"""Динамические нормы по уравнениям GfE (Германия)."""

from __future__ import annotations

from typing import Any

USP_DYNAMIC_KEY = "usp"
NEL_DYNAMIC_KEY = "nel"

# GfE 2001 Milchkühe — Erhaltung + Milch (Standardmilch / FCM)
NEL_MAINTENANCE_COEFF = 0.293  # MJ NEL / (kg LM)^0,75 / Tag
NEL_PER_KG_MILK_MJ = 3.3  # MJ NEL / kg Milch (FCM)


def gfe_usp_min_g(
    mass_kg: float | None,
    milk_yield_kg: float | None = None,
) -> float | None:
    """
    Минимальная суточная потребность в усвояемом протеине (уСП / nXP), г/сут.

    GfE: 0,09 × (масса^0,75) × 6,25 + удой × 85 г.
    """
    if mass_kg is None or mass_kg <= 0:
        return None
    maintenance = 0.09 * (mass_kg**0.75) * 6.25
    milk = max(float(milk_yield_kg or 0), 0.0) * 85.0
    return maintenance + milk


def gfe_nel_min_mj(
    mass_kg: float | None,
    milk_yield_kg: float | None = None,
) -> float | None:
    """
    Минимальная суточная потребность в ЧЭЛ (NEL), МДж/сут.

    GfE 2001: 0,293 × LM^0,75 + удой × 3,3 (MJ NEL на кг молока).
    """
    if mass_kg is None or mass_kg <= 0:
        return None
    maintenance = NEL_MAINTENANCE_COEFF * (mass_kg**0.75)
    milk = max(float(milk_yield_kg or 0), 0.0) * NEL_PER_KG_MILK_MJ
    return maintenance + milk


def preview_dynamic_norms(
    mass_kg: float | None,
    milk_yield_kg: float | None = None,
) -> dict[str, Any]:
    """Расчётные min по GfE для UI (без учёта сохранённых норм)."""
    _, dynamic = apply_dynamic_norms(
        {},
        mass_kg=mass_kg,
        milk_yield_kg=milk_yield_kg,
    )
    return dynamic


def apply_dynamic_norms(
    stored: dict[str, dict[str, float | None]],
    *,
    mass_kg: float | None,
    milk_yield_kg: float | None,
    ration_type: str | None = None,
    force_dynamic: bool = False,
) -> tuple[dict[str, dict[str, float | None]], dict[str, Any]]:
    """
    Заполняет нормы по GfE, если в БД min не задан.
    force_dynamic=True — пересчитать min уСП/ЧЭЛ по массе и удою даже при нормах в БД
    (автоготовка с явными mass_kg / milk_yield_kg).
    Возвращает (resolved_norms, dynamic_meta).
    """
    del ration_type
    resolved: dict[str, dict[str, float | None]] = {
        key: {"min": bounds.get("min"), "max": bounds.get("max")}
        for key, bounds in stored.items()
    }
    dynamic: dict[str, Any] = {}

    for key, compute, formula in (
        (USP_DYNAMIC_KEY, gfe_usp_min_g, "0.09×масса^0.75×6.25 + удой×85"),
        (NEL_DYNAMIC_KEY, gfe_nel_min_mj, "0.293×масса^0.75 + удой×3.3"),
    ):
        bounds = resolved.get(key, {"min": None, "max": None})
        if force_dynamic or bounds.get("min") is None:
            computed = compute(mass_kg, milk_yield_kg)
            if computed is not None:
                entry = dict(bounds)
                entry["min"] = computed
                resolved[key] = entry
                dynamic[key] = {"min": computed, "formula": formula}

    return resolved, dynamic