[Init] Initial commit - NetMesh terminal manager

application/state/sessionPresentationStore.ts

@@ -0,0 +1,163 @@
+import { useSyncExternalStore } from 'react';
+
+import type { CodingCliProviderId } from '../../domain/codingCliProviders';
+
+export type SessionPresentation = {
+  dynamicTitle?: string | null;
+  codingCliProviderId?: CodingCliProviderId | null;
+};
+
+type Listener = () => void;
+
+/** Encode undefined / null / present distinctly for useSyncExternalStore snapshots. */
+function encodePresentationField(value: string | null | undefined): string {
+  if (value === undefined) return 'u';
+  if (value === null) return 'n';
+  return `v:${value}`;
+}
+
+/**
+ * Presentation-only session chrome (tab title / coding-CLI icon) separate from
+ * structural session identity used by TerminalLayer pane equality.
+ */
+class SessionPresentationStore {
+  private bySession = new Map<string, SessionPresentation>();
+  private version = 0;
+  private listeners = new Set<Listener>();
+
+  getVersion = (): number => this.version;
+
+  getPresentation = (sessionId: string): SessionPresentation | undefined =>
+    this.bySession.get(sessionId);
+
+  /**
+   * Stable per-session snapshot for useSyncExternalStore. Global listeners still
+   * fire on any change, but React skips re-render when this string is unchanged
+   * for the subscribed sessionId (Object.is).
+   *
+   * Encodes undefined / null / value distinctly so a null tombstone is not
+   * Object.is-equal to a missing field (both used to collapse to '').
+   */
+  getSessionSnapshot = (sessionId: string): string => {
+    const presentation = this.bySession.get(sessionId);
+    if (!presentation) return '';
+    return `${encodePresentationField(presentation.dynamicTitle)}\0${encodePresentationField(presentation.codingCliProviderId)}`;
+  };
+
+  subscribe = (listener: Listener): (() => void) => {
+    this.listeners.add(listener);
+    return () => {
+      this.listeners.delete(listener);
+    };
+  };
+
+  setPresentation(sessionId: string, patch: SessionPresentation): void {
+    const prev = this.bySession.get(sessionId) ?? {};
+    const next: SessionPresentation = { ...prev, ...patch };
+    // Distinguish missing (undefined) from explicit clear (null) so the first
+    // tombstone is stored even when the session snapshot still has a stale
+    // title/provider and the store had no prior entry.
+    if (
+      prev.dynamicTitle === next.dynamicTitle
+      && prev.codingCliProviderId === next.codingCliProviderId
+    ) {
+      return;
+    }
+    this.bySession.set(sessionId, next);
+    this.version += 1;
+    for (const listener of this.listeners) listener();
+  }
+
+  clearSession(sessionId: string): void {
+    if (!this.bySession.has(sessionId)) return;
+    this.bySession.delete(sessionId);
+    this.version += 1;
+    for (const listener of this.listeners) listener();
+  }
+
+  prune(validSessionIds: ReadonlySet<string>): void {
+    let changed = false;
+    for (const id of this.bySession.keys()) {
+      if (!validSessionIds.has(id)) {
+        this.bySession.delete(id);
+        changed = true;
+      }
+    }
+    if (!changed) return;
+    this.version += 1;
+    for (const listener of this.listeners) listener();
+  }
+}
+
+export const sessionPresentationStore = new SessionPresentationStore();
+
+export function publishSessionDynamicTitle(sessionId: string, title: string | null): void {
+  sessionPresentationStore.setPresentation(sessionId, { dynamicTitle: title });
+}
+
+export function publishSessionCodingCliProvider(
+  sessionId: string,
+  providerId: CodingCliProviderId | null,
+): void {
+  sessionPresentationStore.setPresentation(sessionId, { codingCliProviderId: providerId });
+}
+
+type SessionWithPresentation = {
+  id: string;
+  dynamicTitle?: string;
+  codingCliProviderId?: CodingCliProviderId;
+};
+
+/**
+ * Overlay live presentation chrome onto a session snapshot.
+ * Used by TopTabs, focus sidebar, and pane chrome so title/provider updates
+ * stay live without structural setSessions thrash.
+ */
+export function applySessionPresentation<T extends SessionWithPresentation>(session: T): T {
+  const presentation = sessionPresentationStore.getPresentation(session.id);
+  if (!presentation) return session;
+  const nextTitle = presentation.dynamicTitle === undefined
+    ? session.dynamicTitle
+    : (presentation.dynamicTitle ?? undefined);
+  const nextProvider = presentation.codingCliProviderId === undefined
+    ? session.codingCliProviderId
+    : (presentation.codingCliProviderId ?? undefined);
+  if (
+    nextTitle === session.dynamicTitle
+    && nextProvider === session.codingCliProviderId
+  ) {
+    return session;
+  }
+  return {
+    ...session,
+    dynamicTitle: nextTitle,
+    codingCliProviderId: nextProvider,
+  };
+}
+
+/** Subscribe to live title/provider chrome version for multi-session consumers. */
+export function useSessionPresentationVersion(): number {
+  return useSyncExternalStore(
+    sessionPresentationStore.subscribe,
+    sessionPresentationStore.getVersion,
+    sessionPresentationStore.getVersion,
+  );
+}
+
+/**
+ * Per-session presentation snapshot. Other sessions' title updates notify the
+ * store but do not re-render this consumer when its own snapshot is unchanged.
+ */
+export function useSessionPresentationSnapshot(sessionId: string): string {
+  return useSyncExternalStore(
+    sessionPresentationStore.subscribe,
+    () => sessionPresentationStore.getSessionSnapshot(sessionId),
+    () => sessionPresentationStore.getSessionSnapshot(sessionId),
+  );
+}
+
+/** Session snapshot with live presentation overlay applied (single session). */
+export function usePresentedSession<T extends SessionWithPresentation>(session: T): T {
+  useSessionPresentationSnapshot(session.id);
+  return applySessionPresentation(session);
+}