feat(frontend): support static website demo mode

frontend/src/core/api/api-client.ts

@@ -3,6 +3,13 @@
 import { Client as LangGraphClient } from "@langchain/langgraph-sdk/client";
 
 import { getLangGraphBaseURL } from "../config";
+import { isStaticWebsiteOnly } from "../static-mode";
+import {
+  loadStaticDemoThread,
+  loadStaticDemoThreads,
+  staticDemoThreadState,
+} from "../threads/static-demo";
+import type { AgentThreadState } from "../threads/types";
 
 import { isStateChangingMethod, readCsrfCookie } from "./fetcher";
 import { sanitizeRunStreamOptions } from "./stream-mode";
@@ -32,6 +39,10 @@ function injectCsrfHeader(_url: URL, init: RequestInit): RequestInit {
 }
 
 function createCompatibleClient(isMock?: boolean): LangGraphClient {
+  if (isStaticWebsiteOnly() && !isMock) {
+    return createStaticClient();
+  }
+
   const apiUrl = getLangGraphBaseURL(isMock);
   console.log(`Creating API client with base URL: ${apiUrl}`);
   const client = new LangGraphClient({
@@ -58,6 +69,41 @@ function createCompatibleClient(isMock?: boolean): LangGraphClient {
   return client;
 }
 
+function createStaticClient(): LangGraphClient {
+  const apiUrl =
+    typeof window === "undefined"
+      ? "http://localhost:3000"
+      : window.location.origin;
+  const client = new LangGraphClient({ apiUrl });
+
+  client.threads.search = (async (query) => {
+    return loadStaticDemoThreads(query);
+  }) as typeof client.threads.search;
+
+  client.threads.get = (async (threadId) => {
+    return loadStaticDemoThread(threadId);
+  }) as typeof client.threads.get;
+
+  client.threads.getState = (async (threadId) => {
+    return staticDemoThreadState(await loadStaticDemoThread(threadId));
+  }) as typeof client.threads.getState;
+
+  client.threads.getHistory = (async (threadId) => {
+    return [staticDemoThreadState(await loadStaticDemoThread(threadId))];
+  }) as typeof client.threads.getHistory;
+
+  client.threads.update = (async (threadId) => {
+    return loadStaticDemoThread(threadId);
+  }) as typeof client.threads.update;
+
+  client.runs.list = (async () => []) as typeof client.runs.list;
+  client.runs.stream = async function* () {} as typeof client.runs.stream;
+  client.runs.joinStream =
+    async function* () {} as typeof client.runs.joinStream;
+
+  return client as LangGraphClient<AgentThreadState>;
+}
+
 const _clients = new Map<string, LangGraphClient>();
 export function getAPIClient(isMock?: boolean): LangGraphClient {
   const cacheKey = isMock ? "mock" : "default";