M7-T05: add meter CRUD API + retroactive recompute + OpenAPI regen

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2026-06-25 17:01:54 +02:00
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"""Meter CRUD, swap declaration, and retroactive recompute API (M7-T05).
All endpoints are under /api/energy/meters, require an authenticated session,
and write endpoints (POST/PATCH) additionally require a non-empty X-CSRF-Token
header.
Route semantics
---------------
GET /api/energy/meters — list all meter epochs (ascending started_at)
POST /api/energy/meters — declare a meter swap / initial meter epoch
PATCH /api/energy/meters/{id} — edit label / note, or correct started_at (retroactive)
Retroactive recompute
---------------------
Whenever a write operation changes a meter's ``started_at`` (new declaration
or PATCH correction), the affected billing window is re-judged via
``recompute_range``:
- **POST** (new meter, possibly retroactive):
window = [new_meter.started_at, now)
Rationale: the new meter's ``started_at`` closes the previous meter at that
point; all periods from that boundary forward may have a different meter
attribution. Using ``now`` as the upper bound is safe because
``recompute_range`` only processes closed quarters and the operation is
idempotent.
- **PATCH started_at** (retroactive correction):
window = [min(old_started_at, new_started_at), now)
Rationale: shifting the boundary in either direction affects all periods
between the old and new boundary (and potentially beyond if re-attribution
cascades). Using the minimum of the two timestamps guarantees the entire
affected range is covered; using ``now`` as the upper bound is safe and
idempotent.
``started_at`` localisation (Principle A, FU10 convention)
----------------------------------------------------------
If the client sends a timezone-naive ``started_at`` value, it is interpreted as
the **server's local wall-clock time** and converted to UTC before storage.
Timezone-aware values are converted to UTC as-is. This is identical to the
``_localize_effective_from`` convention used in ``energy_contracts.py``.
"""
from __future__ import annotations
import logging
from datetime import UTC, datetime
from typing import Optional
from fastapi import APIRouter, Depends, HTTPException, status
from sqlalchemy.orm import Session
from app.api.routes.api.deps import require_csrf, require_session
from app.dependencies import get_db
from app.models.energy import Meter
from app.schemas.meter import (
MeterDeclareRequest,
MeterListResponse,
MeterPatchRequest,
MeterResponse,
)
from app.services import timezone as _tz_mod
from app.services.auth import AuthenticatedSession
from app.services.energy_cost import recompute_range
from app.services.meters import (
MeterIntervalError,
MeterOverlapError,
declare_meter,
list_meters,
update_meter,
)
logger = logging.getLogger(__name__)
router = APIRouter(prefix="/api/energy", tags=["api-energy-meters"])
# ---------------------------------------------------------------------------
# Helpers
# ---------------------------------------------------------------------------
def _get_meter_or_404(db: Session, meter_id: int) -> Meter:
"""Return the meter with the given id or raise 404."""
meter: Optional[Meter] = db.get(Meter, meter_id)
if meter is None:
raise HTTPException(
status_code=status.HTTP_404_NOT_FOUND,
detail=f"Meter {meter_id!r} not found.",
)
return meter
def _localize_started_at(dt: datetime) -> datetime:
"""Resolve *dt* to an aware UTC datetime for storage.
Follows the same Principle-A convention as ``_localize_effective_from``
in ``energy_contracts.py`` (FU10):
- Timezone-aware → convert to UTC as-is.
- Timezone-naive → interpret as server local wall-clock time, localize
with ``local_tz()``, then convert to UTC.
A front-end sending ``"2026-06-25T00:00:00"`` (no Z) has it interpreted
as local midnight (e.g. CEST = UTC+2 → stored as 2026-06-24T22:00:00Z),
not as UTC midnight.
"""
if dt.tzinfo is not None:
return dt.astimezone(UTC)
tz = _tz_mod.local_tz()
local_dt = dt.replace(tzinfo=tz)
return local_dt.astimezone(UTC)
def _trigger_recompute(db: Session, start: datetime, label: str) -> int:
"""Trigger recompute_range from *start* to now (UTC).
This is the standard "retroactive window" call: everything from the
affected boundary up to the current moment needs re-attribution.
Using ``now`` as the upper bound is safe because ``recompute_range``
only touches closed quarter-hour periods and the operation is idempotent.
"""
end = datetime.now(UTC)
if start >= end:
# started_at is in the future — nothing to recompute.
logger.info("%s: started_at (%s) is in the future, skipping recompute.", label, start)
return 0
n = recompute_range(db, start, end)
logger.info(
"%s: recomputed %d period(s) in window [%s, %s).",
label,
n,
start.isoformat(),
end.isoformat(),
)
return n
# ---------------------------------------------------------------------------
# GET /api/energy/meters
# ---------------------------------------------------------------------------
@router.get("/meters", response_model=MeterListResponse)
def list_energy_meters(
db: Session = Depends(get_db),
_auth: AuthenticatedSession = Depends(require_session),
) -> MeterListResponse:
"""List all meter epochs in ascending ``started_at`` order.
Returns the full historical sequence of meter installations across all
commodities. The active meter (``ended_at=null``) appears last because it
has the latest ``started_at``.
"""
meters = list_meters(db)
items = [MeterResponse.model_validate(m) for m in meters]
return MeterListResponse(items=items, total=len(items))
# ---------------------------------------------------------------------------
# POST /api/energy/meters
# ---------------------------------------------------------------------------
@router.post(
"/meters",
response_model=MeterResponse,
status_code=status.HTTP_201_CREATED,
)
def declare_energy_meter(
body: MeterDeclareRequest,
db: Session = Depends(get_db),
_auth: AuthenticatedSession = Depends(require_session),
_csrf: None = Depends(require_csrf),
) -> MeterResponse:
"""Declare a new meter epoch (swap, home move, or initial declaration).
Closes the current active meter for the given commodity at ``started_at``
and opens a new active meter. If no active meter exists, the new meter is
simply created without closing anything.
**Validation**: ``started_at`` must be **≥** the current active meter's
own ``started_at`` (no chronological backdate below the active epoch's
start). Equal timestamps are allowed (replaces the current meter at the
same logical moment). Violation → 422.
**Retroactive recompute**: if ``started_at`` is in the past, billing
records from that point forward are re-judged via ``recompute_range`` to
reflect the new meter attribution. The response includes the count of
recomputed periods in ``recomputed_periods`` (not part of ``MeterResponse``
— the recompute is transparent; callers should re-fetch costs if needed).
"""
started_at_utc = _localize_started_at(body.started_at)
try:
new_meter = declare_meter(
db,
label=body.label,
started_at=started_at_utc,
reason=body.reason.value,
commodity=body.commodity,
note=body.note,
)
except MeterOverlapError as exc:
raise HTTPException(
status_code=status.HTTP_422_UNPROCESSABLE_ENTITY,
detail=str(exc),
)
db.flush() # assign PK before recompute (recompute uses session, needs meter in DB)
# Retroactive recompute: re-judge attribution from the new boundary onward.
now = datetime.now(UTC)
if started_at_utc < now:
_trigger_recompute(db, started_at_utc, "POST /api/energy/meters")
db.commit()
db.refresh(new_meter)
logger.info(
"POST /api/energy/meters: declared %r meter id=%d label=%r started_at=%s",
body.commodity,
new_meter.id,
new_meter.label,
started_at_utc.isoformat(),
)
return MeterResponse.model_validate(new_meter)
# ---------------------------------------------------------------------------
# PATCH /api/energy/meters/{id}
# ---------------------------------------------------------------------------
@router.patch("/meters/{meter_id}", response_model=MeterResponse)
def patch_energy_meter(
meter_id: int,
body: MeterPatchRequest,
db: Session = Depends(get_db),
_auth: AuthenticatedSession = Depends(require_session),
_csrf: None = Depends(require_csrf),
) -> MeterResponse:
"""Partially update a meter epoch: rename, edit note, or correct started_at.
- ``label``: updates the human-readable label.
- ``note``: updates the free-form note.
- ``started_at``: **retroactive correction** — shifts this meter's start
boundary. The service layer maintains timeline continuity by also
updating the preceding meter's ``ended_at``. Validation:
* Must be strictly after the previous meter's own ``started_at``.
* Must be strictly before this meter's ``ended_at`` (if closed).
Violation → 422.
**Retroactive recompute when ``started_at`` changes**: billing records in
the window ``[min(old, new), now)`` are re-judged to reflect the corrected
meter attribution.
Not found → 404.
"""
meter = _get_meter_or_404(db, meter_id)
# Capture old started_at before mutation (needed for recompute window).
old_started_at: Optional[datetime] = meter.started_at
# Localise started_at if provided.
new_started_at_utc: Optional[datetime] = None
if body.started_at is not None:
new_started_at_utc = _localize_started_at(body.started_at)
try:
update_meter(
db,
meter,
label=body.label,
note=body.note,
started_at=new_started_at_utc,
)
except MeterIntervalError as exc:
raise HTTPException(
status_code=status.HTTP_422_UNPROCESSABLE_ENTITY,
detail=str(exc),
)
# Retroactive recompute if started_at was changed.
if new_started_at_utc is not None and old_started_at is not None:
# Normalise old_started_at to UTC-aware for comparison.
if old_started_at.tzinfo is None:
old_started_at = old_started_at.replace(tzinfo=UTC)
# Window = [min(old, new), now) — covers all periods whose attribution
# may have changed due to the boundary shift in either direction.
window_start = min(old_started_at, new_started_at_utc)
_trigger_recompute(db, window_start, f"PATCH /api/energy/meters/{meter_id}")
db.commit()
db.refresh(meter)
logger.info(
"PATCH /api/energy/meters/%d: updated meter label=%r started_at=%s",
meter_id,
meter.label,
meter.started_at,
)
return MeterResponse.model_validate(meter)