from datetime import date
from decimal import Decimal
from pathlib import Path

import pytest

from broker_sync.fx import FxCache, convert_to_gbp
from broker_sync.models import FxRateSource


def test_cache_roundtrip(tmp_path: Path) -> None:
    c = FxCache(tmp_path / "fx.db")
    c.put("USD", date(2026, 4, 1), Decimal("0.79"), FxRateSource.ECB_LIVE)
    hit = c.get("USD", date(2026, 4, 1))
    assert hit is not None
    assert hit[0] == Decimal("0.79")
    assert hit[1] is FxRateSource.ECB_LIVE


def test_cache_miss(tmp_path: Path) -> None:
    c = FxCache(tmp_path / "fx.db")
    assert c.get("USD", date(2026, 4, 1)) is None


def test_put_overwrites_on_source_upgrade(tmp_path: Path) -> None:
    # Reconciliation job upgrades ECB_LIVE → HMRC_MONTHLY for historical rows
    c = FxCache(tmp_path / "fx.db")
    c.put("USD", date(2026, 3, 1), Decimal("0.79"), FxRateSource.ECB_LIVE)
    c.put("USD", date(2026, 3, 1), Decimal("0.791"), FxRateSource.HMRC_MONTHLY)
    hit = c.get("USD", date(2026, 3, 1))
    assert hit is not None
    assert hit[0] == Decimal("0.791")
    assert hit[1] is FxRateSource.HMRC_MONTHLY


def test_gbp_passthrough_is_identity() -> None:
    # currency == GBP → rate is 1.0, no network needed
    amount_gbp, rate, source = convert_to_gbp(amount=Decimal("100"),
                                              currency="GBP",
                                              on_date=date(2026, 4, 1),
                                              cache=None)
    assert amount_gbp == Decimal("100")
    assert rate == Decimal("1")
    assert source is FxRateSource.ECB_LIVE


def test_convert_uses_cached_rate(tmp_path: Path) -> None:
    c = FxCache(tmp_path / "fx.db")
    c.put("USD", date(2026, 4, 1), Decimal("0.80"), FxRateSource.ECB_LIVE)
    amount_gbp, rate, source = convert_to_gbp(amount=Decimal("100"),
                                              currency="USD",
                                              on_date=date(2026, 4, 1),
                                              cache=c)
    assert amount_gbp == Decimal("80.00")
    assert rate == Decimal("0.80")
    assert source is FxRateSource.ECB_LIVE


def test_convert_raises_on_cache_miss(tmp_path: Path) -> None:
    c = FxCache(tmp_path / "fx.db")
    with pytest.raises(LookupError, match="USD.*2026-04-01"):
        convert_to_gbp(amount=Decimal("100"), currency="USD", on_date=date(2026, 4, 1), cache=c)