TARIFF-03: static day/night and fully-fixed tariffs, first-class

§9.2 puts a large share of the Belgian installed base on a static profile, and
an EMS that only works under dynamic pricing is an EMS for a minority. A new
`static_profile` option describes a two-period day/night tariff - or a single
fixed price - and app/static_tariff.py turns it into the same canonical
{start, eur_per_kwh, provisional} series the fetched providers emit.

Not a sixth provider plugin, for two mechanical reasons. capabilities() is a
classmethod, so a plugin's PriceProduct is fixed when the class is written -
but §9.2 makes STATIC and FIXED two different products and which one a site is
on is a property of the operator's data; StaticProfile.product derives it from
the number of distinct prices. And the plugin framework exists to stop a
FETCHED figure being marked up twice, which a number typed as all-in cannot be.
So the profile sits where §11.4 already says it does - under the providers, as
the fallback. Configured product and feed-is-down are one generator differing
in one flag, so the degradation path cannot rot unused.

"No arbitrage" is a type. TariffPlan.arbitrage() returns a variant whose
ALLOWED arm carries the spread and the cheapest/dearest hours and whose REFUSED
arm carries a reason and nothing else - .spread_eur_kwh on a refusal raises
rather than answering 0.0, so an optimiser cannot compute a trade from one.
Four refusals, all derived: peak guard holding, no price data, plan
provisional, or the series is FLAT. The last is AC2: a fixed tariff disables
arbitrage by arithmetic, not by matching on an enum. peak_guard_active is a
required keyword argument, so §10.1's priority 2 over 3 cannot be skipped.

Time-window shifting reaches the one shiftable load that exists: main.py's
cheap-window flag falls back to the static profile, and the UI gained a Tariff
row. Cheap is STRICTLY below the seven-day mean - `<=` would call every hour of
a flat tariff cheap, and 48 h taken on a Friday is two-thirds weekend.

A profile must tile every day type exactly once, checked at startup; a gap is
refused with the range named rather than filled in. `22:00-07:00 mon-fri` does
not cover Saturday morning, and that trap is what the check catches.

validate.py rule 7's stated reason expired exactly as TARIFF-02 predicted: the
test_price.py section 12 tripwire went red naming static_tariff.py. The message
now says what is true instead, and the tripwire is re-aimed rather than removed
- consumer set pinned, expired phrase asserted gone. Rule 7 also grew a second
refusal for static_profile alongside the HA price pair, the same silent-loser
conflict and a live one.

CFG-03 is not widened: static_profile went into price.py's PRICE_OPTION_DEFAULTS
- the one in-code mirror pinned to config.yaml by a check - and the new module
carries no defaults dict of its own.

Measured on the two committed days of this house's real P1 meter. 2026-08-20
(Thursday): 15.220 kWh imported, 9.606 day / 5.614 night, EUR 4.7185 under
day/night vs EUR 4.6725 flat, shifting saves EUR 0.8069 = 9.606 kWh x the
0.0840 spread, derived twice. 2026-08-23 (Sunday): 0.728 kWh, all of it
night-priced, which is the weekend row proving itself. §17 names six Belgian
scenarios; this is the seventh, and it is two days rather than a season - the
file says so rather than implying an annual figure.

All 12 suites green. Eleven mutations of static_tariff.py were each caught by
at least one check.

Co-Authored-By: Claude Opus 5 <noreply@anthropic.com>
Claude-Session: https://claude.ai/code/session_015VXjA3LWccN1rJsk3okyPC

goodwe_controller/app/validate.py

@@ -157,6 +157,7 @@ import logging
 
 from .p1 import is_enabled, validate_meter_options
 from .price import PROVIDERS
+from .static_tariff import ProfileInvalid, parse_static_profile
 
 _LOG = logging.getLogger("goodwe.config")
 
@@ -410,8 +411,13 @@ def _price_problems(opts: dict) -> list[str]:
     without a price feed is an add-on that a Belgian fixed-tariff site - a large
     share of the installed base, per §9.2 - cannot run at all.
 
-    Three refusals, all case (a) from this module's docstring: a source the
-    operator SET being overridden by a layer they cannot see.
+    Four refusals and two log lines (TARIFF-03 added one refusal, one parse and
+    two notices), and every refusal is still case (a) from this module's
+    docstring: a source the operator SET being overridden by a layer they cannot
+    see. The additions are `static_profile` alongside the Home Assistant price
+    pair - the same silent-loser shape as provider-plus-pair, and a LIVE one -
+    and a `static_profile` that does not tile the day, which would leave hours
+    with no price at all.
     """
     problems: list[str] = []
     pid = str(opts.get("price_provider", "") or "off").strip() or "off"
@@ -426,24 +432,35 @@ def _price_problems(opts: dict) -> list[str]:
         return problems          # nothing below can be judged against an unknown id
 
     # ⚠️ THE HA-SIDE OVERLAP THE PM TOLD US TO DECIDE ABOUT, DECIDED HERE.
-    # price_now_entity/price_avg_entity are the existing delegation of pricing
-    # to Home Assistant: main.py reduces them to ONE BOOLEAN, `cheap`, read only
-    # by the maintenance cheap-window charge floor. They are KEPT (TARIFF-03 and
-    # OPT-04 are what replace them, and neither has landed), but they may not
-    # run alongside a provider. With both configured the provider series drives
-    # nothing at all while the two entities quietly keep deciding, and the
-    # operator's evidence that they picked a supplier is a status line saying
-    # they picked a supplier. That is (a), and it is the "silently double up"
-    # the PM named on 2026-08-30.
-    # ⚠️ THIS REFUSAL'S REASON EXPIRES, AND THE MESSAGE BELOW MUST BE EDITED IN
-    # THE SAME COMMIT THAT LANDS THE FIRST CONSUMER (TARIFF-03 or OPT-04).
-    # Today the message says the provider "would decide nothing" - true, because
-    # nothing reads the series. Once something does, both sources really decide
-    # and this becomes a straightforward two-writer conflict; the refusal stays
-    # right and its explanation goes wrong, which is worse than either. There is
-    # a tripwire on exactly this in test_price.py section 12: it greps app/ for
-    # a `load_prices` consumer and goes RED the moment one appears. Update the
-    # message, not the check.
+    # price_now_entity/price_avg_entity are the original delegation of pricing
+    # to Home Assistant: main.py reduces them to ONE BOOLEAN, `cheap`, read by
+    # the maintenance cheap-window charge floor. They are KEPT - retiring them
+    # would take a live install's only price signal away - but they may not run
+    # alongside another price source, because main.py reads exactly one and the
+    # loser is silent. That is (a), and it is the "silently double up" the PM
+    # named on 2026-08-30.
+    #
+    # ⚠️ THE REASON THIS REFUSAL GIVES WAS REWRITTEN BY TARIFF-03, AND THE OLD
+    # WORDING IS WHY. Until TARIFF-03 this message said the configured provider
+    # "would decide nothing", which was true only because nothing consumed the
+    # series; test_price.py section 12 carried a tripwire that went red the
+    # moment a consumer landed, with instructions to fix the wording here in the
+    # same commit. It landed, it went red, and this is that fix. What is true
+    # NOW, stated exactly and no wider:
+    #
+    #   * app/static_tariff.py consumes load_prices(). resolve_tariff() turns a
+    #     provider series into a TariffPlan, a cheap-window flag and an
+    #     arbitrage verdict, so the seam is no longer inert.
+    #   * main.py reads the STATIC side of that module every cycle
+    #     (static_status()), which makes static_profile a real writer of `cheap`.
+    #   * main.py does NOT yet call resolve_tariff() on the control tick, and
+    #     that is deliberate: a provider fetch is network I/O and the tick is
+    #     what feeds the ESP32 heartbeat. So a configured PROVIDER still shapes
+    #     no energy decision on its own; a configured STATIC PROFILE does.
+    #
+    # Hence two refusals below rather than one, and neither claims more than
+    # that list. When OPT-04 puts resolve_tariff() on a background refresh, the
+    # first message's middle clause is what changes - not the rule.
     ha_price = [k for k in ("price_now_entity", "price_avg_entity")
                 if str(opts.get(k, "") or "").strip()]
     if pid != "off" and ha_price:
@@ -452,12 +469,65 @@ def _price_problems(opts: dict) -> list[str]:
             f"{'is' if len(ha_price) == 1 else 'are'} set, which is two price "
             "sources on one site. THE HOME ASSISTANT ENTITIES WIN: they are "
             "what main.py reduces to the `cheap` flag the maintenance cycle "
-            "reads, and nothing yet consumes the provider series, so the "
-            "supplier you configured would decide nothing while the status "
-            "page named it. Clear price_now_entity and price_avg_entity to use "
-            f"the {pid!r} plugin, or set price_provider to 'off' to keep the "
+            "reads. The provider series IS consumed now - app/static_tariff.py "
+            "builds a tariff plan and an arbitrage verdict from it - but it is "
+            "not what main.py acts on, so the supplier you configured would "
+            "shape no energy decision while the status page named it. Clear "
+            "price_now_entity and price_avg_entity to use the "
+            f"{pid!r} plugin, or set price_provider to 'off' to keep the "
             "Home Assistant sensors.")
 
+    # ⚠️ THE SAME RULE FOR THE SOURCE TARIFF-03 ADDED, AND THIS ONE IS A LIVE
+    # CONFLICT RATHER THAN A LATENT ONE. main.py's read_inputs() takes `cheap`
+    # from the Home Assistant pair when it is set and from the static profile
+    # otherwise - one flag, first writer wins, and the operator who filled in a
+    # day/night tariff has no way to see that it lost.
+    if ha_price and str(opts.get("static_profile", "") or "").strip():
+        problems.append(
+            f"static_profile is set AND {' and '.join(ha_price)} "
+            f"{'is' if len(ha_price) == 1 else 'are'} set, which is two "
+            "tariff sources feeding one cheap-window flag. THE HOME ASSISTANT "
+            "ENTITIES WIN: main.py reads them first and never looks at the "
+            "static profile, so the day/night tariff you typed would decide "
+            "nothing and nothing would say so. Clear price_now_entity and "
+            "price_avg_entity to use static_profile, or clear static_profile "
+            "to keep the Home Assistant sensors.")
+
+    # ⚠️ THE PROFILE ITSELF, PARSED AT STARTUP RATHER THAN AT 02:00. A profile
+    # that does not tile the day has hours with no price, and the only ways to
+    # serve those are to invent a number or to fail at the moment the clock
+    # reaches them. §14's warning box - refuse to start on a mismatch rather
+    # than clamp quietly - is the same instruction one level down.
+    raw_profile = opts.get("static_profile", "")
+    if str(raw_profile or "").strip() or isinstance(raw_profile, (list, dict)):
+        try:
+            profile = parse_static_profile(raw_profile)
+        except ProfileInvalid as e:
+            profile = None
+            problems.append(f"static_profile cannot be used: {e}")
+        if profile is not None and profile.product is not None \
+                and len(set(profile.prices)) == 1:
+            _LOG.info(
+                "static_profile carries one distinct price (%.4f EUR/kWh "
+                "all-in), so this site is priced as FULLY FIXED. Arbitrage is "
+                "off by arithmetic - a flat series has no spread - and the "
+                "add-on runs self-consumption only, which is §9.2's handling "
+                "for this product. Peak shaving, reserve management and the "
+                "maintenance cycle are unaffected.", profile.prices[0])
+
+    # ⚠️ A WARNING, NOT A REFUSAL, AND THE ASYMMETRY IS DELIBERATE. §11.4 says a
+    # site with no price data falls back to the static profile; a dynamic site
+    # with none configured has nothing to fall back to when its feed dies. That
+    # is a real gap worth naming - but refusing to start over it would break
+    # every install TARIFF-02 shipped, none of which could have had one.
+    if pid != "off" and not str(opts.get("static_profile", "") or "").strip():
+        _LOG.warning(
+            "price_provider is %r but static_profile is empty. §11.4's "
+            "degradation row is 'no price data -> fall back to the static "
+            "profile'; with none configured, a feed outage leaves this site "
+            "with no tariff at all rather than with a coarse one. Not refused, "
+            "but filling it in is what makes that row work.", pid)
+
     if pid == "manual_csv" and not str(opts.get("price_csv_path", "") or "").strip():
         problems.append(
             "price_provider is 'manual_csv' but price_csv_path is empty, so "