"""Роутер методик суточных норм: WESP / Москва / Петербург."""

from __future__ import annotations

from dataclasses import dataclass, field
from typing import Any, Literal

from app.lab.calc.gfe_norms import apply_dynamic_norms
from app.lab.calc.racion.moscow import MoscowDairyParams, resolve_moscow_dairy_norms
from app.lab.calc.racion.piter import PiterDairyParams, PiterPrepError, resolve_piter_dairy_norms
from app.lab.indicators import RATION_ALL_INDICATORS

NormsMethod = Literal["wesp", "racion_moscow", "racion_piter"]

VALID_NORMS_METHODS: frozenset[str] = frozenset({"wesp", "racion_moscow", "racion_piter"})


@dataclass
class NormsParams:
    milk_fat_pct: float | None = None
    lactation_no: int | None = None
    lactation_stage: int | None = None
    body_condition: int | None = None
    housing_system: int | None = None
    konc_oe_sv: float | None = None

    @classmethod
    def from_dict(cls, raw: dict[str, Any] | None) -> NormsParams:
        if not raw:
            return cls()
        return cls(
            milk_fat_pct=_flt(raw.get("milkFatPct", raw.get("milk_fat_pct"))),
            lactation_no=_int(raw.get("lactationNo", raw.get("lactation_no"))),
            lactation_stage=_int(raw.get("lactationStage", raw.get("lactation_stage"))),
            body_condition=_int(raw.get("bodyCondition", raw.get("body_condition"))),
            housing_system=_int(raw.get("housingSystem", raw.get("housing_system"))),
            konc_oe_sv=_flt(raw.get("koncOeSv", raw.get("konc_oe_sv"))),
        )


def _flt(v: Any) -> float | None:
    if v is None or v == "":
        return None
    try:
        return float(v)
    except (TypeError, ValueError):
        return None


def _int(v: Any) -> int | None:
    if v is None or v == "":
        return None
    try:
        return int(v)
    except (TypeError, ValueError):
        return None


def normalize_norms_method(method: str | None) -> NormsMethod:
    m = (method or "wesp").strip().lower()
    if m not in VALID_NORMS_METHODS:
        return "wesp"
    return m  # type: ignore[return-value]


@dataclass
class NormsResolveRequest:
    method: NormsMethod = "wesp"
    stored: dict[str, dict[str, float | None]] = field(default_factory=dict)
    mass_kg: float | None = None
    milk_yield_kg: float | None = None
    ration_type: str | None = None
    force_dynamic: bool = False
    params: NormsParams = field(default_factory=NormsParams)


def merge_hybrid_norms(
    racion_resolved: dict[str, dict[str, float | None]],
    stored: dict[str, dict[str, float | None]],
    *,
    dynamic_meta: dict[str, Any] | None = None,
) -> tuple[dict[str, dict[str, float | None]], dict[str, Any]]:
    """
    RACION + derived имеют приоритет по min.
    stored дополняет ключи без RACION-min; max всегда из stored, если задан.
    """
    out: dict[str, dict[str, float | None]] = {}
    coverage: dict[str, list[str]] = {
        "racion": [],
        "derived": [],
        "fallback": [],
        "missing": [],
    }
    dynamic = dynamic_meta or {}
    all_keys = {d["key"] for d in RATION_ALL_INDICATORS}
    all_keys.update(racion_resolved.keys())
    all_keys.update(stored.keys())

    for key in sorted(all_keys):
        rac = racion_resolved.get(key) or {}
        st = stored.get(key) or {}
        rac_min = rac.get("min")
        st_min = st.get("min")
        st_max = st.get("max")

        source: str | None = None
        min_v: float | None = None
        if rac_min is not None:
            min_v = rac_min
            src = (dynamic.get(key) or {}).get("source")
            source = "derived" if src == "derived" else "racion"
        elif st_min is not None:
            min_v = st_min
            source = "fallback"

        max_v = st_max if st_max is not None else rac.get("max")
        if min_v is not None or max_v is not None:
            out[key] = {"min": min_v, "max": max_v}
        if source == "racion":
            coverage["racion"].append(key)
        elif source == "derived":
            coverage["derived"].append(key)
        elif source == "fallback":
            coverage["fallback"].append(key)
        elif key in {d["key"] for d in RATION_ALL_INDICATORS}:
            coverage["missing"].append(key)

    coverage["withMin"] = len([k for k, b in out.items() if b.get("min") is not None])
    coverage["total"] = len(RATION_ALL_INDICATORS)
    return out, coverage


def _require_dairy_params(req: NormsResolveRequest) -> tuple[float, float]:
    if req.mass_kg is None or req.mass_kg <= 0:
        raise ValueError("Для методики Москва/Петербург укажите живую массу, кг")
    if req.milk_yield_kg is None or req.milk_yield_kg <= 0:
        raise ValueError("Для методики Москва/Петербург укажите суточный удой, кг")
    return float(req.mass_kg), float(req.milk_yield_kg)


def _moscow_params(req: NormsResolveRequest) -> MoscowDairyParams:
    mass, milk = _require_dairy_params(req)
    p = req.params
    return MoscowDairyParams(
        mass_kg=mass,
        milk_yield_kg=milk,
        milk_fat_pct=p.milk_fat_pct if p.milk_fat_pct is not None else 4.0,
        lactation_no=p.lactation_no if p.lactation_no is not None else 2,
        body_condition=p.body_condition if p.body_condition is not None else 1,
        housing_system=p.housing_system if p.housing_system is not None else 1,
    )


def _piter_params(req: NormsResolveRequest) -> PiterDairyParams:
    mass, milk = _require_dairy_params(req)
    p = req.params
    konc = p.konc_oe_sv
    if konc is None or konc <= 0:
        raise ValueError("Для методики Петербург укажите концентрацию ОЭ/СВ, МДж/кг СВ")
    return PiterDairyParams(
        mass_kg=mass,
        milk_yield_kg=milk,
        milk_fat_pct=p.milk_fat_pct if p.milk_fat_pct is not None else 4.0,
        lactation_no=p.lactation_no if p.lactation_no is not None else 2,
        body_condition=p.body_condition if p.body_condition is not None else 1,
        housing_system=p.housing_system if p.housing_system is not None else 1,
        konc_oe_sv=float(konc),
    )


def resolve_norms(req: NormsResolveRequest) -> tuple[dict[str, dict[str, float | None]], dict[str, Any]]:
    method = normalize_norms_method(req.method)
    if method == "wesp":
        resolved, dynamic = apply_dynamic_norms(
            req.stored,
            mass_kg=req.mass_kg,
            milk_yield_kg=req.milk_yield_kg,
            ration_type=req.ration_type,
            force_dynamic=req.force_dynamic,
        )
        return resolved, {"normsMethod": "wesp", "dynamicNorms": dynamic}

    try:
        if method == "racion_moscow":
            racion, pack = resolve_moscow_dairy_norms(_moscow_params(req))
        else:
            racion, pack = resolve_piter_dairy_norms(_piter_params(req))
    except PiterPrepError as exc:
        raise ValueError(str(exc)) from exc

    resolved, coverage = merge_hybrid_norms(racion, req.stored, dynamic_meta=pack.get("dynamic"))
    return resolved, {"normsMethod": method, "coverage": coverage, **pack}