"""回款模型：回款记录与批次追溯。

- shipment_id 为**手动指定**的发货批次（对照表 #18）：可空=暂未指定；
  必须与 business_id 同属一个业务（服务层强校验，无数据库级约束可表达
  跨表同属关系）；指定后回款天数方可由 formula.payment_days 派生
- settlement_status 是 **M3 核算防重锚点**（需规 2.3.3「每笔回款仅核算一次，
  台账记录核销状态」）：预置于本表避免 M3 反向迁移改 M2 表；M3 台账建立后
  由核算服务写入，M2 仅维护 0（未核算）
- receipt_date 是 M3 参数版本匹配日（对照表 #11：按回款到账日取时点参数）
- 一期禁负数金额（≥0）：红字/退款冲销需求出现时先补设计再放开
"""

from datetime import date
from decimal import Decimal

from sqlalchemy import Date, ForeignKey, Index, Numeric, String
from sqlalchemy.orm import Mapped, mapped_column

from app.models.base import (
    BIGINT_UNSIGNED,
    TINYINT_TYPE,
    Base,
    TimestampMixin,
    TPlusSyncMixin,
    mysql_table_args,
)

# 绩效核算状态（receipts.settlement_status）
SETTLEMENT_PENDING = 0
SETTLEMENT_DONE = 1


class Receipt(Base, TimestampMixin, TPlusSyncMixin):
    """回款表（需求 2.2.3）：按业务登记到账款项，批次号系统内唯一。"""

    __tablename__ = "receipts"
    __table_args__ = mysql_table_args(
        "回款表（手动指定发货批次；已核算回款禁改禁删）",
        Index("idx_receipts_business_id", "business_id"),
        Index("idx_receipts_receipt_date", "receipt_date"),
        Index("idx_receipts_settlement_status", "settlement_status"),
        Index("idx_receipts_shipment_id", "shipment_id"),
    )

    id: Mapped[int] = mapped_column(
        BIGINT_UNSIGNED, primary_key=True, autoincrement=True, comment="主键ID"
    )
    receipt_batch_no: Mapped[str] = mapped_column(
        String(32),
        nullable=False,
        unique=True,
        comment="回款批次号，自动生成 HK{YYYYMMDD}-{4位当日序号}（系统内唯一；T+ 同步回款以 source_no 幂等）",
    )
    business_id: Mapped[int] = mapped_column(
        BIGINT_UNSIGNED,
        ForeignKey("businesses.id", ondelete="RESTRICT"),
        nullable=False,
        comment="业务ID（businesses.id）",
    )
    shipment_id: Mapped[int | None] = mapped_column(
        BIGINT_UNSIGNED,
        ForeignKey("shipments.id", ondelete="RESTRICT"),
        comment="发货单ID（shipments.id；手动指定的回款对应批次，须与本行业务一致；NULL=暂未指定）",
    )
    receipt_date: Mapped[date] = mapped_column(
        Date, nullable=False, comment="回款到账日（M3 按此日匹配参数版本，对照表 #11）"
    )
    amount: Mapped[Decimal] = mapped_column(
        Numeric(14, 2), nullable=False, comment="回款金额（≥0；一期禁负数/红字）"
    )
    is_barter: Mapped[int] = mapped_column(
        TINYINT_TYPE,
        nullable=False,
        server_default="0",
        comment="以物抵顶标记：1是 0否（M3 核算按应发绩效×barter.discount 折算，M2 仅标记）",
    )
    settlement_status: Mapped[int] = mapped_column(
        TINYINT_TYPE,
        nullable=False,
        server_default="0",
        comment="绩效核算状态：0未核算 1已核算（M3 核算防重锚点；已核算回款禁改禁删）",
    )
    remark: Mapped[str | None] = mapped_column(String(255), comment="备注")