"""组合再平衡 + Monte Carlo 模拟模型。"""

import uuid
from datetime import datetime, timezone

from sqlalchemy import DateTime, Float, ForeignKey, String, Text
from sqlalchemy.orm import Mapped, mapped_column

from app.core.database import Base
from app.core.types import JSONBType


class PortfolioRebalancing(Base):
    """组合再平衡建议。"""

    __tablename__ = "portfolio_rebalancings"

    id: Mapped[str] = mapped_column(String(36), primary_key=True, default=lambda: str(uuid.uuid4()))
    tenant_id: Mapped[str] = mapped_column(String(36), ForeignKey("tenants.id"), nullable=False, index=True)
    marginal_returns: Mapped[dict | None] = mapped_column(JSONBType, nullable=True, comment="各企业边际回报率")
    reallocation_plan: Mapped[dict | None] = mapped_column(JSONBType, nullable=True, comment="再平衡方案")
    irr_impact: Mapped[float | None] = mapped_column(Float, nullable=True, comment="IRR 影响")
    dpi_impact: Mapped[float | None] = mapped_column(Float, nullable=True, comment="DPI 影响")
    status: Mapped[str] = mapped_column(String(20), nullable=False, default="proposed", comment="proposed/approved/executed")
    created_at: Mapped[datetime] = mapped_column(
        DateTime(timezone=True), default=lambda: datetime.now(timezone.utc)
    )


class MonteCarloSimulation(Base):
    """Monte Carlo 模拟结果。"""

    __tablename__ = "monte_carlo_simulations"

    id: Mapped[str] = mapped_column(String(36), primary_key=True, default=lambda: str(uuid.uuid4()))
    tenant_id: Mapped[str] = mapped_column(String(36), ForeignKey("tenants.id"), nullable=False, index=True)
    iterations: Mapped[int] = mapped_column(nullable=False, default=10000, comment="模拟次数")
    irr_distribution: Mapped[dict | None] = mapped_column(JSONBType, nullable=True, comment="IRR 概率分布")
    dpi_distribution: Mapped[dict | None] = mapped_column(JSONBType, nullable=True, comment="DPI 概率分布")
    percentile_p5: Mapped[float | None] = mapped_column(Float, nullable=True)
    percentile_p50: Mapped[float | None] = mapped_column(Float, nullable=True)
    percentile_p95: Mapped[float | None] = mapped_column(Float, nullable=True)
    created_at: Mapped[datetime] = mapped_column(
        DateTime(timezone=True), default=lambda: datetime.now(timezone.utc)
    )