"""绩效核算服务（M3 ④）：回款 → 台账的固化流水线。

单笔核算（calc_receipt）与计算预览（param_service.preview）**共用同一
公式路径与取值防线**：resolve_snapshot 按回款到账日取参（裁决 #11）、按
岗位模板分派计提比例（‰ 存储口径 ÷1000 转纯比例）、行级折算（混合业务
按行汇总，对照表 #14）。两者的任何口径修改必须同步——预览给业务对数、
核算才是算钱的法定固化点。

策略点（待业务答复，全部集中为单函数，答复后只改函数 + 按回款批量重算）：
- ``_personal_rate``：#12 经理个人户单笔落台账 rate=0/绩效 0（12.5%+5%
  聚合口径在月结时由 manager_team_share 计算）；#20 在 ``_row_profit``
- 核算粒度 #25：业务级一次性计提——首个触发核算的回款计算全额应发，
  后续回款仅置 settlement_status=1（repeated=True），不重复计提
"""

import logging
from dataclasses import dataclass
from decimal import ROUND_HALF_UP, Decimal
from fractions import Fraction
from typing import Any

from sqlalchemy import update
from sqlalchemy.orm import Session

from app.core.constants import MODULE_CALC
from app.core.exceptions import BadRequestError
from app.models import (
    Business,
    BusinessItem,
    Customer,
    PerformanceLedger,
    Receipt,
    Shipment,
    User,
)
from app.models.performance_ledger import CALC_TYPE_RECEIPT
from app.models.receipt import SETTLEMENT_DONE, SETTLEMENT_PENDING
from app.repositories import business_repository, performance_ledger_repository
from app.schemas.calc import CalcReceiptOut
from app.services import audit_service, param_service, personnel_service
from app.services.audit_service import AuditRecord, RequestMeta
from app.services.formula import (
    apply_barter,
    clamp_weight_r,
    converted_profit,
    payment_days,
    payment_weight,
    performance_amount,
    profit_rate,
    salesperson_rate,
    start_payment_ok,
)
from app.services.param_service import parse_fraction, resolve_snapshot

logger = logging.getLogger(__name__)

# snapshot_json 里的策略点注记（答复回填时的检索锚点）
_NOTE_MANAGER_PENDING = "经理个人户单笔不计提（#12 待答复）：聚合口径在月结时由团队聚合计算"


@dataclass(frozen=True, slots=True)
class _RateDecision:
    """单笔计提比例的分派结果。"""

    rate: Fraction  # 纯比例（str() 产出分数原文如 88/9000，直接落台账 rate_text）
    rate_note: str  # 人读说明（入 snapshot）
    base_override: Decimal | None  # 非 None 时绩效基数用它（信息员=销售额）
    manager_pending: bool  # True=经理聚合口径，单笔落 0（#12 策略点）


def calc_receipt(
    session: Session,
    receipt_id: int,
    *,
    operator: User,
    meta: RequestMeta | None = None,
    recalc_reason: str | None = None,
) -> CalcReceiptOut:
    """单笔回款核算 / 重算（recalc_reason 非 None 时为重算模式）。

    防重前两层在本函数（FOR UPDATE 锁行 + settlement_status 校验），第三层
    是落台账 uk(receipt_id, calc_version)。全程一个 audit 事务，出参在
    commit 前固化。

    首算模式：回款必须未核算；业务级一次性计提（#25）——已有生效台账行时
    仅登记进度（repeated=True）。
    重算模式：回款必须已核算过；作废旧版本行（is_active=0），按当前参数
    落 calc_version+1 新行，calc_reason 留痕。
    """
    is_recalc = recalc_reason is not None
    action = "重算" if is_recalc else "核算"
    with audit_service.audit(
        session,
        operator=operator,
        record=AuditRecord(
            module=MODULE_CALC,
            action=action,
            summary=f"{action}回款 #{receipt_id}",
            request_data={
                "receipt_id": receipt_id,
                **({"reason": recalc_reason} if is_recalc else {}),
            },
        ),
        meta=meta,
    ):
        receipt = session.get(Receipt, receipt_id, with_for_update=True)
        if receipt is None:
            raise BadRequestError("回款不存在")
        if is_recalc:
            if receipt.settlement_status == SETTLEMENT_PENDING:
                raise BadRequestError("该回款尚未核算过（无旧版本可重算，走首次核算）")
        elif receipt.settlement_status == SETTLEMENT_DONE:
            raise BadRequestError("该回款已核算，禁止重复核算（重算请走重算入口）")

        # 月结锁定拦截：已审定月份的回款不得再核算/重算——金额已固化，
        # 变动唯一通道是调整单（否则重算会绕开审批改写已锁定月份的应付）
        from app.services import settlement_service

        settlement_service.ensure_month_not_locked(session, receipt.receipt_date.strftime("%Y-%m"))

        business = session.get(Business, receipt.business_id, with_for_update=True)
        if business is None:
            raise BadRequestError("回款关联的业务不存在")
        if business.owner_personnel_id is None:
            raise BadRequestError("业务未指定负责营销人员，无法核算（先在业务归属中指定）")

        # 重算：先作废旧版本行（is_active=0），折算体随后按当前参数重算。
        # 无生效行 = 该回款是「进度登记」（业务级一次性计提 #25 的第二笔及
        # 以后）——本无独立计提，继续重算会凭空落一行生效行，同业务出现
        # 两行生效行导致双重计提 → 一律 400
        if is_recalc:
            old = performance_ledger_repository.get_active_by_receipt(session, receipt_id)
            if old is None:
                raise BadRequestError(
                    "该回款为进度登记（业务已按一次性计提核算），无独立台账行可重算"
                )
            performance_ledger_repository.mark_inactive(session, old)

        # 核算粒度 #25（一期口径，仅首算模式）：业务级一次性计提——已有生效
        # 台账行时，本笔回款仅置已核算状态（支付进度），不重复计提
        repeated = False
        if not is_recalc:
            repeated = performance_ledger_repository.has_active_for_business(
                session, business.id, calc_type=CALC_TYPE_RECEIPT
            )
        if repeated:
            _mark_settled(session, receipt)
            row = performance_ledger_repository.get_active_by_receipt_of_business(
                session, business.id
            )
            session.flush()
            out = CalcReceiptOut(ledger=_to_out(row), repeated=True)
            session.commit()
            logger.info(
                "回款登记进度（业务已核算）| receipt=%s | business=%s", receipt_id, business.id
            )
            return out

        if receipt.shipment_id is None:
            raise BadRequestError("回款未指定发货批次，无法确定发货日期（先指定批次再核算）")
        shipment = session.get(Shipment, receipt.shipment_id)
        if shipment is None or shipment.ship_date is None:
            raise BadRequestError("发货批次缺少发货日期，无法核算")

        person = personnel_service.ensure_active(
            session, business.owner_personnel_id, label="核算归属"
        )
        if person.business_role_id is None:
            raise BadRequestError("归属人员未绑定岗位角色，无法确定计提公式")

        receipt_date = receipt.receipt_date
        snapshot = resolve_snapshot(session, receipt_date)
        items = business_repository.list_items(session, business.id)
        if not items:
            raise BadRequestError("业务无产品明细行，无法核算")

        # 逐行折算（行级 product_category 阈值；成本缺失行毛利按 0 计并标记）
        total_revenue = Decimal("0")
        total_profit = Decimal("0")
        converted_total = Decimal("0")
        missing_cost = False
        line_details: list[dict[str, Any]] = []
        for item in items:
            row_revenue = item.sale_amount
            if item.cost_amount is None:
                missing_cost = True
                row_profit = Decimal("0")
            else:
                row_profit = _row_profit(row_revenue, item.cost_amount)
            total_revenue += row_revenue
            total_profit += row_profit
            threshold = parse_fraction(
                snapshot.get(
                    "product.threshold",
                    role_code=role_code_of(person),
                    product_category=item.product_category,
                )
            )
            row_converted = converted_profit(
                row_revenue, profit_rate(row_profit, row_revenue), threshold
            )
            converted_total += row_converted
            line_details.append(
                {
                    "item_id": item.id,
                    "product_category": item.product_category,
                    "revenue": str(row_revenue),
                    "profit": str(row_profit),
                    # 行级折算同样固化为两位（to_decimal 对整数值无小数位，
                    # 快照/台账口径需与列一致；显式 HALF_UP——Python 默认
                    # 银行家舍入会让 x.xx5 少 1 分）
                    "converted": str(
                        row_converted.quantize(Decimal("0.01"), rounding=ROUND_HALF_UP)
                    ),
                }
            )

        # 天数只依赖发货/回款日期，先于比例分派算出（业务员递减公式的输入）
        days = payment_days(shipment.ship_date, receipt_date)
        decision = _personal_rate(session, snapshot, person, business, days)

        if decision.base_override is not None:
            converted = decision.base_override  # 信息员：基数=本人销售额
        else:
            converted = converted_total

        performance = (
            Decimal("0")
            if decision.manager_pending
            else performance_amount(converted, decision.rate)
        )
        barter_applied = receipt.is_barter == 1
        base_amount = performance
        if barter_applied:
            discount = parse_fraction(
                snapshot.get("barter.discount", role_code=role_code_of(person))
            )
            base_amount = apply_barter(performance, discount)

        received_total = business.total_received_amount or Decimal("0")
        start_ratio = parse_fraction(
            snapshot.get("payment.start.ratio", role_code=role_code_of(person))
        )
        start_ok = start_payment_ok(received_total, total_revenue, start_ratio)
        weight_r = clamp_weight_r(received_total, total_revenue)
        weight = payment_weight(weight_r)
        payable = param_service.to_decimal(Fraction(base_amount) * weight)

        settlement_month = receipt_date.strftime("%Y-%m")
        snapshot_json: dict[str, Any] = {
            "params_as_of": str(receipt_date),
            "line_details": line_details,
            "start_payment_ok": start_ok,
            "rate_note": decision.rate_note,
            "revenue_total": str(total_revenue),
            "profit_total": str(total_profit),
        }
        if decision.manager_pending:
            snapshot_json["strategy_note"] = _NOTE_MANAGER_PENDING

        def q2(value: Decimal | None) -> Decimal | None:
            """金额统一两位小数（HALF_UP）：内存/DB/序列化三方一致。

            显式传 rounding——quantize 缺省是上下文 ROUND_HALF_EVEN（银行家
            舍入），x.xx5 会舍成偶数值，与业务四舍五入口径差 1 分。
            """
            if value is None:
                return None
            return value.quantize(Decimal("0.01"), rounding=ROUND_HALF_UP)

        row = performance_ledger_repository.add(
            session,
            PerformanceLedger(
                receipt_id=receipt.id,
                calc_version=performance_ledger_repository.next_version(session, receipt.id),
                calc_type=CALC_TYPE_RECEIPT,
                business_id=business.id,
                business_no=business.business_no,
                personnel_id=person.id,
                personnel_name=person.personnel_name,
                role_code=role_code_of(person),
                customer_type=_customer_type(session, business),
                product_category=_category_label(items),
                ship_date=shipment.ship_date,
                receipt_date=receipt_date,
                payment_days=days,
                rate_text=str(decision.rate),
                converted_profit=q2(converted),
                performance_amount=q2(performance),
                barter_applied=1 if barter_applied else 0,
                weight_r=weight_r,
                payment_weight=param_service.to_decimal(weight),
                payable_amount=q2(payable),
                settlement_month=settlement_month,
                is_probation=1 if person.is_probation == 1 else 0,
                missing_cost=1 if missing_cost else 0,
                snapshot_json=snapshot_json,
                calc_reason=recalc_reason,
            ),
        )
        # CAS 仅首算执行：重算模式状态本就是已核算（UPDATE ... WHERE status=0
        # 会 rowcount=0 误报并发撞车）
        if not is_recalc:
            _mark_settled(session, receipt)
        session.flush()
        out = CalcReceiptOut(ledger=_to_out(row), repeated=False)
        session.commit()
        logger.info("核算完成 | receipt=%s | ledger=%s | payable=%s", receipt_id, row.id, payable)
        return out


def _personal_rate(
    session: Session,
    snapshot,
    person,
    business: Business,
    days: int,
) -> _RateDecision:
    """按岗位模板分派单笔计提比例（与 param_service._preview_rate 同构）。

    #12 策略点：经理个人户（owner 岗位绑 TPL_MANAGER_SHARE）单笔不计提
    —— 12.5%+5% 是月度团队聚合口径，单笔落 rate=0/绩效 0 的台账行保事实。
    """
    role = _role_of(session, person)
    customer_type = _customer_type(session, business)

    if customer_type == "enterprise":
        # 存储口径 ‰ → 纯比例（漏换算放大 1000 倍，与预览同防线）
        rate = parse_fraction(snapshot.get("enterprise.rate")) / 1000
        return _RateDecision(rate, "企业户固定计提比例", None, False)

    template = role.calc_template if role else "TPL_SALESPERSON_DECAY"
    if template == "TPL_MANAGER_SHARE":
        return _RateDecision(
            Decimal("0"),
            "经理个人户：12.5%+5% 聚合计提（月结时计算），单笔落 0",
            None,
            True,
        )
    if template == "TPL_INFO_SALES_FIXED":
        # 信息员基数=本人销售额（覆盖折算与阈值），‰ 换算同防线
        rate = parse_fraction(snapshot.get("info.rate")) / 1000
        return _RateDecision(rate, "信息员：本人销售额 × 计提比例", None, False)
    if template == "TPL_SALESPERSON_DECAY":
        start = parse_fraction(snapshot.get("salesperson.rate.start"))
        slope = parse_fraction(snapshot.get("salesperson.rate.slope"))
        floor = parse_fraction(snapshot.get("salesperson.rate.floor"))
        # int(参数原文) 对合法入库的 '360.0' 会抛 ValueError 使整月核算 500；
        # 经 Fraction 转换再取整（INT 型参数入库时已校验分母为 1，取整无损）
        boundary = int(parse_fraction(snapshot.get("salesperson.days.boundary")))
        rate = salesperson_rate(days, start=start, slope=slope, floor=floor, boundary_days=boundary)
        note = f"业务员递减：{start}‰ 起，{days} 天（分界 {boundary} 天，超界取 {floor}‰）"
        return _RateDecision(rate, note, None, False)
    raise BadRequestError(f"公式模板 {template} 暂不支持核算")


def _role_of(session: Session, person):
    from app.repositories import business_role_repository

    if person.business_role_id is None:
        return None
    return business_role_repository.get_by_id(session, person.business_role_id)


def role_code_of(person) -> str:
    """人员岗位编码（台账冗余固化用；无岗位为空串——前置校验已拦）。"""
    from app.repositories import business_role_repository

    if person.business_role_id is None:
        return ""
    session = Session.object_session(person)
    role = business_role_repository.get_by_id(session, person.business_role_id)
    return role.role_code if role else ""


def _customer_type(session: Session, business: Business) -> str:
    customer = session.get(Customer, business.customer_id)
    return customer.customer_type if customer else "personal"


def _category_label(items: list[BusinessItem]) -> str:
    """单类别直出；混合业务记 mixed（行级明细在 snapshot_json）。"""
    categories = {item.product_category for item in items}
    return categories.pop() if len(categories) == 1 else "mixed"


def _mark_settled(session: Session, receipt: Receipt) -> None:
    """CAS 置已核算：并发下另一事务先行置 1 时 rowcount=0 → 400。"""
    result = session.execute(
        update(Receipt)
        .where(Receipt.id == receipt.id, Receipt.settlement_status == SETTLEMENT_PENDING)
        .values(settlement_status=SETTLEMENT_DONE)
    )
    if result.rowcount == 0:
        raise BadRequestError("该回款已被并发核算，请刷新后查看台账")


def _row_profit(revenue: Decimal, cost: Decimal) -> Decimal:
    """行毛利 = 行销售额 − 行成本。

    #20 策略点（待业务答复，2026-10-16 暂定口径）：金额暂按**不含税**原样
    相减；答复若为含税口径，只改本函数（含税换算/取不含税金额列）+ 按回款
    批量重算回填。
    """
    return revenue - cost


def recalc_receipt(
    session: Session,
    receipt_id: int,
    reason: str,
    *,
    operator: User,
    meta: RequestMeta | None = None,
) -> CalcReceiptOut:
    """重算（授权动作，管理员/财务）：作废旧版本行、按当前参数重算新版本。

    薄委托 calc_receipt(recalc_reason=...)——折算体只有一份；所属月已审定
    的拦截在 calc_receipt 内（核算与重算同口径）。
    """
    if not reason or not reason.strip():
        raise BadRequestError("重算必须填写原因")
    return calc_receipt(
        session, receipt_id, operator=operator, meta=meta, recalc_reason=reason.strip()
    )


def batch_calc(
    session: Session,
    receipt_ids: list[int],
    *,
    operator: User,
    meta: RequestMeta | None = None,
) -> list[dict]:
    """批量核算：逐笔独立事务（各笔自带 audit），返回逐笔成败清单。

    **不开外层 audit**——外层包 audit 会违反嵌套禁令，且单笔失败不应
    回滚其它笔的核算结果。
    """
    results: list[dict] = []
    for rid in receipt_ids:
        try:
            out = calc_receipt(session, rid, operator=operator, meta=meta)
            results.append(
                {
                    "receipt_id": rid,
                    "ok": True,
                    "repeated": out.repeated,
                    "ledger_id": out.ledger.id,
                }
            )
        except Exception as exc:
            results.append(
                {"receipt_id": rid, "ok": False, "error": f"{type(exc).__name__}: {exc}"}
            )
    ok_count = sum(1 for r in results if r["ok"])
    logger.info("批量核算 | 总数=%s 成功=%s", len(results), ok_count)
    return results


def list_ledger_page(session: Session, query):
    """分页查询台账（api 层转发）。"""
    rows = performance_ledger_repository.list_ledger(session, query)
    total = performance_ledger_repository.count_ledger(session, query)
    from app.core.response import PageResult
    from app.schemas.calc import LedgerOut

    return PageResult[LedgerOut](
        records=[LedgerOut.model_validate(r) for r in rows],
        total=total,
        page_num=query.page_num,
        page_size=query.page_size,
    )


def get_ledger(session: Session, ledger_id: int):
    """台账详情（api 层转发）。"""
    row = performance_ledger_repository.get_by_id(session, ledger_id)
    if row is None:
        from app.core.exceptions import NotFoundError

        raise NotFoundError("台账记录不存在")
    from app.schemas.calc import LedgerOut

    return LedgerOut.model_validate(row)


def _to_out(row: PerformanceLedger):
    from app.schemas.calc import LedgerOut

    return LedgerOut.model_validate(row)