"""指数历史成分表（B1）。

index_weight：指数成分快照（index_code, trade_date, symbol 唯一）。
历史成分查询（members_at）取 <= as_of 最近一期快照 —— Survivorship-free Universe。
"""

from __future__ import annotations

from datetime import date
from decimal import Decimal

from sqlalchemy import BigInteger, Date, Integer, Numeric, String, UniqueConstraint
from sqlalchemy.orm import Mapped, mapped_column

from app.infrastructure.persistence.sqlalchemy.base import Base

PK_INT = BigInteger().with_variant(Integer, "sqlite")


class IndexWeightModel(Base):
    __tablename__ = "index_weight"
    __table_args__ = (
        UniqueConstraint("index_code", "trade_date", "symbol", name="uq_idxw_code_date_sym"),
    )

    id: Mapped[int] = mapped_column(PK_INT, primary_key=True, autoincrement=True)
    index_code: Mapped[str] = mapped_column(String(12), index=True)
    index_name: Mapped[str | None] = mapped_column(String(64), nullable=True)
    trade_date: Mapped[date] = mapped_column(Date, index=True)
    symbol: Mapped[str] = mapped_column(String(12))
    weight: Mapped[Decimal | None] = mapped_column(Numeric(10, 6), nullable=True)