from datetime import datetime

import pytest
import swisseph as swe

from scripts.gulika import calculate_gulika
from ayanamsa_utils import DEFAULT_AYANAMSA_NAME, apply_ayanamsa


def _moon_longitude() -> float:
    jd = swe.julday(2000, 1, 1, 12.0)
    return float(swe.calc_ut(jd, swe.MOON, swe.FLG_SWIEPH | swe.FLG_SIDEREAL)[0][0])


@pytest.mark.parametrize(("previous", "requested"), [("lahiri", "raman"), ("raman", "lahiri")])
def test_gulika_restores_process_ayanamsa(previous: str, requested: str) -> None:
    try:
        assert apply_ayanamsa(previous, swe)
        before = _moon_longitude()

        result = calculate_gulika(
            datetime(1990, 1, 1, 12, 0),
            lat=39.9042,
            lon=116.4074,
            tz=8,
            ayanamsa=requested,
        )

        assert result["ayanamsa"] == requested
        assert _moon_longitude() == pytest.approx(before, abs=1e-10)
    finally:
        apply_ayanamsa(DEFAULT_AYANAMSA_NAME, swe)