import hashlib
import os
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)



class User(Base):
    __tablename__ = "users"

    id: Mapped[int] = mapped_column(primary_key=True)
    username: Mapped[str] = mapped_column(String(50), unique=True)
    password_hash: Mapped[str] = mapped_column(String(128))
    role: Mapped[str] = mapped_column(String(20), default="user")

    @staticmethod
    def hash_password(password: str) -> str:
        salt = os.urandom(16)
        dk = hashlib.pbkdf2_hmac("sha256", password.encode(), salt, 100000)
        return salt.hex() + ":" + dk.hex()

    def check_password(self, password: str) -> bool:
        try:
            salt_hex, dk_hex = self.password_hash.split(":")
            salt = bytes.fromhex(salt_hex)
            dk = hashlib.pbkdf2_hmac("sha256", password.encode(), salt, 100000)
            return dk.hex() == dk_hex
        except (ValueError, AttributeError):
            return False