#!/usr/bin/env python3
"""Shared Swiss Ephemeris ayanamsa helpers.

Swiss Ephemeris stores sidereal mode globally inside the process. Any helper
that calls calc_ut(..., FLG_SIDEREAL) must set the intended mode explicitly.

Unknown names fail; they never silently collapse to Lahiri. VedAstro / oracle
comparison fixtures must pass an explicit `lahiri` name.
"""

from __future__ import annotations

from typing import Any

try:
    import swisseph as swe
except ImportError:  # pragma: no cover
    swe = None


AYANAMSA_MODES = {
    'lahiri': getattr(swe, 'SIDM_LAHIRI', 1) if swe else 1,
    'raman': getattr(swe, 'SIDM_RAMAN', 3) if swe else 3,
    'kp': getattr(swe, 'SIDM_KRISHNAMURTI', 5) if swe else 5,
    'krishnamurti': getattr(swe, 'SIDM_KRISHNAMURTI', 5) if swe else 5,
    'fagan_bradley': getattr(swe, 'SIDM_FAGAN_BRADLEY', 0) if swe else 0,
    'djwhal_khul': getattr(swe, 'SIDM_DJWHAL_KHUL', 6) if swe else 6,
    'sassanian': getattr(swe, 'SIDM_SASSANIAN', 16) if swe else 16,
    'true_citra': getattr(swe, 'SIDM_TRUE_CITRA', 27) if swe else 27,
    'true_pushya': getattr(swe, 'SIDM_TRUE_PUSHYA', 29) if swe else 29,
}

AYANAMSA_DISPLAY_NAMES = {
    'lahiri': 'Lahiri',
    'raman': 'Raman',
    'kp': 'Krishnamurti/KP',
    'krishnamurti': 'Krishnamurti/KP',
    'fagan_bradley': 'Fagan-Bradley',
    'djwhal_khul': 'Djwhal Khul',
    'sassanian': 'Sassanian',
    'true_citra': 'True Citra',
    'true_pushya': 'True Pushya',
}

DEFAULT_AYANAMSA_NAME = 'raman'
ACTIVE_AYANAMSA_NAME = DEFAULT_AYANAMSA_NAME


class UnsupportedAyanamsaError(ValueError):
    """Raised when a caller asks for an ayanamsa that is not in AYANAMSA_MODES."""


def _canonical_ayanamsa_key(name: Any) -> str:
    key = str(name or '').strip().lower().replace('-', '_')
    if key in ('krishnamurti_paddhati', 'krishnamurti/kp'):
        key = 'kp'
    if key == 'true_chitra':
        key = 'true_citra'
    return key


def is_supported_ayanamsa_name(name: Any = None) -> bool:
    key = _canonical_ayanamsa_key(name if name not in (None, '') else DEFAULT_AYANAMSA_NAME)
    return key in AYANAMSA_MODES


def supported_ayanamsa_names() -> list[str]:
    return sorted(AYANAMSA_MODES)


def normalize_ayanamsa_name(name: Any = None) -> str:
    if name is None or (isinstance(name, str) and not name.strip()):
        return DEFAULT_AYANAMSA_NAME
    key = _canonical_ayanamsa_key(name)
    if key not in AYANAMSA_MODES:
        raise UnsupportedAyanamsaError(
            f"unsupported ayanamsa name {name!r}; supported: {', '.join(supported_ayanamsa_names())}"
        )
    return key


def ayanamsa_display_name(name: Any = None) -> str:
    key = normalize_ayanamsa_name(name)
    return AYANAMSA_DISPLAY_NAMES.get(key, key.title())


def current_ayanamsa_name(args: Any = None) -> str:
    name = getattr(args, 'ayanamsa', None) if args is not None else None
    return normalize_ayanamsa_name(name)


def apply_ayanamsa(name: Any = None, swe_module: Any = None) -> bool:
    """Set Swiss Ephemeris sidereal mode explicitly."""
    module = swe_module or swe
    if module is None:
        return False
    key = normalize_ayanamsa_name(name)
    try:
        module.set_sid_mode(AYANAMSA_MODES[key])
    except Exception:
        return False
    return True


def sidereal_flags(swe_module: Any, ayanamsa_name: Any = None) -> int:
    apply_ayanamsa(ayanamsa_name, swe_module)
    return getattr(swe_module, 'FLG_SWIEPH', 2) | getattr(swe_module, 'FLG_SIDEREAL', 65536)