contract: type more of the game values the API passes as numbers

CLAUDE.md

@@ -597,17 +597,18 @@ literal, in this order:
    (`D2C_UnitTypes`), `D2Monsters.h` (`D2C_MonTypeFlags`). Most are already in scope
    through `imports/D2Common.h`. Platform values likewise: `WM_LBUTTONDOWN`, not `0x201`.
 2. **`src/contract/game/`** - `Constants.h` and the enums in `Types.h` (`UnitType`,
-   `MonsterSpecType`, `ItemLocation`, ...). The frontend and the contract cannot see
-   D2MOO, so these mirror the handful of values the JS API needs; use them there
-   instead of re-typing the literal.
+   `Stat`, `State`, `Skill`, `StatListFlags`, `ItemLocation`, ...). The frontend and the
+   contract cannot see D2MOO, so these mirror the values the JS API needs; use them there
+   instead of re-typing the literal. A backend takes the contract enum in its typed
+   imports and `static_assert`s it against D2MOO's constant where the two meet.
 3. **The backend's shared headers** - e.g. `SUBTILE_SCALE` in
    `backends/lod114d/game/DrlgHelpers.h`.
 
 When a value genuinely has to be restated, derive it from the canonical definition
 rather than repeating the literal:
 
 ```cpp
-constexpr uint32_t STAT_FIXED_POINT_FIRST = STAT_HITPOINTS;
+constexpr uint32_t UNIT_TYPE_NPC = UNIT_MONSTER;
 ```
 
 **Scope it to its use.** A constant used by one file stays in that file's anonymous

scripts/gen_dts.py

@@ -45,6 +45,10 @@ def ts_type(t, *, is_return=False):
     t = str(t).strip()
     if t in _NUMBER_TYPES:
         return "number"
+    # A bitfield / namespace name inside a composite type (`CollisionFlag[][]`,
+    # `{flags:StatListFlags}`) is `number` too.
+    if _NUMBER_TYPES:
+        t = re.sub(r"\b(?:" + "|".join(map(re.escape, sorted(_NUMBER_TYPES))) + r")\b", "number", t)
     if is_return and t == "null":
         return "void"  # "returns null" is the API's way of saying "no result"
     # a bare `function` param type with no callback detail -> the Function type

src/backends/lod114d/game/Control.cpp

@@ -162,15 +162,12 @@ uint32_t Control::SelectEnd() const {
     return ctrl ? ctrl->dwSelectEnd : 0U;
 }
 
-bool Control::HasLocaleText(int32_t localeId) const {
-    if (localeId < 0) {
-        return false;
-    }
+bool Control::HasLocaleText(uint16_t localeId) const {
     const auto ctrl = Resolve<D2WinControlStrc>();
     if (!ctrl) {
         return false;
     }
-    const auto* localeText = lod114d::imports::d2lang::D2LANG_GetLocaleText(static_cast<uint16_t>(localeId));
+    const auto* localeText = lod114d::imports::d2lang::D2LANG_GetLocaleText(localeId);
     if (localeText == nullptr) {
         return false;
     }

src/backends/lod114d/game/DrlgHelpers.h

@@ -38,7 +38,7 @@ constexpr int32_t SUBTILE_SCALE = 5;
 // `D2UnitStrc::pDrlgAct` is typed as D2MOO's `::D2DrlgActStrc*`, but the bytes
 // at that address follow the 1.14d allocation modeled by
 // `extras::D2DrlgActStrc`. Reinterpret at the unit boundary.
-inline D2DrlgLevelStrc* FindLevelInChain(uint32_t levelId) {
+inline D2DrlgLevelStrc* FindLevelInChain(LevelId levelId) {
     auto* player = lod114d::imports::d2client::UNITS_GetPlayerUnit();
     if (player == nullptr) {
         return nullptr;
@@ -48,7 +48,7 @@ inline D2DrlgLevelStrc* FindLevelInChain(uint32_t levelId) {
         return nullptr;
     }
     for (auto* level = act->pDrlg->pLevel; level != nullptr; level = level->pNextLevel) {
-        if (static_cast<uint32_t>(level->nLevelId) != levelId) {
+        if (static_cast<LevelId>(level->nLevelId) != levelId) {
             continue;
         }
         if (level->pFirstRoomEx == nullptr) {