from typing import Any

from app.fitness.activity_budget import workouts_kcal_total

DEFAULT_NEAT_KCAL = 200.0
NEAT_KCAL_MIN = 200.0
NEAT_KCAL_MAX = 300.0
KCAL_PER_STEP_REF = 0.04 / 86  # ~0.04 kcal/step at 86 kg
WATER_ML_PER_KG = 33  # middle of 30–35 ml/kg range

GOAL_CALORIE_ADJUST = {
    "lose": -500,
    "maintain": 0,
    "gain": 300,
}

PROTEIN_G_PER_KG = {
    "lose": 2.2,
    "maintain": 1.8,
    "gain": 1.8,
}
FAT_G_PER_KG = 1.0


def bmr_mifflin(*, sex: str, weight_kg: float, height_cm: float, age: int) -> float:
    base = 10 * weight_kg + 6.25 * height_cm - 5 * age
    if sex.lower() in ("m", "male", "м", "мужской"):
        return base + 5
    return base - 161


def neat_base_kcal(profile: dict[str, Any]) -> float:
    raw = profile.get("neat_base_kcal")
    if raw is not None:
        return max(NEAT_KCAL_MIN, min(NEAT_KCAL_MAX, float(raw)))
    return DEFAULT_NEAT_KCAL


def steps_kcal(*, steps: int, weight_kg: float) -> float:
    if steps <= 0:
        return 0.0
    return round(steps * weight_kg * KCAL_PER_STEP_REF, 1)


def bmi(weight_kg: float, height_cm: float) -> float:
    if height_cm <= 0:
        return 0.0
    h = height_cm / 100
    return weight_kg / (h * h)


def water_target_l(weight_kg: float) -> float:
    return round(weight_kg * WATER_ML_PER_KG / 1000, 1)


def macro_targets(
    calorie_target: float,
    weight_kg: float,
    goal: str = "maintain",
) -> dict[str, float]:
    protein_g = round(weight_kg * PROTEIN_G_PER_KG.get(goal, 1.8), 0)
    fat_g = round(weight_kg * FAT_G_PER_KG, 0)
    protein_cal = protein_g * 4
    fat_cal = fat_g * 9
    carbs_g = max(0, round((calorie_target - protein_cal - fat_cal) / 4, 0))
    return {"protein_g": protein_g, "fat_g": fat_g, "carbs_g": carbs_g}


def one_rep_max(weight_kg: float, reps: int) -> float:
    if reps <= 0:
        return weight_kg
    if reps == 1:
        return weight_kg
    return round(weight_kg * (1 + reps / 30), 1)


def _profile_fields(profile: dict[str, Any]) -> tuple[float, float, int, str, str]:
    weight = float(profile.get("weight_kg") or 70)
    height = float(profile.get("height_cm") or 170)
    age = int(profile.get("age") or 30)
    sex = str(profile.get("sex") or "male")
    goal = str(profile.get("goal") or "maintain")
    return weight, height, age, sex, goal


def compute_tdee(
    profile: dict[str, Any],
    *,
    steps_total: int = 0,
    workouts: list[dict[str, Any]] | None = None,
) -> dict[str, float]:
    weight, height, age, sex, _ = _profile_fields(profile)
    bmr = bmr_mifflin(sex=sex, weight_kg=weight, height_cm=height, age=age)
    neat = neat_base_kcal(profile)
    s_kcal = steps_kcal(steps=steps_total, weight_kg=weight)
    w_kcal = workouts_kcal_total(workouts or [], weight_kg=weight)
    tdee_val = bmr + neat + s_kcal + w_kcal
    return {
        "bmr": round(bmr, 0),
        "neat_kcal": round(neat, 0),
        "steps_kcal": s_kcal,
        "workout_kcal": w_kcal,
        "tdee": round(tdee_val, 0),
    }


def compute_daily_targets(
    profile: dict[str, Any],
    *,
    steps_total: int = 0,
    workouts: list[dict[str, Any]] | None = None,
) -> dict[str, Any]:
    weight, height, age, sex, goal = _profile_fields(profile)
    breakdown = compute_tdee(profile, steps_total=steps_total, workouts=workouts)
    calorie_target = round(breakdown["tdee"] + GOAL_CALORIE_ADJUST.get(goal, 0), 0)
    macros = macro_targets(calorie_target, weight, goal)
    water = water_target_l(weight)

    return {
        **breakdown,
        "calorie_target": calorie_target,
        "protein_g": macros["protein_g"],
        "fat_g": macros["fat_g"],
        "carbs_g": macros["carbs_g"],
        "water_l": water,
        "bmi": round(bmi(weight, height), 1),
        "steps": steps_total,
    }


def targets_to_api(daily: dict[str, Any]) -> dict[str, float]:
    return {
        "calories": daily["calorie_target"],
        "protein_g": daily["protein_g"],
        "fat_g": daily["fat_g"],
        "carbs_g": daily["carbs_g"],
        "water_ml": round(daily["water_l"] * 1000),
    }


def tdee_breakdown_to_api(daily: dict[str, Any]) -> dict[str, Any]:
    return {
        "bmr": daily["bmr"],
        "neat_kcal": daily["neat_kcal"],
        "steps_kcal": daily["steps_kcal"],
        "workout_kcal": daily["workout_kcal"],
        "tdee": daily["tdee"],
        "calorie_target": daily["calorie_target"],
        "steps": daily.get("steps", 0),
    }


def compute_targets(profile: dict[str, Any]) -> dict[str, Any]:
    """Rest-day targets (BMR + NEAT, no steps/workouts) for profile storage."""
    daily = compute_daily_targets(profile, steps_total=0, workouts=[])
    return {
        "bmr": daily["bmr"],
        "tdee": daily["tdee"],
        "bmi": daily["bmi"],
        "neat_kcal": daily["neat_kcal"],
        "steps_kcal": 0,
        "workout_kcal": 0,
        "calorie_target": daily["calorie_target"],
        "protein_g": daily["protein_g"],
        "fat_g": daily["fat_g"],
        "carbs_g": daily["carbs_g"],
        "water_l": daily["water_l"],
    }