from __future__ import annotations

from decimal import Decimal

import pytest

from app.domain.backtesting_math import AssetQuantity, PricePerAsset
from app.domain.instruments import (
    asset_quantity_from_weight,
    price_per_weight_from_asset_price,
    weight_from_asset_quantity,
)
from app.domain.units import BaseCurrency, Weight, WeightUnit


def test_gld_share_quantity_converts_to_troy_ounce_weight() -> None:
    quantity = AssetQuantity(amount=Decimal("10"), symbol="GLD")

    weight = weight_from_asset_quantity(quantity)

    assert weight == Weight(amount=Decimal("1.0"), unit=WeightUnit.OUNCE_TROY)


def test_gld_troy_ounce_weight_converts_to_share_quantity() -> None:
    weight = Weight(amount=Decimal("1"), unit=WeightUnit.OUNCE_TROY)

    quantity = asset_quantity_from_weight("GLD", weight)

    assert quantity == AssetQuantity(amount=Decimal("10"), symbol="GLD")


def test_gld_share_quote_converts_to_ounce_equivalent_spot() -> None:
    quote = PricePerAsset(amount=Decimal("404.19"), currency=BaseCurrency.USD, symbol="GLD")

    spot = price_per_weight_from_asset_price(quote, per_unit=WeightUnit.OUNCE_TROY)

    assert spot.amount == Decimal("4041.9")
    assert spot.currency is BaseCurrency.USD
    assert spot.per_unit is WeightUnit.OUNCE_TROY


def test_instrument_conversions_fail_closed_for_unsupported_symbols() -> None:
    quote = PricePerAsset(amount=Decimal("28.50"), currency=BaseCurrency.USD, symbol="SLV")

    with pytest.raises(ValueError, match="Unsupported instrument metadata"):
        price_per_weight_from_asset_price(quote, per_unit=WeightUnit.OUNCE_TROY)

    with pytest.raises(ValueError, match="Unsupported instrument metadata"):
        weight_from_asset_quantity(AssetQuantity(amount=Decimal("10"), symbol="SLV"))

    with pytest.raises(ValueError, match="Unsupported instrument metadata"):
        asset_quantity_from_weight("SLV", Weight(amount=Decimal("1"), unit=WeightUnit.OUNCE_TROY))