[Init] Initial commit - NetMesh terminal manager

application/state/sessionActivityStore.ts

@@ -0,0 +1,112 @@
+import { useSyncExternalStore } from 'react';
+
+type Listener = () => void;
+
+class SessionActivityStore {
+  private snapshot: Record<string, boolean> = {};
+  private listeners = new Set<Listener>();
+
+  getSnapshot = () => this.snapshot;
+
+  subscribe = (listener: Listener) => {
+    this.listeners.add(listener);
+    return () => this.listeners.delete(listener);
+  };
+
+  private emit() {
+    this.listeners.forEach((listener) => listener());
+  }
+
+  setTabActive = (tabId: string, hasActivity: boolean) => {
+    const alreadyActive = !!this.snapshot[tabId];
+    if (alreadyActive === hasActivity) return;
+
+    if (hasActivity) {
+      this.snapshot = { ...this.snapshot, [tabId]: true };
+    } else {
+      const { [tabId]: _removed, ...rest } = this.snapshot;
+      this.snapshot = rest;
+    }
+
+    this.emit();
+  };
+
+  clearTab = (tabId: string) => {
+    this.setTabActive(tabId, false);
+  };
+
+  clearTabs = (tabIds: Iterable<string>) => {
+    let changed = false;
+    const next = { ...this.snapshot };
+
+    for (const tabId of tabIds) {
+      if (!next[tabId]) continue;
+      delete next[tabId];
+      changed = true;
+    }
+
+    if (!changed) return;
+    this.snapshot = next;
+    this.emit();
+  };
+
+  prune = (validTabIds: Set<string>) => {
+    let changed = false;
+    const next: Record<string, boolean> = {};
+
+    for (const tabId of Object.keys(this.snapshot)) {
+      if (validTabIds.has(tabId)) {
+        next[tabId] = true;
+      } else {
+        changed = true;
+      }
+    }
+
+    if (!changed) return;
+    this.snapshot = next;
+    this.emit();
+  };
+}
+
+export const sessionActivityStore = new SessionActivityStore();
+
+export const useSessionActivityMap = () => {
+  return useSyncExternalStore(
+    sessionActivityStore.subscribe,
+    sessionActivityStore.getSnapshot,
+    sessionActivityStore.getSnapshot,
+  );
+};
+
+/**
+ * Per-tab activity boolean. Store notify is still global, but React skips re-render
+ * when this tab's boolean is unchanged (Object.is on the snapshot primitive).
+ */
+export const useSessionActivity = (tabId: string): boolean => {
+  return useSyncExternalStore(
+    sessionActivityStore.subscribe,
+    () => !!sessionActivityStore.getSnapshot()[tabId],
+    () => !!sessionActivityStore.getSnapshot()[tabId],
+  );
+};
+
+/** True if any of the given session ids currently has activity. */
+export const useAnySessionActivity = (sessionIds: readonly string[]): boolean => {
+  return useSyncExternalStore(
+    sessionActivityStore.subscribe,
+    () => {
+      const snap = sessionActivityStore.getSnapshot();
+      for (const id of sessionIds) {
+        if (snap[id]) return true;
+      }
+      return false;
+    },
+    () => {
+      const snap = sessionActivityStore.getSnapshot();
+      for (const id of sessionIds) {
+        if (snap[id]) return true;
+      }
+      return false;
+    },
+  );
+};