PIN a 4 cifre: migrazione 017, login-pin, pin-users, PUT pin, capoturno via PIN (#59)

Co-Authored-By: Claude Sonnet 5.5 <noreply@anthropic.com>

src/backend/services/auth_service.py

@@ -54,7 +54,79 @@ async def authenticate_user(
     return user
 
 
-async def authorise_supervisor(db: AsyncSession, username: str, password: str) -> User:
+# #59: PIN a 4 cifre. Hash identico alle password (bcrypt); 5 errori -> blocco 15 minuti.
+PIN_MAX_FAILURES = 5
+PIN_LOCK_MINUTES = 15
+
+
+async def set_user_pin(db: AsyncSession, user: User, pin: str | None) -> None:
+    """Imposta o toglie (None) il PIN; azzera contatore e blocco. Admin esclusi (#59)."""
+    if pin is not None and user.is_admin:
+        raise HTTPException(
+            status_code=status.HTTP_422_UNPROCESSABLE_ENTITY,
+            detail="Admin users cannot have a PIN",
+        )
+    user.pin_hash = hash_password(pin) if pin is not None else None
+    user.pin_failed_count = 0
+    user.pin_locked_until = None
+    await db.flush()
+
+
+async def authenticate_pin(db: AsyncSession, user_id: int, pin: str) -> User:
+    """Verifica user_id+PIN con blocco dopo 5 errori consecutivi (#59).
+
+    401 PIN errato (o utente non idoneo: stessa risposta, niente enumerazione),
+    423 utente bloccato. Il contatore va committato prima di sollevare: get_db fa
+    rollback su eccezione e l'errore andrebbe perso.
+    """
+    result = await db.execute(
+        select(User).where(User.id == user_id, User.active == True)  # noqa: E712
+    )
+    user = result.scalar_one_or_none()
+    if user is None or user.is_admin or user.pin_hash is None:
+        verify_password(pin, _DUMMY_PASSWORD_HASH)  # stesso costo di un PIN errato
+        raise HTTPException(
+            status_code=status.HTTP_401_UNAUTHORIZED, detail="Invalid PIN"
+        )
+    now = utcnow()
+    if user.pin_locked_until is not None:
+        if user.pin_locked_until > now:
+            raise HTTPException(
+                status_code=status.HTTP_423_LOCKED,
+                detail="PIN locked until "
+                + user.pin_locked_until.strftime("%Y-%m-%d %H:%M:%S")
+                + " UTC",
+            )
+        # blocco scaduto: si riparte da zero
+        user.pin_locked_until = None
+        user.pin_failed_count = 0
+    if verify_password(pin, user.pin_hash):
+        if user.pin_failed_count:
+            user.pin_failed_count = 0
+            await db.flush()
+        return user
+    user.pin_failed_count += 1
+    locked = user.pin_failed_count >= PIN_MAX_FAILURES
+    if locked:
+        user.pin_locked_until = now + timedelta(minutes=PIN_LOCK_MINUTES)
+    await db.commit()
+    if locked:
+        raise HTTPException(
+            status_code=status.HTTP_423_LOCKED,
+            detail="PIN locked until "
+            + user.pin_locked_until.strftime("%Y-%m-%d %H:%M:%S")
+            + " UTC",
+        )
+    raise HTTPException(status_code=status.HTTP_401_UNAUTHORIZED, detail="Invalid PIN")
+
+
+async def authorise_supervisor(
+    db: AsyncSession,
+    username: str | None = None,
+    password: str | None = None,
+    user_id: int | None = None,
+    pin: str | None = None,
+) -> User:
     """Check the credentials of the supervisor authorising something.
 
     Used wherever the shop floor needs a capoturno: a line stop, a closure, an
@@ -65,7 +137,16 @@ async def authorise_supervisor(db: AsyncSession, username: str, password: str) -
     Uses authenticate_user rather than a full login: logging in would issue a
     needless API key for the supervisor.
     """
-    supervisor = await authenticate_user(db, username, password)
+    if user_id is not None and pin is not None:
+        # #59: via PIN, stesso blocco del login con PIN (401/423 sollevati da li')
+        supervisor = await authenticate_pin(db, user_id, pin)
+    elif username is not None and password is not None:
+        supervisor = await authenticate_user(db, username, password)
+    else:
+        raise HTTPException(
+            status_code=status.HTTP_422_UNPROCESSABLE_ENTITY,
+            detail="Supervisor credentials required",
+        )
     if supervisor is None:
         raise HTTPException(
             status_code=status.HTTP_401_UNAUTHORIZED,