from datetime import date
from sqlalchemy import String, Integer, Float, Date, ForeignKey, Boolean, UniqueConstraint
from sqlalchemy.orm import Mapped, mapped_column, relationship
from app.database import Base


class Product(Base):
    __tablename__ = "products"

    id: Mapped[int] = mapped_column(primary_key=True)
    code: Mapped[str] = mapped_column(String(10), unique=True, index=True)
    name: Mapped[str] = mapped_column(String(20))
    exchange: Mapped[str] = mapped_column(String(10), default="CZCE")

    contracts: Mapped[list["Contract"]] = relationship(
        back_populates="product", cascade="all, delete-orphan"
    )


class Contract(Base):
    __tablename__ = "contracts"
    __table_args__ = (UniqueConstraint("code"),)

    id: Mapped[int] = mapped_column(primary_key=True)
    product_id: Mapped[int] = mapped_column(ForeignKey("products.id"), index=True)
    code: Mapped[str] = mapped_column(String(10), unique=True, index=True)
    name: Mapped[str] = mapped_column(String(30))
    is_active: Mapped[bool] = mapped_column(Boolean, default=True)

    product: Mapped["Product"] = relationship(back_populates="contracts")


class DailyBar(Base):
    __tablename__ = "daily_bars"
    __table_args__ = (UniqueConstraint("contract", "date"),)

    id: Mapped[int] = mapped_column(primary_key=True)
    contract: Mapped[str] = mapped_column(String(10), index=True)
    date: Mapped[date] = mapped_column(Date, index=True)
    open: Mapped[float] = mapped_column(Float)
    close: Mapped[float] = mapped_column(Float)
    high: Mapped[float] = mapped_column(Float)
    low: Mapped[float] = mapped_column(Float)
    amp_5d: Mapped[float | None] = mapped_column(Float, nullable=True)

    @property
    def diff(self) -> float:
        """最高-最低价差"""
        return self.high - self.low


class PositionSnapshot(Base):
    __tablename__ = "position_snapshots"
    __table_args__ = (UniqueConstraint("institution", "direction", "date"),)

    id: Mapped[int] = mapped_column(primary_key=True)
    institution: Mapped[str] = mapped_column(String(20), index=True)
    direction: Mapped[str] = mapped_column(String(10))  # "long" or "short"
    date: Mapped[date] = mapped_column(Date, index=True)
    position: Mapped[int] = mapped_column(Integer)
    delta: Mapped[int] = mapped_column(Integer, default=0)
    avg_cost: Mapped[float] = mapped_column(Float)