M4-T05: add TOTP service and setup/enable/disable/status API

app/api/routes/api/session.py

@@ -14,6 +14,12 @@ from app.schemas.session import (
     SessionResponse,
     SessionUser,
 )
+from app.schemas.totp import (
+    TotpDisableRequest,
+    TotpEnableRequest,
+    TotpSetupResponse,
+    TotpStatusResponse,
+)
 from app.services.auth import (
     AuthPasswordChangeError,
     AuthenticatedSession,
@@ -23,6 +29,7 @@ from app.services.auth import (
     revoke_session,
 )
 from app.services import login_throttle
+from app.services import totp as totp_service
 
 logger = logging.getLogger(__name__)
 
@@ -179,3 +186,109 @@ def post_change_password(
 
     logger.info("Password updated for user '%s'", auth.user.username)
     return Response(status_code=status.HTTP_204_NO_CONTENT)
+
+
+# ---------------------------------------------------------------------------
+# TOTP endpoints (M4-T05)
+# ---------------------------------------------------------------------------
+
+
+@router.post("/auth/totp/setup", response_model=TotpSetupResponse)
+def post_totp_setup(
+    db: Session = Depends(get_db),
+    settings: Settings = Depends(get_app_settings),
+    auth: AuthenticatedSession = Depends(require_session),
+    _csrf: None = Depends(require_csrf),
+) -> TotpSetupResponse:
+    """
+    Generate a new pending TOTP secret, otpauth URI, and one-time recovery codes.
+
+    The secret is stored in the DB but TOTP is NOT yet enabled (totp_enabled stays
+    False until the user confirms with POST /api/auth/totp/enable).
+
+    Recovery codes are returned here as plaintext exactly once; their Argon2 hashes
+    are persisted immediately so enable only needs to flip the enabled flag.
+
+    Repeating this call replaces any prior pending secret and regenerates codes.
+
+    Requires: session cookie + X-CSRF-Token.
+    """
+    secret, otpauth_uri, recovery_codes = totp_service.setup(
+        db,
+        user=auth.user,
+        issuer=settings.effective_totp_issuer,
+    )
+    return TotpSetupResponse(
+        secret=secret,
+        otpauth_uri=otpauth_uri,
+        recovery_codes=recovery_codes,
+    )
+
+
+@router.post("/auth/totp/enable", status_code=status.HTTP_204_NO_CONTENT)
+def post_totp_enable(
+    body: TotpEnableRequest,
+    db: Session = Depends(get_db),
+    auth: AuthenticatedSession = Depends(require_session),
+    _csrf: None = Depends(require_csrf),
+) -> Response:
+    """
+    Enable TOTP by confirming with the current 6-digit code from the authenticator app.
+
+    Requires a prior call to POST /api/auth/totp/setup (so that a pending secret
+    exists).  On success, totp_enabled becomes True.
+
+    Returns 400 if the code is wrong or there is no pending secret.
+    Requires: session cookie + X-CSRF-Token.
+    """
+    ok = totp_service.enable(db, user=auth.user, code=body.code)
+    if not ok:
+        raise HTTPException(
+            status_code=status.HTTP_400_BAD_REQUEST,
+            detail="invalid TOTP code or no pending setup",
+        )
+    return Response(status_code=status.HTTP_204_NO_CONTENT)
+
+
+@router.post("/auth/totp/disable", status_code=status.HTTP_204_NO_CONTENT)
+def post_totp_disable(
+    body: TotpDisableRequest,
+    db: Session = Depends(get_db),
+    auth: AuthenticatedSession = Depends(require_session),
+    _csrf: None = Depends(require_csrf),
+) -> Response:
+    """
+    Disable TOTP.  The caller must provide exactly one of:
+    - ``password``: the user's current login password, OR
+    - ``code``: the current 6-digit TOTP code.
+
+    On success: totp_enabled=False, totp_secret cleared, all recovery codes deleted.
+    Returns 400 if neither credential matches or neither is provided.
+    Requires: session cookie + X-CSRF-Token.
+    """
+    ok = totp_service.disable(
+        db,
+        user=auth.user,
+        password=body.password,
+        code=body.code,
+    )
+    if not ok:
+        raise HTTPException(
+            status_code=status.HTTP_400_BAD_REQUEST,
+            detail="invalid credential; provide a valid password or TOTP code",
+        )
+    return Response(status_code=status.HTTP_204_NO_CONTENT)
+
+
+@router.get("/auth/totp", response_model=TotpStatusResponse)
+def get_totp_status(
+    auth: AuthenticatedSession = Depends(require_session),
+) -> TotpStatusResponse:
+    """
+    Return the current TOTP status for the authenticated user.
+
+    Response contains only ``{"enabled": bool}``.
+    Secret and recovery codes are NEVER returned here.
+    Requires: session cookie only (no CSRF — read-only).
+    """
+    return TotpStatusResponse(enabled=auth.user.totp_enabled)