zkxw/backend/app/services/protocol_pay_mode_switch.py

"""缴费模式切换校验（与前端 protocol-pay-mode-switch.ts 规则一致）"""

from __future__ import annotations

from decimal import Decimal
from typing import Any, Dict, Optional

LOCKED_STATUSES = frozenset({"jfqrz", "yjf", "tfqrz", "ytf"})
BLOCKING_STATUSES = frozenset({"jfqrz", "tfqrz", "ytf"})


def _dec(v: Any) -> float:
    if v is None:
        return 0.0
    return float(Decimal(str(v)))


def validate_payment_details_for_save(
    pay_mode: str,
    contract_amount: Optional[Any],
    installment_count: Optional[int],
    details: Optional[list],
) -> None:
    """保存缴费明细前的 P0 校验。"""
    rows = [dict(d) for d in (details or [])]
    contract = _dec(contract_amount)

    for r in rows:
        status = (r.get("pay_status") or r.get("payStatus") or "dfj").strip()
        if status in BLOCKING_STATUSES:
            raise ValueError("存在缴费确认中或退费处理中的明细，无法保存")

    paid_sum = sum(
        _dec(r.get("due_amount") if r.get("due_amount") is not None else r.get("dueAmount"))
        for r in rows
        if (r.get("pay_status") or r.get("payStatus")) == "yjf"
    )
    dfj_rows = [
        r
        for r in rows
        if (r.get("pay_status") or r.get("payStatus") or "dfj") == "dfj"
    ]
    yjf_rows = [r for r in rows if (r.get("pay_status") or r.get("payStatus")) == "yjf"]

    if pay_mode == "dj":
        if len(dfj_rows) > 1:
            raise ValueError("趸交模式仅允许一条待缴费明细")
        remaining = round(contract - paid_sum, 2)
        if dfj_rows:
            due = _dec(
                dfj_rows[0].get("due_amount")
                if dfj_rows[0].get("due_amount") is not None
                else dfj_rows[0].get("dueAmount")
            )
            expected = remaining if yjf_rows else contract
            if abs(due - expected) > 0.015:
                raise ValueError(
                    f"趸交待缴金额应为 {expected:.2f}，当前为 {due:.2f}"
                )

    elif pay_mode == "fq":
        count = int(installment_count or 0)
        if count < 1:
            raise ValueError("分期模式须填写分期期数")
        if len(rows) != count:
            raise ValueError(f"分期明细条数应等于分期期数（{count}）")
        fq_forbidden = frozenset({"jfqrz", "tfqrz", "ytf"})
        for r in rows:
            status = (r.get("pay_status") or r.get("payStatus") or "dfj").strip()
            if status in fq_forbidden:
                raise ValueError("分期模式下存在不可保存的缴费状态")
        total_due = sum(
            _dec(r.get("due_amount") if r.get("due_amount") is not None else r.get("dueAmount"))
            for r in rows
        )
        if contract and abs(total_due - contract) > 0.015:
            raise ValueError("分期各期应缴金额之和应等于合同金额")
        if yjf_rows:
            max_paid_no = max(
                int(r.get("installment_no") or r.get("installmentNo") or 0)
                for r in yjf_rows
            )
            if max_paid_no > count:
                raise ValueError("分期期数不能少于已缴费的最大期次")