Jyotisha/tests/test_birth_sky.py

"""Birth-sky cover computation (TASK-birth-sky-cover-20260928 T1).

Golden instant is the fictional sample from the brief: 1994-05-18 07:40 UTC+8,
30.27N 120.15E. Values are geometric altitudes (no refraction), azimuth from
north increasing eastward.
"""

from __future__ import annotations

import json
from io import BytesIO

import pytest
import swisseph as swe

from scripts.api_heavy_compute_gate import reset_heavy_compute_gate
from scripts.birth_sky import (
    STAR_FILE,
    BirthSkyError,
    compute_birth_sky,
    compute_birth_sky_from_request,
    precess_j2000,
)
from scripts.jyotish_api_server import (
    DEFAULT_ALLOWED_HOSTS,
    DEFAULT_ALLOWED_ORIGINS,
    JyotishAPIHandler,
)

LAT = 30.27
LON = 120.15


def _sky(time: str = "07:40", date: str = "1994-05-18", lat: float = LAT, lon: float = LON, tz: float = 8):
    return compute_birth_sky(date, time, tz, lat, lon)


def _planet(sky: dict, key: str) -> dict:
    return next(item for item in sky["planets"] if item["id"] == key)


def test_golden_sample_sun_saturn_and_below_horizon_bodies() -> None:
    sky = _sky()
    sun = _planet(sky, "sun")
    saturn = _planet(sky, "saturn")
    assert sun["altitude"] == pytest.approx(31.7, abs=0.2)
    assert sun["azimuth"] == pytest.approx(84.7, abs=0.3)
    assert saturn["altitude"] == pytest.approx(50.3, abs=0.2)
    assert saturn["azimuth"] == pytest.approx(191.1, abs=0.3)
    assert _planet(sky, "moon")["altitude"] < 0
    assert _planet(sky, "jupiter")["altitude"] < 0
    assert sky["phase"] == "day"
    assert sky["sun_altitude"] == pytest.approx(31.7, abs=0.2)
    assert [item["id"] for item in sky["planets"]] == [
        "sun", "moon", "mercury", "venus", "mars", "jupiter", "saturn",
    ]


def test_response_does_not_echo_birth_inputs() -> None:
    sky = _sky()
    text = json.dumps(sky)
    for key in ("date", "time", "latitude", "longitude", "timezone", "lat", "lon"):
        assert f'"{key}"' not in text
    assert "1994" not in text
    assert "07:40" not in text


@pytest.mark.parametrize(
    ("date", "lat"),
    [("1994-05-18", 30.27), ("2001-12-21", -33.87), ("2010-03-20", 51.5)],
)
def test_local_apparent_noon_altitude_matches_90_minus_lat_minus_declination(date: str, lat: float) -> None:
    # Independent check: scan the local noon hour for the Sun's highest point
    # and compare with 90 - |lat - dec|, dec from swe's equatorial position.
    best = max(
        (_sky(f"{hour:02d}:{minute:02d}", date=date, lat=lat)["sun_altitude"], hour, minute)
        for hour in range(10, 15)
        for minute in range(60)
    )
    altitude, hour, minute = best
    jd = swe.julday(*map(int, date.split("-")), hour + minute / 60 - 8)
    declination = swe.calc_ut(jd, swe.SUN, swe.FLG_EQUATORIAL)[0][1]
    assert altitude == pytest.approx(90 - abs(lat - declination), abs=0.5)


def test_polaris_altitude_is_about_the_latitude() -> None:
    polaris = next(star for star in _sky()["stars"] if star["hr"] == 424)
    assert polaris["altitude"] == pytest.approx(30.0, abs=1.0)
    assert polaris["azimuth"] < 3 or polaris["azimuth"] > 357


@pytest.mark.parametrize(
    ("time", "phase"),
    [
        ("07:40", "day"),
        ("04:50", "twilight_morning"),
        ("19:10", "twilight_evening"),
        ("00:00", "night"),
    ],
)
def test_phase_has_four_states(time: str, phase: str) -> None:
    sky = _sky(time)
    assert sky["phase"] == phase
    if phase.startswith("twilight"):
        assert -18 <= sky["sun_altitude"] <= 0


def test_stars_are_above_horizon_and_lines_use_known_hr_numbers() -> None:
    sky = _sky("00:00")
    assert sky["stars"]
    assert all(star["altitude"] > 0 for star in sky["stars"])
    assert all(star["magnitude"] <= 4.0 for star in sky["stars"])
    assert [line["id"] for line in sky["lines"]] == ["big_dipper", "cassiopeia", "orion"]
    catalog = json.loads(STAR_FILE.read_text(encoding="utf-8"))
    known = {row[0] for row in catalog["stars"]}
    for line in sky["lines"]:
        for stroke in line["strokes"]:
            assert set(stroke) <= known


def test_star_catalogue_records_public_domain_source() -> None:
    catalog = json.loads(STAR_FILE.read_text(encoding="utf-8"))
    assert "Yale Bright Star Catalogue" in catalog["source"]
    assert catalog["source_url"].startswith("https://cdsarc.cds.unistra.fr/ftp/V/50/")
    assert len(catalog["source_sha256"]) == 64
    assert "Public domain" in catalog["license"]
    assert all(row[3] <= 4.0 for row in catalog["stars"])
    assert len(catalog["stars"]) > 400


def test_iau_1976_precession_matches_meeus_example_21b() -> None:
    # Meeus, Astronomical Algorithms, example 21.b (theta Persei, J2000 -> 2028-11-13.19).
    ra, dec = precess_j2000(41.054063, 49.227750, 2462088.69)
    assert ra == pytest.approx(41.547214, abs=1e-5)
    assert dec == pytest.approx(49.348483, abs=1e-5)


def test_request_validation_rejects_bad_input() -> None:
    good = {"date": "1994-05-18", "time": "07:40", "timezone_offset": 8, "latitude": LAT, "longitude": LON}
    assert compute_birth_sky_from_request(good)["phase"] == "day"
    for patch in ({"latitude": 91}, {"longitude": None}, {"date": "1994/05/18"}, {"time": "7h"}, {"timezone_offset": "x"}):
        with pytest.raises(BirthSkyError):
            compute_birth_sky_from_request({**good, **patch})


class _FakeHeaders(dict):
    def get(self, key, default=None):
        return super().get(key, default)


class _FakeServer:
    allowed_origins = DEFAULT_ALLOWED_ORIGINS
    allowed_hosts = DEFAULT_ALLOWED_HOSTS


class _PostCaptureHandler(JyotishAPIHandler):
    def __init__(self, path: str, payload: dict) -> None:
        raw = json.dumps(payload).encode("utf-8")
        self.headers = _FakeHeaders({"Content-Length": str(len(raw)), "Content-Type": "application/json"})
        self.server = _FakeServer()
        self.path = path
        self.rfile = BytesIO(raw)
        self.wfile = BytesIO()
        self.status_code = None
        self.client_address = ("test-birth-sky", 0)

    def send_response(self, code, message=None):  # noqa: ANN001
        self.status_code = code

    def send_header(self, key, value):  # noqa: ANN001
        return None

    def end_headers(self):
        return None

    def payload(self) -> dict:
        return json.loads(self.wfile.getvalue().decode("utf-8"))


@pytest.fixture
def api_env(monkeypatch):
    monkeypatch.setenv("JYOTISH_API_RATE_LIMIT_PER_MINUTE", "0")
    reset_heavy_compute_gate()
    yield
    reset_heavy_compute_gate()


def test_http_endpoint_is_thinly_registered(api_env) -> None:
    handler = _PostCaptureHandler(
        "/api/birth_sky",
        {"date": "1994-05-18", "time": "07:40", "timezone_offset": 8, "latitude": LAT, "longitude": LON},
    )
    handler.do_POST()
    assert handler.status_code == 200
    payload = handler.payload()
    assert payload["phase"] == "day"
    assert _planet(payload, "saturn")["azimuth"] == pytest.approx(191.1, abs=0.3)

    bad = _PostCaptureHandler("/api/birth_sky", {"date": "1994-05-18", "time": "07:40"})
    bad.do_POST()
    assert bad.status_code == 400