fix(tibber): fetch forward-looking today+tomorrow via priceInfo(QUARTER_HOURLY)

priceInfoRange is a historical cursor connection whose range ends at "now": it
never returns upcoming slots. With it, the DB only ever held prices up to the
last hourly refresh, which caused two problems:

  1. The price chart could only show history up to now, never a forward curve.
  2. Worse, per-slot billing was subtly wrong. _tibber_strategy looks up the
     price via `starts_at <= t0` (nearest slot at or before the period). Because
     a period's exact 15-min slot was not fetched until the next hourly refresh
     (~1h later), intra-hour periods were billed with the PREVIOUS quarter's
     price and then locked in by the immutability guard — never corrected.

Switch to priceInfo(resolution: QUARTER_HOURLY) { today tomorrow }, which is
forward-looking AND quarter-hourly: today is always the full local day (96
slots) and tomorrow fills in once Tibber publishes day-ahead prices (picked up
by the next hourly refresh). Every 15-min slot's exact price is now in the DB
before the slot closes, so each period finds its own slot (accurate billing)
and the live current-price entity stays fresh.

Verified against the live Tibber API: fetch_price_range returns 192 points
(96 today + 96 tomorrow), spanning local today 00:00 → tomorrow 23:45, with
future slots present (previously 0).

app/api/routes/api/modbus.py

@@ -488,6 +488,7 @@ def test_read(
             device.port,
             device.unit_id,
             [{"start": b.start, "count": b.count} for b in profile.blocks],
+            function_code=profile.function_code,
         )
         payload: dict[str, Any] = decode_profile(profile, registers)
         return ModbusTestReadResponse(ok=True, payload=payload)

app/integrations/expose.py

@@ -27,6 +27,7 @@ from __future__ import annotations
 
 import logging
 from dataclasses import dataclass, field
+from datetime import timedelta
 from typing import Any, Callable, Optional, Protocol
 
 from sqlalchemy.orm import Session
@@ -369,6 +370,10 @@ register_provider(_modbus_provider)
 # Energy Cost provider
 # ---------------------------------------------------------------------------
 
+# *_today 当日窗口翻天的宽限：本地午夜后 5 秒才切到新的一天，避免在 00:00:0x 把
+# 归零后的值发出去、被慢几秒的 HA 钟记成前一天的 23:59:59（归错小时桶）。
+_TODAY_RESET_GRACE = timedelta(seconds=5)
+
 
 def _energy_cost_provider(session: Session) -> list[ExposableEntity]:
     """Enumerate ExposableEntity objects for the energy cost subsystem.
@@ -735,7 +740,11 @@ def _energy_cost_provider(session: Session) -> list[ExposableEntity]:
                 return None
 
             # Today's window in UTC, using monkeypatch-safe module attribute calls.
-            today_local = _tz_mod.local_now().date()
+            # Grace: subtract _TODAY_RESET_GRACE so that in the first 5 seconds after
+            # local midnight the getter still returns yesterday's window.  This prevents
+            # a "归零后的值" from being published while HA's clock (which may lag a few
+            # seconds) would stamp it as 23:59:59 of the previous day.
+            today_local = (_tz_mod.local_now() - _TODAY_RESET_GRACE).date()
             tomorrow_local = today_local + _td(days=1)
             today_start_utc = _tz_mod.local_midnight_utc(today_local)
             tomorrow_start_utc = _tz_mod.local_midnight_utc(tomorrow_local)
@@ -772,7 +781,8 @@ def _energy_cost_provider(session: Session) -> list[ExposableEntity]:
             if not versions:
                 return None
 
-            today_local = _tz_mod.local_now().date()
+            # Grace: same logic as import_cost_today — see that getter's comment.
+            today_local = (_tz_mod.local_now() - _TODAY_RESET_GRACE).date()
             tomorrow_local = today_local + _td(days=1)
             today_start_utc = _tz_mod.local_midnight_utc(today_local)
             tomorrow_start_utc = _tz_mod.local_midnight_utc(tomorrow_local)

app/integrations/modbus/driver.py

@@ -1,8 +1,11 @@
 """Modbus TCP driver — thin wrapper around pymodbus.
 
 This module provides a single public function ``read_blocks`` that performs
-one or more FC04 (Read Input Registers) block reads against a Modbus TCP
+one or more block reads against a Modbus TCP gateway — using either FC04
-gateway and returns a flat ``dict[register_address -> 16-bit_value]`` map.
+(Read Input Registers) or FC03 (Read Holding Registers), selected per call
+via the ``function_code`` argument — and returns a flat
+``dict[register_address -> 16-bit_value]`` map.  The function code comes from
+the device profile (e.g. SDM120 uses FC04, DDSU666 uses FC03).
 
 Design decisions
 ----------------
@@ -80,9 +83,10 @@ def read_blocks(
     unit_id: int,
     blocks: Sequence[Block],
     *,
+    function_code: int = 4,
     timeout: float = 3.0,
 ) -> dict[int, int]:
-    """Read one or more contiguous register blocks via FC04 (input registers).
+    """Read one or more contiguous register blocks via FC03 or FC04.
 
     Parameters
     ----------
@@ -96,6 +100,11 @@ def read_blocks(
         Sequence of ``{"start": int, "count": int}`` dicts describing the
         contiguous register ranges to read.  ``count`` is the number of
         16-bit registers (not bytes).
+    function_code:
+        Modbus read function code: ``4`` for FC04 (Read Input Registers,
+        default — SDM120) or ``3`` for FC03 (Read Holding Registers —
+        DDSU666 and other devices that expose measurements as holding
+        registers).  Comes from the device profile's ``function_code`` field.
     timeout:
         TCP connect/read timeout in seconds (default 3 s).
 
@@ -107,12 +116,21 @@ def read_blocks(
 
     Raises
     ------
+    ModbusDriverError
+        If ``function_code`` is neither 3 nor 4 (validated before any
+        connection is attempted).
     ModbusConnectionError
         If the TCP connection to the gateway fails.
     ModbusResponseError
         If the gateway returns a Modbus exception frame or an unexpected
         number of registers.
     """
+    if function_code not in (3, 4):
+        raise ModbusDriverError(
+            f"Unsupported read function code FC{function_code:02d} "
+            f"(only FC03 holding-register and FC04 input-register reads are supported)"
+        )
+
     client = ModbusTcpClient(host, port=port, timeout=timeout)
     try:
         connected = client.connect()
@@ -125,7 +143,7 @@ def read_blocks(
         for block in blocks:
             start: int = block["start"]
             count: int = block["count"]
-            _read_block(client, unit_id, start, count, registers)
+            _read_block(client, unit_id, start, count, registers, function_code=function_code)
 
         return registers
 
@@ -145,10 +163,19 @@ def _read_block(
     start: int,
     count: int,
     result: dict[int, int],
+    *,
+    function_code: int,
 ) -> None:
-    """Read one block and merge into *result*.  Raises on any error."""
+    """Read one block and merge into *result*.  Raises on any error.
+
+    ``function_code`` is assumed already validated to be 3 or 4 by the caller
+    (``read_blocks``); 3 dispatches FC03 (holding) and 4 dispatches FC04 (input).
+    """
     try:
-        response = client.read_input_registers(start, count=count, device_id=unit_id)
+        if function_code == 3:
+            response = client.read_holding_registers(start, count=count, device_id=unit_id)
+        else:  # function_code == 4 (input registers)
+            response = client.read_input_registers(start, count=count, device_id=unit_id)
     except ConnectionException as exc:
         raise ModbusConnectionError(
             f"Lost connection while reading registers 0x{start:04X}+{count}: {exc}"

app/integrations/modbus/profiles/ddsu666.yaml

@@ -0,0 +1,82 @@
+name: ddsu666
+description: CHINT DDSU666 single-phase smart meter
+function_code: 3          # holding registers (FC03) — DDSU666 has NO input registers (no FC04)
+word_order: big           # high register first — ASSUMED; verify with a known voltage reading
+byte_order: big           # high byte first within each register (confirmed by manual CRC example)
+
+# NOTE: the manual gives no worked float-decode example, so word_order is a best-guess
+# (standard big-endian, high register first, matching sdm120).  After wiring the meter,
+# read 0x2000 (voltage) — it should decode to ~230 V.  If it decodes to garbage, the
+# device uses the opposite word order and this profile (and the decoder) need adjusting.
+# Byte order is confirmed big-endian from the manual (Appendix A, Table A.4: 0x1388 -> 13 88).
+
+blocks:
+  # Instantaneous quantities 0x2000–0x200F: voltage, current, P, Q, (rsv), PF, (rsv), Freq.
+  # 16 contiguous registers — single bulk read.  (DDSU666 manual Table 9.)
+  - { start: 0x2000, count: 0x0010 }
+  # Active energy — import (0x4000) and export (0x400A) read as two small blocks rather
+  # than one span, to avoid touching the undocumented/reserved 0x4002–0x4009 gap.
+  - { start: 0x4000, count: 0x0002 }
+  - { start: 0x400A, count: 0x0002 }
+
+metrics:
+  # Addresses are the raw Modbus protocol addresses (hex) from DDSU666 manual Table 9,
+  # read via FC03.  Each float32 occupies two consecutive 16-bit registers.
+
+  - key: voltage
+    address: 0x2000        # U — Voltage (V)
+    type: float32
+    unit: "V"
+    device_class: voltage
+    ha_component: sensor
+
+  - key: current
+    address: 0x2002        # I — Current (A)
+    type: float32
+    unit: "A"
+    device_class: current
+    ha_component: sensor
+
+  - key: active_power
+    address: 0x2004        # P — Active power.  Manual unit is kW (NOT W like sdm120).
+    type: float32
+    unit: "kW"
+    device_class: power
+    ha_component: sensor
+
+  - key: reactive_power
+    address: 0x2006        # Q — Reactive power (kvar)
+    type: float32
+    unit: "kvar"
+    device_class: reactive_power
+    ha_component: sensor
+
+  - key: power_factor
+    address: 0x200A        # PF — Power factor (dimensionless)
+    type: float32
+    unit: ""
+    device_class: power_factor
+    ha_component: sensor
+
+  - key: frequency
+    address: 0x200E        # Freq — Frequency (Hz)
+    type: float32
+    unit: "Hz"
+    device_class: frequency
+    ha_component: sensor
+
+  - key: import_energy
+    address: 0x4000        # Ep — positive/forward active energy (kWh)
+    type: float32
+    unit: "kWh"
+    device_class: energy
+    state_class: total_increasing
+    ha_component: sensor
+
+  - key: export_energy
+    address: 0x400A        # -Ep — reverse active energy (kWh)
+    type: float32
+    unit: "kWh"
+    device_class: energy
+    state_class: total_increasing
+    ha_component: sensor

app/integrations/tibber/client.py

@@ -30,20 +30,39 @@ logger = logging.getLogger(__name__)
 _TIBBER_API_URL = "https://api.tibber.com/v1-beta/gql"
 _DEFAULT_TIMEOUT = 15.0
 
-# GraphQL query to fetch a range of 15-minute price nodes.
+# GraphQL query to fetch the forward-looking today + tomorrow price curve at
-# ``priceInfoRange(resolution: QUARTER_HOURLY, first: 96)`` fetches up to
+# 15-minute resolution.
-# 96 quarter-hourly slots which covers today + tomorrow (2 × 24 × 4 = 192 max,
+#
-# but the Tibber API typically starts from the current slot and returns at
+# ``priceInfo(resolution: QUARTER_HOURLY)`` returns two node lists:
-# most the remaining hours of today plus tomorrow, so 96 is a good cap for
+#   * ``today``    — always the full current local day (96 quarter-hourly slots,
-# "today + tomorrow").
+#                    00:00 → 23:45 local), regardless of the current time.
+#   * ``tomorrow`` — the full next local day (96 slots) once Tibber publishes the
+#                    day-ahead prices (around 13:00–15:00 local); empty before that.
+#
+# This is deliberately NOT ``priceInfoRange``: that field is a historical cursor
+# connection whose range ends at "now" (it never returns future slots), so it
+# cannot supply upcoming prices.  ``priceInfo`` is forward-looking, so every
+# 15-minute slot's price is present in the DB *before* the slot closes — which is
+# what makes per-slot billing accurate (each period finds its own exact slot
+# instead of falling back to a stale earlier price) and keeps the live current-
+# price entity fresh.  The hourly refresh job re-runs this query, so tomorrow's
+# prices are picked up within an hour of publication without a restart.
 _PRICE_RANGE_QUERY = """
 {
   viewer {
     homes {
       id
       currentSubscription {
-        priceInfoRange(resolution: QUARTER_HOURLY, first: 96) {
+        priceInfo(resolution: QUARTER_HOURLY) {
-          nodes {
+          today {
+            startsAt
+            total
+            energy
+            tax
+            currency
+            level
+          }
+          tomorrow {
             startsAt
             total
             energy
@@ -230,11 +249,15 @@ def fetch_price_range(
     *,
     timeout: float = _DEFAULT_TIMEOUT,
 ) -> list[PricePoint]:
-    """Fetch a range of 15-minute price nodes from the Tibber API.
+    """Fetch the forward-looking today + tomorrow 15-minute price curve from Tibber.
 
-    Sends the ``priceInfoRange(resolution: QUARTER_HOURLY, first: 96)`` query
+    Sends the ``priceInfo(resolution: QUARTER_HOURLY) { today tomorrow }`` query
-    and parses every returned node into a ``PricePoint``.  The number of nodes
+    and parses every node from both lists (today first, then tomorrow) into a
-    is not assumed — all returned nodes are parsed regardless of count.
+    ``PricePoint``.  ``priceInfo`` is forward-looking — ``today`` is always the
+    full current local day and ``tomorrow`` is populated once Tibber publishes the
+    day-ahead prices — so upcoming slots are returned, unlike ``priceInfoRange``
+    which only reaches "now".  ``tomorrow`` may be empty (before publication); the
+    number of nodes is not assumed and all returned nodes are parsed.
 
     Parameters
     ----------
@@ -268,10 +291,15 @@ def fetch_price_range(
     home = _pick_home(homes, home_id)
 
     try:
-        nodes = home["currentSubscription"]["priceInfoRange"]["nodes"]
+        price_info = home["currentSubscription"]["priceInfo"]
+        today = price_info["today"]
+        tomorrow = price_info["tomorrow"]
     except (KeyError, TypeError) as exc:
-        raise TibberError("Tibber API response missing priceInfoRange nodes") from exc
+        raise TibberError("Tibber API response missing priceInfo today/tomorrow") from exc
 
+    # tomorrow is null/empty until Tibber publishes the day-ahead prices; treat
+    # a missing list as empty so we still return today's slots.
+    nodes = list(today or []) + list(tomorrow or [])
     return [_parse_node(node, "QUARTER_HOURLY") for node in nodes]
 
 

app/main.py

@@ -7,6 +7,7 @@ from fastapi import FastAPI, HTTPException, Request
 from fastapi.responses import FileResponse
 from fastapi.staticfiles import StaticFiles
 from apscheduler.schedulers.background import BackgroundScheduler
+from apscheduler.triggers.cron import CronTrigger
 from apscheduler.triggers.interval import IntervalTrigger
 from sqlalchemy.orm import Session
 
@@ -36,6 +37,7 @@ from app.services.modbus_poll import poll_all_enabled_devices, BASE_POLL_TICK_SE
 from app.services.ha_discovery import publish_discovery, publish_states
 from app.services.tibber_prices import refresh_prices
 from app.services.energy_cost import compute_closed_periods
+from app.services.timezone import local_tz
 from scripts.app_db_adopt import AppDatabaseAdoptionError, validate_app_runtime_db
 
 logger = logging.getLogger(__name__)
@@ -159,6 +161,20 @@ def _run_scheduled_ha_state_publish() -> None:
         session.close()
 
 
+def _run_midnight_state_publish() -> None:
+    """本地午夜后不久专门发布一次状态，让 *_today 的每日归零稳稳落在午夜之后
+    （对 HA 钟慢几秒鲁棒）。best-effort：失败仅记日志，不影响调度器。"""
+    session_local = get_session_local()
+    session = session_local()
+    try:
+        from app.services.ha_discovery import publish_states
+        publish_states(session)
+    except Exception:
+        logger.exception("_run_midnight_state_publish: failed (non-fatal)")
+    finally:
+        session.close()
+
+
 def ensure_auth_db_ready() -> None:
     session_local = get_session_local()
     session: Session = session_local()
@@ -233,6 +249,17 @@ async def lifespan(_: FastAPI):
         max_instances=1,
         coalesce=True,
     )
+    # Dedicated midnight publish: fire at local 00:00:10 so *_today grace (5 s) has
+    # already elapsed and the day-rolled value is pushed to HA immediately, rather
+    # than waiting for the next 60-second ha-state-publish sweep.
+    scheduler.add_job(
+        _run_midnight_state_publish,
+        trigger=CronTrigger(hour=0, minute=0, second=10, timezone=local_tz()),
+        id="midnight-today-publish",
+        replace_existing=True,
+        max_instances=1,
+        coalesce=True,
+    )
     scheduler.start()
 
     # MQTT: connect using DB-merged runtime settings so broker configured via UI

app/services/energy_cost.py

@@ -123,6 +123,10 @@ _READING_MAX_STALENESS = timedelta(minutes=_PERIOD_MINUTES)
 # degraded to prevent negative costs or grossly inflated charges.
 _MAX_DELTA_KWH = Decimal("100")
 
+# 每日固定费/税补在"本地午夜后多久"才结算入账。延后到 01:05 是为了让累计成本的
+# 整天阶跃落在新一天、且避开 01:00 整点（HA 长期统计的小时桶边界）。
+_SETTLEMENT_OFFSET = timedelta(hours=1, minutes=5)
+
 # DSMR payload register keys (cumulative kWh, JSON string values).
 _KEY_D1 = "electricity_delivered_1"   # delivered low-tariff  (dal / _1)
 _KEY_D2 = "electricity_delivered_2"   # delivered high-tariff (normal / _2)
@@ -764,7 +768,8 @@ def summarize(session: Session, start: datetime, end: datetime) -> dict[str, Any
     days = _to_decimal(str(total_seconds)) / _to_decimal("86400")
 
     # --- Fixed costs and credits: Principle C cross-version whole-day counting ---
-    today_local: _date = local_now().date()
+    _now_local = local_now()
+    today_local: _date = _now_local.date()
 
     # --- Compute [first_counted, last_counted] local date range (inclusive) ---
     #
@@ -811,8 +816,16 @@ def summarize(session: Session, start: datetime, end: datetime) -> dict[str, Any
     else:
         last_counted = local_end_date - _td(days=1)
 
-    # Cap: only elapsed or today's days.
+    # Settlement cap: "today" is only counted once the local clock has passed the
-    last_counted = min(last_counted, today_local)
+    # settlement offset since midnight (01:05).  This defers the daily standing-charge
+    # step from 00:00 to 01:05, ensuring the cumulative-cost adiabatic jump lands
+    # inside the new calendar day and avoids the HA 01:00 hourly-bucket boundary.
+    _today_midnight_utc = _lmu(today_local)
+    if _now_local >= _today_midnight_utc + _SETTLEMENT_OFFSET:
+        settled_cap = today_local
+    else:
+        settled_cap = today_local - _td(days=1)
+    last_counted = min(last_counted, settled_cap)
 
     # If the range is empty (first_counted > last_counted), no days are counted.
 

app/services/modbus_poll.py

@@ -64,6 +64,7 @@ def poll_device(session: Session, device: ModbusDevice) -> ModbusReading | None:
             device.port,
             device.unit_id,
             [{"start": b.start, "count": b.count} for b in profile.blocks],
+            function_code=profile.function_code,
         )
         payload = profiles.decode(profile, registers)
 

docs/references/DDSU666-Modbus-Protocol.md

@@ -0,0 +1,198 @@
+# DDSU666 Modbus 协议（从官方 PDF 提取）
+
+> 来源：`docs/references/DDSU666 Single phase Smart Meter.pdf`
+> （CHINT / 正泰仪表 **DDSU666 Single phase Smart Meter — Operation Manual**，文档号 `ZTY0.464.1224`，版本 **V2**，2020 年 8 月；厂商 Zhejiang Chint Instrument & Meter Co., Ltd.）
+> 本文件是 PDF 的可读化提取，供本项目的 Modbus 采集驱动设计参考。**以官方 PDF 为准**，本文件如有出入以 PDF 为准。
+> 同类文档见 SDM120 的 `SDM120-Modbus-Protocol.md`；两表差异较大，见下方 §6「与 SDM120 的关键差异」。
+
+## 设备速览（来自手册 Table 1 / Table 5）
+
+| 项 | DDSU666（直接接入） | DDSU666-CT（经互感器） |
+| --- | --- | --- |
+| 精度等级 | Active Class B | Active Class C |
+| 参考电压 | 230 V | 230 V |
+| 电流规格 | 0.25–5(80) A | 0.015–1.5(6) A |
+| 表常数 | 800 imp/kWh | 6400 imp/kWh |
+| 接入方式 | 直接接入 | 经电流互感器 |
+
+- 单相电子式电能表，DIN35mm 导轨安装；测量电压、电流、有功/无功功率、频率、功率因数、正/反向有功电能。
+- 电能测量范围 `0～999999.99 kWh`（LCD 只显示 6 位，自动移动小数点）。
+- 通信：RS485，**Modbus-RTU**（也支持 DL/T 645-2007，可切换，见 §5 `0005H ChangeProtocol`）。
+- 手册 Table 1 标注 Frequency Reference = 60Hz，但 LCD 示例又写 `F=50.00Hz`（手册自身不一致）；**实际频率以寄存器 `200EH` 读数为准**，不要把 50/60 写死。
+
+## 0. 本项目的接入方式（重要）
+
+DDSU666 物理层是 **Modbus RTU（RS-485 串口）**，半双工。和 SDM120 一样，本项目通过一个 **Modbus-TCP 网关**接入：
+
+- 后端用 **Modbus TCP**（`IP:port`）连到网关，网关在串口侧转成 RTU 与电表通信。
+- TCP 帧用 MBAP header、**无 CRC**（CRC 由网关在 RTU 侧处理）。本文档里 RTU 帧的 `CRC (Lo/Hi)` 字段在 TCP 模式下不需要我们关心。
+- **Slave Address / Unit ID = 电表的通信地址 Addr**（范围 1–247；面板按键只能设 1–99；见 §5 `0006H`），在 TCP 请求里作为 unit id 传入。
+- 若以后直连串口（RTU），才需要管波特率 / 数据格式 / CRC：**默认串口格式是 8 数据位、无校验、2 停止位（8N2）**，与 SDM120 的 8N1 不同——直连时务必对齐。
+- 电表必须处于 **Modbus 协议模式**（而非 DL/T 645）才能用本协议；可经面板长按切换，或写 `0005H = 2`（见 §5）。
+
+## 1. 协议帧格式（Appendix A）
+
+异步传输，按字节为单位。一帧 10 位字符 = **1 起始位(0) + 8 数据位(无校验) + 2 停止位(1)**（其它格式可定制）。
+
+### 信息帧结构（Table A.1）
+
+| 字段 | 长度 | 说明 |
+| --- | --- | --- |
+| Start（起始） | >3.5 字符静默 | 帧间至少 3.5 字符空闲时间作为分隔 |
+| Address code（地址码） | 1 字节 | 目标从机地址 1–247；每个从机在总线上地址唯一 |
+| Function code（功能码） | 1 字节 | 仅支持 **03H / 10H**（见 §2） |
+| Data（数据域） | n 字节 | 随功能码不同而不同（起始地址、寄存器数、寄存器数据等） |
+| CRC check code（CRC 校验） | 2 字节 | 16-bit CRC（**低字节在前、高字节在后**；多项式 `A001`） |
+| End（结束） | >3.5 字符静默 | 帧间静默 |
+
+> TCP 网关模式下 Start/End 静默与 CRC 由网关处理，本项目不关心。
+
+### 功能码 03H 示例（读寄存器，Table A.3/A.4）
+
+读从机 `01H`、起始地址 `0CH`、2 个寄存器：
+
+- 主机发送：`01 03 00 0C 00 02 04 08`（最后 `04 08` 是 CRC，低字节 `04` 在前）。
+- 从机返回（设 `0CH/0DH` 内容为 `0000H`、`1388H`）：`01 03 04 00 00 13 88 F7 65`
+  - `04` = 字节数；`00 00` = `0CH` 数据；`13 88` = `0DH` 数据；`F7 65` = CRC（低字节 `F7` 在前）。
+
+> **注意**：单个 16-bit 寄存器内是「高字节在前、低字节在后」（Table A.4 里 `0DH` 数据返回 `13 88` = `0x1388`）。这一点对解码浮点的字节序很关键，见 §3。
+
+### 功能码 10H 示例（写多个寄存器，Table A.5/A.6）
+
+向从机 `01H`、起始地址 `00H` 连续写 3 个寄存器 `0002H,1388H,000AH`：
+
+- 主机发送：`01 10 00 00 00 03 06 00 02 13 88 00 0A 9B E9`
+  - `06` = 写入字节数（3 寄存器 × 2 字节）；随后是 3 个寄存器的数据；末尾 `9B E9` CRC。
+- 从机返回：`01 10 00 00 00 03 80 08`（回显起始地址 + 寄存器数 + CRC `80 08`）。
+
+### 异常响应（Table A.7/A.8）
+
+- 异常时返回的 Function Code = **原功能码 + 128**（即最高位置 1，`03H→83H`、`10H→90H`）。
+- 数据为单字节 Error Code：
+
+| Error Code | 含义 | 说明 |
+| --- | --- | --- |
+| `01H` | Illegal function code | 收到的功能码本表不支持 |
+| `02H` | Illegal register address | 寄存器地址超出有效范围 |
+| `03H` | Illegal data value | 数据值超出对应地址的取值范围 |
+
+## 2. 功能码
+
+DDSU666 **只支持两个功能码**（Table A.2）：
+
+| 功能码 | 作用 | 说明 |
+| --- | --- | --- |
+| **03H** | Read register（读寄存器） | 读一个或多个寄存器——**测量值、电量、配置全部走它** |
+| **10H** | Write multiple registers（写多个寄存器） | 向 n 个连续寄存器写 n 个 16-bit 数据（改配置 / 清电量） |
+
+> ⚠️ **DDSU666 没有「输入寄存器 / FC04」概念**——所有数据（包括电压电流功率）都用 **FC 03H** 读保持寄存器。这是它和 SDM120（测量值走 FC04）最大的踩坑差异，见 §6。
+
+## 3. 数据编码
+
+DDSU666 有两类数据：
+
+1. **配置 / 参数寄存器（§5，`0000H`–`0010H`）**：每个 1 个寄存器、`16-bit with symbols`（**16 位有符号整数**）。
+2. **测量 / 电量寄存器（§4，`2000H`+ / `4000H`+）**：每个参数 = **32-bit IEEE-754 单精度浮点**（手册写 “single precision floating decimal”），占 **2 个相邻寄存器**（Length = 2 Word）。
+
+**浮点字节序 / 字序**
+
+- **字节序（byte order）= 大端：寄存器内高字节在前** —— 由 Table A.4 的 `0x1388` 返回为 `13 88` 确认。
+- **字序（word order，两个寄存器谁是高 16 位）**：手册**没有给出浮点解码的实例**，未明确标注。按标准 Modbus 浮点惯例应为**大端字序（高寄存器在前，`ABCD`）**，与本项目 SDM120 驱动一致（`registers_to_float` 用 `>f`，高寄存器在前）。
+- ⚠️ **需上机实测确认**：读 `2000H`（电压）应解出 ~230V 这样的合理值；若解出乱数，多半是字序相反，改成「低寄存器在前」再试。CHINT 同系列（DTSU/DDSU666）现场固件偶有字序差异，**首次接入务必用一个已知量（电压）校验**，不要凭手册想当然。
+
+> Python 解码（大端、高寄存器在前）：`struct.unpack('>f', struct.pack('>HH', hi_reg, lo_reg))[0]`。
+> pymodbus：`BinaryPayloadDecoder.fromRegisters(regs, byteorder=Endian.BIG, wordorder=Endian.BIG)`。
+
+## 4. 测量 / 电量寄存器表（FC 03H 读）
+
+全部为只读、`Float`（32-bit），每项占 **2 个寄存器**。地址为 Modbus 协议原始地址（即帧里的 Start Register Address Hi/Lo），手册用十六进制。
+
+### 4.1 瞬时量（“Electric quantity of the secondary side”，`2000H` 段）
+
+| 地址(hex) | 参数 | 代号 | 单位 | 备注 |
+| --- | --- | --- | --- | --- |
+| `2000H` | 电压 Voltage | U | V | |
+| `2002H` | 电流 Current | I | A | |
+| `2004H` | 有功功率 Active power | P | **kW** | 手册标注 “the unit is KW”——**不是 W** |
+| `2006H` | 无功功率 Reactive power | Q | **kvar** | |
+| `2008H` | （保留 RESERVED） | — | — | 占 2 寄存器，跳过 |
+| `200AH` | 功率因数 Power factor | PF | — | 无量纲 |
+| `200CH` | （保留 RESERVED） | — | — | 占 2 寄存器，跳过 |
+| `200EH` | 频率 Frequency | Freq | Hz | |
+
+### 4.2 电量（“Electrical data of the secondary side”，`4000H` 段）
+
+| 地址(hex) | 参数 | 代号 | 单位 | 备注 |
+| --- | --- | --- | --- | --- |
+| `4000H` | 正向（导入）有功电能 Active in electricity | Ep | kWh | 正向 / forward active energy |
+| `400AH` | 反向（导出）有功电能 Reverse in electricity | -Ep | kWh | 反向 / reverse active energy |
+
+> 手册里 `4000H` 与 `400AH` 之间（`4002H`–`4009H`）未列出，视为保留/未文档化。
+
+**读取分块建议**
+
+- 瞬时量：`2000H`–`200FH` 共 **16 个寄存器连续**，一次块读即可覆盖 U…Freq（含两段 RESERVED，解码时跳过）。
+- 电量：`4000H`（2 寄存器）与 `400AH`（2 寄存器）相距较远，分两小块读，或读 `4000H`–`400BH`（12 寄存器）一次取出后挑用——以网关 / 电表是否允许跨保留地址块读为准，谨慎起见分开读更稳。
+
+### 常用核心子集（日常监控够用）
+
+电压 `2000H`、电流 `2002H`、有功功率 `2004H`（kW）、功率因数 `200AH`、频率 `200EH`、正向有功电能 `4000H`、反向有功电能 `400AH`。
+
+## 5. 配置 / 参数寄存器表（FC 03H 读 / FC 10H 写）（Table 9）
+
+每个 1 个寄存器、**16-bit 有符号整数**。`R/W` 列来自手册。
+
+| 地址(hex) | 代号 | 含义 | R/W | 取值 / 说明 |
+| --- | --- | --- | --- | --- |
+| `0000H` | UCode | 编程密码 Programming password code | R/W | 写配置前的密码字 |
+| `0001H` | REV. | 保留；**实际读出的是版本号** | R | |
+| `0002H` | ClrE | 电能清零 CLr.E | R/W | **写 `1` 清除总电量**（不可逆，慎用） |
+| `0003H`–`0004H` | RESERVED | 保留 | — | |
+| `0005H` | ChangeProtocol | 协议切换 | R/W | **`2` = Modbus-RTU**，`1` = DL/T 645-2007 |
+| `0006H` | Addr | 通信地址 | R/W | 1–247（面板按键仅 1–99） |
+| `0007H`–`000AH` | RESERVED | 保留 | — | |
+| `000BH` | Meter type | 表型 Meter type | R | 只读设备类型标识 |
+| `000CH` | BAud | 通信波特率 | R/W | **`1`=2400bps，`2`=4800bps，`3`=9600bps**（手册寄存器仅列这三档；通信章另提到也支持 1200bps） |
+| `000DH`–`0010H` | RESERVED | 保留 | — | |
+
+> ⚠️ 写 `0002H`（清电量）、`0006H`（改地址）、`000CH`（改波特率）、`0005H`（切协议）都会改变电表状态或通信参数，配错可能**清空累计电量**或**导致通信中断**。本项目默认**只读采集**，不在自动化链路里写电表配置寄存器。
+> 写配置通常需先经 `0000H UCode` 密码字校验；具体密码值手册正文未给出，需向厂商确认或经面板操作。
+
+## 6. 与 SDM120 的关键差异（迁移 / 复用驱动时必看）
+
+本项目已有 SDM120 profile（`app/integrations/modbus/profiles/sdm120.yaml`）。DDSU666 **不能照搬**，主要差异：
+
+| 维度 | SDM120 (Eastron) | DDSU666 (CHINT) |
+| --- | --- | --- |
+| 读测量值功能码 | **FC 04**（输入寄存器 3X） | **FC 03**（保持寄存器，无 FC04） |
+| 测量值起始地址 | `0x0000` 起（30001） | 瞬时量 `0x2000` 起；电量 `0x4000`/`0x400A` |
+| 有功功率单位 | **W**（瓦） | **kW（千瓦）** —— 入库前注意换算 / 单位标注 |
+| 无功功率单位 | VAr | kvar |
+| 配置寄存器格式 | Float（FC03/16） | **16-bit 有符号整数**（FC03/10） |
+| 写功能码 | 16 / 0x10 | 10H（同 0x10） |
+| 串口默认格式 | 8N1（1 停止位） | **8N2（2 停止位）** |
+| 多协议 | 仅 Modbus | Modbus **与 DL/T 645-2007 可切换**（需确保在 Modbus 模式） |
+| 浮点字序 | 大端、高寄存器在前（手册有实例佐证） | 字节序大端已确认；**字序手册无实例，需上机实测** |
+
+## 7. 给本项目采集驱动的要点小结
+
+1. 走 **Modbus TCP 网关**：`ModbusTcpClient(host, port)`，`slave=<Addr>`；电表须在 **Modbus 协议模式**。
+2. 所有读取（测量 + 电量 + 配置）都用 **FC 03H**——**没有 FC04**。
+3. 测量值在 `0x2000` 段、电量在 `0x4000`/`0x400A`，均为 **float32**；解码大端字节序，**字序默认高寄存器在前但务必用电压实测校验**。
+4. **有功功率单位是 kW、无功是 kvar**——与 SDM120 的 W/VAr 不同，新建 profile / 入库映射时单位别抄错。
+5. 配置寄存器（`0x0000`–`0x0010`）是 **16-bit 有符号整数**，不是 float。
+6. 默认**只读**；`0002H` 写 1 会**清空累计电量**、`0006H/000CH/0005H` 会改通信参数，自动化链路里一律不写。
+7. 新建 profile 时这是 `ddsu666` 这一个 register profile 的定义；建议 `function_code: 3`、`word_order: big`（先按大端字序，接入后用电压读数验证）、瞬时量与电量分块读。
+
+## 8. 实测记录（真机验证，2026-06-30）
+
+首次接入一台 **DDSU666 直接接入版（5(80)A）** 实测，确认以下几点：
+
+- **字序大端，确认无误**：电压 / 电流 / 频率 / 电能用「大端、高寄存器在前」解码全部得到合理值（如 233.9 V / 0.055 A / 49.99 Hz），与 §3 的假设一致。`ddsu666.yaml` 的 `word_order: big` / `byte_order: big` **无需修改**，§3 里「字序需上机实测」一项可视为已关闭。
+- **FC03 读通**：所有量走 FC03，profile `ddsu666` 在采集链路（CLI `read` / 设备 `/test` / 后台轮询）中工作正常。
+- **低电流下「瞬时功率读 0、但电能照常累加」**：测试负载仅为一台 PoE 交换机（≈230 V / 0.05 A，真实有功仅几瓦），**远低于本表测量量程下限 Imin≈0.25 A**。此工况下：
+  - 瞬时 `active_power`（`0x2004`）与 `power_factor`（`0x200A`）寄存器返回**全零**（原始 hex `0x0000 0x0000`）；电表 LCD 上功率在 0~3.3 W、PF 在 0~0.6 之间抖动。
+  - 抖动成因 = **低电流测量噪声 + 开关电源（SMPS，无 PFC）畸变电流**（电流为电压峰值附近的窄脉冲、谐波重 → 畸变功率因数天然偏低）。**不是**「采样率与开关频率拍频」：计量芯片 SH79F7019 采样在 kHz 量级，远低于开关电源 50–200 kHz 的开关频率，两者不在一个频段。
+  - 但累计电能 `import_energy`（`0x4000`）**正常累加**（实测 0 → 0.01 kWh）——电表内部积分器在防潜动起始电流（`0.004·Ib`≈0.02 A）之上照常计量。
+  - **结论**：低于量程下限时**瞬时功率 / PF 不可信，但电能计量不丢**；电流进入量程（正常负载）后瞬时量即稳定可信。这是 5(80)A 大量程表对极小负载的固有特性，**非缺陷、非解码问题**。
+- **排错提示**：若日后看到 DDSU666「功率一直 0」，先确认负载电流是否在 Imin 以上——多半是负载太轻而非链路故障；可用 `scripts/modbus_cli probe --fc 3 --address 0x2000 --count 16` 看 `0x2004/0x2005` 原始寄存器是否真为全零佐证。

docs/roadmap.md

@@ -288,11 +288,36 @@ httpx / paho-mqtt / pyyaml / apscheduler 均为 M5 已有依赖，M6 复用，
 
 **动机**：浏览器端走 session cookie 即可，但**脚本 / 设备 / 外部程序调用 API** 需要一种长期有效、可随身携带的凭据。在设置页加一组功能，由 admin **手动签发 long-lived token**，之后用它来调 API。
 
+**本次明确的首要目标 = 给现在裸奔的 ingestion 端点上鉴权**（2026-06-27 与用户确认）：
+
+- `POST /location/record`（`app/api/routes/location.py:18`）——位置记录上报。**目前无任何鉴权**。当前数据经 Home Assistant 转发进来，上 token 后 **HA 侧需携带该 token**；也可由其他客户端直接上报。
+- `POST /poo/record`（`app/api/routes/poo.py:21`）+ `GET /poo/latest`（`poo.py:57`）——小狗排便记录上报 / 最新查询。**目前无任何鉴权**。
+- 这些是设备 / 脚本（非浏览器）端点，session cookie 不适用，正是 long-lived token 的用武之地。（浏览器 CRUD `/api/data/*` 已由 session 保护，不在此列。）
+
 **范围（粗略，待细化）**：
 
 - 设置页新增「API Token」区：生成 / 命名 / 吊销 long-lived token；明文只在**生成时展示一次**，此后只存哈希。
-- 后端支持用该 token 鉴权访问 API（与现有 session cookie 并存，互不影响）。
+- 后端支持用该 token 鉴权访问 API（与现有 session cookie 并存，互不影响）；给上述 ingestion 端点加 token 鉴权依赖。
 - 与 [M3](#m3--开放与移动端远期试水) 的 token 主题相关，但**这条是 Web 设置页手动签发的 PAT 风格**，不依赖移动端 OAuth 流程；两者实现时可复用同一套 token 存储 / 校验。
+- 与下面第 3 条「Session 滑动续期」同属 Authentication 主题（一个是设备/脚本的长期凭据，一个是浏览器短会话体验），实现时鉴权层可一并梳理。
+
+### 3. Session 滑动自动续期（Authentication）
+
+**动机**（2026-06-27 与用户确认）：当前 session 是**绝对过期**——登录即定死、活动不续期，满 TTL 必须重新登录，体验割裂。希望改成**滑动续期（sliding / rolling）**：只要用户还在活动就自动延长，提供"在用就不掉线"的体验。
+
+**现状（实现起点，便于快速拾起）**：
+
+- TTL 默认 **12 小时**：`auth_session_ttl_hours`（`app/config.py:38`；配置页 `app/services/config_page.py:45` 可运行时改）。
+- 登录时**一次性写死**：`create_session` 设 `expires_at = now + ttl`（`app/services/auth.py:94`）+ cookie `max_age = ttl`（`app/api/routes/api/session.py:153`）。
+- 每请求**只读校验、从不延长**：`get_authenticated_session`（`app/services/auth.py:103`）只判断 `expires_at <= now`，过期时仅顺手标 `revoked`。`set_cookie` 只在登录路由调用一次，**无 per-request 中间件**。→ 所以是绝对过期，不是滑动。
+
+**设计要点（待写设计文档时展开）**：
+
+- 校验通过时 bump `expires_at = now + ttl` 并**重发 cookie**（滑动窗口）。
+- **写节流**：不要每个请求都写 DB——仅当剩余寿命已过半（或距上次续期 > N 分钟）才续期，避免高频写放大。
+- **绝对寿命硬顶**：除滑动 TTL 外再设 `created_at + max_lifetime` 上限，防止"永不过期"的会话（安全考量）。
+- 新增配置项：滑动 TTL、绝对寿命上限、续期节流阈值。
+- 注意：改动只对**新逻辑生效**，已存在 session 的 `expires_at` 行为按新校验路径走即可；上线前过校验闸门。
 
 ## Future Ideas（暂不排期，想到先记下）
 

scripts/modbus_cli.py

@@ -131,6 +131,7 @@ def cmd_read(args: argparse.Namespace) -> None:
 
     print(f"Profile  : {profile.name} — {profile.description}")
     print(f"Gateway  : {host}:{port}  unit_id={unit_id}")
+    print(f"Function : FC{profile.function_code:02d}")
     print(f"Blocks   : {[(b.start, b.count) for b in profile.blocks]}")
     print()
 
@@ -141,7 +142,7 @@ def cmd_read(args: argparse.Namespace) -> None:
     from app.integrations.modbus.driver import read_blocks
 
     try:
-        registers = read_blocks(host, port, unit_id, blocks)
+        registers = read_blocks(host, port, unit_id, blocks, function_code=profile.function_code)
     except ModbusConnectionError as exc:
         print(f"Connection error: {exc}", file=sys.stderr)
         sys.exit(1)

tests/test_energy_cost.py

@@ -1199,10 +1199,16 @@ def _ams_midnight(year: int, month: int, day: int) -> datetime:
 
 
 class TestSummarizePrincipleC:
-    """Principle C whole-day counting with pinned Europe/Amsterdam timezone."""
+    """Principle C whole-day counting with pinned Europe/Amsterdam timezone.
+
+    Tests that assert a specific "today" (e.g. June 25) must also pin
+    ``local_now`` via *pinned_now* to remain deterministic as wall-clock
+    time advances.  Tests that only care about windows entirely in the past
+    or entirely in the future do not need to pin ``local_now``.
+    """
 
     # Effective_from: June 1 CEST local midnight = May 31 22:00 UTC.
-    # Today local = June 25 CEST (since today is 2026-06-25).
+    # Reference "today" pinned in individual tests = June 25 CEST.
 
     def _make_single_version_contract(self, session: Session, *, effective_from_utc: datetime) -> None:
         """Create an active manual contract with a single version."""
@@ -1210,10 +1216,27 @@ class TestSummarizePrincipleC:
         _make_version(session, contract, _MANUAL_VALUES, effective_from=effective_from_utc)
         session.commit()
 
-    def _run_summarize_ams(self, session: Session, start_utc: datetime, end_utc: datetime) -> dict:
+    def _run_summarize_ams(
-        """Run summarize with Europe/Amsterdam local_tz monkeypatched."""
+        self,
+        session: Session,
+        start_utc: datetime,
+        end_utc: datetime,
+        *,
+        pinned_now: datetime | None = None,
+    ) -> dict:
+        """Run summarize with Europe/Amsterdam local_tz monkeypatched.
+
+        If *pinned_now* is given, also patches ``app.services.energy_cost.local_now``
+        to that fixed value, making settlement-offset logic deterministic
+        regardless of wall-clock time.
+        """
         from unittest.mock import patch
+        import app.services.energy_cost as _ec
+
         with patch.object(tz_module, "local_tz", return_value=_ams()):
+            if pinned_now is not None:
+                with patch.object(_ec, "local_now", return_value=pinned_now):
+                    return summarize(session, start_utc, end_utc)
             return summarize(session, start_utc, end_utc)
 
     def test_today_window_counts_1_day(self, energy_db: Session) -> None:
@@ -1240,6 +1263,9 @@ class TestSummarizePrincipleC:
     def test_future_window_counts_0_days(self, energy_db: Session) -> None:
         """A fully future window (all local dates > today) counts 0 days.
 
+        Pins ``local_now`` to June 25 2026 noon AMS so the 7/1→8/1 window is
+        genuinely in the future regardless of the actual wall-clock date
+        (mirrors the sibling window tests, which all pin ``local_now``).
         Matches table row: 7/1→8/1 (all future) → 0 days.
         """
         eff_utc = _ams_midnight(2026, 6, 1)
@@ -1247,7 +1273,9 @@ class TestSummarizePrincipleC:
 
         start = _ams_midnight(2026, 7, 1)
         end = _ams_midnight(2026, 8, 1)
-        result = self._run_summarize_ams(energy_db, start, end)
+        # Pin local_now to June 25 2026 noon AMS so 7/1→8/1 stays fully future.
+        pinned_now = datetime(2026, 6, 25, 12, 0, 0, tzinfo=_ams())
+        result = self._run_summarize_ams(energy_db, start, end, pinned_now=pinned_now)
 
         assert result["fixed_costs"] == 0.0, (
             f"All-future window must count 0 days; got fixed_costs={result['fixed_costs']}"
@@ -1259,7 +1287,10 @@ class TestSummarizePrincipleC:
     def test_this_month_window_counts_25_days(self, energy_db: Session) -> None:
         """This Month (June 1 → July 1 local) counts 25 elapsed days (June 1..25).
 
-        Today = June 25 local, so June 26–30 are not yet elapsed.
+        Pins ``local_now`` to June 25 noon AMS so the test is deterministic
+        regardless of the actual wall-clock date.  June 25 is well past the
+        01:05 settlement offset, so ``settled_cap = June 25``.
+        Today = June 25 local, so June 26–30 are not yet elapsed → 25 days.
         Matches table row: 6/1→7/1 (This Month) → 25 days.
         """
         eff_utc = _ams_midnight(2026, 6, 1)
@@ -1267,7 +1298,9 @@ class TestSummarizePrincipleC:
 
         start = _ams_midnight(2026, 6, 1)
         end = _ams_midnight(2026, 7, 1)
-        result = self._run_summarize_ams(energy_db, start, end)
+        # Pin local_now to June 25 2026 noon AMS (well past 01:05 settlement).
+        pinned_now = datetime(2026, 6, 25, 12, 0, 0, tzinfo=_ams())
+        result = self._run_summarize_ams(energy_db, start, end, pinned_now=pinned_now)
 
         daily_fixed = (9.87 + 9.87) / 30
         daily_credit = 600.0 / 365
@@ -1304,8 +1337,9 @@ class TestSummarizePrincipleC:
     def test_partial_future_window_caps_at_today(self, energy_db: Session) -> None:
         """A window partially in the future caps at today (only elapsed days counted).
 
+        Pins ``local_now`` to June 25 noon AMS so the test is deterministic.
         Window: June 25 → June 28 local (4 dates, but June 26/27 are future).
-        Today = June 25 → only 1 day elapsed (June 25).
+        Today = June 25 → settled_cap = June 25 → only 1 day elapsed (June 25).
         Matches table row: 6/25→6/28 → 1 day.
         """
         eff_utc = _ams_midnight(2026, 6, 1)
@@ -1313,7 +1347,9 @@ class TestSummarizePrincipleC:
 
         start = _ams_midnight(2026, 6, 25)
         end = _ams_midnight(2026, 6, 28)
-        result = self._run_summarize_ams(energy_db, start, end)
+        # Pin local_now to June 25 2026 noon AMS (well past 01:05 settlement).
+        pinned_now = datetime(2026, 6, 25, 12, 0, 0, tzinfo=_ams())
+        result = self._run_summarize_ams(energy_db, start, end, pinned_now=pinned_now)
 
         daily_fixed = (9.87 + 9.87) / 30
         daily_credit = 600.0 / 365
@@ -1366,8 +1402,12 @@ class TestSummarizePrincipleC:
         start = _ams_midnight(2026, 6, 1)
         end = _ams_midnight(2026, 7, 1)
         from unittest.mock import patch
+        import app.services.energy_cost as _ec
+        # Pin local_now to June 25 2026 noon AMS: today=June 25, settled_cap=June 25.
+        pinned_now = datetime(2026, 6, 25, 12, 0, 0, tzinfo=_ams())
         with patch.object(tz_module, "local_tz", return_value=_ams()):
-            result = summarize(energy_db, start, end)
+            with patch.object(_ec, "local_now", return_value=pinned_now):
+                result = summarize(energy_db, start, end)
 
         # V1: 24 days × (6+6)/30; V2: 1 day × (12+12)/30
         expected_fixed = 24 * 12 / 30 + 1 * 24 / 30
@@ -1408,12 +1448,16 @@ class TestSummarizePrincipleC:
         _make_version(energy_db, contract, _VALUES_V2, effective_from=v2_from)
         energy_db.commit()
 
-        # Window = June 25 only (today, 1 day elapsed at V2 rate)
+        # Window = June 25 only (today, 1 day elapsed at V2 rate).
+        # Pin local_now to June 25 noon AMS: today=June 25, settled_cap=June 25.
         start = _ams_midnight(2026, 6, 25)
         end = _ams_midnight(2026, 7, 1)
         from unittest.mock import patch
+        import app.services.energy_cost as _ec
+        pinned_now = datetime(2026, 6, 25, 12, 0, 0, tzinfo=_ams())
         with patch.object(tz_module, "local_tz", return_value=_ams()):
-            result = summarize(energy_db, start, end)
+            with patch.object(_ec, "local_now", return_value=pinned_now):
+                result = summarize(energy_db, start, end)
 
         # Only 1 day at V2 rate
         expected_fixed = 1 * 24 / 30
@@ -1434,13 +1478,11 @@ class TestSummarizePrincipleC:
           within the day start_utc falls.  June 24 is the anchor day → its charge is counted.
 
         Window: [June 24 07:18 UTC (= 09:18 CEST), June 26 22:00 UTC (= June 27 00:00 CEST)).
-        Today local = June 25 (2026-06-25).
+        Pins local_now to June 25 noon AMS → today=June 25, settled_cap=June 25.
         first_counted = June 24 (anchor day, previously dropped).
         last_counted = min(June 26, June 25) = June 25.
         n_days = June 25 - June 24 + 1 = 2.
         """
-        from unittest.mock import patch
-
         eff_utc = _ams_midnight(2026, 6, 1)
         self._make_single_version_contract(energy_db, effective_from_utc=eff_utc)
 
@@ -1449,8 +1491,9 @@ class TestSummarizePrincipleC:
         # end = June 26 22:00 UTC = June 27 00:00 CEST (past today June 25, capped)
         end_utc = datetime(2026, 6, 26, 22, 0, 0, tzinfo=_UTC)
 
-        with patch.object(tz_module, "local_tz", return_value=_ams()):
+        # Pin local_now to June 25 noon AMS: today=June 25, settled_cap=June 25.
-            result = self._run_summarize_ams(energy_db, anchor_utc, end_utc)
+        pinned_now = datetime(2026, 6, 25, 12, 0, 0, tzinfo=_ams())
+        result = self._run_summarize_ams(energy_db, anchor_utc, end_utc, pinned_now=pinned_now)
 
         daily_fixed = (9.87 + 9.87) / 30
         daily_credit = 600.0 / 365
@@ -2409,3 +2452,266 @@ class TestMeterAwareComputePeriod:
         assert row.degraded is False, "All-zero deltas must not trigger the D6 guard"
         assert row.import_cost == 0.0
         assert row.net_cost == 0.0
+
+
+# ---------------------------------------------------------------------------
+# FUE-T08. summarize — settlement offset (local 01:05)
+# ---------------------------------------------------------------------------
+
+
+class TestSummarizeSettlementOffset:
+    """FUE-T08: daily fixed-fee/heffingskorting settled after local 01:05.
+
+    Reference date: June 26, 2026 AMS (CEST = UTC+2).
+      - AMS midnight June 26  = June 25 22:00 UTC
+      - Settlement threshold  = June 25 22:00 + 01:05 = June 25 23:05 UTC
+                              = June 26 01:05 AMS
+      - "before offset" now   = June 26 00:30 AMS = June 25 22:30 UTC
+      - "after  offset" now   = June 26 01:10 AMS = June 25 23:10 UTC
+
+    All tests monkeypatch both local_tz (Europe/Amsterdam) and
+    ``app.services.energy_cost.local_now`` to be fully deterministic.
+    """
+
+    # UTC instants used as "now":
+    # June 25 22:30 UTC = June 26 00:30 AMS (before settlement threshold 23:05 UTC)
+    _NOW_BEFORE = datetime(2026, 6, 25, 22, 30, 0, tzinfo=UTC)
+    # June 25 23:10 UTC = June 26 01:10 AMS (after settlement threshold 23:05 UTC)
+    _NOW_AFTER = datetime(2026, 6, 25, 23, 10, 0, tzinfo=UTC)
+
+    def _setup_single_version_contract(self, session: Session) -> None:
+        """Insert a manual contract effective Jan 1 2026 (covers all test dates)."""
+        c = _make_contract(session, kind="manual", active=True)
+        _make_version(session, c, _MANUAL_VALUES, effective_from=_ams_midnight(2026, 1, 1))
+        session.commit()
+
+    def _run(
+        self,
+        session: Session,
+        start_utc: datetime,
+        end_utc: datetime,
+        *,
+        now_utc: datetime,
+    ) -> dict:
+        """Run summarize with AMS timezone and pinned local_now.
+
+        *now_utc* is converted to AMS before being used as the ``local_now``
+        return value, so ``.date()`` yields the correct AMS local date.
+        """
+        from unittest.mock import patch
+        import app.services.energy_cost as _ec
+
+        now_ams = now_utc.astimezone(_ams())
+        with patch.object(tz_module, "local_tz", return_value=_ams()):
+            with patch.object(_ec, "local_now", return_value=now_ams):
+                return summarize(session, start_utc, end_utc)
+
+    # --- AC1: before 01:05 → today not settled → fixed_costs/credits == 0 ---
+
+    def test_today_window_before_offset_yields_zero(self, energy_db: Session) -> None:
+        """AC1: At local 00:30 (before 01:05), today's window → credits == 0 and fixed_costs == 0.
+
+        Window: [June 26 AMS midnight, June 27 AMS midnight).
+        now = June 26 00:30 AMS (before 01:05) → settled_cap = June 25.
+        first_counted = June 26 > last_counted = June 25 → 0 days.
+        """
+        self._setup_single_version_contract(energy_db)
+        start = _ams_midnight(2026, 6, 26)   # June 25 22:00 UTC
+        end = _ams_midnight(2026, 6, 27)     # June 26 22:00 UTC
+
+        result = self._run(energy_db, start, end, now_utc=self._NOW_BEFORE)
+
+        assert result["fixed_costs"] == 0.0, (
+            "AC1: before settlement offset, today's fixed_costs must be 0; "
+            f"got {result['fixed_costs']}"
+        )
+        assert result["credits"] == 0.0, (
+            "AC1: before settlement offset, today's credits must be 0; "
+            f"got {result['credits']}"
+        )
+
+    # --- AC2: >= 01:05 → today settled → 1 day fixed/credits ---
+
+    def test_today_window_after_offset_yields_one_day(self, energy_db: Session) -> None:
+        """AC2: At local 01:10 (>= 01:05), today's window → 1 day of fixed/credits.
+
+        Window: [June 26 AMS midnight, June 27 AMS midnight).
+        now = June 26 01:10 AMS (after 01:05) → settled_cap = June 26.
+        first_counted = June 26 = last_counted → 1 day.
+        """
+        self._setup_single_version_contract(energy_db)
+        start = _ams_midnight(2026, 6, 26)
+        end = _ams_midnight(2026, 6, 27)
+
+        result = self._run(energy_db, start, end, now_utc=self._NOW_AFTER)
+
+        daily_fixed = (9.87 + 9.87) / 30
+        daily_credit = 600.0 / 365
+        assert abs(result["fixed_costs"] - daily_fixed) < 1e-9, (
+            "AC2: after settlement offset, today's fixed_costs must equal 1 day; "
+            f"expected {daily_fixed:.6f}, got {result['fixed_costs']}"
+        )
+        assert abs(result["credits"] - daily_credit) < 1e-9, (
+            "AC2: after settlement offset, today's credits must equal 1 day; "
+            f"expected {daily_credit:.6f}, got {result['credits']}"
+        )
+
+    # --- AC3a: cumulative window, before offset → today (June 26) not counted ---
+
+    def test_cumulative_before_offset_excludes_today(self, energy_db: Session) -> None:
+        """AC3: Cumulative window at 00:30 (before offset) excludes today from count.
+
+        Window: [June 24 AMS midnight, June 26 00:30 AMS).
+          first_counted = June 24.
+          last_counted (from window) = June 26 (lmu(June 26) = June 25 22:00 < 22:30).
+          settled_cap = June 25 (before offset) → min(June 26, June 25) = June 25.
+          Counted: June 24 + June 25 = 2 days (today June 26 excluded).
+        """
+        self._setup_single_version_contract(energy_db)
+        start = _ams_midnight(2026, 6, 24)   # June 23 22:00 UTC
+        end = self._NOW_BEFORE               # June 25 22:30 UTC = June 26 00:30 AMS
+
+        result = self._run(energy_db, start, end, now_utc=self._NOW_BEFORE)
+
+        daily_fixed = (9.87 + 9.87) / 30
+        daily_credit = 600.0 / 365
+        assert abs(result["fixed_costs"] - daily_fixed * 2) < 1e-9, (
+            "AC3 before offset: today (June 26) must not be counted; expected 2 days; "
+            f"got {result['fixed_costs']}"
+        )
+        assert abs(result["credits"] - daily_credit * 2) < 1e-9, (
+            "AC3 before offset: credits must be 2 days; "
+            f"got {result['credits']}"
+        )
+
+    # --- AC3b: cumulative window, after offset → today (June 26) counted ---
+
+    def test_cumulative_after_offset_includes_today(self, energy_db: Session) -> None:
+        """AC3: Cumulative window at 01:10 (after offset) includes today.
+
+        Window: [June 24 AMS midnight, June 26 01:10 AMS).
+          first_counted = June 24.
+          last_counted (from window) = June 26 (lmu(June 26) < 23:10 UTC).
+          settled_cap = June 26 (after offset) → last_counted = June 26.
+          Counted: June 24 + June 25 + June 26 = 3 days.
+        """
+        self._setup_single_version_contract(energy_db)
+        start = _ams_midnight(2026, 6, 24)   # June 23 22:00 UTC
+        end = self._NOW_AFTER               # June 25 23:10 UTC = June 26 01:10 AMS
+
+        result = self._run(energy_db, start, end, now_utc=self._NOW_AFTER)
+
+        daily_fixed = (9.87 + 9.87) / 30
+        daily_credit = 600.0 / 365
+        assert abs(result["fixed_costs"] - daily_fixed * 3) < 1e-9, (
+            "AC3 after offset: today (June 26) must be counted; expected 3 days; "
+            f"got {result['fixed_costs']}"
+        )
+        assert abs(result["credits"] - daily_credit * 3) < 1e-9, (
+            "AC3 after offset: credits must be 3 days; "
+            f"got {result['credits']}"
+        )
+
+    # --- AC4: past days always fully counted regardless of offset ---
+
+    def test_past_days_always_counted_regardless_of_offset(self, energy_db: Session) -> None:
+        """AC4: Past days (all before today) are fully counted even before 01:05.
+
+        Window: [June 20 AMS midnight, June 26 AMS midnight) — all before today.
+        now = June 26 00:30 AMS (before offset) → settled_cap = June 25.
+        last_counted (from window) = June 25 (lmu(June 26) = end_utc, not <).
+        min(June 25, June 25) = June 25 → 6 days (June 20-25), all past.
+        """
+        self._setup_single_version_contract(energy_db)
+        start = _ams_midnight(2026, 6, 20)   # June 19 22:00 UTC
+        end = _ams_midnight(2026, 6, 26)     # June 25 22:00 UTC
+
+        result = self._run(energy_db, start, end, now_utc=self._NOW_BEFORE)
+
+        daily_fixed = (9.87 + 9.87) / 30
+        daily_credit = 600.0 / 365
+        # June 20-25 = 6 days, all past — unaffected by settlement offset.
+        assert abs(result["fixed_costs"] - daily_fixed * 6) < 1e-9, (
+            "AC4: past days must be fully counted regardless of settlement offset; "
+            f"expected 6 days = {daily_fixed * 6:.6f}, got {result['fixed_costs']}"
+        )
+        assert abs(result["credits"] - daily_credit * 6) < 1e-9, (
+            "AC4: past credits must be 6 days; "
+            f"got {result['credits']}"
+        )
+
+    # --- AC5: cross-version segments still correct with settlement offset ---
+
+    def test_cross_version_with_settlement_offset(self, energy_db: Session) -> None:
+        """AC5: Cross-version day split is correct when settlement offset is active.
+
+        V1 covers June 24; V2 covers June 25+.
+        Window: [June 24 AMS midnight, June 26 01:10 AMS).
+        After offset (01:10) → settled_cap = June 26 → 3 days: V1=1, V2=2.
+
+        V1: network_fee=6, management_fee=6 → daily_fixed = 12/30
+            heffingskorting=300           → daily_credit = 300/365
+        V2: network_fee=12, management_fee=12 → daily_fixed = 24/30
+            heffingskorting=600            → daily_credit = 600/365
+
+        Expected:
+          fixed_costs = 1×(12/30) + 2×(24/30) = 0.4 + 1.6 = 2.0
+          credits     = 1×(300/365) + 2×(600/365) = 1500/365
+        """
+        _VALUES_V1 = {
+            "energy": {"buy": {"normal": 0.10, "dal": 0.10},
+                       "sell": {"normal": 0.05, "dal": 0.05},
+                       "energy_tax": 0.0, "ode": 0.0},
+            "standing": {"network_fee": 6.0, "management_fee": 6.0},
+            "credits": {"heffingskorting": 300.0},
+        }
+        _VALUES_V2 = {
+            "energy": {"buy": {"normal": 0.20, "dal": 0.20},
+                       "sell": {"normal": 0.08, "dal": 0.08},
+                       "energy_tax": 0.0, "ode": 0.0},
+            "standing": {"network_fee": 12.0, "management_fee": 12.0},
+            "credits": {"heffingskorting": 600.0},
+        }
+        v1_from = _ams_midnight(2026, 6, 24)   # June 23 22:00 UTC
+        v2_from = _ams_midnight(2026, 6, 25)   # June 24 22:00 UTC
+
+        c = _make_contract(energy_db, kind="manual", active=True)
+        _make_version(energy_db, c, _VALUES_V1, effective_from=v1_from, effective_to=v2_from)
+        _make_version(energy_db, c, _VALUES_V2, effective_from=v2_from)
+        energy_db.commit()
+
+        start = _ams_midnight(2026, 6, 24)   # June 23 22:00 UTC
+        end = self._NOW_AFTER               # June 25 23:10 UTC = June 26 01:10 AMS
+
+        result = self._run(energy_db, start, end, now_utc=self._NOW_AFTER)
+
+        expected_fixed = 1 * 12 / 30 + 2 * 24 / 30    # V1: 1 day, V2: 2 days
+        expected_credits = 1 * 300 / 365 + 2 * 600 / 365
+        assert abs(result["fixed_costs"] - expected_fixed) < 1e-9, (
+            f"AC5: cross-version fixed_costs wrong; expected {expected_fixed}, "
+            f"got {result['fixed_costs']}"
+        )
+        assert abs(result["credits"] - expected_credits) < 1e-9, (
+            f"AC5: cross-version credits wrong; expected {expected_credits}, "
+            f"got {result['credits']}"
+        )
+
+    # --- AC6: return dict key-set unchanged ---
+
+    def test_return_dict_keys_unchanged(self, energy_db: Session) -> None:
+        """AC6: summarize() return dict keys are unchanged by the settlement offset."""
+        self._setup_single_version_contract(energy_db)
+        start = _ams_midnight(2026, 6, 26)
+        end = _ams_midnight(2026, 6, 27)
+
+        result = self._run(energy_db, start, end, now_utc=self._NOW_AFTER)
+
+        expected_keys = {
+            "currency", "metered_import", "metered_export", "metered_net",
+            "fixed_costs", "credits", "total_payable", "period_count",
+            "degraded_count", "days",
+        }
+        assert set(result.keys()) == expected_keys, (
+            f"AC6: summarize() key set changed; expected {expected_keys}, "
+            f"got {set(result.keys())}"
+        )

tests/test_energy_expose.py

@@ -1729,10 +1729,13 @@ def test_import_cost_today_getter_uses_local_day_window(energy_db) -> None:
     """FU11: import_cost_today getter returns value for today's local window.
 
     Setup: period at local 'today' (within today's UTC window), active contract.
-    Timezone pinned to UTC. Verifies: value = metered_import + fixed_costs for 1 day
+    Timezone pinned to UTC, local_now pinned to 2026-06-26 12:00:00 UTC (deterministic midday).
+    Verifies: value = metered_import + fixed_costs for 1 day
     (Principle C: today counts as elapsed if we're past local midnight — which UTC is).
 
     FUE-T05: provider requires an active electricity meter.
+    FUE-T09: local_now pinned (not real time) to eliminate the ~5s flaky window introduced
+    by the grace period: (local_now()-5s).date() is unpredictable near UTC 00:00:00–00:00:04.
     """
     from datetime import timedelta
     from unittest.mock import patch
@@ -1740,17 +1743,16 @@ def test_import_cost_today_getter_uses_local_day_window(energy_db) -> None:
     from app.integrations.expose import build_catalog
     from app.services import timezone as _tz_mod
 
-    now_utc = datetime.now(timezone.utc)
+    # Pin to a deterministic midday moment — (fake_now - 5s).date() == fake_now.date() always.
-    # Place a period in today's window (1 hour ago, well within today UTC midnight→tomorrow)
+    fake_now = datetime(2026, 6, 26, 12, 0, 0, tzinfo=timezone.utc)
-    # When TZ=UTC, local today = UTC today, so a period 1h ago is in today's window.
+    today_midnight = fake_now.replace(hour=0, minute=0, second=0, microsecond=0)
-    t0 = now_utc.replace(minute=0, second=0, microsecond=0) - timedelta(hours=1)
+
-    # Ensure t0 is still today UTC (handle edge case where now is < 1h past UTC midnight)
+    # Place a period 1 hour before fake_now — well within today's [midnight, tomorrow midnight).
-    if t0.date() < now_utc.date():
+    t0 = fake_now.replace(hour=11, minute=0, second=0, microsecond=0)
-        t0 = now_utc.replace(hour=0, minute=0, second=0, microsecond=0)
 
     # Contract starting well before today
-    effective_from = now_utc.replace(hour=0, minute=0, second=0, microsecond=0) - timedelta(days=30)
+    effective_from = today_midnight - timedelta(days=30)
-    meter_start = now_utc.replace(hour=0, minute=0, second=0, microsecond=0) - timedelta(days=30)
+    meter_start = today_midnight - timedelta(days=30)
 
     import_cost_today = 1.23
 
@@ -1766,8 +1768,12 @@ def test_import_cost_today_getter_uses_local_day_window(energy_db) -> None:
         session.commit()
 
     with Session(energy_db) as session:
-        # Pin timezone to UTC so today_local = UTC date (deterministic on any CI host).
+        # Pin both local_tz (UTC) and local_now (deterministic midday) so the today window
-        with patch.object(_tz_mod, "local_tz", return_value=ZoneInfo("UTC")):
+        # is always [2026-06-26 00:00:00 UTC, 2026-06-27 00:00:00 UTC), regardless of CI clock.
+        with (
+            patch.object(_tz_mod, "local_tz", return_value=ZoneInfo("UTC")),
+            patch.object(_tz_mod, "local_now", return_value=fake_now),
+        ):
             catalog = build_catalog(session)
             today_entry = next(
                 e for e in catalog if e.entity.key == "energy.import_cost_today"
@@ -1789,6 +1795,8 @@ def test_export_revenue_today_getter_uses_local_day_window(energy_db) -> None:
     """FU11: export_revenue_today getter returns value for today's local window.
 
     FUE-T05: provider requires an active electricity meter.
+    FUE-T09: local_now pinned (not real time) to eliminate the ~5s flaky window introduced
+    by the grace period: (local_now()-5s).date() is unpredictable near UTC 00:00:00–00:00:04.
     """
     from datetime import timedelta
     from unittest.mock import patch
@@ -1796,13 +1804,15 @@ def test_export_revenue_today_getter_uses_local_day_window(energy_db) -> None:
     from app.integrations.expose import build_catalog
     from app.services import timezone as _tz_mod
 
-    now_utc = datetime.now(timezone.utc)
+    # Pin to a deterministic midday moment — (fake_now - 5s).date() == fake_now.date() always.
-    t0 = now_utc.replace(minute=0, second=0, microsecond=0) - timedelta(hours=1)
+    fake_now = datetime(2026, 6, 26, 12, 0, 0, tzinfo=timezone.utc)
-    if t0.date() < now_utc.date():
+    today_midnight = fake_now.replace(hour=0, minute=0, second=0, microsecond=0)
-        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)
+    # Place a period 1 hour before fake_now — well within today's [midnight, tomorrow midnight).
-    meter_start = now_utc.replace(hour=0, minute=0, second=0, microsecond=0) - timedelta(days=30)
+    t0 = fake_now.replace(hour=11, minute=0, second=0, microsecond=0)
+
+    effective_from = today_midnight - timedelta(days=30)
+    meter_start = today_midnight - timedelta(days=30)
     export_today = 0.75
 
     with Session(energy_db) as session:
@@ -1817,7 +1827,12 @@ def test_export_revenue_today_getter_uses_local_day_window(energy_db) -> None:
         session.commit()
 
     with Session(energy_db) as session:
-        with patch.object(_tz_mod, "local_tz", return_value=ZoneInfo("UTC")):
+        # Pin both local_tz (UTC) and local_now (deterministic midday) so the today window
+        # is always [2026-06-26 00:00:00 UTC, 2026-06-27 00:00:00 UTC), regardless of CI clock.
+        with (
+            patch.object(_tz_mod, "local_tz", return_value=ZoneInfo("UTC")),
+            patch.object(_tz_mod, "local_now", return_value=fake_now),
+        ):
             catalog = build_catalog(session)
             today_entry = next(
                 e for e in catalog if e.entity.key == "energy.export_revenue_today"
@@ -2468,3 +2483,205 @@ def test_energy_cost_identifiers_change_after_meter_swap(energy_db) -> None:
         assert entity.device.identifiers[1] != old_uuid, (
             f"After swap, old uuid {old_uuid!r} must not appear in identifiers"
         )
+
+
+# ---------------------------------------------------------------------------
+# FUE-T09: *_today grace — window selection at / around local midnight
+# ---------------------------------------------------------------------------
+#
+# Strategy: patch local_now + local_tz (to UTC) and spy on summarize to capture
+# the start/end arguments.  Verifies that the 5-second grace means:
+#   - 00:00:03 → today_local = yesterday   (grace not yet elapsed)
+#   - 00:00:12 → today_local = today       (grace elapsed)
+#   - 12:00:00 → today_local = today       (midday, unaffected)
+
+
+def _spy_summarize_factory(captured: dict):
+    """Return a summarize spy that records start/end and returns a zero-value dict."""
+    def _spy(sess, start, end):
+        captured["start"] = start
+        captured["end"] = end
+        return {"metered_import": 0.0, "fixed_costs": 0.0, "metered_export": 0.0, "credits": 0.0}
+    return _spy
+
+
+def _setup_grace_db(energy_db) -> None:
+    """Insert active meter + active contract + one non-degraded period for grace tests."""
+    anchor = datetime(2026, 6, 25, 0, 0, 0, tzinfo=timezone.utc)
+    with Session(energy_db) as session:
+        _make_active_meter(session, started_at=anchor, label="Grace Test Meter")
+        _make_contract_with_version(
+            session,
+            values=_STANDING_VALUES,
+            effective_from=anchor,
+            active=True,
+        )
+        _make_period(session, period_start=anchor, import_cost=1.0, export_revenue=0.5, degraded=False)
+        session.commit()
+
+
+def test_today_getter_grace_uses_yesterday_window_at_00_00_03(energy_db) -> None:
+    """FUE-T09 AC1a: at local 00:00:03 (< grace=5s), both today getters use YESTERDAY's window.
+
+    With grace=5s, (local_now() - 5s) = 2026-06-25 23:59:58, so today_local = 2026-06-25
+    (yesterday).  summarize must be called with start = 2026-06-25 00:00:00 UTC.
+    Verifies both import and export today getters.
+    """
+    from unittest.mock import patch
+    from zoneinfo import ZoneInfo
+    from app.integrations.expose import build_catalog
+    from app.services import timezone as _tz_mod
+
+    _setup_grace_db(energy_db)
+
+    # 2026-06-26 00:00:03 UTC — 3 seconds past midnight, still within 5-second grace.
+    fake_now = datetime(2026, 6, 26, 0, 0, 3, tzinfo=timezone.utc)
+
+    captured_import: dict = {}
+    captured_export: dict = {}
+
+    with Session(energy_db) as session:
+        with (
+            patch.object(_tz_mod, "local_tz", return_value=ZoneInfo("UTC")),
+            patch.object(_tz_mod, "local_now", return_value=fake_now),
+            patch("app.services.energy_cost.summarize", side_effect=_spy_summarize_factory(captured_import)),
+        ):
+            catalog = build_catalog(session)
+            import_entry = next(e for e in catalog if e.entity.key == "energy.import_cost_today")
+            import_entry.entity.value_getter(session)
+
+    # Reset and test export getter (separate patch context so we get a fresh spy dict)
+    captured_export = {}
+    with Session(energy_db) as session:
+        with (
+            patch.object(_tz_mod, "local_tz", return_value=ZoneInfo("UTC")),
+            patch.object(_tz_mod, "local_now", return_value=fake_now),
+            patch("app.services.energy_cost.summarize", side_effect=_spy_summarize_factory(captured_export)),
+        ):
+            catalog = build_catalog(session)
+            export_entry = next(e for e in catalog if e.entity.key == "energy.export_revenue_today")
+            export_entry.entity.value_getter(session)
+
+    # Grace not elapsed: today_local = 2026-06-25 (yesterday), so window starts there.
+    expected_start = datetime(2026, 6, 25, 0, 0, 0, tzinfo=timezone.utc)
+    assert captured_import.get("start") == expected_start, (
+        f"import_cost_today at 00:00:03: window start must be yesterday ({expected_start}), "
+        f"got {captured_import.get('start')}"
+    )
+    assert captured_export.get("start") == expected_start, (
+        f"export_revenue_today at 00:00:03: window start must be yesterday ({expected_start}), "
+        f"got {captured_export.get('start')}"
+    )
+
+
+def test_today_getter_grace_uses_today_window_at_00_00_12(energy_db) -> None:
+    """FUE-T09 AC1b: at local 00:00:12 (> grace=5s), both today getters use TODAY's window.
+
+    With grace=5s, (local_now() - 5s) = 2026-06-26 00:00:07, so today_local = 2026-06-26
+    (today).  summarize must be called with start = 2026-06-26 00:00:00 UTC.
+    """
+    from unittest.mock import patch
+    from zoneinfo import ZoneInfo
+    from app.integrations.expose import build_catalog
+    from app.services import timezone as _tz_mod
+
+    _setup_grace_db(energy_db)
+
+    # 2026-06-26 00:00:12 UTC — 12 seconds past midnight, beyond the 5-second grace.
+    fake_now = datetime(2026, 6, 26, 0, 0, 12, tzinfo=timezone.utc)
+
+    captured_import: dict = {}
+    captured_export: dict = {}
+
+    with Session(energy_db) as session:
+        with (
+            patch.object(_tz_mod, "local_tz", return_value=ZoneInfo("UTC")),
+            patch.object(_tz_mod, "local_now", return_value=fake_now),
+            patch("app.services.energy_cost.summarize", side_effect=_spy_summarize_factory(captured_import)),
+        ):
+            catalog = build_catalog(session)
+            import_entry = next(e for e in catalog if e.entity.key == "energy.import_cost_today")
+            import_entry.entity.value_getter(session)
+
+    captured_export = {}
+    with Session(energy_db) as session:
+        with (
+            patch.object(_tz_mod, "local_tz", return_value=ZoneInfo("UTC")),
+            patch.object(_tz_mod, "local_now", return_value=fake_now),
+            patch("app.services.energy_cost.summarize", side_effect=_spy_summarize_factory(captured_export)),
+        ):
+            catalog = build_catalog(session)
+            export_entry = next(e for e in catalog if e.entity.key == "energy.export_revenue_today")
+            export_entry.entity.value_getter(session)
+
+    # Grace elapsed: today_local = 2026-06-26 (today), window starts there.
+    expected_start = datetime(2026, 6, 26, 0, 0, 0, tzinfo=timezone.utc)
+    assert captured_import.get("start") == expected_start, (
+        f"import_cost_today at 00:00:12: window start must be today ({expected_start}), "
+        f"got {captured_import.get('start')}"
+    )
+    assert captured_export.get("start") == expected_start, (
+        f"export_revenue_today at 00:00:12: window start must be today ({expected_start}), "
+        f"got {captured_export.get('start')}"
+    )
+
+
+def test_today_getter_grace_unaffected_at_midday(energy_db) -> None:
+    """FUE-T09 AC2: at 12:00, grace doesn't shift the window — today_local still = today.
+
+    Well past midnight, (local_now() - 5s).date() == local_now().date() always.
+    """
+    from unittest.mock import patch
+    from zoneinfo import ZoneInfo
+    from app.integrations.expose import build_catalog
+    from app.services import timezone as _tz_mod
+
+    _setup_grace_db(energy_db)
+
+    # 2026-06-26 12:00:00 UTC — midday.
+    fake_now = datetime(2026, 6, 26, 12, 0, 0, tzinfo=timezone.utc)
+
+    captured: dict = {}
+
+    with Session(energy_db) as session:
+        with (
+            patch.object(_tz_mod, "local_tz", return_value=ZoneInfo("UTC")),
+            patch.object(_tz_mod, "local_now", return_value=fake_now),
+            patch("app.services.energy_cost.summarize", side_effect=_spy_summarize_factory(captured)),
+        ):
+            catalog = build_catalog(session)
+            import_entry = next(e for e in catalog if e.entity.key == "energy.import_cost_today")
+            import_entry.entity.value_getter(session)
+
+    # At 12:00 the grace (5s) does not push the date back: today_local = 2026-06-26.
+    expected_start = datetime(2026, 6, 26, 0, 0, 0, tzinfo=timezone.utc)
+    assert captured.get("start") == expected_start, (
+        f"import_cost_today at 12:00: window start must be today ({expected_start}), "
+        f"got {captured.get('start')}"
+    )
+
+
+def test_midnight_state_publish_no_raise_when_mqtt_disabled() -> None:
+    """FUE-T09 AC3: _run_midnight_state_publish is safe when MQTT is disabled.
+
+    _run_midnight_state_publish delegates to publish_states, which is internally
+    guarded (_should_publish returns False when MQTT is disabled or not connected).
+    This test verifies publish_states itself doesn't raise under those conditions —
+    the job's try/except swallows any other exception as well.
+    """
+    settings = _make_settings(mqtt_enabled=False)
+    mock_mgr = _make_mock_manager(is_connected=False)
+
+    with (
+        patch("app.services.ha_discovery.build_runtime_settings", return_value=settings),
+        patch("app.services.ha_discovery.mqtt_manager", mock_mgr),
+    ):
+        from app.services.ha_discovery import publish_states
+        from sqlalchemy import create_engine as _ce
+        from sqlalchemy.orm import Session as _S
+
+        eng = _ce("sqlite:///:memory:")
+        with _S(eng) as sess:
+            publish_states(sess)  # must not raise
+
+    mock_mgr.publish.assert_not_called()

tests/test_modbus_driver.py

@@ -217,6 +217,57 @@ class TestReadBlocks:
 
         mock_client.close.assert_called_once()
 
+    @patch("app.integrations.modbus.driver.ModbusTcpClient")
+    def test_default_function_code_uses_fc04_input_registers(
+        self, mock_client_cls: MagicMock
+    ) -> None:
+        """With no function_code given, read_blocks uses FC04 (read_input_registers)."""
+        mock_client = MagicMock()
+        mock_client_cls.return_value = mock_client
+        mock_client.connect.return_value = True
+        mock_client.read_input_registers.return_value = _make_ok_response([0x4366, 0x3334])
+
+        read_blocks("127.0.0.1", 502, 1, [{"start": 0x0000, "count": 2}])
+
+        mock_client.read_input_registers.assert_called_once_with(0x0000, count=2, device_id=1)
+        mock_client.read_holding_registers.assert_not_called()
+
+    @patch("app.integrations.modbus.driver.ModbusTcpClient")
+    def test_function_code_3_uses_fc03_holding_registers(
+        self, mock_client_cls: MagicMock
+    ) -> None:
+        """function_code=3 dispatches FC03 (read_holding_registers), e.g. DDSU666."""
+        mock_client = MagicMock()
+        mock_client_cls.return_value = mock_client
+        mock_client.connect.return_value = True
+        mock_client.read_holding_registers.return_value = _make_ok_response(
+            [0x4366, 0x3334, 0x3F80, 0x0000]
+        )
+
+        blocks = [{"start": 0x2000, "count": 4}]
+        result = read_blocks("127.0.0.1", 502, 1, blocks, function_code=3)
+
+        assert result == {0x2000: 0x4366, 0x2001: 0x3334, 0x2002: 0x3F80, 0x2003: 0x0000}
+        mock_client.read_holding_registers.assert_called_once_with(
+            0x2000, count=4, device_id=1
+        )
+        mock_client.read_input_registers.assert_not_called()
+
+    @patch("app.integrations.modbus.driver.ModbusTcpClient")
+    def test_invalid_function_code_raises_before_connecting(
+        self, mock_client_cls: MagicMock
+    ) -> None:
+        """An unsupported function code is rejected without opening a connection."""
+        mock_client = MagicMock()
+        mock_client_cls.return_value = mock_client
+
+        with pytest.raises(ModbusDriverError, match="Unsupported read function code"):
+            read_blocks("127.0.0.1", 502, 1, [{"start": 0, "count": 2}], function_code=16)
+
+        # No client should have been constructed or connected for a bad FC.
+        mock_client_cls.assert_not_called()
+        mock_client.connect.assert_not_called()
+
     @patch("app.integrations.modbus.driver.ModbusTcpClient")
     def test_unit_id_passed_as_device_id(self, mock_client_cls: MagicMock) -> None:
         """unit_id is forwarded as device_id= keyword argument (pymodbus 3.13.x)."""

tests/test_tibber_client.py

@@ -69,22 +69,28 @@ _THREE_NODES = [
     },
 ]
 
-_PRICE_RANGE_RESPONSE = {
+def _price_info_response(today: list[dict], tomorrow: list[dict] | None = None) -> dict:
-    "data": {
+    """Build a priceInfo(resolution: QUARTER_HOURLY) { today tomorrow } response."""
-        "viewer": {
+    return {
-            "homes": [
+        "data": {
-                {
+            "viewer": {
-                    "id": "home-id-1",
+                "homes": [
-                    "currentSubscription": {
+                    {
-                        "priceInfoRange": {
+                        "id": "home-id-1",
-                            "nodes": _THREE_NODES,
+                        "currentSubscription": {
-                        }
+                            "priceInfo": {
-                    },
+                                "today": today,
-                }
+                                "tomorrow": tomorrow if tomorrow is not None else [],
-            ]
+                            }
+                        },
+                    }
+                ]
+            }
         }
     }
-}
+
+
+_PRICE_RANGE_RESPONSE = _price_info_response(_THREE_NODES)
 
 _CURRENT_PRICE_RESPONSE = {
     "data": {
@@ -173,23 +179,8 @@ def test_fetch_price_range_parses_nodes(monkeypatch):
 
 def test_fetch_price_range_does_not_assume_node_count(monkeypatch):
     """Parser handles an arbitrary number of nodes (not hardcoded to 96)."""
-    # Build a response with a single node only.
+    # Build a response with a single today node and no tomorrow yet.
-    one_node_response = {
+    one_node_response = _price_info_response([_THREE_NODES[0]])
-        "data": {
-            "viewer": {
-                "homes": [
-                    {
-                        "id": "home-id-1",
-                        "currentSubscription": {
-                            "priceInfoRange": {
-                                "nodes": [_THREE_NODES[0]],
-                            }
-                        },
-                    }
-                ]
-            }
-        }
-    }
     transport = _make_transport(200, one_node_response)
 
     def _patched_post(url, *, json, headers, timeout):  # noqa: A002
@@ -202,6 +193,68 @@ def test_fetch_price_range_does_not_assume_node_count(monkeypatch):
     assert len(points) == 1
 
 
+def test_fetch_price_range_concatenates_today_and_tomorrow(monkeypatch):
+    """today and tomorrow node lists are both parsed (today first, then tomorrow)."""
+    tomorrow_nodes = [
+        {
+            "startsAt": "2026-06-24T00:00:00.000+02:00",
+            "total": 0.40,
+            "energy": 0.32,
+            "tax": 0.08,
+            "currency": "EUR",
+            "level": "EXPENSIVE",
+        },
+    ]
+    response = _price_info_response(_THREE_NODES, tomorrow_nodes)
+    transport = _make_transport(200, response)
+
+    def _patched_post(url, *, json, headers, timeout):  # noqa: A002
+        client = httpx.Client(transport=transport)
+        return client.post(url, json=json, headers=headers, timeout=timeout)
+
+    monkeypatch.setattr("app.integrations.tibber.client.httpx.post", _patched_post)
+
+    points = fetch_price_range(_FAKE_TOKEN)
+    # 3 today + 1 tomorrow, in order.
+    assert len(points) == 4
+    # First node is today's first; last node is tomorrow's.
+    assert points[0].starts_at == datetime(2026, 6, 22, 22, 0, 0, tzinfo=UTC)
+    # 2026-06-24T00:00:00+02:00 → 2026-06-23T22:00:00Z
+    assert points[-1].starts_at == datetime(2026, 6, 23, 22, 0, 0, tzinfo=UTC)
+    assert points[-1].total == pytest.approx(0.40)
+
+
+def test_fetch_price_range_tomorrow_null_returns_today_only(monkeypatch):
+    """A null tomorrow (before day-ahead publication) yields today's nodes only."""
+    response = {
+        "data": {
+            "viewer": {
+                "homes": [
+                    {
+                        "id": "home-id-1",
+                        "currentSubscription": {
+                            "priceInfo": {
+                                "today": _THREE_NODES,
+                                "tomorrow": None,
+                            }
+                        },
+                    }
+                ]
+            }
+        }
+    }
+    transport = _make_transport(200, response)
+
+    def _patched_post(url, *, json, headers, timeout):  # noqa: A002
+        client = httpx.Client(transport=transport)
+        return client.post(url, json=json, headers=headers, timeout=timeout)
+
+    monkeypatch.setattr("app.integrations.tibber.client.httpx.post", _patched_post)
+
+    points = fetch_price_range(_FAKE_TOKEN)
+    assert len(points) == 3
+
+
 def test_fetch_price_range_home_id_selection(monkeypatch):
     """When home_id is specified, the matching home is selected."""
     two_homes_response = {
@@ -211,16 +264,18 @@ def test_fetch_price_range_home_id_selection(monkeypatch):
                     {
                         "id": "home-id-first",
                         "currentSubscription": {
-                            "priceInfoRange": {
+                            "priceInfo": {
-                                "nodes": [_THREE_NODES[0]],
+                                "today": [_THREE_NODES[0]],
+                                "tomorrow": [],
                             }
                         },
                     },
                     {
                         "id": "home-id-second",
                         "currentSubscription": {
-                            "priceInfoRange": {
+                            "priceInfo": {
-                                "nodes": [_THREE_NODES[1], _THREE_NODES[2]],
+                                "today": [_THREE_NODES[1], _THREE_NODES[2]],
+                                "tomorrow": [],
                             }
                         },
                     },