Add hook to replace race on character

Closes #384

src/main/typescript/hooks/index.ts

@@ -1,6 +1,7 @@
 import registerForDragRulerReady from "./dragRuler/ready.js";
 import registerForHotbarDrop from "./hotbarDrop.js";
 import registerForInit from "./init.js";
+import registerForPreCreateItem from "./preCreateItem.js";
 import registerForPreUpdateToken from "./preUpdateToken.js";
 import registerForQuenchReady from "./quench/ready.js";
 import registerForReady from "./ready.js";
@@ -17,6 +18,8 @@ export default function registerForHooks(): void {
   registerForRenderChatLog();
   registerForRenderChatMessage();
 
+  registerForPreCreateItem();
+
   registerForPreUpdateToken();
 
   registerForUpdateActor();

src/main/typescript/hooks/preCreateItem.ts

@@ -0,0 +1,30 @@
+import WvActor from "../actor/wvActor.js";
+import { TYPES } from "../constants.js";
+import type WvItem from "../item/wvItem.js";
+
+export default function registerForPreCreateItem(): void {
+  Hooks.on<Hooks.PreCreateDocument<typeof Item>>(
+    "preCreateItem",
+    replaceCharacterRace
+  );
+}
+
+type HookParams = Parameters<Hooks.PreCreateDocument<typeof Item>>;
+
+/**
+ * Replace existing Race items on an actor, if a Race is created on an actor.
+ */
+function replaceCharacterRace(document: HookParams[0]): false | void {
+  if (
+    document.data.type !== TYPES.ITEM.RACE ||
+    !(document.parent instanceof WvActor)
+  )
+    return;
+
+  document.parent.deleteEmbeddedDocuments(
+    "Item",
+    document.parent.itemTypes.race
+      .filter((item): item is StoredDocument<WvItem> => item.id !== null)
+      .map((item) => item.id)
+  );
+}

src/main/typescript/hooks/preUpdateToken.ts

@@ -7,7 +7,10 @@ import { LOG } from "../systemLogger.js";
 
 /** Register system callbacks for the preUpdateToken hook. */
 export default function registerForPreUpdateToken(): void {
-  Hooks.on("preUpdateToken", checkApCostForMovement);
+  Hooks.on<Hooks.PreUpdateDocument<typeof TokenDocument>>(
+    "preUpdateToken",
+    checkApCostForMovement
+  );
 }
 
 type HookParams = Parameters<Hooks.PreUpdateDocument<typeof TokenDocument>>;