moved friend cursor data aggregation from frontend to backend

src/events/friend-cursor.ts

@@ -1,81 +1,32 @@
 import { writable } from "svelte/store";
-import {
-  events,
-  type CursorPositions,
-  type DollDto,
-  type OutgoingFriendCursorPayload,
-} from "$lib/bindings";
-import { createEventSource, removeFromStore } from "./listener-utils";
-
-type FriendCursorData = {
-  position: CursorPositions;
-  lastUpdated: number;
-};
+import { events, type CursorPositions } from "$lib/bindings";
+import { createEventSource } from "./listener-utils";
 
 export const friendsCursorPositions = writable<Record<string, CursorPositions>>(
   {},
 );
-export const friendsActiveDolls = writable<Record<string, DollDto | null>>({});
+
+// Here for now. Will extract into shared
+// util when there's more similar cases.
+function toCursorPositionsRecord(
+  payload: Partial<Record<string, CursorPositions>>,
+): Record<string, CursorPositions> {
+  return Object.fromEntries(
+    Object.entries(payload).filter(
+      (entry): entry is [string, CursorPositions] => {
+        return entry[1] !== undefined;
+      },
+    ),
+  );
+}
 
 export const {
   start: startFriendCursorTracking,
   stop: stopFriendCursorTracking,
 } = createEventSource(async (addEventListener) => {
-  let friendCursorState: Record<string, FriendCursorData> = {};
   addEventListener(
-    await events.friendCursorPositionUpdated.listen((event) => {
-      const data: OutgoingFriendCursorPayload = event.payload;
-
-      friendCursorState[data.userId] = {
-        position: data.position,
-        lastUpdated: Date.now(),
-      };
-
-      friendsCursorPositions.update((current) => {
-        return {
-          ...current,
-          [data.userId]: data.position,
-        };
-      });
-    }),
-  );
-
-  addEventListener(
-    await events.friendDisconnected.listen((event) => {
-      const data = event.payload;
-
-      if (friendCursorState[data.userId]) {
-        delete friendCursorState[data.userId];
-      }
-
-      friendsCursorPositions.update((current) =>
-        removeFromStore(current, data.userId),
-      );
-    }),
-  );
-
-  addEventListener(
-    await events.friendActiveDollChanged.listen((event) => {
-      const payload = event.payload;
-
-      if (!payload.doll) {
-        friendsActiveDolls.update((current) => {
-          const next = { ...current };
-          next[payload.friendId] = null;
-          return next;
-        });
-
-        friendsCursorPositions.update((current) =>
-          removeFromStore(current, payload.friendId),
-        );
-      } else {
-        friendsActiveDolls.update((current) => {
-          return {
-            ...current,
-            [payload.friendId]: payload.doll,
-          };
-        });
-      }
+    await events.friendCursorPositionsUpdated.listen((event) => {
+      friendsCursorPositions.set(toCursorPositionsRecord(event.payload));
     }),
   );
 });