq_id

    def cash_resp_desc(self) -> str:
        v = None
        if self.trans_order_info:
            v = self.trans_order_info.cash_resp_desc
        return v or ""

    def actual_ref_amt(self) -> Optional[float]:
        extra_val = None
        if self.extra and isinstance(self.extra, dict):
            extra_val = self.extra.get("actual_ref_amt")
        return extra_val or (self.trans_order_info.ref_amt if self.trans_order_info and self.trans_order_info.ref_amt is not None else self.settlement_amt)