feat(web): Core Refactor Phase A — extract sampling and cache modules; add adaptive TTL + eviction heuristics, Redis PoC, and metrics wiring. Tests added for TTL, eviction, exports, splash-adaptive, card index, and service worker. Docs+roadmap updated.

code/tests/test_sampling_splash_adaptive.py

@@ -0,0 +1,67 @@
+from __future__ import annotations
+
+from code.web.services.sampling import sample_real_cards_for_theme
+
+# We'll construct a minimal in-memory index by monkeypatching card_index structures directly
+# to avoid needing real CSV files. This keeps the test fast & deterministic.
+
+
+def test_adaptive_splash_penalty_scaling(monkeypatch):
+    # Prepare index
+    theme = "__AdaptiveSplashTest__"
+    # Commander (4-color) enabling splash path
+    commander_name = "Test Commander"
+    commander_tags = [theme, "Value", "ETB"]
+    commander_entry = {
+        "name": commander_name,
+        "color_identity": "WUBR",  # 4 colors
+        "tags": commander_tags,
+        "mana_cost": "WUBR",
+        "rarity": "mythic",
+        "color_identity_list": list("WUBR"),
+        "pip_colors": list("WUBR"),
+    }
+    pool = [commander_entry]
+    def add_card(name: str, color_identity: str, tags: list[str]):
+        pool.append({
+            "name": name,
+            "color_identity": color_identity,
+            "tags": tags,
+            "mana_cost": "1G",
+            "rarity": "uncommon",
+            "color_identity_list": list(color_identity),
+            "pip_colors": [c for c in "1G" if c in {"W","U","B","R","G"}],
+        })
+    # On-color payoff (no splash penalty)
+    add_card("On Color Card", "WUB", [theme, "ETB"])
+    # Off-color splash (adds G)
+    add_card("Splash Card", "WUBG", [theme, "ETB", "Synergy"])
+
+    # Monkeypatch lookup_commander to return our commander
+    from code.web.services import card_index as ci
+    # Patch underlying card_index (for direct calls elsewhere)
+    monkeypatch.setattr(ci, "lookup_commander", lambda name: commander_entry if name == commander_name else None)
+    monkeypatch.setattr(ci, "maybe_build_index", lambda: None)
+    monkeypatch.setattr(ci, "get_tag_pool", lambda tag: pool if tag == theme else [])
+    # Also patch symbols imported into sampling at import time
+    import code.web.services.sampling as sampling_mod
+    monkeypatch.setattr(sampling_mod, "maybe_build_index", lambda: None)
+    monkeypatch.setattr(sampling_mod, "get_tag_pool", lambda tag: pool if tag == theme else [])
+    monkeypatch.setattr(sampling_mod, "lookup_commander", lambda name: commander_entry if name == commander_name else None)
+    monkeypatch.setattr(sampling_mod, "SPLASH_ADAPTIVE_ENABLED", True)
+    monkeypatch.setenv("SPLASH_ADAPTIVE", "1")
+    monkeypatch.setenv("SPLASH_ADAPTIVE_SCALE", "1:1.0,2:1.0,3:1.0,4:0.5,5:0.25")
+
+    # Invoke sampler (limit large enough to include both cards)
+    cards = sample_real_cards_for_theme(theme, 10, None, synergies=[theme, "ETB", "Synergy"], commander=commander_name)
+    by_name = {c["name"]: c for c in cards}
+    assert "Splash Card" in by_name, cards
+    splash_reasons = [r for r in by_name["Splash Card"]["reasons"] if r.startswith("splash_off_color_penalty")]
+    assert splash_reasons, by_name["Splash Card"]["reasons"]
+    # Adaptive variant reason format: splash_off_color_penalty_adaptive:<color_count>:<value>
+    adaptive_reason = next(r for r in splash_reasons if r.startswith("splash_off_color_penalty_adaptive"))
+    parts = adaptive_reason.split(":")
+    assert parts[1] == "4"  # commander color count
+    penalty_value = float(parts[2])
+    # With base -0.3 and scale 0.5 expect -0.15 (+/- float rounding)
+    assert abs(penalty_value - (-0.3 * 0.5)) < 1e-6