"""
Backtest related Pydantic schemas.
"""
from datetime import date, datetime
from decimal import Decimal
from typing import Optional, List, Dict, Any
from enum import Enum

from pydantic import BaseModel, Field


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


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


class BacktestCreate(BaseModel):
    """Request to create a new backtest."""
    strategy_type: str = Field(..., description="multi_factor, quality, or value_momentum")
    strategy_params: Dict[str, Any] = Field(default_factory=dict)
    start_date: date
    end_date: date
    rebalance_period: RebalancePeriod = RebalancePeriod.QUARTERLY
    initial_capital: Decimal = Field(default=Decimal("100000000"), gt=0)
    commission_rate: Decimal = Field(default=Decimal("0.00015"), ge=0, le=1)
    slippage_rate: Decimal = Field(default=Decimal("0.001"), ge=0, le=1)
    benchmark: str = Field(default="KOSPI")
    top_n: int = Field(default=30, ge=1, le=100)


class BacktestMetrics(BaseModel):
    """Backtest result metrics."""
    total_return: Decimal
    cagr: Decimal
    mdd: Decimal
    sharpe_ratio: Decimal
    volatility: Decimal
    benchmark_return: Decimal
    excess_return: Decimal


class BacktestResponse(BaseModel):
    """Backtest response with status and optional results."""
    id: int
    user_id: int
    strategy_type: str
    strategy_params: Dict[str, Any]
    start_date: date
    end_date: date
    rebalance_period: str
    initial_capital: Decimal
    commission_rate: Decimal
    slippage_rate: Decimal
    benchmark: str
    status: str
    created_at: datetime
    completed_at: Optional[datetime] = None
    error_message: Optional[str] = None
    result: Optional[BacktestMetrics] = None

    class Config:
        from_attributes = True


class BacktestListItem(BaseModel):
    """Backtest item for list view."""
    id: int
    strategy_type: str
    start_date: date
    end_date: date
    rebalance_period: str
    status: str
    created_at: datetime
    total_return: Optional[Decimal] = None
    cagr: Optional[Decimal] = None
    mdd: Optional[Decimal] = None

    class Config:
        from_attributes = True


class EquityCurvePoint(BaseModel):
    """Single point in equity curve."""
    date: date
    portfolio_value: Decimal
    benchmark_value: Decimal
    drawdown: Decimal

    class Config:
        from_attributes = True


class HoldingItem(BaseModel):
    """Single holding at a rebalance date."""
    ticker: str
    name: str
    weight: Decimal
    shares: int
    price: Decimal


class RebalanceHoldings(BaseModel):
    """Holdings at a specific rebalance date."""
    rebalance_date: date
    holdings: List[HoldingItem]


class TransactionItem(BaseModel):
    """Single transaction."""
    id: int
    date: date
    ticker: str
    action: str
    shares: int
    price: Decimal
    commission: Decimal

    class Config:
        from_attributes = True