feat(modelling): detect single-glazing code 15 + glazing before/after pins

With the mapper now in main, cert 001431 parses: it lodges four single-glazed
windows — codes 1 ("Single") and 15 ("single glazing, known data", a single
pane with manufacturer U/g). The generator only detected code 1, so it missed
two panes. Detect {1, 15}; set the secondary target to code 11 ("Secondary
glazing - Normal emissivity", what the cert re-lodges; score-neutral vs 7 but
exact).

A deterministic green pin proves the overlay reproduces the after's 14 windows
exactly. The full-SAP before->after pins are xfail(strict) tripwires: the
overlay nails the windows, but the measure also re-lodges percent_draughtproofed
84->100 (sealed units draught-proof the replaced openings) plus a ~0.4 SAP
fabric residual the overlay doesn't model yet — a glazing-measure coupling to
close later.

Co-Authored-By: Claude Opus 4.8 <noreply@anthropic.com>

domain/modelling/generators/glazing_recommendation.py

@@ -27,10 +27,12 @@ from domain.modelling.recommendation import Cost, MeasureOption, Recommendation
 from domain.modelling.simulation import EpcSimulation, WindowOverlay
 from repositories.product.product_repository import ProductRepository
 
-# SAP10.2 Table U2 code 1 = single glazing — the only windows this generator
+# Single-glazing codes — the only windows this generator upgrades. Code 1 is
-# upgrades (the Elmhurst mapper sends "Single"/"Single glazing" → 1 and the API
+# bare "Single"/"Single glazing"; code 15 is "single glazing, known data" (a
-# passes int 1, so the trigger is path-consistent).
+# single pane with manufacturer U/g lodged — same g_L=0.90 as code 1, per
-_SINGLE_GLAZED: Final[int] = 1
+# RdSAP-21). Both are single-glazed and must be detected, or a cert that lodges
+# manufacturer data on its single panes (e.g. 001431 windows 12-13) is missed.
+_SINGLE_GLAZED_CODES: Final[frozenset[int]] = frozenset({1, 15})
 
 
 @dataclass(frozen=True)
@@ -57,13 +59,14 @@ _DOUBLE: Final[_GlazingTarget] = _GlazingTarget(
     solar_transmittance=0.72,
 )
 # Protected (conservation/listed/heritage): fit an internal secondary pane
-# (gt=7 "Secondary glazing"; U→2.90, g unchanged at 0.85 — the existing outer
+# (gt=11 "Secondary glazing - Normal emissivity", what cert 001431 re-lodges;
-# single pane still drives solar gain). The external units can't be replaced on
+# U→2.90, g unchanged at 0.85 — the existing outer single pane still drives
-# a protected/over-looked building, so this is the planning-picked Measure.
+# solar gain). The external units can't be replaced on a protected/over-looked
+# building, so this is the planning-picked Measure.
 _SECONDARY: Final[_GlazingTarget] = _GlazingTarget(
     measure_type="secondary_glazing",
     description="Fit secondary glazing to the single-glazed windows",
-    glazing_type=7,
+    glazing_type=11,
     u_value=2.90,
     solar_transmittance=0.85,
 )
@@ -81,7 +84,7 @@ def recommend_glazing(
     single_indices = tuple(
         index
         for index, window in enumerate(epc.sap_windows)
-        if window.glazing_type == _SINGLE_GLAZED
+        if window.glazing_type in _SINGLE_GLAZED_CODES
     )
     if not single_indices:
         return None

tests/domain/modelling/test_elmhurst_cascade_pins.py

@@ -17,6 +17,8 @@ from __future__ import annotations
 from dataclasses import replace
 from typing import Final
 
+import pytest
+
 from datatypes.epc.domain.epc_property_data import (
     BuildingPartIdentifier,
     EpcPropertyData,
@@ -34,6 +36,8 @@ from domain.geospatial.planning_restrictions import PlanningRestrictions
 from domain.modelling.generators.solid_wall_recommendation import (
     recommend_solid_wall,
 )
+from domain.modelling.generators.glazing_recommendation import recommend_glazing
+from domain.modelling.scoring.overlay_applicator import apply_simulations
 from domain.modelling.recommendation import MeasureOption
 from domain.sap10_calculator.calculator import Sap10Calculator, SapResult
 from repositories.product.product_repository import ProductRepository
@@ -442,3 +446,94 @@ def test_suspended_floor_overlay_reproduces_the_relodged_after() -> None:
     _assert_overlay_reproduces_after(
         before, after, recommendation.options[0].overlay
     )
+
+
+def test_double_glazing_overlay_reproduces_the_relodged_after_windows() -> None:
+    # The full-SAP pin below is xfail (draught-proofing coupling), but the
+    # overlay's actual job — turning every single-glazed window into the
+    # relodged spec — is deterministic and must hold exactly: it proves the
+    # generator detects BOTH single-glazing codes (1 and 15) on the real cert.
+    # Arrange
+    before: EpcPropertyData = parse_recommendation_summary(
+        "double_glazing_001431_before.pdf"
+    )
+    after: EpcPropertyData = parse_recommendation_summary(
+        "double_glazing_001431_after.pdf"
+    )
+    recommendation: Recommendation | None = recommend_glazing(before, _AnyProduct())
+    assert recommendation is not None
+
+    # Act — apply the overlay to the parsed before.
+    applied: EpcPropertyData = apply_simulations(
+        before, [recommendation.options[0].overlay]
+    )
+
+    # Assert — every window's glazing_type + lodged U/g matches the after.
+    def _window_spec(epc: EpcPropertyData) -> list[tuple[object, object, object]]:
+        specs: list[tuple[object, object, object]] = []
+        for window in epc.sap_windows:
+            details = window.window_transmission_details
+            specs.append(
+                (
+                    window.glazing_type,
+                    details.u_value if details is not None else None,
+                    details.solar_transmittance if details is not None else None,
+                )
+            )
+        return specs
+
+    assert _window_spec(applied) == _window_spec(after)
+
+
+_GLAZING_DRAUGHT_COUPLING_REASON: Final[str] = (
+    "Blocked on the glazing measure's draught-proofing coupling. The window "
+    "U/g overlay reproduces the after's 14 windows EXACTLY (all four single-"
+    "glazed panes — codes 1 and 15 — become the relodged double/secondary "
+    "spec). The residual ~0.7 SAP is a secondary effect the overlay does not "
+    "model: replacing the single-glazed (lodged draught_proofed=No) windows "
+    "with sealed units re-lodges percent_draughtproofed 84->100 (~0.3 SAP) and "
+    "lowers fabric heat loss by ~+150 kWh space heating (~0.4 SAP) not yet "
+    "isolated. Flips green once the glazing overlay propagates draught-proofing "
+    "(and the residual fabric coupling is modelled)."
+)
+
+
+@pytest.mark.xfail(strict=True, reason=_GLAZING_DRAUGHT_COUPLING_REASON)
+def test_double_glazing_overlay_reproduces_the_relodged_after() -> None:
+    # Arrange — cert 001431 lodges four single-glazed windows (codes 1 and 15,
+    # "single glazing, known data"); the after re-lodges every one as double
+    # (gt=5, U=1.40, g=0.72).
+    before: EpcPropertyData = parse_recommendation_summary(
+        "double_glazing_001431_before.pdf"
+    )
+    after: EpcPropertyData = parse_recommendation_summary(
+        "double_glazing_001431_after.pdf"
+    )
+    recommendation: Recommendation | None = recommend_glazing(before, _AnyProduct())
+    assert recommendation is not None
+
+    # Act / Assert
+    _assert_overlay_reproduces_after(
+        before, after, recommendation.options[0].overlay
+    )
+
+
+@pytest.mark.xfail(strict=True, reason=_GLAZING_DRAUGHT_COUPLING_REASON)
+def test_secondary_glazing_overlay_reproduces_the_relodged_after() -> None:
+    # Arrange — a planning protection forces secondary glazing; the after
+    # re-lodges every single-glazed window as secondary (gt=11, U=2.90, g=0.85).
+    before: EpcPropertyData = parse_recommendation_summary(
+        "secondary_glazing_001431_before.pdf"
+    )
+    after: EpcPropertyData = parse_recommendation_summary(
+        "secondary_glazing_001431_after.pdf"
+    )
+    recommendation: Recommendation | None = recommend_glazing(
+        before, _AnyProduct(), PlanningRestrictions(in_conservation_area=True)
+    )
+    assert recommendation is not None
+
+    # Act / Assert
+    _assert_overlay_reproduces_after(
+        before, after, recommendation.options[0].overlay
+    )

tests/domain/modelling/test_glazing_recommendation.py

@@ -116,11 +116,11 @@ def test_planning_protection_picks_secondary_glazing_over_double() -> None:
     )
 
     # Assert — one secondary-glazing Option; each single window upgraded to the
-    # pinned secondary target (gt=7, U=2.90, g unchanged at 0.85).
+    # pinned secondary target (gt=11, U=2.90, g unchanged at 0.85).
     assert recommendation is not None
     option = recommendation.options[0]
     assert option.measure_type == "secondary_glazing"
     assert dict(option.overlay.windows) == {
-        0: WindowOverlay(glazing_type=7, u_value=2.90, solar_transmittance=0.85),
+        0: WindowOverlay(glazing_type=11, u_value=2.90, solar_transmittance=0.85),
-        2: WindowOverlay(glazing_type=7, u_value=2.90, solar_transmittance=0.85),
+        2: WindowOverlay(glazing_type=11, u_value=2.90, solar_transmittance=0.85),
     }