"""Swiss Ephemeris sunrise/sunset evidence for Saham day/night formula selection."""

from __future__ import annotations

from datetime import datetime
from typing import Any

import swisseph as swe


class SahamDayNightError(ValueError):
    pass


def determine_daytime(
    moment: datetime,
    *,
    lat: float,
    lon: float,
    tz: float,
    rising: str = "apparent",
) -> dict[str, Any]:
    """Day/night window.

    ``rising="apparent"`` is the historical disk-edge window. Rectification and
    Panchanga rely on that default and must not pick up Hindu rising.
    ``rising="hindu"`` is disk-center, no refraction, with the real next
    sunrise. Saham day/night, Gulika, and Shayanadi pass it explicitly.
    """
    if rising not in ("apparent", "hindu"):
        raise SahamDayNightError("unsupported sunrise convention")
    if not -90 <= float(lat) <= 90 or not -180 <= float(lon) <= 180:
        raise SahamDayNightError("invalid WGS84 latitude/longitude")
    local = moment.replace(tzinfo=None)
    jd = swe.julday(local.year, local.month, local.day, local.hour + local.minute / 60 + local.second / 3600 - float(tz))
    geopos = (float(lon), float(lat), 0.0)
    if rising == "apparent":
        rise_status, rise = swe.rise_trans(jd - 1.0, swe.SUN, swe.CALC_RISE, geopos)
        set_status, sunset = swe.rise_trans(jd - 1.0, swe.SUN, swe.CALC_SET, geopos)
        if rise_status != 0 or set_status != 0:
            raise SahamDayNightError("sunrise_or_sunset_unavailable_for_location_date")
        sunrise_jd, sunset_jd = rise[0], sunset[0]
        # Normalize the next daily events around the queried instant.
        while sunrise_jd > jd:
            sunrise_jd -= 1.0
        while sunset_jd > jd:
            sunset_jd -= 1.0
        is_day = sunrise_jd <= jd < sunset_jd if sunrise_jd < sunset_jd else not (sunset_jd <= jd < sunrise_jd)
        return {
            "scope": "saham_daynight_swiss",
            "status": "computed",
            "is_daytime": is_day,
            "julian_day_ut": jd,
            "sunrise_jd_ut": sunrise_jd,
            "sunset_jd_ut": sunset_jd,
            "method": "swisseph.rise_trans",
            "boundary": "Formula-specific +30 degree exceptions must be applied by the Saham rule layer, not inferred from house placement.",
        }

    flags = swe.FLG_SWIEPH | swe.FLG_TRUEPOS

    def event(after, kind):
        status, times = swe.rise_trans(after, swe.SUN, kind | swe.BIT_HINDU_RISING, geopos, flags=flags)
        if status != 0:
            raise SahamDayNightError("sunrise_or_sunset_unavailable_for_location_date")
        return times[0]

    # Consecutive rise/set events. Adding one Julian day to a sunrise is not
    # the next sunrise, and it moves the night-segment endpoint.
    midnight_jd = swe.julday(local.year, local.month, local.day, -float(tz))
    sunrise_jd = event(midnight_jd, swe.CALC_RISE)
    if sunrise_jd > jd:
        midnight_jd -= 1.0
        sunrise_jd = event(midnight_jd, swe.CALC_RISE)
    next_sunrise_jd = event(midnight_jd + 1.0, swe.CALC_RISE)
    sunset_jd = event(midnight_jd, swe.CALC_SET)
    if not sunrise_jd <= jd < next_sunrise_jd or not sunrise_jd < sunset_jd < next_sunrise_jd:
        raise SahamDayNightError("solar_day_window_unavailable")
    is_day = sunrise_jd <= jd < sunset_jd
    return {
        "scope": "saham_daynight_swiss",
        "status": "computed",
        "is_daytime": is_day,
        "julian_day_ut": jd,
        "sunrise_jd_ut": sunrise_jd,
        "sunset_jd_ut": sunset_jd,
        "next_sunrise_jd_ut": next_sunrise_jd,
        "method": "swisseph.rise_trans_hindu_rising",
        "boundary": "Formula-specific +30 degree exceptions must be applied by the Saham rule layer, not inferred from house placement.",
    }