from __future__ import annotations

from dataclasses import dataclass

from app.services.boundary_values import boundary_decimal


@dataclass(frozen=True, slots=True)
class NormalizedHistoricalScenarioInputs:
    underlying_units: float
    loan_amount: float
    margin_call_ltv: float
    currency: str = "USD"
    cash_balance: float = 0.0
    financing_rate: float = 0.0


def normalize_historical_scenario_inputs(
    *,
    underlying_units: object,
    loan_amount: object,
    margin_call_ltv: object,
    currency: object = "USD",
    cash_balance: object = 0.0,
    financing_rate: object = 0.0,
) -> NormalizedHistoricalScenarioInputs:
    normalized_currency = str(currency).strip().upper()
    if not normalized_currency:
        raise ValueError("Currency is required")

    units = float(boundary_decimal(underlying_units, field_name="underlying_units"))
    normalized_loan_amount = float(boundary_decimal(loan_amount, field_name="loan_amount"))
    ltv = float(boundary_decimal(margin_call_ltv, field_name="margin_call_ltv"))
    normalized_cash_balance = float(boundary_decimal(cash_balance, field_name="cash_balance"))
    normalized_financing_rate = float(boundary_decimal(financing_rate, field_name="financing_rate"))

    if units <= 0:
        raise ValueError("Underlying units must be positive")
    if normalized_loan_amount < 0:
        raise ValueError("Loan amount must be non-negative")
    if not 0 < ltv < 1:
        raise ValueError("Margin call LTV must be between 0 and 1")

    return NormalizedHistoricalScenarioInputs(
        underlying_units=units,
        loan_amount=normalized_loan_amount,
        margin_call_ltv=ltv,
        currency=normalized_currency,
        cash_balance=normalized_cash_balance,
        financing_rate=normalized_financing_rate,
    )