Per-entity game-patch history in the Version history sections

backend/app/main.py

@@ -43,6 +43,7 @@
     names,
     exports,
     entity_history,
+    update_history,
     ancient_pools,
     runs,
     pairings,
@@ -660,6 +661,7 @@ async def dispatch(self, request: Request, call_next):
 app.include_router(names.router)
 app.include_router(exports.router)
 app.include_router(entity_history.router)
+app.include_router(update_history.router)
 app.include_router(ancient_pools.router)
 app.include_router(runs.router)
 app.include_router(pairings.router)

backend/app/routers/update_history.py

@@ -0,0 +1,35 @@
+"""Per-entity game-patch update history from data/entity_history.json
+(maintained by tools/entity_history_sync.py). English-only."""
+
+import json
+from functools import lru_cache
+
+from fastapi import APIRouter, HTTPException
+
+from ..services.data_service import DATA_DIR
+
+router = APIRouter(prefix="/api/update-history", tags=["Update History"])
+
+
+@lru_cache(maxsize=1)
+def _histories() -> dict[str, dict[str, list]]:
+    try:
+        with open(DATA_DIR / "entity_history.json", "r", encoding="utf-8") as f:
+            data = json.load(f)
+    except (OSError, ValueError):
+        return {}
+    types = data.get("types") if isinstance(data, dict) else None
+    return types if isinstance(types, dict) else {}
+
+
+@router.get("/{entity_type}/{entity_id}")
+def get_update_history(entity_type: str, entity_id: str):
+    """Game-patch changes for one entity, newest first. 404s when nothing is
+    recorded, so the frontend can fall back to the changelog timeline."""
+    entries = _histories().get(entity_type, {}).get(entity_id.upper())
+    if not entries:
+        raise HTTPException(
+            status_code=404,
+            detail=f"No update history for '{entity_type}/{entity_id}'",
+        )
+    return entries

backend/tests/test_update_history.py

@@ -0,0 +1,65 @@
+"""The per-entity update-history endpoint serves the game-patch tables in
+data/entity_history.json; unknown entities 404 so the frontend can fall
+back to the site-changelog timeline."""
+
+import pytest
+from fastapi import HTTPException
+
+from app.routers.update_history import _histories, get_update_history
+
+
+def test_history_file_loads_and_is_well_formed():
+    types = _histories()
+    assert len(types["cards"]) > 400
+    assert len(types["relics"]) > 150
+    for entity_type, entities in types.items():
+        for entity_id, entries in list(entities.items())[:30]:
+            assert entity_id == entity_id.upper(), (entity_type, entity_id)
+            assert entries
+            for entry in entries:
+                assert set(entry) == {"version", "type", "date", "changes"}
+                assert isinstance(entry["changes"], list)
+                assert all(isinstance(c, str) and c for c in entry["changes"])
+
+
+def test_dated_entries_are_newest_first():
+    checked = 0
+    for entities in _histories().values():
+        for entries in entities.values():
+            dates = [e["date"] for e in entries if e["date"]]
+            if len(dates) > 1:
+                assert dates == sorted(dates, reverse=True)
+                checked += 1
+    assert checked > 50
+
+
+def test_known_entity_returns_its_entries():
+    types = _histories()
+    card_id = next(iter(types["cards"]))
+    assert get_update_history("cards", card_id.lower()) == types["cards"][card_id]
+
+
+def test_unknown_entity_404s():
+    for entity_type, entity_id in [
+        ("cards", "NOT_A_REAL_CARD"),
+        ("no_such_type", "WHATEVER"),
+    ]:
+        with pytest.raises(HTTPException) as exc:
+            get_update_history(entity_type, entity_id)
+        assert exc.value.status_code == 404
+
+
+def test_starter_variants_have_history():
+    # Duplicate-named starters resolve to per-character pages
+    # (e.g. "Strike (Ironclad)"), which regressed once already.
+    cards = _histories()["cards"]
+    assert "STRIKE_IRONCLAD" in cards
+    assert "DEFEND_IRONCLAD" in cards
+
+
+def test_name_collisions_stay_in_their_type():
+    types = _histories()
+    # Accelerant is both a card and a power; the power page lookup must not
+    # pick up the card page's history.
+    assert "ACCELERANT" in types["cards"]
+    assert "ACCELERANT" not in types.get("powers", {})