"""Backtest settings model for configuring backtest scenarios independently of portfolio settings."""

from __future__ import annotations

from dataclasses import dataclass
from datetime import date
from typing import Literal
from uuid import UUID, uuid4

# Self type annotation
from app.models.backtest import ProviderRef


@dataclass(frozen=True)
class BacktestSettings:
    """Configuration for running backtests independent of portfolio settings.

    These settings determine what data to fetch and how to run backtests,
    separate from the actual portfolio configurations being tested.
    """

    settings_id: UUID
    name: str
    data_source: Literal["databento", "yfinance", "synthetic"]
    dataset: str
    schema: str
    start_date: date
    end_date: date
    underlying_symbol: Literal["GLD", "GC", "XAU"]
    start_price: float
    underlying_units: float
    loan_amount: float
    margin_call_ltv: float
    template_slugs: tuple[str, ...]
    cache_key: str
    data_cost_usd: float
    provider_ref: ProviderRef

    def __post_init__(self) -> None:
        if not self.settings_id:
            raise ValueError("settings_id is required")
        if not self.name:
            raise ValueError("name is required")
        if self.start_date > self.end_date:
            raise ValueError("start_date must be on or before end_date")
        if self.data_source not in ("databento", "yfinance", "synthetic"):
            raise ValueError("data_source must be 'databento', 'yfinance', or 'synthetic'")
        if self.underlying_symbol not in ("GLD", "GC", "XAU"):
            raise ValueError("underlying_symbol must be 'GLD', 'GC', or 'XAU'")
        if self.start_price < 0:
            raise ValueError("start_price must be non-negative")
        if self.underlying_units <= 0:
            raise ValueError("underlying_units must be positive")
        if self.loan_amount < 0:
            raise ValueError("loan_amount must be non-negative")
        if not 0 < self.margin_call_ltv < 1:
            raise ValueError("margin_call_ltv must be between 0 and 1")
        if not self.template_slugs:
            raise ValueError("at least one template slug is required")
        if self.data_cost_usd < 0:
            raise ValueError("data_cost_usd must be non-negative")

    @classmethod
    def create_default(cls, name: str = "Default Backtest Settings") -> BacktestSettings:
        """Create default backtest settings configuration."""
        return cls(
            settings_id=uuid4(),
            name=name,
            data_source="databento",
            dataset="XNAS.BASIC",
            schema="ohlcv-1d",
            start_date=date(2020, 1, 1),
            end_date=date(2023, 12, 31),
            underlying_symbol="GLD",
            start_price=0.0,
            underlying_units=1000.0,
            loan_amount=0.0,
            margin_call_ltv=0.75,
            template_slugs=("default-template",),
            cache_key="",
            data_cost_usd=0.0,
            provider_ref=ProviderRef(provider_id="default", pricing_mode="standard"),
        )


# For backward compatibility - alias to existing models
BacktestScenario = "app.models.backtest.BacktestScenario"
# TemplateRef and ProviderRef imported from app.models.backtest