import pytest
from datetime import datetime, timezone, timedelta

from planetarytime import Body, EpochType, Moon, PlanetaryTime
from planetarytime.exceptions import EpochUnavailableError
from planetarytime.epoch import get_epoch_date


# ── Moon dataclass ─────────────────────────────────────────────────────────────

def test_body_getitem_returns_moon() -> None:
    assert isinstance(Body.MARS[0], Moon)


def test_mars_first_moon_is_phobos() -> None:
    assert Body.MARS[0].name == "Phobos"


def test_mars_second_moon_is_deimos() -> None:
    assert Body.MARS[1].name == "Deimos"


def test_mars_index_out_of_range_raises() -> None:
    with pytest.raises(IndexError):
        Body.MARS[99]


def test_mercury_has_no_moons() -> None:
    with pytest.raises(IndexError):
        Body.MERCURY[0]


def test_tidally_locked_sols_per_year_is_one() -> None:
    phobos = Body.MARS[0]
    assert phobos.is_tidally_locked is True
    assert phobos.sols_per_year == 1


def test_moon_hours_per_sol_equals_rounded_rotation() -> None:
    phobos = Body.MARS[0]
    assert phobos.hours_per_sol == round(phobos.rotation_hours)


def test_titan_has_contact_date() -> None:
    titan = Body.SATURN[0]
    assert titan.name == "Titan"
    assert titan.contact_date is not None


def test_display_name_returns_moon_name() -> None:
    assert Body.MARS[0].display_name == "Phobos"


# ── Epoch ──────────────────────────────────────────────────────────────────────

def test_moon_discovery_epoch_date() -> None:
    phobos = Body.MARS[0]
    assert get_epoch_date(phobos, EpochType.DISCOVERY) == datetime(1877, 8, 18, tzinfo=timezone.utc)


def test_moon_contact_epoch_date() -> None:
    titan = Body.SATURN[0]
    assert get_epoch_date(titan, EpochType.CONTACT) == datetime(2005, 1, 14, tzinfo=timezone.utc)


def test_moon_contact_epoch_unavailable_raises() -> None:
    phobos = Body.MARS[0]
    with pytest.raises(EpochUnavailableError):
        get_epoch_date(phobos, EpochType.CONTACT)


# ── PlanetaryTime with Moon ────────────────────────────────────────────────────

def test_planetary_time_from_earth_with_moon() -> None:
    phobos = Body.MARS[0]
    epoch_dt = get_epoch_date(phobos, EpochType.DISCOVERY)
    pt = PlanetaryTime.from_earth(epoch_dt, phobos, EpochType.DISCOVERY)
    assert pt.year == 0
    assert pt.sol == 0
    assert pt.hour == 0


def test_planetary_time_moon_one_sol_later_tidally_locked() -> None:
    # Phobos is tidally locked: sols_per_year == 1, so after 1 sol the year rolls over.
    phobos = Body.MARS[0]
    assert phobos.sols_per_year == 1
    epoch_dt = get_epoch_date(phobos, EpochType.DISCOVERY)
    one_sol_later = epoch_dt + timedelta(hours=phobos.hours_per_sol)
    pt = PlanetaryTime.from_earth(one_sol_later, phobos, EpochType.DISCOVERY)
    assert pt.year == 1
    assert pt.sol == 0


def test_planetary_time_moon_one_year_later() -> None:
    phobos = Body.MARS[0]
    epoch_dt = get_epoch_date(phobos, EpochType.DISCOVERY)
    one_year_seconds = phobos.sols_per_year * phobos.hours_per_sol * 3600
    pt = PlanetaryTime.from_earth(epoch_dt + timedelta(seconds=one_year_seconds), phobos, EpochType.DISCOVERY)
    assert pt.year == 1
    assert pt.sol == 0


def test_str_contains_moon_name() -> None:
    phobos = Body.MARS[0]
    epoch_dt = get_epoch_date(phobos, EpochType.DISCOVERY)
    pt = PlanetaryTime.from_earth(epoch_dt, phobos, EpochType.DISCOVERY)
    assert "Phobos" in str(pt)


def test_repr_contains_moon_name() -> None:
    phobos = Body.MARS[0]
    epoch_dt = get_epoch_date(phobos, EpochType.DISCOVERY)
    pt = PlanetaryTime.from_earth(epoch_dt, phobos, EpochType.DISCOVERY)
    assert "Phobos" in repr(pt)