M8-T12: scope energy contracts

app/services/contracts.py

@@ -11,8 +11,8 @@ Design decisions
   setting its ``effective_to`` to the new version's ``effective_from``; raises
   ``ContractVersionError`` if the new date is strictly earlier than the previous
   version's ``effective_from``.
-- ``activate_contract``: mutual-exclusion; sets all other contracts' ``active``
-  to False, then sets the given contract's ``active`` to True.
+- ``activate_contract``: scope-local mutual exclusion; sets other contracts in
+  the target scope inactive, then sets the given contract active.
 - ``active_contract_version_at``: returns the single version of the currently
   active contract that covers *ts* (``effective_from ≤ ts < effective_to``,
   or open-ended when ``effective_to`` is None).
@@ -32,7 +32,7 @@ import logging
 from datetime import UTC, datetime
 from typing import Any
 
-from sqlalchemy import select
+from sqlalchemy import select, update
 from sqlalchemy.orm import Session
 
 from app.integrations.pricing.profiles import validate_values
@@ -41,6 +41,32 @@ from app.models.energy import EnergyContract, EnergyContractVersion
 logger = logging.getLogger(__name__)
 
 
+# This is deliberately separate from the pricing-profile loader. T12 needs to
+# reserve the thermal domain before T13 supplies its actual profile.
+CONTRACT_KIND_SCOPES: dict[str, str] = {
+    "manual": "electricity",
+    "tibber": "electricity",
+    "district_heating": "thermal",
+}
+
+
+class ContractScopeError(ValueError):
+    """Raised when a contract kind is unknown or its supplied scope disagrees."""
+
+
+def contract_scope_for_kind(kind: str, requested_scope: str | None = None) -> str:
+    """Return the registry-owned scope for *kind*, rejecting client mismatches."""
+    try:
+        scope = CONTRACT_KIND_SCOPES[kind]
+    except KeyError as exc:
+        raise ContractScopeError(f"Unknown energy contract kind: {kind!r}") from exc
+    if requested_scope is not None and requested_scope != scope:
+        raise ContractScopeError(
+            f"Contract kind {kind!r} belongs to scope {scope!r}, not {requested_scope!r}."
+        )
+    return scope
+
+
 # ---------------------------------------------------------------------------
 # Internal helpers
 # ---------------------------------------------------------------------------
@@ -86,10 +112,14 @@ def get_contract_or_none(session: Session, contract_id: int) -> EnergyContract |
     ).scalar_one_or_none()
 
 
-def list_contracts(session: Session) -> list[EnergyContract]:
-    """Return all contracts ordered by id (ascending)."""
+def list_contracts(session: Session, *, scope: str = "electricity") -> list[EnergyContract]:
+    """Return contracts in one scope, ordered by id (ascending)."""
     return list(
-        session.execute(select(EnergyContract).order_by(EnergyContract.id)).scalars().all()
+        session.execute(
+            select(EnergyContract)
+            .where(EnergyContract.scope == scope)
+            .order_by(EnergyContract.id)
+        ).scalars().all()
     )
 
 
@@ -117,6 +147,7 @@ def create_contract(
     name: str,
     kind: str,
     currency: str = "EUR",
+    scope: str | None = None,
     values: dict[str, Any],
     effective_from: datetime,
 ) -> EnergyContract:
@@ -150,6 +181,7 @@ def create_contract(
     ProfileValidationError
         If *values* does not conform to the profile structure.
     """
+    resolved_scope = contract_scope_for_kind(kind, scope)
     # Validate (and fill defaults) before any DB write.
     filled_values = validate_values(kind, values)
 
@@ -157,6 +189,7 @@ def create_contract(
     contract = EnergyContract(
         name=name,
         kind=kind,
+        scope=resolved_scope,
         currency=currency,
         active=False,  # New contracts are inactive; caller must explicitly activate.
         created_at=now,
@@ -262,15 +295,18 @@ def add_version(
 def activate_contract(session: Session, contract: EnergyContract) -> None:
     """Activate a contract with mutual exclusion.
 
-    Sets every other contract's ``active`` flag to False, then sets the given
-    contract's ``active`` to True.  This guarantees at most one active contract
-    at any time.
+    Sets every other contract in the same scope inactive, then sets the given
+    contract active. This guarantees at most one active contract per scope.
 
     Caller must commit after this returns.
     """
-    # Deactivate all contracts (including the target; we re-activate below).
-    for other in session.execute(select(EnergyContract)).scalars().all():
-        other.active = False
+    # This bulk update is a single write statement inside the caller's
+    # transaction. SQLite serializes writers, and another scope is never touched.
+    session.execute(
+        update(EnergyContract)
+        .where(EnergyContract.scope == contract.scope, EnergyContract.id != contract.id)
+        .values(active=False)
+    )
     contract.active = True
     contract.updated_at = datetime.now(UTC)
     logger.info("Activated contract %r (id=%d)", contract.name, contract.id)
@@ -286,7 +322,9 @@ def deactivate_contract(session: Session, contract: EnergyContract) -> None:
     logger.info("Deactivated contract %r (id=%d)", contract.name, contract.id)
 
 
-def active_contract_versions(session: Session) -> list[EnergyContractVersion]:
+def active_contract_versions(
+    session: Session, *, scope: str = "electricity"
+) -> list[EnergyContractVersion]:
     """Return all versions of the currently active contract, ordered by effective_from ascending.
 
     Returns an empty list when there is no active contract.  The list spans the
@@ -295,7 +333,9 @@ def active_contract_versions(session: Session) -> list[EnergyContractVersion]:
     cost / credit accumulation (Principle C).
     """
     active = session.execute(
-        select(EnergyContract).where(EnergyContract.active.is_(True)).limit(1)
+        select(EnergyContract)
+        .where(EnergyContract.active.is_(True), EnergyContract.scope == scope)
+        .limit(1)
     ).scalar_one_or_none()
 
     if active is None:
@@ -313,7 +353,7 @@ def active_contract_versions(session: Session) -> list[EnergyContractVersion]:
 
 
 def active_contract_version_at(
-    session: Session, ts: datetime
+    session: Session, ts: datetime, *, scope: str = "electricity"
 ) -> EnergyContractVersion | None:
     """Return the active contract's version that covers *ts*.
 
@@ -336,7 +376,9 @@ def active_contract_version_at(
     EnergyContractVersion | None
     """
     active = session.execute(
-        select(EnergyContract).where(EnergyContract.active.is_(True)).limit(1)
+        select(EnergyContract)
+        .where(EnergyContract.active.is_(True), EnergyContract.scope == scope)
+        .limit(1)
     ).scalar_one_or_none()
 
     if active is None: