from __future__ import annotations

from typing import Any, Mapping

from app.modules.zootech.lab.nutrient_schema import resolve_sv_g_per_kg


def normalize_key(value: str) -> str:
    return " ".join((value or "").split()).strip().lower()


def parse_num(value: Any) -> float | None:
    if value is None or value == "":
        return None
    try:
        n = float(value)
    except (TypeError, ValueError):
        return None
    return None if n != n else n


def get_nutrient_value(
    dry_matter: float | None,
    nutrients: Mapping[str, Any] | None,
    nutrient_keys: list[str],
    *,
    indicator_key: str | None = None,
) -> float | None:
    """Только точное совпадение ключа (заголовок или indicator_key slug)."""
    nutrients = nutrients or {}
    if indicator_key:
        for k, v in nutrients.items():
            if normalize_key(str(k)) == normalize_key(indicator_key):
                n = parse_num(v)
                if n is not None:
                    return n
    for search in nutrient_keys:
        target = normalize_key(search)
        for k, v in nutrients.items():
            if normalize_key(str(k)) != target:
                continue
            n = parse_num(v)
            if n is not None:
                return n
    if any(normalize_key(k) == "св" for k in nutrient_keys):
        return resolve_sv_g_per_kg(nutrients, dry_matter)
    return None


def weighted_average(
    lines: list[dict[str, Any]],
    total_kg: float,
    nutrient_keys: list[str],
    *,
    indicator_key: str | None = None,
) -> float | None:
    if total_kg <= 0:
        return None
    total = 0.0
    weight = 0.0
    for line in lines:
        kg = float(line.get("daily_kg") or 0)
        if kg <= 0:
            continue
        v = get_nutrient_value(
            line.get("dry_matter"),
            line.get("nutrients"),
            nutrient_keys,
            indicator_key=indicator_key,
        )
        if v is None:
            continue
        total += kg * v
        weight += kg
    if weight <= 0:
        return None
    return total / weight


def daily_intake_total(
    lines: list[dict[str, Any]],
    nutrient_keys: list[str],
    *,
    heads_per_trip: int = 1,
    indicator_key: str | None = None,
) -> float | None:
    """Суточная доза на голову (г или МДж): Σ (кг/день/гол × г/кг). Как Excel Рацион КРС."""
    heads = max(int(heads_per_trip or 1), 1)
    total = 0.0
    any_value = False
    for line in lines:
        herd_kg = float(line.get("daily_kg") or 0)
        if herd_kg <= 0:
            continue
        kg = herd_kg / heads
        v = get_nutrient_value(
            line.get("dry_matter"),
            line.get("nutrients"),
            nutrient_keys,
            indicator_key=indicator_key,
        )
        if v is None:
            continue
        total += kg * v
        any_value = True
    return total if any_value else None


def rnb(
    crude_protein: float | None,
    usp: float | None,
) -> float | None:
    """RNB (ruminal nitrogen balance, GfE): (сырой протеин − уСП) / 6,25."""
    if crude_protein is None or usp is None:
        return None
    return (crude_protein - usp) / 6.25


def bra_rnb(crude_protein: float | None, usp: float | None) -> float | None:
    """Deprecated alias for :func:`rnb`."""
    return rnb(crude_protein, usp)


def norm_diff(
    content: float | None,
    min_val: float | None,
    max_val: float | None,
) -> float | None:
    if content is None:
        return None
    if min_val is not None and content < min_val:
        return content - min_val
    if max_val is not None and content > max_val:
        return content - max_val
    return 0.0