"""HTTP dasha registry.

`DASHA_REGISTRY_METADATA` is the old `extended_dashas.DASHA_REGISTRY` moved
verbatim so `/api/chart` `available_dashas` stays byte-identical.

`compute_dasha` calls the same modules `cmd_full_reading` calls, with the same
birth-info fields. Systems without that module return "not implemented"
instead of a fabricated timeline.

This module must not import `jyotish_api_server` or PyJHora.
"""

from __future__ import annotations

from datetime import datetime
from typing import Any

try:
    from source_bounded_child_periods import PYJHORA_PARENT_SEEDED_EQUAL_SPLIT_PROFILE
except ModuleNotFoundError:  # pragma: no cover - package import
    from scripts.source_bounded_child_periods import PYJHORA_PARENT_SEEDED_EQUAL_SPLIT_PROFILE

DASHA_REGISTRY_METADATA = {
    "vimshottari": {"name": "Vimshottari", "years": 120, "type": "nakshatra"},
    "ashtottari": {"name": "Ashtottari", "years": 108, "type": "nakshatra"},
    "yogini": {"name": "Yogini", "years": 36, "type": "nakshatra"},
    "kalachakra": {"name": "Kalachakra", "years": 94, "type": "nakshatra"},
    "tara": {"name": "Tara Dasha", "years": 81, "type": "nakshatra"},
    "shodasottari": {"name": "Shodasottari", "years": 128, "type": "nakshatra"},
    "panchottari": {"name": "Panchottari", "years": 105, "type": "nakshatra"},
    "satabdika": {"name": "Satabdika", "years": 100, "type": "nakshatra"},
    "chara": {"name": "Chara (Jaimini)", "years": 36, "type": "rasi"},
    "narayana": {"name": "Narayana", "years": 36, "type": "rasi"},
    "shoola": {"name": "Shoola Dasha", "years": 9, "type": "rasi"},
    "sudasa": {"name": "Sudasa", "years": 36, "type": "rasi"},
    "drig": {"name": "Drig Dasha", "years": 36, "type": "rasi"},
    "sthira": {"name": "Sthira Dasha", "years": 36, "type": "rasi"},
    "mandooka": {"name": "Mandooka Dasha", "years": 36, "type": "rasi"},
    "lagnamsaka": {"name": "Lagnamsaka Dasha", "years": 36, "type": "rasi"},
    "yogardha": {"name": "Yogardha Dasha", "years": 36, "type": "rasi"},
    "brahma": {"name": "Brahma Dasha", "years": 36, "type": "rasi"},
    "dwisaptati": {"name": "Dwisaptati Sama", "years": 72, "type": "conditional"},
    "shattrimsa": {"name": "Shattrimsa Sama", "years": 36, "type": "conditional"},
    "dwadashottari": {"name": "Dwadashottari", "years": 112, "type": "conditional"},
    "shasti_hayani": {"name": "Shasti-Hayani", "years": 60, "type": "conditional"},
    "chaturaaseeti": {"name": "Chaturaaseeti Sama", "years": 84, "type": "conditional"},
    "tithi_ashtottari": {"name": "Tithi Ashtottari", "years": 108, "type": "conditional"},
    "tithi_yogini": {"name": "Tithi Yogini", "years": 36, "type": "conditional"},
    "patyayini": {"name": "Patyayini", "years": 36, "type": "conditional"},
    "navamsa": {"name": "Navamsa Dasha", "years": 36, "type": "varga"},
    "kendradi": {"name": "Kendradi", "years": 38, "type": "bhav"},
    "paryaaya": {"name": "Paryaaya Dasha", "years": 36, "type": "varga"},
    "rashmi": {"name": "Rashmi Dasha", "years": 36, "type": "special"},
    "naisargika": {"name": "Naisargika Dasha", "years": 120, "type": "special"},
    "aayu": {"name": "Aayu Dasha", "years": 36, "type": "special"},
    "karaka": {"name": "Karaka Dasha", "years": 36, "type": "special"},
    "panchasvara": {"name": "Panchasvara Dasha", "years": 36, "type": "special"},
    "sudarsana": {"name": "Sudarsana Chakra Dasha", "years": 36, "type": "special"},
}

_CONDITIONAL_CALLS = {
    "shodasottari": ("shodashottari_dasha", "calculate_shodashottari_dasha", {}),
    "dwadashottari": (
        "dwadashottari_dasha",
        "calculate_dwadashottari_dasha",
        {"sukramsaka_profile": "navamsa_lagna_taurus_or_libra"},
    ),
    "dwisaptati": ("dwisaptatisama_dasha", "calculate_dwisaptatisama_dasha", {}),
    "shattrimsa": ("shattrimshatsama_dasha", "calculate_shattrimshatsama_dasha", {}),
    "panchottari": ("panchottari_dasha", "calculate_panchottari_dasha", {}),
    "satabdika": ("satabdika_dasha", "calculate_satabdika_dasha", {}),
    "chaturaaseeti": ("chaturshitisama_dasha", "calculate_chaturshitisama_dasha", {}),
}

SIGNS = [
    "Aries", "Taurus", "Gemini", "Cancer", "Leo", "Virgo",
    "Libra", "Scorpio", "Sagittarius", "Capricorn", "Aquarius", "Pisces",
]
SIGN_LORDS = {
    "Aries": "Mars", "Taurus": "Venus", "Gemini": "Mercury", "Cancer": "Moon",
    "Leo": "Sun", "Virgo": "Mercury", "Libra": "Venus", "Scorpio": "Mars",
    "Sagittarius": "Jupiter", "Capricorn": "Saturn", "Aquarius": "Saturn", "Pisces": "Jupiter",
}


class DashaNotImplemented(Exception):
    """The registry key exists, but there is no engine module behind it."""


def available_dasha_rows() -> list[dict[str, Any]]:
    """`/api/chart` `available_dashas` rows, same order and fields as before."""
    return [
        {"key": key, "name": info["name"], "years": info["years"], "type": info["type"]}
        for key, info in DASHA_REGISTRY_METADATA.items()
    ]


def _load(module_name: str):
    try:
        return __import__(module_name)
    except ModuleNotFoundError:  # pragma: no cover - package import
        return __import__(f"scripts.{module_name}", fromlist=[module_name])


def _longitude(value: Any) -> float | None:
    if isinstance(value, (int, float)):
        return float(value) % 360.0
    if not isinstance(value, dict):
        return None
    for key in ("lon", "longitude", "degree"):
        raw = value.get(key)
        if isinstance(raw, (int, float)):
            return float(raw) % 360.0
    sign_idx = value.get("sign_idx")
    if sign_idx is None and value.get("sign") in SIGNS:
        sign_idx = SIGNS.index(value["sign"])
    degree = value.get("degree_in_sign", value.get("degree", 0))
    try:
        if sign_idx is None:
            return None
        return (int(sign_idx) * 30 + float(degree or 0)) % 360.0
    except (TypeError, ValueError):
        return None


def _planet_longitudes(planets: dict) -> dict[str, float]:
    longitudes = {}
    if not isinstance(planets, dict):
        return longitudes
    for name, data in planets.items():
        longitude = _longitude(data)
        if longitude is not None:
            longitudes[str(name)] = longitude
    return longitudes


def _optional_float(body: dict, *keys: str) -> float | None:
    for key in keys:
        raw = body.get(key)
        if isinstance(raw, (int, float)):
            return float(raw)
    return None


def _reference_datetime(birth_dt: datetime, body: dict) -> datetime:
    raw = body.get("today") or body.get("current_date")
    if isinstance(raw, datetime):
        return raw
    if isinstance(raw, str) and raw.strip():
        return datetime.strptime(raw.strip()[:10], "%Y-%m-%d")
    return datetime.now()


def build_reading_birth_info(
    birth_dt: datetime,
    planets: dict,
    ascendant: dict | None,
    body: dict | None = None,
) -> tuple[dict[str, Any], dict[str, Any], dict[str, float]]:
    """Same fields `cmd_full_reading` puts in `conditional_birth_info`.

    Returns `(alt_dasha_info, conditional_birth_info, planet_longitudes)`.
    Kept here, not extracted from the engine, so the full-reading dict
    construction and its output stay untouched.
    """
    body = body or {}
    ascendant = ascendant or {}
    planet_lons = _planet_longitudes(planets)
    moon_lon = planet_lons.get("Moon", _longitude(body.get("moon_lon")) or 0.0)
    sun_lon = planet_lons.get("Sun", _longitude(body.get("sun_lon")) or 0.0)
    asc_lon = _longitude(ascendant)
    if asc_lon is None:
        asc_lon = _longitude(body.get("ascendant_longitude"))
    if asc_lon is None:
        sign_idx = ascendant.get("sign_idx", body.get("asc_sign_idx", 0))
        try:
            asc_idx = int(sign_idx) % 12
        except (TypeError, ValueError):
            asc_idx = 0
        asc_lon = float(asc_idx * 30)
    asc_idx = int(float(asc_lon) / 30) % 12
    moon_nakshatra_index = int(moon_lon / (360 / 27)) % 27
    moon_pada = int((moon_lon % (360 / 27)) / (360 / 108)) + 1
    tithi_number = int(((moon_lon - sun_lon) % 360) / 12) + 1
    lagna_lord_name = SIGN_LORDS[SIGNS[asc_idx]]
    tenth_lord_name = SIGN_LORDS[SIGNS[(asc_idx + 9) % 12]]
    try:
        varga = _load("varga")
        navamsa_ascendant_sign_index = int(varga.calc_varga(asc_lon, 9).get("sign_idx", 0)) % 12
        venus_navamsa_sign_index = int(varga.calc_varga(float(planet_lons.get("Venus", 0)), 9).get("sign_idx", 0)) % 12
    except Exception:
        navamsa_ascendant_sign_index = None
        venus_navamsa_sign_index = None
    degree_in_sign = float(asc_lon) % 30.0
    ascendant_hora_lord = (
        "Sun"
        if (asc_idx % 2 == 0 and degree_in_sign < 15.0)
        or (asc_idx % 2 == 1 and degree_in_sign >= 15.0)
        else "Moon"
    )
    birth_is_daytime = None
    lat = _optional_float(body, "lat", "latitude")
    lon = _optional_float(body, "lon", "longitude")
    tz = _optional_float(body, "tz", "timezone")
    if lat is not None and lon is not None and tz is not None:
        try:
            daynight = _load("saham_daynight")
            birth_is_daytime = bool(daynight.determine_daytime(birth_dt, lat=lat, lon=lon, tz=tz).get("is_daytime"))
        except Exception:
            birth_is_daytime = None
    applicability_rule_family = (
        "rahu_from_lagna_lord_kendra_trikona_plus_paksha_daynight"
        if birth_is_daytime is not None
        else "moon_nakshatra_plus_paksha"
    )
    alt = {
        "birth_datetime": birth_dt,
        "moon_nakshatra_index": moon_nakshatra_index,
        "moon_pada": moon_pada,
        "is_shukla_paksha": 1 <= tithi_number <= 15,
        "lagna_rashi_index": asc_idx,
    }
    conditional = {
        **alt,
        "ascendant_longitude": asc_lon,
        "sun_longitude": sun_lon,
        "moon_longitude": moon_lon,
        "birth_is_daytime": birth_is_daytime,
        "ascendant_sign_index": asc_idx,
        "ascendant_hora_lord": ascendant_hora_lord,
        "navamsa_ascendant_sign_index": navamsa_ascendant_sign_index,
        "venus_rasi_sign_index": int(float(planet_lons.get("Venus", 0)) / 30) % 12,
        "venus_navamsa_sign_index": venus_navamsa_sign_index,
        "tenth_lord_sign_index": int(float(planet_lons.get(tenth_lord_name, 0)) / 30) % 12,
        "rahu_sign_index": int(float(planet_lons.get("Rahu", 0)) / 30) % 12,
        "lagna_lord_sign_index": int(float(planet_lons.get(lagna_lord_name, 0)) / 30) % 12,
        "applicability_rule_family": applicability_rule_family,
    }
    return alt, conditional, planet_lons


def _major_rows(payload: Any) -> list:
    if isinstance(payload, dict):
        majors = payload.get("major")
        if isinstance(majors, list):
            return majors
        periods = payload.get("periods")
        if isinstance(periods, list):
            return periods
        sequence = payload.get("mahadasha_sequence")
        if isinstance(sequence, list):
            return sequence
        return []
    if isinstance(payload, list):
        return payload
    return []


def _conditional_payload(key: str, conditional: dict) -> dict:
    module_name, function_name, extra = _CONDITIONAL_CALLS[key]
    module = _load(module_name)
    birth_info = {
        **conditional,
        **extra,
        "child_period_profile": PYJHORA_PARENT_SEEDED_EQUAL_SPLIT_PROFILE,
    }
    return getattr(module, function_name)(birth_info)


def compute_dasha(
    key: str,
    *,
    birth_dt: datetime,
    planets: dict,
    ascendant: dict | None,
    body: dict | None = None,
) -> dict[str, Any]:
    """Return engine major periods for one registry key.

    Raises `DashaNotImplemented` when the key has no engine module. Vimshottari
    stays on the handler's existing canonical branch and is not computed here.
    """
    if key not in DASHA_REGISTRY_METADATA:
        raise DashaNotImplemented("Unknown dasha system")
    if key == "chara":
        raise DashaNotImplemented("chara dasha is served at /api/dasha/chara")
    body = body or {}
    alt, conditional, planet_lons = build_reading_birth_info(birth_dt, planets or {}, ascendant, body)
    if key == "yogini":
        payload = _load("yogini_dasha").calculate_yogini_dasha({**alt, "moon_longitude": conditional["moon_longitude"]})
        return {"periods": _major_rows(payload)}
    if key == "ashtottari":
        payload = _load("ashtottari_dasha").calculate_ashtottari_dasha({
            **alt,
            "moon_longitude": conditional["moon_longitude"],
        })
        return {"periods": _major_rows(payload)}
    if key == "kalachakra":
        payload = _load("kalachakra_dasha").calculate_kalachakra_dasha(alt)
        return {"periods": _major_rows(payload)}
    if key == "shasti_hayani":
        birth_info = dict(conditional)
        birth_info["child_period_profile"] = PYJHORA_PARENT_SEEDED_EQUAL_SPLIT_PROFILE
        payload = _load("shastihayani_dasha").calculate_shastihayani_dasha(birth_info)
        return {"periods": _major_rows(payload)}
    if key in _CONDITIONAL_CALLS:
        return {"periods": _major_rows(_conditional_payload(key, conditional))}
    if key == "narayana":
        asc_idx = int(conditional["ascendant_sign_index"])
        reference = _reference_datetime(birth_dt, body)
        current_age = (reference - birth_dt).days / 365.25
        birth_year = int(body.get("year") or birth_dt.year)
        narayana = _load("narayana_dasha")
        report = narayana.narayana_dasha_full_report(
            lagna_sign_idx=asc_idx,
            planet_lons=planet_lons,
            current_age=current_age,
            birth_year=birth_year,
        )
        labeled = _load("narayana_legacy_label").label_legacy_narayana(
            report,
            lagna_sign_idx=asc_idx,
            planet_lons=planet_lons,
            current_age=current_age,
            birth_year=birth_year,
        )
        return {
            "periods": _major_rows(labeled),
            "algorithm_label": labeled.get("algorithm_label") if isinstance(labeled, dict) else None,
            "algorithm_note": labeled.get("algorithm_note") if isinstance(labeled, dict) else None,
            "profile": labeled.get("profile") if isinstance(labeled, dict) else None,
        }
    if key == "shoola":
        rashi = _load("rashi_dashas_native")
        try:
            section = rashi.calculate_rashi_dashas(
                birth_dt.date(), conditional["ascendant_longitude"], planet_lons
            )["shoola"]
        except ValueError as exc:
            raise DashaNotImplemented(str(exc)) from exc
        return {"periods": _major_rows(section)}
    raise DashaNotImplemented("dasha system not implemented")