"""Sidereal Sun and Moon on the chart function's frame.

One process import. Ayanamsa is recomputed per instant so a year-long
search does not freeze the precession. This is not the apparent path.
"""

from __future__ import annotations

import swisseph as swe

try:
    from jyotish_engine import _apply_ayanamsa, _sidereal_calculation_profile
except ImportError:  # pragma: no cover - package import
    from scripts.jyotish_engine import _apply_ayanamsa, _sidereal_calculation_profile

_SPEED = getattr(swe, "FLG_SPEED", 256)


class SiderealFrame:
    def __init__(self, ayanamsa_name: str, node_mode: str = "mean") -> None:
        self.ayanamsa_name = str(ayanamsa_name or "lahiri")
        self.node_mode = node_mode if node_mode in ("mean", "true") else "mean"
        _apply_ayanamsa(self.ayanamsa_name)

    def sun_moon(self, jd: float) -> tuple[float, float]:
        _mode, calc_flags, ayanamsa = _sidereal_calculation_profile(float(jd), "legacy")
        flags = calc_flags | _SPEED
        sun = _body(float(jd), swe.SUN, flags, ayanamsa)
        moon = _body(float(jd), swe.MOON, flags, ayanamsa)
        return sun, moon


def _body(jd: float, body: int, flags: int, ayanamsa: float) -> float:
    pos, ret = swe.calc_ut(jd, body, flags)
    if ret < 0:
        raise RuntimeError(f"swisseph calc_ut failed for body {body} at jd {jd}: code {ret}")
    return (float(pos[0]) - float(ayanamsa)) % 360.0


def birth_jd(year: int, month: int, day: int, hour: float, tz_hours: float) -> float:
    """Same Julian day the chart function uses: local clock minus the offset."""
    return float(swe.julday(int(year), int(month), int(day), float(hour) - float(tz_hours)))


def year_start_jd(year: int) -> float:
    return float(swe.julday(int(year), 1, 1, 0.0))