M7-T04: anchor cumulative cost entities to active meter start (per-meter reset)

app/integrations/expose.py

@@ -549,53 +549,57 @@ def _energy_cost_provider(session: Session) -> list[ExposableEntity]:
     def _make_import_cost_getter() -> Callable[["Session"], Any]:
         """Return a getter for the cumulative import cost plus prorated standing charges.
 
-        Principle B/D: delegates entirely to ``summarize(sess, anchor_utc, now_utc)``,
+        D2 (M7): anchor = current active electricity meter's ``started_at``.
-        where ``anchor_utc`` is the **max** of:
+        After a meter swap the cumulative resets to zero for the new meter —
-          - the earliest version's effective_from (contract billing start), and
+        old-meter periods have ``period_start < new_meter.started_at`` and fall
-          - the earliest non-degraded EnergyCostPeriod.period_start (recording start).
+        outside the [anchor, now) window, so they are naturally excluded.
+        Cross-meter boundary periods are already degraded and also excluded.
 
-        This prevents counting fixed costs for the period before any data was recorded
+        No active electricity meter → returns None (cannot anchor; safer than
-        (e.g. contract starts Jan 1 but data recording only starts Jun 17 — we do not
+        returning a stale or wrong value).  The check is done via an inline
-        want to include ~€270 of standing charges for a period with no meter data).
+        query (``ended_at IS NULL``) rather than ``meter_at(now)`` to be robust
+        against the edge case where the active meter's ``started_at`` is in the
+        future (``meter_at(now)`` would return None in that scenario).
+
+        No non-degraded periods at all → returns None (has_data guard).
+
+        No active contract → ``summarize`` still runs but fixed_costs = 0;
+        the return value is the pure metered sum within the current meter window.
+        This is consistent with D2: the anchor is the meter, not the contract.
 
             value = summarize(anchor → now).metered_import + summarize(anchor → now).fixed_costs
-
-        Returns None when no non-degraded period exists.
-        No arithmetic is done here — all fixed-cost/credit accounting lives in summarize().
         """
         def _getter(sess: "Session") -> Any:
             from datetime import UTC, datetime as _dt
-            from app.services.contracts import active_contract_versions
+            from app.models.energy import EnergyCostPeriod as _ECP, Meter as _Meter
-            from app.services.contracts import _as_utc as _cu
             from app.services.energy_cost import summarize as _summarize
-            from app.models.energy import EnergyCostPeriod as _ECP
+            from sqlalchemy import func as _func, select as _select
-            from sqlalchemy import func as _func
 
-            # Quick check: any non-degraded period at all? (avoids full summarize overhead
+            # Quick check: any non-degraded period at all?
-            # when there are zero periods, which should return None)
             has_data = sess.query(_func.sum(_ECP.import_cost)).filter(
                 _ECP.degraded.is_(False)
             ).scalar()
             if has_data is None:
                 return None
 
-            versions = active_contract_versions(sess)
+            # D2: anchor = active electricity meter's started_at.
-            if not versions:
+            # Inline query (ended_at IS NULL) is more robust than meter_at(now)
-                # No active contract — return pure SUM(import_cost) without standing charges.
+            # because it avoids the edge case where started_at is in the future.
-                return float(has_data)
+            active_meter = sess.execute(
+                _select(_Meter)
+                .where(
+                    _Meter.commodity == "electricity",
+                    _Meter.ended_at.is_(None),
+                )
+                .limit(1)
+            ).scalar_one_or_none()
 
-            # anchor = max(contract billing start, earliest recording start).
+            if active_meter is None:
-            # This prevents accumulating fixed costs for days with no meter data.
+                # No active electricity meter — cannot anchor; return None.
-            contract_anchor_utc = _cu(versions[0].effective_from)
+                return None
-            earliest_period_start = sess.query(_func.min(_ECP.period_start)).filter(
-                _ECP.degraded.is_(False)
-            ).scalar()
-            if earliest_period_start is not None:
-                recording_anchor_utc = _cu(earliest_period_start)
-                anchor_utc = max(contract_anchor_utc, recording_anchor_utc)
-            else:
-                anchor_utc = contract_anchor_utc
 
+            from app.services.contracts import _as_utc as _cu
+            anchor_utc = _cu(active_meter.started_at)
             now_utc = _dt.now(UTC)
 
             result = _summarize(sess, anchor_utc, now_utc)
@@ -608,20 +612,18 @@ def _energy_cost_provider(session: Session) -> list[ExposableEntity]:
     def _make_export_revenue_getter() -> Callable[["Session"], Any]:
         """Return a getter for the cumulative export revenue plus prorated tax credit.
 
-        Principle B/D: delegates entirely to ``summarize(sess, anchor_utc, now_utc)``.
+        D2 (M7): anchor = current active electricity meter's ``started_at``.
-        Anchor is the same max(contract_start, recording_start) logic as import getter.
+        Same reasoning as the import cost getter — see its docstring.
 
             value = summarize(anchor → now).metered_export + summarize(anchor → now).credits
 
-        Returns None when no non-degraded period exists in [anchor, now].
+        Returns None when no non-degraded period exists or no active electricity meter.
         """
         def _getter(sess: "Session") -> Any:
             from datetime import UTC, datetime as _dt
-            from app.services.contracts import active_contract_versions
+            from app.models.energy import EnergyCostPeriod as _ECP, Meter as _Meter
-            from app.services.contracts import _as_utc as _cu
             from app.services.energy_cost import summarize as _summarize
-            from app.models.energy import EnergyCostPeriod as _ECP
+            from sqlalchemy import func as _func, select as _select
-            from sqlalchemy import func as _func
 
             # Quick check: any non-degraded period at all?
             has_data = sess.query(_func.sum(_ECP.export_revenue)).filter(
@@ -630,22 +632,22 @@ def _energy_cost_provider(session: Session) -> list[ExposableEntity]:
             if has_data is None:
                 return None
 
-            versions = active_contract_versions(sess)
+            # D2: anchor = active electricity meter's started_at.
-            if not versions:
+            active_meter = sess.execute(
-                # No active contract — return pure SUM(export_revenue) without credits.
+                _select(_Meter)
-                return float(has_data)
+                .where(
+                    _Meter.commodity == "electricity",
+                    _Meter.ended_at.is_(None),
+                )
+                .limit(1)
+            ).scalar_one_or_none()
 
-            # anchor = max(contract billing start, earliest recording start).
+            if active_meter is None:
-            contract_anchor_utc = _cu(versions[0].effective_from)
+                # No active electricity meter — cannot anchor; return None.
-            earliest_period_start = sess.query(_func.min(_ECP.period_start)).filter(
+                return None
-                _ECP.degraded.is_(False)
-            ).scalar()
-            if earliest_period_start is not None:
-                recording_anchor_utc = _cu(earliest_period_start)
-                anchor_utc = max(contract_anchor_utc, recording_anchor_utc)
-            else:
-                anchor_utc = contract_anchor_utc
 
+            from app.services.contracts import _as_utc as _cu
+            anchor_utc = _cu(active_meter.started_at)
             now_utc = _dt.now(UTC)
 
             result = _summarize(sess, anchor_utc, now_utc)

tests/test_energy_expose.py

@@ -90,6 +90,37 @@ def _make_period(
     return p
 
 
+def _make_active_meter(
+    session: Session,
+    *,
+    started_at: datetime,
+    label: str = "Test Meter",
+    commodity: str = "electricity",
+    reason: str = "initial",
+) -> Any:
+    """Insert an active (ended_at=None) Meter row and flush.
+
+    Helper for M7-T04 tests: every cumulative-getter test that expects a
+    non-None return value must declare an active electricity meter so the
+    D2 anchor (meter.started_at) can be resolved.
+    """
+    from app.models.energy import Meter
+
+    now = datetime.now(tz=timezone.utc)
+    m = Meter(
+        label=label,
+        commodity=commodity,
+        started_at=started_at,
+        ended_at=None,
+        reason=reason,
+        note=None,
+        created_at=now,
+    )
+    session.add(m)
+    session.flush()
+    return m
+
+
 def _make_settings(
     *,
     mqtt_enabled: bool = True,
@@ -398,14 +429,21 @@ def test_sell_price_getter_reads_manual_snapshot(energy_db) -> None:
 
 
 def test_import_cost_total_sums_non_degraded_rows(energy_db) -> None:
-    """import_cost_total must return SUM of non-degraded import_cost values only."""
+    """import_cost_total must return SUM of non-degraded import_cost values only.
+
+    M7-T04 (D2): active electricity meter required so the getter can anchor on
+    meter.started_at.  The meter is started before t0 so both non-degraded rows
+    fall within [anchor, now).
+    """
     from app.integrations.expose import build_catalog
 
     t0 = datetime(2025, 3, 1, 6, 0, tzinfo=timezone.utc)
     t1 = datetime(2025, 3, 1, 6, 15, tzinfo=timezone.utc)
     t2 = datetime(2025, 3, 1, 6, 30, tzinfo=timezone.utc)
+    meter_start = datetime(2025, 3, 1, 0, 0, tzinfo=timezone.utc)
 
     with Session(energy_db) as session:
+        _make_active_meter(session, started_at=meter_start)
         # Two good rows: 0.10 + 0.20 = 0.30
         _make_period(session, period_start=t0, import_cost=0.10, degraded=False)
         _make_period(session, period_start=t1, import_cost=0.20, degraded=False)
@@ -420,20 +458,26 @@ def test_import_cost_total_sums_non_degraded_rows(energy_db) -> None:
         )
         value = import_entry.entity.value_getter(session)
 
+    # No active contract → fixed_costs = 0; only metered sum = 0.30.
     assert value == pytest.approx(0.30), (
         f"Expected cumulative import_cost 0.30 (non-degraded only), got {value!r}"
     )
 
 
 def test_export_revenue_total_sums_non_degraded_rows(energy_db) -> None:
-    """export_revenue_total must return SUM of non-degraded export_revenue values only."""
+    """export_revenue_total must return SUM of non-degraded export_revenue values only.
+
+    M7-T04 (D2): active electricity meter required so the getter can anchor.
+    """
     from app.integrations.expose import build_catalog
 
     t0 = datetime(2025, 3, 2, 6, 0, tzinfo=timezone.utc)
     t1 = datetime(2025, 3, 2, 6, 15, tzinfo=timezone.utc)
     t2 = datetime(2025, 3, 2, 6, 30, tzinfo=timezone.utc)
+    meter_start = datetime(2025, 3, 2, 0, 0, tzinfo=timezone.utc)
 
     with Session(energy_db) as session:
+        _make_active_meter(session, started_at=meter_start)
         # Two good rows: 0.05 + 0.07 = 0.12
         _make_period(session, period_start=t0, export_revenue=0.05, degraded=False)
         _make_period(session, period_start=t1, export_revenue=0.07, degraded=False)
@@ -448,6 +492,7 @@ def test_export_revenue_total_sums_non_degraded_rows(energy_db) -> None:
         )
         value = export_entry.entity.value_getter(session)
 
+    # No active contract → credits = 0; only metered sum = 0.12.
     assert value == pytest.approx(0.12), (
         f"Expected cumulative export_revenue 0.12 (non-degraded only), got {value!r}"
     )
@@ -459,13 +504,17 @@ def test_cumulative_getter_excludes_degraded_import_cost_row(energy_db) -> None:
     This verifies the exclusion filter on degraded=True rows.
     (In practice compute_period writes 0.0 for degraded rows; but if a row was
     previously successful and then set degraded, its import_cost could be non-zero.)
+
+    M7-T04 (D2): active electricity meter required.
     """
     from app.integrations.expose import build_catalog
 
     t0 = datetime(2025, 4, 1, 10, 0, tzinfo=timezone.utc)
     t1 = datetime(2025, 4, 1, 10, 15, tzinfo=timezone.utc)
+    meter_start = datetime(2025, 4, 1, 0, 0, tzinfo=timezone.utc)
 
     with Session(energy_db) as session:
+        _make_active_meter(session, started_at=meter_start)
         _make_period(session, period_start=t0, import_cost=0.50, degraded=False)
         # A row that is degraded but somehow has a non-zero import_cost (edge case):
         _make_period(session, period_start=t1, import_cost=0.99, degraded=True)
@@ -478,7 +527,7 @@ def test_cumulative_getter_excludes_degraded_import_cost_row(energy_db) -> None:
         )
         value = import_entry.entity.value_getter(session)
 
-    # Only the non-degraded row should contribute: 0.50
+    # Only the non-degraded row should contribute: 0.50 (no contract → fixed_costs=0).
     assert value == pytest.approx(0.50), (
         f"Degraded row must not be included in SUM; expected 0.50, got {value!r}"
     )
@@ -880,18 +929,17 @@ _STANDING_VALUES = {
 def test_import_cost_total_includes_standing_charges(energy_db) -> None:
     """import_cost_total getter must add prorated standing charges from active contract.
 
-    Principle B/D + FU11 anchor guardrail: the getter delegates to
+    M7-T04 (D2): anchor = active electricity meter's started_at.
-    summarize(anchor → now), where anchor = max(contract_start, recording_start).
+    The getter delegates to summarize(anchor → now), where anchor = meter.started_at.
 
     With network_fee=30 EUR/month + management_fee=60 EUR/month, daily_standing = 3.0 EUR/day.
     The getter uses summarize, which counts whole *local* elapsed days under Principle C.
     We pin the timezone to UTC for simplicity: local days = UTC days.
 
     Setup:
-      - effective_from = 10 full UTC days ago (exact UTC midnight).
+      - meter.started_at = effective_from = 10 full UTC days ago (exact UTC midnight).
-      - First period placed AT effective_from (same UTC midnight), so recording_start =
+      - First period placed AT meter.started_at → anchor = meter.started_at.
-        contract_start → anchor = max(contract_start, recording_start) = contract_start.
+      - Under UTC pinned, Principle C counts days [meter.started_at.date(), today] = 11 days.
-      - Under UTC pinned, Principle C counts days [effective_from.date(), today] = 11 days.
     """
     from decimal import Decimal
     from datetime import timedelta
@@ -901,20 +949,20 @@ def test_import_cost_total_includes_standing_charges(energy_db) -> None:
     from app.services import timezone as _tz_mod
 
     now_utc = datetime.now(timezone.utc)
-    # anchor = exactly 10 UTC days ago at midnight
+    # D2 anchor = meter.started_at = 10 UTC days ago at midnight
-    effective_from = now_utc.replace(hour=0, minute=0, second=0, microsecond=0) - timedelta(days=10)
+    meter_started_at = now_utc.replace(hour=0, minute=0, second=0, microsecond=0) - timedelta(days=10)
+    effective_from = meter_started_at  # contract also starts at the same time
 
-    # Under UTC timezone (pinned), Principle C counts whole days from effective_from.date()
+    # Under UTC timezone (pinned), Principle C counts whole days from meter.started_at.date()
     # to today (inclusive) = 11 days total (10 + today).
-    expected_days = (now_utc.date() - effective_from.date()).days + 1  # = 11
+    expected_days = (now_utc.date() - meter_started_at.date()).days + 1  # = 11
 
     import_cost_sum = 5.00  # EUR
-    # Place period rows AT effective_from (= recording_start = contract_start → same anchor).
+    t0 = meter_started_at  # first period at anchor
-    # This ensures anchor = max(effective_from, effective_from) = effective_from exactly.
-    t0 = effective_from  # first period starts exactly at contract effective_from
     t1 = t0 + timedelta(minutes=15)
 
     with Session(energy_db) as session:
+        _make_active_meter(session, started_at=meter_started_at)
         _make_contract_with_version(
             session,
             values=_STANDING_VALUES,
@@ -953,12 +1001,11 @@ def test_import_cost_total_includes_standing_charges(energy_db) -> None:
 def test_export_revenue_total_includes_tax_credit(energy_db) -> None:
     """export_revenue_total getter must add prorated heffingskorting from active contract.
 
-    Principle B/D + FU11 anchor guardrail: delegates to summarize(anchor → now),
+    M7-T04 (D2): anchor = active electricity meter's started_at.
-    where anchor = max(contract_start, recording_start).
     With heffingskorting=365 EUR/year, daily_credit = 365/365 = 1.0 EUR/day.
     Timezone pinned to UTC for deterministic local-day counting.
 
-    Setup: period placed AT effective_from → recording_start = contract_start → same anchor.
+    Setup: meter.started_at = effective_from = 4 days ago → 5 days total (incl. today).
     """
     from decimal import Decimal
     from datetime import timedelta
@@ -968,17 +1015,18 @@ def test_export_revenue_total_includes_tax_credit(energy_db) -> None:
     from app.services import timezone as _tz_mod
 
     now_utc = datetime.now(timezone.utc)
-    effective_from = now_utc.replace(hour=0, minute=0, second=0, microsecond=0) - timedelta(days=4)
+    meter_started_at = now_utc.replace(hour=0, minute=0, second=0, microsecond=0) - timedelta(days=4)
+    effective_from = meter_started_at
 
-    # Under UTC pinned: expected_days = days from effective_from.date() to today inclusive.
+    # Under UTC pinned: expected_days = days from meter.started_at.date() to today inclusive.
-    expected_days = (now_utc.date() - effective_from.date()).days + 1  # = 5
+    expected_days = (now_utc.date() - meter_started_at.date()).days + 1  # = 5
 
-    # Place period rows AT effective_from → recording_start = contract_start = same anchor.
+    t0 = meter_started_at
-    t0 = effective_from
     t1 = t0 + timedelta(minutes=15)
     export_sum = 2.50  # EUR
 
     with Session(energy_db) as session:
+        _make_active_meter(session, started_at=meter_started_at)
         _make_contract_with_version(
             session,
             values=_STANDING_VALUES,
@@ -1014,19 +1062,18 @@ def test_export_revenue_total_includes_tax_credit(energy_db) -> None:
 
 
 def test_import_cost_standing_zero_when_effective_from_in_future(energy_db) -> None:
-    """When contract version effective_from is in the future, standing cumulative must be 0.
+    """When contract version effective_from is in the future, standing charges must be 0.
 
-    Principle D: anchor = effective_from (future).
+    M7-T04 (D2): anchor = active electricity meter's started_at (in the past).
-    summarize(anchor → now) has a negative/empty window → 0 days, 0 fixed_costs.
+    The summarize window [meter.started_at, now) DOES include the period data,
-    The global `has_data` check passes (there are non-degraded rows from the past),
+    but Principle C does not count future local days for fixed costs.  Since
-    but no periods fall within [anchor, now] window → metered = 0, fixed = 0.
+    the contract's effective_from is in the future, no days in [meter.started_at,
-    The getter returns 0 + 0 = 0.
+    today] fall under a valid contract version, so fixed_costs = 0.
 
-    Note: under the new design, if a contract has a future effective_from, the
+    With the D2 anchor in the past, the metered sum IS returned (unlike the old
-    getter returns the pure metered sum from the summarize window (which is 0
+    FU11 design where the anchor was the future effective_from → empty window → 0).
-    since no periods exist after the future anchor). The old test expected to
+
-    return the raw global SUM, but with Principle D the anchor is the future
+    Expected:  value = import_cost_sum + 0 (no standing days)
-    date → window is empty → metered = 0.
     """
     from datetime import timedelta
     from unittest.mock import patch
@@ -1035,14 +1082,15 @@ def test_import_cost_standing_zero_when_effective_from_in_future(energy_db) -> N
     from app.services import timezone as _tz_mod
 
     now_utc = datetime.now(timezone.utc)
+    # Meter started 2 days ago; period is 1 day ago (within meter window).
+    meter_started_at = now_utc.replace(hour=0, minute=0, second=0, microsecond=0) - timedelta(days=2)
     future_effective = now_utc + timedelta(days=30)
 
-    # Place a period BEFORE the future effective_from (global sum = 4.00)
-    # but it won't be in [anchor, now] window.
     t0 = now_utc.replace(hour=6, minute=0, second=0, microsecond=0) - timedelta(days=1)
     import_cost_sum = 4.00
 
     with Session(energy_db) as session:
+        _make_active_meter(session, started_at=meter_started_at)
         _make_contract_with_version(
             session,
             values=_STANDING_VALUES,
@@ -1060,19 +1108,21 @@ def test_import_cost_standing_zero_when_effective_from_in_future(energy_db) -> N
             )
             value = import_entry.entity.value_getter(session)
 
-    # anchor is in future → summarize([future, now]) is empty → metered=0, fixed_costs=0
+    # D2: anchor = meter.started_at (past) → metered_import = import_cost_sum.
-    # Principle C: no future local days counted → 0 fixed costs.
+    # Principle C: contract effective_from is in the future → 0 standing days → fixed_costs = 0.
-    # Result = 0 (no periods in window) + 0 (0 standing days) = 0.
+    # Result = import_cost_sum + 0.
-    assert value == pytest.approx(0.0, abs=1e-9), (
+    assert value == pytest.approx(import_cost_sum, rel=1e-9), (
-        f"When effective_from is in future, summarize window is empty → value must be 0.0; "
+        f"When effective_from is in future, standing = 0, value = metered sum; "
-        f"got {value!r}"
+        f"expected {import_cost_sum}, got {value!r}"
     )
 
 
 def test_export_revenue_credit_zero_when_effective_from_in_future(energy_db) -> None:
-    """When contract version effective_from is in the future, credit cumulative must be 0.
+    """When contract version effective_from is in the future, tax credit must be 0.
 
-    Same logic as import: anchor is future → summarize window empty → 0 credits.
+    M7-T04 (D2): anchor = active electricity meter's started_at (in the past).
+    Summarize window includes the period, but Principle C does not count future
+    days, so credits = 0.  Expected: value = export_sum + 0 credits.
     """
     from datetime import timedelta
     from unittest.mock import patch
@@ -1081,12 +1131,14 @@ def test_export_revenue_credit_zero_when_effective_from_in_future(energy_db) ->
     from app.services import timezone as _tz_mod
 
     now_utc = datetime.now(timezone.utc)
+    meter_started_at = now_utc.replace(hour=0, minute=0, second=0, microsecond=0) - timedelta(days=2)
     future_effective = now_utc + timedelta(days=60)
 
     t0 = now_utc.replace(hour=6, minute=0, second=0, microsecond=0) - timedelta(days=1)
     export_sum = 3.00
 
     with Session(energy_db) as session:
+        _make_active_meter(session, started_at=meter_started_at)
         _make_contract_with_version(
             session,
             values=_STANDING_VALUES,
@@ -1104,9 +1156,10 @@ def test_export_revenue_credit_zero_when_effective_from_in_future(energy_db) ->
             )
             value = export_entry.entity.value_getter(session)
 
-    # anchor is in future → empty window → 0 credits
+    # D2: metered_export = export_sum; Principle C: future effective_from → 0 credits.
-    assert value == pytest.approx(0.0, abs=1e-9), (
+    assert value == pytest.approx(export_sum, rel=1e-9), (
-        f"When effective_from is in future, credit must be 0; got {value!r}"
+        f"When effective_from is in future, credit = 0, value = metered sum; "
+        f"expected {export_sum}, got {value!r}"
     )
 
 
@@ -1115,14 +1168,22 @@ def test_export_revenue_credit_zero_when_effective_from_in_future(energy_db) ->
 # ---------------------------------------------------------------------------
 
 
-def test_import_cost_total_falls_back_to_sum_when_no_active_contract(energy_db) -> None:
+def test_import_cost_total_returns_metered_sum_when_no_active_contract(energy_db) -> None:
-    """When no active contract exists, import_cost_total must return the raw SUM only."""
+    """When active meter exists but no active contract, import_cost_total returns metered sum.
+
+    M7-T04 (D2): anchor = meter.started_at; summarize runs without a contract
+    → fixed_costs = 0; the return value is the pure metered sum within the meter window.
+    This is a behaviour change from FU11 (which returned a global SUM) — D2 only
+    counts periods since meter.started_at.
+    """
     from app.integrations.expose import build_catalog
 
     t0 = datetime(2026, 1, 1, 6, 0, tzinfo=timezone.utc)
     t1 = datetime(2026, 1, 1, 6, 15, tzinfo=timezone.utc)
+    meter_start = datetime(2026, 1, 1, 0, 0, tzinfo=timezone.utc)
 
     with Session(energy_db) as session:
+        _make_active_meter(session, started_at=meter_start)
         # Inactive contract — active=False
         _make_contract_with_version(
             session,
@@ -1141,20 +1202,27 @@ def test_import_cost_total_falls_back_to_sum_when_no_active_contract(energy_db)
         )
         value = import_entry.entity.value_getter(session)
 
-    # No active contract → standing cumulative = 0 → value = pure SUM = 4.00
+    # D2: anchor = meter.started_at; both periods fall within [anchor, now].
+    # No active contract → fixed_costs = 0 → value = pure metered SUM = 4.00.
     assert value == pytest.approx(4.00, rel=1e-9), (
-        f"Expected pure SUM=4.00 with no active contract, got {value!r}"
+        f"Expected metered SUM=4.00 (no contract → no standing), got {value!r}"
     )
 
 
-def test_export_revenue_total_falls_back_to_sum_when_no_active_contract(energy_db) -> None:
+def test_export_revenue_total_returns_metered_sum_when_no_active_contract(energy_db) -> None:
-    """When no active contract exists, export_revenue_total must return the raw SUM only."""
+    """When active meter exists but no active contract, export_revenue_total returns metered sum.
+
+    M7-T04 (D2): anchor = meter.started_at; summarize with no contract → credits = 0;
+    return value = pure metered export sum within the meter window.
+    """
     from app.integrations.expose import build_catalog
 
     t0 = datetime(2026, 2, 1, 6, 0, tzinfo=timezone.utc)
     t1 = datetime(2026, 2, 1, 6, 15, tzinfo=timezone.utc)
+    meter_start = datetime(2026, 2, 1, 0, 0, tzinfo=timezone.utc)
 
     with Session(energy_db) as session:
+        _make_active_meter(session, started_at=meter_start)
         # Inactive contract — active=False
         _make_contract_with_version(
             session,
@@ -1173,9 +1241,9 @@ def test_export_revenue_total_falls_back_to_sum_when_no_active_contract(energy_d
         )
         value = export_entry.entity.value_getter(session)
 
-    # No active contract → credit cumulative = 0 → value = pure SUM = 2.00
+    # D2: anchor = meter.started_at; no contract → credits = 0 → value = metered sum = 2.00.
     assert value == pytest.approx(2.00, rel=1e-9), (
-        f"Expected pure SUM=2.00 with no active contract, got {value!r}"
+        f"Expected metered SUM=2.00 (no contract → no credits), got {value!r}"
     )
 
 
@@ -1629,14 +1697,15 @@ def test_daily_getter_returns_none_when_no_non_degraded_periods(energy_db) -> No
 # ---------------------------------------------------------------------------
 
 
-def test_cumulative_anchor_uses_recording_start_when_later_than_contract(energy_db) -> None:
+def test_cumulative_anchor_is_meter_started_at(energy_db) -> None:
-    """FU11: anchor = max(contract_start, recording_start) — no pre-recording fixed costs.
+    """M7-T04 (D2): anchor = active electricity meter's started_at, not recording_start.
 
-    Scenario: contract effective_from = 180 days ago (lots of standing charges if used
+    Scenario: contract effective_from = 180 days ago; meter.started_at = 7 days ago;
-    as anchor), but first non-degraded period_start = 7 days ago.  Expected: anchor is
+    first non-degraded period_start = 7 days ago.
-    7 days ago → only 8 days of standing charges (7 + today under Principle C).
+    Expected: anchor = meter.started_at (7 days ago) → 8 days of standing charges.
 
-    Without the fix, anchor would be 180 days ago → ~180 days × 3 EUR/day = €540+.
+    This replaces the old FU11 test (anchor=recording_start).  Under D2 the anchor
+    is always the active meter's started_at, irrespective of when data recording began.
     """
     from decimal import Decimal
     from datetime import timedelta
@@ -1648,14 +1717,15 @@ def test_cumulative_anchor_uses_recording_start_when_later_than_contract(energy_
     now_utc = datetime.now(timezone.utc)
     midnight_today = now_utc.replace(hour=0, minute=0, second=0, microsecond=0)
 
-    # Contract starts 180 days ago (far before any data)
+    # Contract starts 180 days ago (far before the meter)
     contract_start = midnight_today - timedelta(days=180)
-    # First (and only) data period starts 7 days ago
+    # Active meter started 7 days ago — this is the D2 anchor
-    recording_start = midnight_today - timedelta(days=7)
+    meter_started_at = midnight_today - timedelta(days=7)
 
-    t0 = recording_start  # first period at recording start
+    t0 = meter_started_at  # first period at meter start
 
     with Session(energy_db) as session:
+        _make_active_meter(session, started_at=meter_started_at)
         _make_contract_with_version(
             session,
             values=_STANDING_VALUES,
@@ -1673,25 +1743,244 @@ def test_cumulative_anchor_uses_recording_start_when_later_than_contract(energy_
             )
             value = import_entry.entity.value_getter(session)
 
-    # Anchor = recording_start (7 days ago UTC midnight).
+    # Anchor = meter.started_at (7 days ago).
-    # Principle C (UTC pinned): count local days from recording_start.date() to today inclusive.
+    # Principle C (UTC pinned): count local days from meter_started_at.date() to today inclusive.
-    # That's 7+1 = 8 days.
+    # That's 7 + 1 = 8 days.
-    expected_days = (now_utc.date() - recording_start.date()).days + 1  # = 8
+    expected_days = (now_utc.date() - meter_started_at.date()).days + 1  # = 8
     daily_standing = Decimal("90") / Decimal("30")  # = 3.0 EUR/day
     expected = float(Decimal("5.00") + daily_standing * expected_days)
 
-    # Without the fix, value would include ~180 days × 3 EUR/day = ~€540+ of extra standing.
-    # With the fix, value ≈ 5.00 + 3.0 × 8 = 29.00.
     assert value == pytest.approx(expected, rel=1e-6), (
-        f"Expected anchor=recording_start anchor, "
+        f"Expected anchor=meter.started_at anchor, "
         f"import_cost_total={expected} (metered=5.00 + standing={float(daily_standing*expected_days)} "
         f"over {expected_days} days), got {value!r}"
     )
 
-    # Also verify that using the old anchor (contract start) would give a very different result.
+    # Verify that using the old FU11 anchor (contract start, 180 days ago) would give a
+    # very different result (>€500 more standing), confirming we're NOT using it.
     old_expected_days = (now_utc.date() - contract_start.date()).days + 1  # ~181 days
     old_expected = float(Decimal("5.00") + daily_standing * old_expected_days)
     assert abs(value - old_expected) > 100, (
-        f"Old (wrong) anchor would yield ~{old_expected:.2f}, "
+        f"D2 anchor (meter.started_at) expected ~{expected:.2f}, "
-        f"the new value {value:.2f} should differ by >€100"
+        f"old FU11 anchor (contract_start) would yield ~{old_expected:.2f}; "
+        f"difference must be >€100"
+    )
+
+
+# ---------------------------------------------------------------------------
+# M7-T04 new tests: per-meter cumulative reset (D2)
+# ---------------------------------------------------------------------------
+
+
+def test_cumulative_returns_none_when_no_active_meter(energy_db) -> None:
+    """M7-T04 None protection: no active electricity meter → import/export total = None.
+
+    This is the key D2 None protection: without an active meter the anchor
+    cannot be resolved, so the getter returns None rather than a stale/wrong value.
+    Periods exist (non-degraded), but no Meter row with ended_at IS NULL is present.
+    """
+    from app.integrations.expose import build_catalog
+
+    t0 = datetime(2026, 3, 1, 10, 0, tzinfo=timezone.utc)
+    t1 = datetime(2026, 3, 1, 10, 15, tzinfo=timezone.utc)
+
+    with Session(energy_db) as session:
+        # No Meter row at all — cumulative getters must return None.
+        _make_period(session, period_start=t0, import_cost=1.00, degraded=False)
+        _make_period(session, period_start=t1, export_revenue=0.50, degraded=False)
+        session.commit()
+
+    with Session(energy_db) as session:
+        catalog = build_catalog(session)
+        import_entry = next(e for e in catalog if e.entity.key == "energy.import_cost_total")
+        export_entry = next(e for e in catalog if e.entity.key == "energy.export_revenue_total")
+        import_val = import_entry.entity.value_getter(session)
+        export_val = export_entry.entity.value_getter(session)
+
+    assert import_val is None, (
+        f"import_cost_total must be None with no active meter, got {import_val!r}"
+    )
+    assert export_val is None, (
+        f"export_revenue_total must be None with no active meter, got {export_val!r}"
+    )
+
+
+def test_cumulative_resets_after_meter_swap(energy_db) -> None:
+    """M7-T04 (D2): after a meter swap the cumulative only counts the new meter's periods.
+
+    Scenario:
+      - Old meter:  started_at = 30 days ago.  Two non-degraded periods (€3.00 total).
+      - Swap at:    7 days ago.  Old meter closed, new active meter opened.
+      - New meter:  started_at = 7 days ago.  One non-degraded period (€1.00).
+      - Expected:   import_cost_total = €1.00 + any standing charges from [7 days ago, now].
+
+    Old-meter periods (period_start < new_meter.started_at) fall outside the
+    [anchor, now) window and are excluded, giving a clean reset to zero for the
+    new meter epoch.
+    """
+    from decimal import Decimal
+    from datetime import timedelta
+    from unittest.mock import patch
+    from zoneinfo import ZoneInfo
+    from app.models.energy import Meter as _Meter
+    from app.integrations.expose import build_catalog
+    from app.services import timezone as _tz_mod
+
+    now_utc = datetime.now(timezone.utc)
+    midnight_today = now_utc.replace(hour=0, minute=0, second=0, microsecond=0)
+
+    old_meter_start = midnight_today - timedelta(days=30)
+    swap_at = midnight_today - timedelta(days=7)  # new meter anchor
+
+    # Old-meter periods (before the swap)
+    old_t0 = old_meter_start
+    old_t1 = old_meter_start + timedelta(minutes=15)
+    # New-meter period (after the swap)
+    new_t0 = swap_at  # first period of the new meter epoch
+
+    new_meter_import = 1.00  # EUR — only this should be counted (old-meter 3.00 must be excluded)
+
+    with Session(energy_db) as session:
+        # Old meter: closed at swap_at
+        old_m = _Meter(
+            label="Old Meter",
+            commodity="electricity",
+            started_at=old_meter_start,
+            ended_at=swap_at,  # closed
+            reason="initial",
+            note=None,
+            created_at=datetime.now(timezone.utc),
+        )
+        session.add(old_m)
+        session.flush()
+
+        # New meter: active (ended_at IS NULL) — D2 anchor
+        new_m = _Meter(
+            label="New Meter",
+            commodity="electricity",
+            started_at=swap_at,
+            ended_at=None,  # active
+            reason="meter_swap",
+            note=None,
+            created_at=datetime.now(timezone.utc),
+        )
+        session.add(new_m)
+        session.flush()
+
+        # Old-meter periods (before swap): should NOT appear in post-swap cumulative
+        _make_period(session, period_start=old_t0, import_cost=2.00, degraded=False)
+        _make_period(session, period_start=old_t1, import_cost=1.00, degraded=False)
+        # New-meter period (at swap point / after swap)
+        _make_period(session, period_start=new_t0, import_cost=new_meter_import, degraded=False)
+
+        # Active contract starting well before the old meter
+        _make_contract_with_version(
+            session,
+            values=_STANDING_VALUES,
+            effective_from=old_meter_start,
+            active=True,
+        )
+        session.commit()
+
+    with Session(energy_db) as session:
+        with patch.object(_tz_mod, "local_tz", return_value=ZoneInfo("UTC")):
+            catalog = build_catalog(session)
+            import_entry = next(
+                e for e in catalog if e.entity.key == "energy.import_cost_total"
+            )
+            value = import_entry.entity.value_getter(session)
+
+    # Anchor = new meter's started_at (7 days ago).
+    # Old-meter periods (period_start < swap_at) fall outside [anchor, now) → excluded.
+    # Only new_t0 (= swap_at = anchor) is within the window → metered = 1.00.
+    # Standing charges: anchor = 7 days ago → 8 days (Principle C, UTC pinned).
+    expected_days = (now_utc.date() - swap_at.date()).days + 1  # = 8
+    daily_standing = Decimal("90") / Decimal("30")  # = 3.0 EUR/day
+    expected = float(Decimal(str(new_meter_import)) + daily_standing * expected_days)
+
+    assert value == pytest.approx(expected, rel=1e-6), (
+        f"Post-swap cumulative must only include new meter periods. "
+        f"Expected {expected} (metered={new_meter_import} + "
+        f"standing={float(daily_standing * expected_days)} over {expected_days} days), "
+        f"got {value!r}"
+    )
+
+    # Paranoia: if old-meter periods were accidentally included, value would be
+    # much larger (old_meter_import = 3.00 would inflate it).
+    assert value < new_meter_import + float(daily_standing * (expected_days + 1)) + 0.5, (
+        f"Value suspiciously large — old-meter periods may be included: {value!r}"
+    )
+
+
+def test_daily_getters_unaffected_by_d2_meter_anchor(energy_db) -> None:
+    """M7-T04: daily import/export getters must still use the local-day window.
+
+    D2 only changes the cumulative (*_total) anchor.  The *_today getters
+    use today's local-day window [local midnight, local tomorrow midnight) in UTC.
+    They must continue to work correctly regardless of the meter anchor change,
+    and do NOT require an active meter (they use today's window directly).
+
+    Setup: period 1h ago (today's local window, TZ=UTC), active contract.
+    Expected: value = import_today + fixed_for_today, independent of any meter.
+    """
+    from decimal import Decimal
+    from datetime import timedelta
+    from unittest.mock import patch
+    from zoneinfo import ZoneInfo
+    from app.integrations.expose import build_catalog
+    from app.services import timezone as _tz_mod
+
+    now_utc = datetime.now(timezone.utc)
+    # Period 1h ago — in today's UTC window
+    t0 = now_utc.replace(minute=0, second=0, microsecond=0) - timedelta(hours=1)
+    if t0.date() < now_utc.date():
+        t0 = now_utc.replace(hour=0, minute=0, second=0, microsecond=0)
+
+    effective_from = now_utc.replace(hour=0, minute=0, second=0, microsecond=0) - timedelta(days=30)
+    import_cost_today = 0.88
+    export_today = 0.44
+
+    with Session(energy_db) as session:
+        # No active meter added intentionally — daily getters must not need it.
+        _make_contract_with_version(
+            session,
+            values=_STANDING_VALUES,
+            effective_from=effective_from,
+            active=True,
+        )
+        _make_period(
+            session,
+            period_start=t0,
+            import_cost=import_cost_today,
+            export_revenue=export_today,
+            degraded=False,
+        )
+        session.commit()
+
+    with Session(energy_db) as session:
+        with patch.object(_tz_mod, "local_tz", return_value=ZoneInfo("UTC")):
+            catalog = build_catalog(session)
+            import_today_entry = next(
+                e for e in catalog if e.entity.key == "energy.import_cost_today"
+            )
+            export_today_entry = next(
+                e for e in catalog if e.entity.key == "energy.export_revenue_today"
+            )
+            import_val = import_today_entry.entity.value_getter(session)
+            export_val = export_today_entry.entity.value_getter(session)
+
+    # Principle C: today counts as 1 day.
+    daily_standing = Decimal("90") / Decimal("30")  # = 3.0 EUR/day
+    daily_credit = Decimal("365") / Decimal("365")   # = 1.0 EUR/day
+
+    expected_import = float(Decimal(str(import_cost_today)) + daily_standing * 1)
+    expected_export = float(Decimal(str(export_today)) + daily_credit * 1)
+
+    assert import_val == pytest.approx(expected_import, rel=1e-6), (
+        f"import_cost_today must use local-day window regardless of meter; "
+        f"expected {expected_import}, got {import_val!r}"
+    )
+    assert export_val == pytest.approx(expected_export, rel=1e-6), (
+        f"export_revenue_today must use local-day window regardless of meter; "
+        f"expected {expected_export}, got {export_val!r}"
     )