feat(backend): moteur de règles de recommandations et route de génération

`recommendation` n'avait aucun écrivain : les quatre couches de lecture étaient
livrées, mais rien ne produisait de ligne. Le moteur comble ce trou.

Le catalogue `REGLES` vit dans `app/services/`, pas dans `ml/` : il lit `alert.type`,
`alert.severity`, `alert.value` et `alert.threshold`, sans modèle ni feature, et
s'appuie sur deux repositories existants. L'arbitrage avec l'ADR 0005, qui annonçait
#38 du côté ML, est tranché par l'ADR 0006.

Sept règles, cinq par type d'alerte et deux transverses (sévérité critique,
dépassement d'au moins 20 % du seuil), donc une à trois recommandations par alerte.
L'idempotence est portée par la base : `create_missing()` insère en
`ON CONFLICT DO NOTHING` sur `uq_recommendation_alert_rule`, ce qui supprime la
fenêtre entre un contrôle préalable et l'insertion. `rule_reference` devient de ce
fait une clé fonctionnelle, d'où le suffixe de version sur chaque référence.

Deux déclencheurs : `POST /api/v1/recommendations/generate` réservé `admin`, et
`python -m app.cli generate-recommendations` (cible `make recommendations`).

Limite connue : aucune source n'alimente `alert` aujourd'hui, ni détection interne
(#104) ni ingestion de l'API Mock. La route répond, le rapport reste à zéro, et la
chaîne s'allume sans retoucher le moteur le jour où les alertes existent.

Tests : 80 unitaires et API verts, plus 6 d'intégration dont l'idempotence jouée
contre PostgreSQL.

Closes #38

apps/backend/tests/api/acces.py

@@ -51,6 +51,7 @@ ROLE_MINIMUM: Final[dict[Route, Role]] = {
     ("GET", "/api/v1/alerts"): Role.LECTEUR,
     ("GET", "/api/v1/recommendations"): Role.LECTEUR,
     ("GET", "/api/v1/recommendations/{recommendation_id}"): Role.LECTEUR,
+    ("POST", "/api/v1/recommendations/generate"): Role.ADMIN,
     ("GET", "/api/v1/stats/summary"): Role.LECTEUR,
     ("GET", "/api/v1/readings"): Role.LECTEUR,
     ("GET", "/api/v1/predictions"): Role.LECTEUR,

apps/backend/tests/api/test_recommendations.py

@@ -10,7 +10,7 @@ from app.api.deps import get_current_principal, get_recommendation_service
 from app.core.principal import Principal
 from app.core.roles import AccountKind, Role
 from app.models.energy import Recommendation
-from app.services.recommendation import RecommendationNotFoundError
+from app.services.recommendation import RapportGeneration, RecommendationNotFoundError
 
 MOMENT = datetime(2024, 1, 1, tzinfo=UTC)
 
@@ -40,6 +40,7 @@ class FauxService:
     def __init__(self, erreur: Exception | None = None) -> None:
         self._erreur = erreur
         self.recommendation = recommendation()
+        self.site_demande: str | None = None
 
     async def list_all(self) -> list[Recommendation]:
         return [self.recommendation]
@@ -49,6 +50,10 @@ class FauxService:
             raise self._erreur
         return self.recommendation
 
+    async def generate(self, *, site_id: str | None = None) -> RapportGeneration:
+        self.site_demande = site_id
+        return RapportGeneration(alertes_examinees=2, recommandations_creees=3, deja_presentes=1)
+
 
 @pytest.fixture
 def lecteur_connecte(app: FastAPI) -> Iterator[None]:
@@ -142,3 +147,56 @@ async def test_get_recommendation_returns_404_when_the_session_finds_nothing(
     response = await client.get("/api/v1/recommendations/404")
 
     assert response.status_code == 404
+
+
+@pytest.fixture
+def admin_connecte(app: FastAPI) -> Iterator[None]:
+    app.dependency_overrides[get_current_principal] = lambda: principal(Role.ADMIN)
+    yield
+    app.dependency_overrides.pop(get_current_principal, None)
+
+
+@pytest.fixture
+def servi_en_admin(app: FastAPI, admin_connecte: None) -> Iterator[Callable[[], FauxService]]:
+    def installe() -> FauxService:
+        service = FauxService()
+        app.dependency_overrides[get_recommendation_service] = lambda: service
+        return service
+
+    yield installe
+    app.dependency_overrides.pop(get_recommendation_service, None)
+
+
+async def test_generate_recommendations_returns_the_generation_report(
+    servi_en_admin: Callable[[], FauxService], client: AsyncClient
+) -> None:
+    servi_en_admin()
+
+    response = await client.post("/api/v1/recommendations/generate")
+
+    assert response.status_code == 200
+    assert response.json() == {
+        "alerts_examined": 2,
+        "recommendations_created": 3,
+        "already_present": 1,
+    }
+
+
+async def test_generate_recommendations_forwards_the_requested_site(
+    servi_en_admin: Callable[[], FauxService], client: AsyncClient
+) -> None:
+    service = servi_en_admin()
+
+    await client.post("/api/v1/recommendations/generate", params={"site_id": "SITE002"})
+
+    assert service.site_demande == "SITE002"
+
+
+async def test_generate_recommendations_refuses_a_reader(
+    servi: Callable[..., FauxService], client: AsyncClient
+) -> None:
+    servi()
+
+    response = await client.post("/api/v1/recommendations/generate")
+
+    assert response.status_code == 403

apps/backend/tests/repositories/test_recommendation.py

@@ -5,7 +5,7 @@ import pytest
 from sqlalchemy.ext.asyncio import AsyncSession
 
 from app.models.energy import Alert, Recommendation, Site
-from app.repositories.recommendation import RecommendationRepository
+from app.repositories.recommendation import NouvelleRecommandation, RecommendationRepository
 
 pytestmark = pytest.mark.integration
 
@@ -83,3 +83,43 @@ async def test_list_all_returns_the_recommendations_sorted_by_identifier(
     await session.rollback()
 
     assert identifiants == sorted(identifiants)
+
+
+def nouvelle(alert_id: int, reference: str = "spike-delestage-v1") -> NouvelleRecommandation:
+    return NouvelleRecommandation(
+        alert_id=alert_id,
+        action="Délester les équipements non prioritaires",
+        explanation="Pic de consommation signalé.",
+        rule_reference=reference,
+    )
+
+
+async def test_create_missing_inserts_the_proposals(session: AsyncSession) -> None:
+    depot = RecommendationRepository(session)
+    alert_id = await creer_alerte(session)
+
+    creees = await depot.create_missing(
+        [nouvelle(alert_id), nouvelle(alert_id, "escalade-astreinte-v1")]
+    )
+    await session.rollback()
+
+    assert creees == 2
+
+
+async def test_create_missing_ignores_a_rule_already_held_for_the_alert(
+    session: AsyncSession,
+) -> None:
+    depot = RecommendationRepository(session)
+    alert_id = await creer_alerte(session)
+    await depot.create_missing([nouvelle(alert_id)])
+
+    creees = await depot.create_missing([nouvelle(alert_id)])
+    await session.rollback()
+
+    assert creees == 0
+
+
+async def test_create_missing_returns_zero_without_any_proposal(session: AsyncSession) -> None:
+    creees = await RecommendationRepository(session).create_missing([])
+
+    assert creees == 0

apps/backend/tests/services/test_recommendation.py

@@ -1,10 +1,14 @@
+from collections.abc import Sequence
 from datetime import UTC, datetime
 
 import pytest
 
-from app.models.energy import Recommendation
+from app.models.energy import Alert, Recommendation
+from app.repositories.recommendation import NouvelleRecommandation
 from app.services.recommendation import RecommendationNotFoundError, RecommendationService
 
+MOMENT = datetime(2024, 1, 1, tzinfo=UTC)
+
 
 def recommendation(recommendation_id: int = 1) -> Recommendation:
     return Recommendation(
@@ -13,13 +17,33 @@ def recommendation(recommendation_id: int = 1) -> Recommendation:
         action="Vérifier la consommation",
         explanation="Pic détecté",
         rule_reference="spike-v1",
-        created_at=datetime(2024, 1, 1, tzinfo=UTC),
+        created_at=MOMENT,
+    )
+
+
+def alerte(alert_id: int = 1, site_id: str = "SITE001", severity: str = "high") -> Alert:
+    return Alert(
+        alert_id=alert_id,
+        source_alert_id=f"ALR-{alert_id}",
+        site_id=site_id,
+        source="api_mock",
+        timestamp=MOMENT,
+        type="spike",
+        severity=severity,
+        message="Pic de consommation",
+        value=None,
+        threshold=None,
+        metric=None,
+        prediction_id=None,
+        raw_data={},
     )
 
 
 class FakeRepository:
-    def __init__(self, recommendations: list[Recommendation]) -> None:
+    def __init__(self, recommendations: list[Recommendation], creees: int | None = None) -> None:
         self._recommendations = recommendations
+        self._creees = creees
+        self.recues: list[NouvelleRecommandation] = []
 
     async def list_all(self) -> list[Recommendation]:
         return self._recommendations
@@ -29,27 +53,111 @@ class FakeRepository:
             (r for r in self._recommendations if r.recommendation_id == recommendation_id), None
         )
 
+    async def create_missing(self, nouvelles: Sequence[NouvelleRecommandation]) -> int:
+        self.recues = list(nouvelles)
+        return len(self.recues) if self._creees is None else self._creees
 
-async def test_list_all_returns_the_repository_recommendations() -> None:
-    service = RecommendationService(
-        recommendations=FakeRepository([recommendation(1), recommendation(2)])
+
+class FakeAlertRepository:
+    def __init__(self, alertes: list[Alert]) -> None:
+        self._alertes = alertes
+        self.site_demande: str | None = None
+
+    async def list_all(
+        self, *, site_id: str | None = None, severity: str | None = None
+    ) -> list[Alert]:
+        self.site_demande = site_id
+        if site_id is None:
+            return self._alertes
+        return [a for a in self._alertes if a.site_id == site_id]
+
+
+class FakeTransaction:
+    def __init__(self) -> None:
+        self.commits = 0
+
+    async def commit(self) -> None:
+        self.commits += 1
+
+
+def service(
+    recommendations: FakeRepository | None = None,
+    alerts: FakeAlertRepository | None = None,
+    transaction: FakeTransaction | None = None,
+) -> RecommendationService:
+    return RecommendationService(
+        recommendations=recommendations or FakeRepository([]),
+        alerts=alerts or FakeAlertRepository([]),
+        transaction=transaction or FakeTransaction(),
     )
 
-    recommendations = await service.list_all()
+
+async def test_list_all_returns_the_repository_recommendations() -> None:
+    depot = FakeRepository([recommendation(1), recommendation(2)])
+
+    recommendations = await service(recommendations=depot).list_all()
 
     assert [r.recommendation_id for r in recommendations] == [1, 2]
 
 
 async def test_get_by_id_returns_the_matching_recommendation() -> None:
-    service = RecommendationService(recommendations=FakeRepository([recommendation(1)]))
-
-    trouve = await service.get_by_id(1)
+    trouve = await service(recommendations=FakeRepository([recommendation(1)])).get_by_id(1)
 
     assert trouve.recommendation_id == 1
 
 
 async def test_get_by_id_raises_when_the_recommendation_is_unknown() -> None:
-    service = RecommendationService(recommendations=FakeRepository([]))
-
     with pytest.raises(RecommendationNotFoundError):
-        await service.get_by_id(404)
+        await service().get_by_id(404)
+
+
+async def test_generate_persists_one_proposal_per_triggered_rule() -> None:
+    depot = FakeRepository([])
+
+    rapport = await service(
+        recommendations=depot, alerts=FakeAlertRepository([alerte(severity="critical")])
+    ).generate()
+
+    assert {n.rule_reference for n in depot.recues} == {
+        "spike-delestage-v1",
+        "escalade-astreinte-v1",
+    }
+    assert rapport.recommandations_creees == 2
+
+
+async def test_generate_commits_once() -> None:
+    transaction = FakeTransaction()
+
+    await service(alerts=FakeAlertRepository([alerte()]), transaction=transaction).generate()
+
+    assert transaction.commits == 1
+
+
+async def test_generate_restricts_the_alerts_to_the_requested_site() -> None:
+    alertes = FakeAlertRepository([alerte(1, site_id="SITE001"), alerte(2, site_id="SITE002")])
+    depot = FakeRepository([])
+
+    rapport = await service(recommendations=depot, alerts=alertes).generate(site_id="SITE002")
+
+    assert alertes.site_demande == "SITE002"
+    assert rapport.alertes_examinees == 1
+    assert {n.alert_id for n in depot.recues} == {2}
+
+
+async def test_generate_reports_nothing_when_no_alert_matches() -> None:
+    rapport = await service().generate()
+
+    assert rapport.alertes_examinees == 0
+    assert rapport.recommandations_creees == 0
+    assert rapport.deja_presentes == 0
+
+
+async def test_generate_counts_the_proposals_the_database_already_held() -> None:
+    depot = FakeRepository([], creees=0)
+
+    rapport = await service(
+        recommendations=depot, alerts=FakeAlertRepository([alerte()])
+    ).generate()
+
+    assert rapport.recommandations_creees == 0
+    assert rapport.deja_presentes == 1

apps/backend/tests/services/test_recommendation_rules.py

@@ -0,0 +1,142 @@
+from datetime import UTC, datetime
+
+import pytest
+
+from app.models.energy import Alert
+from app.services.recommendation_rules import FACTEUR_DEPASSEMENT_MAJEUR, applique_les_regles
+
+MOMENT = datetime(2024, 1, 1, tzinfo=UTC)
+
+
+def alerte(
+    *,
+    alert_id: int = 1,
+    type_alerte: str = "spike",
+    severity: str = "high",
+    value: float | None = None,
+    threshold: float | None = None,
+    metric: str | None = None,
+    site_id: str = "SITE001",
+) -> Alert:
+    return Alert(
+        alert_id=alert_id,
+        source_alert_id=f"ALR-{alert_id}",
+        site_id=site_id,
+        source="api_mock",
+        timestamp=MOMENT,
+        type=type_alerte,
+        severity=severity,
+        message="Alerte de test",
+        value=value,
+        threshold=threshold,
+        metric=metric,
+        prediction_id=None,
+        raw_data={},
+    )
+
+
+@pytest.mark.parametrize(
+    ("type_alerte", "attendue"),
+    [
+        ("spike", "spike-delestage-v1"),
+        ("threshold", "threshold-reduction-v1"),
+        ("outage", "outage-secours-v1"),
+        ("sensor", "sensor-maintenance-v1"),
+        ("anomaly", "anomaly-verification-v1"),
+    ],
+    ids=["pic", "seuil", "coupure", "capteur", "anomalie"],
+)
+def test_each_alert_type_yields_its_own_rule(type_alerte: str, attendue: str) -> None:
+    proposees = applique_les_regles(alerte(type_alerte=type_alerte))
+
+    assert [p.rule_reference for p in proposees] == [attendue]
+
+
+def test_a_critical_alert_adds_the_escalation_rule() -> None:
+    proposees = applique_les_regles(alerte(severity="critical"))
+
+    assert "escalade-astreinte-v1" in {p.rule_reference for p in proposees}
+
+
+@pytest.mark.parametrize("severity", ["low", "medium", "high"], ids=["faible", "moyenne", "haute"])
+def test_a_non_critical_alert_does_not_escalate(severity: str) -> None:
+    proposees = applique_les_regles(alerte(severity=severity))
+
+    assert "escalade-astreinte-v1" not in {p.rule_reference for p in proposees}
+
+
+def test_a_large_overshoot_adds_the_contract_rule() -> None:
+    proposees = applique_les_regles(
+        alerte(value=720.0 * FACTEUR_DEPASSEMENT_MAJEUR, threshold=720.0)
+    )
+
+    assert "contrat-puissance-v1" in {p.rule_reference for p in proposees}
+
+
+def test_an_overshoot_below_the_factor_does_not_add_the_contract_rule() -> None:
+    proposees = applique_les_regles(alerte(value=800.0, threshold=720.0))
+
+    assert "contrat-puissance-v1" not in {p.rule_reference for p in proposees}
+
+
+@pytest.mark.parametrize(
+    ("value", "threshold"),
+    [(None, 720.0), (900.0, None), (900.0, 0.0), (900.0, -10.0)],
+    ids=["sans mesure", "sans seuil", "seuil nul", "seuil negatif"],
+)
+def test_the_contract_rule_stays_silent_without_an_exploitable_threshold(
+    value: float | None, threshold: float | None
+) -> None:
+    proposees = applique_les_regles(alerte(value=value, threshold=threshold))
+
+    assert "contrat-puissance-v1" not in {p.rule_reference for p in proposees}
+
+
+def test_the_explanation_quotes_the_measure_and_the_threshold() -> None:
+    proposees = applique_les_regles(alerte(value=812.5, threshold=720.0, metric="consumption_kw"))
+
+    assert "(consumption_kw mesurée à 812.5, seuil 720.0)" in proposees[0].explanation
+
+
+def test_the_explanation_quotes_the_measure_alone_when_no_threshold_is_known() -> None:
+    proposees = applique_les_regles(alerte(value=812.5, metric="consumption_kw"))
+
+    assert "(consumption_kw mesurée à 812.5)" in proposees[0].explanation
+
+
+def test_the_explanation_omits_the_measure_when_the_alert_carries_none() -> None:
+    proposees = applique_les_regles(alerte())
+
+    assert "(" not in proposees[0].explanation
+
+
+def test_the_explanation_names_the_site() -> None:
+    proposees = applique_les_regles(alerte(site_id="SITE042"))
+
+    assert "SITE042" in proposees[0].explanation
+
+
+def test_every_proposal_carries_the_alert_identifier() -> None:
+    proposees = applique_les_regles(alerte(alert_id=77, severity="critical"))
+
+    assert {p.alert_id for p in proposees} == {77}
+
+
+def test_an_alert_never_yields_the_same_rule_twice() -> None:
+    proposees = applique_les_regles(
+        alerte(severity="critical", value=900.0, threshold=720.0, metric="consumption_kw")
+    )
+
+    assert len(proposees) == len({p.rule_reference for p in proposees})
+
+
+def test_a_critical_alert_over_the_threshold_yields_the_three_rules() -> None:
+    proposees = applique_les_regles(
+        alerte(severity="critical", value=900.0, threshold=720.0, metric="consumption_kw")
+    )
+
+    assert {p.rule_reference for p in proposees} == {
+        "spike-delestage-v1",
+        "escalade-astreinte-v1",
+        "contrat-puissance-v1",
+    }

apps/backend/tests/test_cli.py

@@ -118,3 +118,30 @@ def test_main_exports_the_contract_without_asking_for_a_password(
     assert code == 0
     assert destination.exists()
     assert str(destination) in capsys.readouterr().out
+
+
+def test_build_parser_reads_the_generate_recommendations_arguments() -> None:
+    arguments = cli.build_parser().parse_args(["generate-recommendations", "--site-id", "SITE002"])
+
+    assert arguments.commande == "generate-recommendations"
+    assert arguments.site_id == "SITE002"
+
+
+def test_build_parser_defaults_the_generation_to_every_site() -> None:
+    arguments = cli.build_parser().parse_args(["generate-recommendations"])
+
+    assert arguments.site_id is None
+
+
+def test_main_generates_the_recommendations_without_asking_for_a_password(
+    monkeypatch: pytest.MonkeyPatch, capsys: pytest.CaptureFixture[str]
+) -> None:
+    async def fausse_generation(*, site_id: str | None) -> str:
+        return f"génération lancée pour {site_id}"
+
+    monkeypatch.setattr(cli, "generate_recommendations", fausse_generation)
+
+    code = cli.main(["generate-recommendations", "--site-id", "SITE002"])
+
+    assert code == 0
+    assert "SITE002" in capsys.readouterr().out