"""
成本域 ORM 模型
映射: erp_order_item_costs
"""

from __future__ import annotations

import uuid
from datetime import datetime

from sqlalchemy import DateTime, ForeignKey, Numeric, func
from sqlalchemy.dialects.postgresql import UUID
from sqlalchemy.orm import Mapped, mapped_column, relationship

from app.models.base import Base


class ErpOrderItemCost(Base):
    """订单明细成本快照表 —— 发货/确认瞬间锚定 MWA 成本"""
    __tablename__ = "erp_order_item_costs"

    id: Mapped[uuid.UUID] = mapped_column(
        UUID(as_uuid=True), primary_key=True, default=uuid.uuid4
    )
    order_item_id: Mapped[uuid.UUID] = mapped_column(
        UUID(as_uuid=True), ForeignKey("erp_order_items.id"), nullable=False, unique=True,
        comment="关联订单明细"
    )
    purchase_unit_price: Mapped[float] = mapped_column(
        Numeric(12, 4), nullable=False, comment="MWA 成本快照"
    )
    profit_amount: Mapped[float] = mapped_column(
        Numeric(14, 2), default=0, comment="利润额 = (售价-成本)*数量"
    )
    profit_rate: Mapped[float] = mapped_column(
        Numeric(5, 4), default=0, comment="利润率"
    )
    created_at: Mapped[datetime] = mapped_column(DateTime, server_default=func.now())

    # 关系
    order_item: Mapped["ErpOrderItem"] = relationship("ErpOrderItem", lazy="selectin")  # noqa: F821