# -*- coding: utf-8 -*-
"""
Corrigé Python - Bac NSI 2026 - Épreuve pratique - Sujet 19
Thème : gestion de réservoirs d'eau, dictionnaires et agrégations
"""

from __future__ import annotations


reservoirs = [
    {"nom": "Nuiavai", "capacite": 100000, "volume": 55000, "district": "Tepua"},
    {"nom": "Farepape", "capacite": 120000, "volume": 45000, "district": "Fare"},
    {"nom": "Vaipuna", "capacite": 80000, "volume": 60000, "district": "Hiva Oro"},
    {"nom": "Vaihere", "capacite": 95000, "volume": 20000, "district": "Fare"},
    {"nom": "Teanavai", "capacite": 110000, "volume": 90000, "district": "Avera"},
    {"nom": "Matavai", "capacite": 70000, "volume": 25000, "district": "Tepua"},
    {"nom": "Anaʻitea", "capacite": 85000, "volume": 30000, "district": "Hiva Oro"},
    {"nom": "Faaroa", "capacite": 60000, "volume": 40000, "district": "Avera"},
    {"nom": "Vaitiare", "capacite": 105000, "volume": 95000, "district": "Fare"},
    {"nom": "Motuavai", "capacite": 90000, "volume": 10000, "district": "Tepua"},
]


def taux_remplissage(reservoir: dict, changement: int = 0) -> float:
    volume_modifie = reservoir["volume"] + changement
    capacite = reservoir["capacite"]
    if volume_modifie < 0:
        volume_modifie = 0
    if volume_modifie > capacite:
        volume_modifie = capacite
    return volume_modifie * 100 / capacite


def est_en_penurie(reservoirs: list[dict], nom_reservoir: str) -> bool:
    """Renvoie True si le taux de remplissage du réservoir est strictement inférieur à 20 %."""
    for reservoir in reservoirs:
        if reservoir["nom"] == nom_reservoir:
            return taux_remplissage(reservoir) < 20
    return False


def volume_par_district(reservoirs: list[dict]) -> dict[str, int]:
    """Renvoie le volume total disponible par district."""
    volumes = {}
    for reservoir in reservoirs:
        district = reservoir["district"]
        if district not in volumes:
            volumes[district] = 0
        volumes[district] += reservoir["volume"]
    return volumes


def volume_moyen(reservoirs: list[dict]) -> float:
    """Renvoie le volume moyen disponible dans les réservoirs."""
    assert len(reservoirs) > 0, "La liste doit contenir au moins un réservoir."
    somme = 0
    for reservoir in reservoirs:
        somme += reservoir["volume"]
    return somme / len(reservoirs)


def liste_districts(reservoirs: list[dict]) -> list[str]:
    liste = []
    for r in reservoirs:
        if r["district"] not in liste:
            liste.append(r["district"])
    return liste


def reservoirs_par_district(reservoirs: list[dict]) -> dict[str, list[dict]]:
    dico = {}
    for r in reservoirs:
        district = r["district"]
        if district not in dico:
            dico[district] = []
        dico[district].append(r)
    return dico


def districts_vulnerables(reservoirs: list[dict]) -> list[str]:
    """Renvoie les districts dont le volume moyen est inférieur à 80 % du volume moyen global."""
    moyenne_globale = volume_moyen(reservoirs)
    limite = 0.8 * moyenne_globale
    par_district = reservoirs_par_district(reservoirs)
    vulnerables = []
    for district, liste in par_district.items():
        if volume_moyen(liste) < limite:
            vulnerables.append(district)
    return vulnerables


def tests() -> None:
    assert est_en_penurie(reservoirs, "Motuavai") is True
    assert est_en_penurie(reservoirs, "Nuiavai") is False
    volumes = volume_par_district(reservoirs)
    assert volumes["Tepua"] == 90000
    assert volume_moyen([{"volume": 10}, {"volume": 10}]) == 10
    assert volume_moyen(reservoirs) <= max(r["capacite"] for r in reservoirs)
    assert "Tepua" in districts_vulnerables(reservoirs)
    print("Tous les tests du sujet 19 sont passés.")


if __name__ == "__main__":
    tests()