feat: implement basic web app

frontend/src/core/api/client.ts

@@ -0,0 +1,17 @@
+"use client";
+
+import { Client as LangGraphClient } from "@langchain/langgraph-sdk/client";
+
+let _singleton: LangGraphClient | null = null;
+export function getLangGraphClient(): LangGraphClient {
+  let url: URL | null = null;
+  if (typeof window === "undefined") {
+    url = new URL("/api/langgraph", "http://localhost:3000");
+  } else {
+    url = new URL("/api/langgraph", window.location.origin);
+  }
+  _singleton ??= new LangGraphClient({
+    apiUrl: "http://localhost:2024",
+  });
+  return _singleton;
+}

frontend/src/core/api/hooks.ts

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+import type { ThreadsClient } from "@langchain/langgraph-sdk/client";
+import { useMutation, useQuery, useQueryClient } from "@tanstack/react-query";
+
+import type { MessageThread, MessageThreadState } from "../thread";
+
+import { getLangGraphClient } from "./client";
+
+export function useThreads(
+  params: Parameters<ThreadsClient["search"]>[0] = {
+    limit: 50,
+    sortBy: "updated_at",
+    sortOrder: "desc",
+  },
+) {
+  const langGraphClient = getLangGraphClient();
+  return useQuery<MessageThread[]>({
+    queryKey: ["threads", "search", params],
+    queryFn: async () => {
+      const response =
+        await langGraphClient.threads.search<MessageThreadState>(params);
+      return response as MessageThread[];
+    },
+  });
+}
+
+export function useDeleteThread() {
+  const queryClient = useQueryClient();
+  const langGraphClient = getLangGraphClient();
+  return useMutation({
+    mutationFn: async ({ threadId }: { threadId: string }) => {
+      await langGraphClient.threads.delete(threadId);
+    },
+    onSuccess(_, { threadId }) {
+      queryClient.setQueriesData(
+        {
+          queryKey: ["threads", "search"],
+          exact: false,
+        },
+        (oldData: Array<MessageThread>) => {
+          return oldData.filter((t) => t.thread_id !== threadId);
+        },
+      );
+    },
+  });
+}

frontend/src/core/api/index.ts

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+export * from "./client";
+export * from "./hooks";