OPT-17: the solar forecast can come from several entities, summed

New list options pv_forecast_entities and pv_forecast_tomorrow_entities
(same shape as pv_entities); the single-entity keys are unchanged.

- Each member is read in its own unit (Wh/kWh/MWh) in one gather and the
  day is summed. Hourly splits are merged when every member has one, else
  the total goes on the bell.
- A member missing, unavailable, stale, non-energy or bad makes that
  day's forecast unusable (no partial sum). A caution row names it by
  position; the action log names the entity once per change.
- Single key and list both set for one day: refused at start.
- A one-member list behaves exactly like the single key (test_opt17.py);
  the single-key path is byte-identical to e36565f over 24 scenarios.
- Supervisor shape measured: tools/supervisor_shape_probe.py section J.

DECISIONS/OPT-17-several-forecast-entities.md has the rules.

Co-Authored-By: Claude Opus 5.5 <noreply@anthropic.com>
Claude-Session: https://claude.ai/code/session_01Bdqr7PiaHcBnzPituu2yTC

goodwe_controller/app/solarfc.py

@@ -27,6 +27,11 @@ Without an hourly split, the day's energy is spread over a fixed bell from
 A reading older than `FRESH_S`, or from before local midnight, is stale,
 and a stale or missing forecast is no forecast: the day plan is off and
 every mode acts as in P3 option A.
+
+OPT-17: each day may instead name a list (`pv_forecast_entities`,
+`pv_forecast_tomorrow_entities`), summed by `read_sum()`. One member that is
+not usable makes that day's sum unusable, never a partial sum.
+DECISIONS/OPT-17-several-forecast-entities.md.
 """
 
 import math
@@ -49,6 +54,12 @@ BELL_FROM_H, BELL_TO_H = 6.0, 20.0
 NOT_SET, MISSING, UNIT, STALE, BAD = (
     "not_set", "missing", "unit", "stale", "bad")
 
+# OPT-17: (single key, list key) per day. A set list replaces the single key;
+# the validator refuses both set for the same day.
+TODAY_KEYS = ("pv_forecast_entity", "pv_forecast_entities")
+TOMORROW_KEYS = ("pv_forecast_tomorrow_entity",
+                 "pv_forecast_tomorrow_entities")
+
 
 @dataclass(frozen=True)
 class Day:
@@ -223,6 +234,52 @@ def _reported(state):
     return max(ts) if ts else None
 
 
+def entities(opts: dict, *, tomorrow=False) -> tuple:
+    """The forecast entities one day names, in configured order: the list
+    if it has any entry, else the single key, else (). A repeated id is
+    dropped, as `pv.entities()` does: it would count one forecast twice."""
+    one, many = TOMORROW_KEYS if tomorrow else TODAY_KEYS
+    listed = [e for e in (str(x or "").strip()
+                          for x in (opts.get(many) or [])) if e]
+    if listed:
+        return tuple(dict.fromkeys(listed))
+    e = str(opts.get(one) or "").strip()
+    return (e,) if e else ()
+
+
+def _bounds(now):
+    here = now.astimezone(BILLING_TZ)
+    d0 = datetime(here.year, here.month, here.day, tzinfo=BILLING_TZ)
+    nd = d0.date() + timedelta(days=1)
+    d1 = datetime(nd.year, nd.month, nd.day, tzinfo=BILLING_TZ)
+    return d0.astimezone(timezone.utc), d1.astimezone(timezone.utc)
+
+
+def _today(state, day0, now):
+    """`(Day, at, None)` or `(None, None, why)` for one today sensor."""
+    today, why = _day(state, day0, now, today=True)
+    if today is None:
+        return None, None, why
+    at = _reported(state)
+    # A reading from before local midnight is yesterday's "left today" (0
+    # after sunset) until the integration refreshes: stale, not a dark day.
+    if at is None or at < day0 or (now - at).total_seconds() > FRESH_S \
+            or (at - now).total_seconds() > 300:
+        return None, None, STALE
+    return today, at, None
+
+
+def _tomorrow(state, day0, day1, now):
+    """`(Day, None)` or `(None, why)` for one tomorrow sensor."""
+    t, why = _day(state, day1, now, today=False)
+    if t is None:
+        return None, why
+    t_at = _reported(state)
+    if t_at is None or t_at < day0 or (now - t_at).total_seconds() > FRESH_S:
+        return None, STALE
+    return t, None
+
+
 def read(today_state, tomorrow_state, now: datetime, *,
          configured=True):
     """`(Forecast, None)` or `(None, why)`. `tomorrow_state` may be None
@@ -230,25 +287,64 @@ def read(today_state, tomorrow_state, now: datetime, *,
     covers today only."""
     if not configured:
         return None, NOT_SET
-    here = now.astimezone(BILLING_TZ)
-    d0 = datetime(here.year, here.month, here.day, tzinfo=BILLING_TZ)
-    nd = d0.date() + timedelta(days=1)
-    d1 = datetime(nd.year, nd.month, nd.day, tzinfo=BILLING_TZ)
-    day0, day1 = d0.astimezone(timezone.utc), d1.astimezone(timezone.utc)
-    today, why = _day(today_state, day0, now, today=True)
+    day0, day1 = _bounds(now)
+    today, at, why = _today(today_state, day0, now)
     if today is None:
         return None, why
-    at = _reported(today_state)
-    # A reading from before local midnight is yesterday's "left today" (0
-    # after sunset) until the integration refreshes: stale, not a dark day.
-    if at is None or at < day0 or (now - at).total_seconds() > FRESH_S \
-            or (at - now).total_seconds() > 300:
-        return None, STALE
     tomorrow = None
     if tomorrow_state is not None:
-        t, _w = _day(tomorrow_state, day1, now, today=False)
-        t_at = _reported(tomorrow_state)
-        if t is not None and t_at is not None and t_at >= day0 \
-                and (now - t_at).total_seconds() <= FRESH_S:
-            tomorrow = t
+        tomorrow, _w = _tomorrow(tomorrow_state, day0, day1, now)
     return Forecast(today, tomorrow, at), None
+
+
+def _sum(days):
+    """One Day from several members' Days. The hourly split is kept only if
+    every member has one: the splits are then joined (`_day_between()`
+    adds overlapping periods). Else the total goes on the bell."""
+    if len(days) == 1:
+        return days[0]
+    periods = ()
+    if all(d.periods for d in days):
+        periods = tuple(sorted(p for d in days for p in d.periods))
+    return Day(days[0].day0, sum(d.kwh for d in days), periods)
+
+
+def read_sum(today, tomorrow, now: datetime):
+    """OPT-17: `(Forecast or None, why, gaps)` over lists of
+    `(entity, state)`, one per configured member, in configured order.
+
+    Each member is read exactly as `read()` reads one sensor, in its own
+    unit. A member that is missing, unavailable, stale, not in an energy
+    unit or bad makes that DAY unusable, as one such sensor does today: no
+    today means no forecast, no tomorrow means today only. A partial sum
+    would under-count the sun and mislead the day plan.
+
+    `gaps` is `((day, position, entity, why), ...)` for every unusable
+    member (`day` "today" or "tomorrow", `position` 1-based), so the page
+    and the log can name it. With one member per day the forecast is what
+    `read()` gives (test_opt17.py proves it)."""
+    if not today:
+        return None, NOT_SET, ()
+    day0, day1 = _bounds(now)
+    gaps, days, ats, why0 = [], [], [], None
+    for i, (ent, st) in enumerate(today, 1):
+        d, at, why = _today(st, day0, now)
+        if d is None:
+            gaps.append(("today", i, ent, why))
+            why0 = why0 or why
+        else:
+            days.append(d)
+            ats.append(at)
+    tdays = []
+    for i, (ent, st) in enumerate(tomorrow, 1):
+        t, why = _tomorrow(st, day0, day1, now)
+        if t is None:
+            gaps.append(("tomorrow", i, ent, why))
+        else:
+            tdays.append(t)
+    gaps = tuple(gaps)
+    if why0 is not None:
+        return None, why0, gaps
+    tday = _sum(tdays) if tomorrow and len(tdays) == len(tomorrow) else None
+    # The oldest member's report is when the sum was last fully known.
+    return Forecast(_sum(days), tday, min(ats)), None, gaps