"""
Backtest related models.
"""
from datetime import datetime
from sqlalchemy import (
    Column, Integer, String, Numeric, DateTime, Date,
    Text, ForeignKey, JSON, Enum as SQLEnum
)
from sqlalchemy.orm import relationship
import enum

from app.core.database import Base


class BacktestStatus(str, enum.Enum):
    PENDING = "pending"
    RUNNING = "running"
    COMPLETED = "completed"
    FAILED = "failed"


class RebalancePeriod(str, enum.Enum):
    MONTHLY = "monthly"
    QUARTERLY = "quarterly"
    SEMI_ANNUAL = "semi_annual"
    ANNUAL = "annual"


class Backtest(Base):
    __tablename__ = "backtests"

    id = Column(Integer, primary_key=True, index=True)
    user_id = Column(Integer, ForeignKey("users.id"), nullable=False)
    strategy_type = Column(String(50), nullable=False)
    strategy_params = Column(JSON, default={})
    start_date = Column(Date, nullable=False)
    end_date = Column(Date, nullable=False)
    rebalance_period = Column(SQLEnum(RebalancePeriod), default=RebalancePeriod.QUARTERLY)
    initial_capital = Column(Numeric(20, 2), nullable=False)
    commission_rate = Column(Numeric(10, 6), default=0.00015)
    slippage_rate = Column(Numeric(10, 6), default=0.001)
    benchmark = Column(String(20), default="KOSPI")
    top_n = Column(Integer, default=30)
    status = Column(SQLEnum(BacktestStatus), default=BacktestStatus.PENDING)
    created_at = Column(DateTime, default=datetime.utcnow)
    completed_at = Column(DateTime, nullable=True)
    error_message = Column(Text, nullable=True)

    # Relationships
    result = relationship("BacktestResult", back_populates="backtest", uselist=False)
    equity_curve = relationship("BacktestEquityCurve", back_populates="backtest")
    holdings = relationship("BacktestHolding", back_populates="backtest")
    transactions = relationship("BacktestTransaction", back_populates="backtest")


class BacktestResult(Base):
    __tablename__ = "backtest_results"

    backtest_id = Column(Integer, ForeignKey("backtests.id"), primary_key=True)
    total_return = Column(Numeric(10, 4))
    cagr = Column(Numeric(10, 4))
    mdd = Column(Numeric(10, 4))
    sharpe_ratio = Column(Numeric(10, 4))
    volatility = Column(Numeric(10, 4))
    benchmark_return = Column(Numeric(10, 4))
    excess_return = Column(Numeric(10, 4))

    backtest = relationship("Backtest", back_populates="result")


class BacktestEquityCurve(Base):
    __tablename__ = "backtest_equity_curve"

    backtest_id = Column(Integer, ForeignKey("backtests.id"), primary_key=True)
    date = Column(Date, primary_key=True)
    portfolio_value = Column(Numeric(20, 2))
    benchmark_value = Column(Numeric(20, 2))
    drawdown = Column(Numeric(10, 4))

    backtest = relationship("Backtest", back_populates="equity_curve")


class BacktestHolding(Base):
    __tablename__ = "backtest_holdings"

    backtest_id = Column(Integer, ForeignKey("backtests.id"), primary_key=True)
    rebalance_date = Column(Date, primary_key=True)
    ticker = Column(String(20), primary_key=True)
    name = Column(String(100))
    weight = Column(Numeric(10, 4))
    shares = Column(Integer)
    price = Column(Numeric(12, 2))

    backtest = relationship("Backtest", back_populates="holdings")


class BacktestTransaction(Base):
    __tablename__ = "backtest_transactions"

    id = Column(Integer, primary_key=True, index=True)
    backtest_id = Column(Integer, ForeignKey("backtests.id"), nullable=False)
    date = Column(Date, nullable=False)
    ticker = Column(String(20), nullable=False)
    action = Column(String(10), nullable=False)  # buy/sell
    shares = Column(Integer, nullable=False)
    price = Column(Numeric(12, 2), nullable=False)
    commission = Column(Numeric(12, 2), nullable=False)

    backtest = relationship("Backtest", back_populates="transactions")