MAINT-10: maintenance start hour in local time, default 19:00

The start hour was compared with the UTC hour, so the shipped 10 started at
12:00 in a Belgian summer. It is now read in Home Assistant's time zone
(fallback: the container's TZ, then UTC, one log line says which), and the
default moves to 19. DST: a missing hour starts at the first hour after the
jump; a repeated hour starts only in its first pass. Stored options are not
rewritten: a saved 10 now means 10:00 local (DOCS, CHANGELOG).

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

goodwe_controller/app/maintenance.py

@@ -34,7 +34,7 @@ simply not do.
 import logging
 import math
 from dataclasses import dataclass, field
-from datetime import datetime, timedelta, timezone
+from datetime import datetime, timedelta, timezone, tzinfo
 
 from .store import MAINT_UNIT_KEYS, unit_key
 
@@ -112,7 +112,9 @@ RESTART_COOLDOWN_MIN = 90
 MAINT_OPTION_DEFAULTS = {
     "maintenance_enabled": False,
     "maintenance_interval_days": 28,
-    "maintenance_start_hour": 10,
+    # MAINT-10: a LOCAL hour (site_zone() below), 19:00 so the drain runs
+    # into the night rather than through the solar day.
+    "maintenance_start_hour": 19,
     # ⚠️ 2000, NOT THE 2500 THIS SHIPPED AS, and config.yaml carries the
     # argument: both rates must stay at or below `max_w` (2000) or the
     # cheap-window charge shaping asks the arbiter for `hi = -charge_w` against
@@ -177,6 +179,69 @@ class MaintConfig:
         )
 
 
+# --------------------------------------------------------------------------- #
+# MAINT-10: the start hour is local time. See DECISIONS/MAINT-10-local-start-hour.md.
+# --------------------------------------------------------------------------- #
+def _load_zone(name):
+    """A tzinfo for an IANA name, or `(None, why)`."""
+    if not name or not isinstance(name, str):
+        return None, "none given"
+    try:
+        from zoneinfo import ZoneInfo
+        return ZoneInfo(name.strip()), ""
+    except Exception as err:                      # noqa: BLE001 - any failure
+        return None, f"{name!r} is not a known zone ({type(err).__name__})"
+
+
+def site_zone(ha_zone, ha_why: str, env_tz) -> tuple:
+    """`(tzinfo, name, source, why)`: Home Assistant's zone (source "ha"), else
+    the container's TZ ("tz"), else UTC ("utc"). `why` says what was missing."""
+    tz, why = _load_zone(ha_zone)
+    if tz is not None:
+        return tz, ha_zone, "ha", ""
+    ha_why = ha_why or why
+    tz, env_why = _load_zone(env_tz)
+    if tz is not None:
+        return tz, env_tz, "tz", ha_why
+    return timezone.utc, "UTC", "utc", f"Home Assistant: {ha_why}, TZ: {env_why}"
+
+
+def in_start_slot(now: datetime, start_hour: int, tz: tzinfo) -> bool:
+    """Is `now` inside today's one-hour start slot, read on the local clock?
+
+    Normally the slot is the local hour `start_hour`. On the day the clocks go
+    forward and that hour does not exist, it is the first hour after the jump.
+    On the day they go back and it happens twice, only the first one counts.
+    Worked from UTC instants only (`astimezone`), so it does not depend on how
+    a tzinfo resolves a wall time that is missing or doubled.
+    """
+    if now.tzinfo is None:
+        now = now.replace(tzinfo=timezone.utc)
+    here = now.astimezone(tz).replace(tzinfo=None)
+    before = (now - timedelta(hours=1)).astimezone(tz).replace(tzinfo=None)
+    if here.hour == start_hour:
+        # the second pass through a repeated hour: an hour ago read the same
+        return not (before.date() == here.date() and before.hour == start_hour)
+    slot = here.replace(hour=start_hour, minute=0, second=0, microsecond=0)
+    # the clock jumped over the start of the slot within the last hour
+    return before < slot and here >= slot + timedelta(hours=1)
+
+
+def next_slot_start(now: datetime, start_hour: int, tz: tzinfo):
+    """The start of the slot `now` is in, or else of the next one; None if
+    there is none within 50 h (no real zone does that)."""
+    step = timedelta(minutes=15)
+    t = now.replace(minute=now.minute - now.minute % 15, second=0,
+                    microsecond=0) - timedelta(hours=1)
+    for _ in range(4 * 50):
+        if (in_start_slot(t, start_hour, tz)
+                and not in_start_slot(t - step, start_hour, tz)
+                and t + timedelta(hours=1) > now):
+            return t
+        t += step
+    return None
+
+
 @dataclass
 class MaintResult:
     phase: str
@@ -256,8 +321,12 @@ class Maintenance:
     """
 
     def __init__(self, cfg: MaintConfig, store, unit: str | None = None,
-                 name: str = "", mirror_flat: bool = False):
+                 name: str = "", mirror_flat: bool = False,
+                 tz: tzinfo | None = None):
         self.cfg = cfg
+        # MAINT-10: the zone `cfg.start_hour` is read in - main.py resolves it
+        # once at startup (`site_zone()`). UTC when nobody says, as before.
+        self.tz = tz or timezone.utc
         # ⚠️ `self.store` IS THE VIEW, NOT THE Store. Everything in this class
         # names an UNQUALIFIED key - "phase", "last_completed" - and the view is
         # the one place that turns it into the key this pack owns. A raw
@@ -331,7 +400,8 @@ class Maintenance:
         about who was asking - so the IDLE branch of `tick()` calls this one.
         """
         return (self.phase == IDLE and self.cfg.enabled
-                and now.hour == self.cfg.start_hour and self.due(now)
+                and in_start_slot(now, self.cfg.start_hour, self.tz)
+                and self.due(now)
                 and self._cooled(now))
 
     # -- operations ----------------------------------------------------------