refactor(server): extract the shop routes + inject get_progression_content into the seam (R3) (#851)

The progression-content substrate: `_get_progression_content` (a lazy,
double-checked-locking content cache) is now published into the appstate seam as
a CALLABLE. The cache global + lock + the function stay in server.py (startup
uses it, and test_progression_api patches `server._progression_content`
directly), so ZERO test retargeting — routers just call
`appstate.get_progression_content()`.

Because the accessor is defined at server.py:1152 but the import-top configure()
runs at :346, a second `appstate.configure(get_progression_content=...)` publishes
it right after the def (configure is idempotent/additive).

First consumer: routers/shop.py (3 routes: buy/equip/list). Bodies verbatim;
@app -> @router, meta_db -> appstate.meta_db, _clean_str from reqfields,
_get_progression_content() -> appstate.get_progression_content(). This unblocks
stats/progression/profile next (all share the accessor).

server.py: 7,880 -> 7,845.

Verified: pyflakes clean; route table IDENTICAL (143); pytest 2401 passed
(test_progression_api's server._progression_content patch still works via the
kept cache); packaging guard; eslint 0. Boot smoke: GET /api/shop 200 (drives
appstate.get_progression_content), buy 400 on bad body.

Co-authored-by: Claude Opus 4.8 (1M context) <noreply@anthropic.com>

docs/size-exemptions.md

@@ -55,8 +55,8 @@ without a *signed* exemption" is unenforceable.
 ## Planned, NOT exempt (owned by split plans — listed so nothing falls between states)
 
 core `static/app.js` (11,852) · `static/highway.js` (4,168, whole file) · `server.py`
-(7,833 — was 14,037; ratcheted by the R3 `MetadataDB` + `AudioEffectsMappingDB`
+(7,798 — was 14,037; ratcheted by the R3 `MetadataDB` + `AudioEffectsMappingDB`
-extractions and eight `routers/` modules) ·
+extractions and nine `routers/` modules) ·
 `lib/metadata_db.py` (4,373 — new in R3; the `MetadataDB` class alone is 4,018 lines
 and is a monolith in its own right, to be split per-table once the router train
 lands) · `static/v3/songs.js` (4,134) · `static/capabilities/audio-session.js`

lib/appstate.py

@@ -82,10 +82,16 @@ static_dir = None
 sloppak_cache_dir = None
 audio_cache_dir = None
 
+# Injected callables (not values): server owns the impl + its state, routers call
+# through the seam. get_progression_content wraps a lazy content cache that stays
+# in server.py (its `setattr(server, "_progression_content")` test is untouched).
+get_progression_content = None
+
 _SLOTS = frozenset({
     "meta_db", "audio_effect_mappings",
     "config_dir", "dlc_dir", "dlc_dir_env",
     "static_dir", "sloppak_cache_dir", "audio_cache_dir",
+    "get_progression_content",
 })
 
 

lib/routers/shop.py

@@ -0,0 +1,62 @@
+"""Cosmetics shop (spec 010) — buy/equip avatars & themes with earned currency.
+
+Extracted verbatim from ``server.py`` (R3); edits: ``@app`` -> ``@router``,
+``meta_db`` -> ``appstate.meta_db``, ``_get_progression_content()`` ->
+``appstate.get_progression_content()`` (the accessor is injected into the seam;
+its lazy content cache stays in server.py).
+"""
+
+from fastapi import APIRouter
+from fastapi.responses import JSONResponse
+
+import appstate
+from reqfields import _clean_str
+
+router = APIRouter()
+
+
+@router.get("/api/shop")
+def api_shop():
+    content = appstate.get_progression_content()
+    owned = appstate.meta_db.get_owned_items()
+    equipped = appstate.meta_db.get_equipped()
+    items = [
+        {**item, "owned": iid in owned, "equipped": equipped.get(item["slot"]) == iid}
+        for iid, item in sorted(content["shop"].items())
+    ]
+    return {"items": items, "wallet": appstate.meta_db.get_wallet()}
+
+
+@router.post("/api/shop/buy")
+def api_shop_buy(data: dict):
+    """Spend Decibels on a cosmetic. Atomic: balance check + spend + ownership
+    in one transaction. Decibels are earned by playing only — never purchasable."""
+    item_id = _clean_str(data.get("item_id"))
+    item = appstate.get_progression_content()["shop"].get(item_id)
+    if not item:
+        return JSONResponse({"error": f"unknown item: {item_id!r}"}, status_code=400)
+    status, wallet = appstate.meta_db.buy_shop_item(item)
+    if status == "owned":
+        return JSONResponse({"error": "already owned", "wallet": wallet}, status_code=409)
+    if status == "insufficient":
+        return JSONResponse({"error": "insufficient balance", "wallet": wallet}, status_code=402)
+    return {"ok": True, "item_id": item_id, "wallet": wallet}
+
+
+@router.post("/api/shop/equip")
+def api_shop_equip(data: dict):
+    """Equip an owned cosmetic into its slot. Body: {slot, item_id|null}
+    (null unequips, restoring the default look)."""
+    import progression as progression_mod
+    slot = _clean_str(data.get("slot"))
+    if slot not in progression_mod.SHOP_SLOTS:
+        return JSONResponse({"error": f"slot must be one of {sorted(progression_mod.SHOP_SLOTS)}"}, status_code=400)
+    item_id = data.get("item_id")
+    if item_id is not None:
+        item_id = _clean_str(item_id)
+        item = appstate.get_progression_content()["shop"].get(item_id)
+        if not item or item["slot"] != slot:
+            return JSONResponse({"error": f"unknown item for slot {slot}: {item_id!r}"}, status_code=400)
+        if item_id not in appstate.meta_db.get_owned_items():
+            return JSONResponse({"error": "item not owned"}, status_code=403)
+    return {"ok": True, "equipped": appstate.meta_db.equip_item(slot, item_id)}

server.py

@@ -55,7 +55,7 @@ from dlc_paths import _get_dlc_dir, _resolve_dlc_path
 # Lives in lib/ because that is the one core dir every packaging path copies.
 import appstate
 # Extracted route modules. They import `appstate`, never `server` — one-way graph.
-from routers import audio_effects, artist_aliases, loops, playlists, ws_highway, chart, wanted, library_extras
+from routers import audio_effects, artist_aliases, loops, playlists, ws_highway, chart, wanted, library_extras, shop
 import sloppak as sloppak_mod
 import loosefolder as loosefolder_mod
 # Pure text-matching engine for MusicBrainz enrichment (P8): denoise/score/
@@ -1164,6 +1164,13 @@ def _get_progression_content() -> dict:
     return _progression_content
 
 
+# Publish the progression-content accessor into the seam now that it's defined
+# (the main configure() at import-top runs before this def). The cache global +
+# lock stay in server.py, so the `setattr(server, "_progression_content")` test
+# path is unchanged; routers call `appstate.get_progression_content()`.
+appstate.configure(get_progression_content=_get_progression_content)
+
+
 def _copy_builtin_packs(
     root: Path,
     dest_dir: Path,
@@ -5005,51 +5012,9 @@ def api_progression_events(data: dict):
     return {"ok": True, "progression": summary}
 
 
-@app.get("/api/shop")
+# ── Cosmetics shop (spec 010) ────────────────────────────────────────────────
-def api_shop():
+# Mounted here (registration order). Implementation in lib/routers/shop.py.
-    content = _get_progression_content()
+app.include_router(shop.router)
-    owned = meta_db.get_owned_items()
-    equipped = meta_db.get_equipped()
-    items = [
-        {**item, "owned": iid in owned, "equipped": equipped.get(item["slot"]) == iid}
-        for iid, item in sorted(content["shop"].items())
-    ]
-    return {"items": items, "wallet": meta_db.get_wallet()}
-
-
-@app.post("/api/shop/buy")
-def api_shop_buy(data: dict):
-    """Spend Decibels on a cosmetic. Atomic: balance check + spend + ownership
-    in one transaction. Decibels are earned by playing only — never purchasable."""
-    item_id = _clean_str(data.get("item_id"))
-    item = _get_progression_content()["shop"].get(item_id)
-    if not item:
-        return JSONResponse({"error": f"unknown item: {item_id!r}"}, status_code=400)
-    status, wallet = meta_db.buy_shop_item(item)
-    if status == "owned":
-        return JSONResponse({"error": "already owned", "wallet": wallet}, status_code=409)
-    if status == "insufficient":
-        return JSONResponse({"error": "insufficient balance", "wallet": wallet}, status_code=402)
-    return {"ok": True, "item_id": item_id, "wallet": wallet}
-
-
-@app.post("/api/shop/equip")
-def api_shop_equip(data: dict):
-    """Equip an owned cosmetic into its slot. Body: {slot, item_id|null}
-    (null unequips, restoring the default look)."""
-    import progression as progression_mod
-    slot = _clean_str(data.get("slot"))
-    if slot not in progression_mod.SHOP_SLOTS:
-        return JSONResponse({"error": f"slot must be one of {sorted(progression_mod.SHOP_SLOTS)}"}, status_code=400)
-    item_id = data.get("item_id")
-    if item_id is not None:
-        item_id = _clean_str(item_id)
-        item = _get_progression_content()["shop"].get(item_id)
-        if not item or item["slot"] != slot:
-            return JSONResponse({"error": f"unknown item for slot {slot}: {item_id!r}"}, status_code=400)
-        if item_id not in meta_db.get_owned_items():
-            return JSONResponse({"error": "item not owned"}, status_code=403)
-    return {"ok": True, "equipped": meta_db.equip_item(slot, item_id)}
 
 
 # ── Per-song practice stats (fee[dB]ack v0.3.0) ───────────────────────────────