Initial ChatGPT Agent demo

services/indexed-db/chat-store.ts

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+import type { UIMessage } from 'ai';
+
+const DATABASE_NAME = 'chatgpt-agent-demo';
+const DATABASE_VERSION = 1;
+const CHATS_STORE = 'chats';
+const MESSAGES_STORE = 'messages';
+
+export interface StoredChat {
+  id: string;
+  title: string;
+  created_at: string;
+  updated_at: string;
+}
+
+interface StoredMessages {
+  chatId: string;
+  messages: UIMessage[];
+  updated_at: string;
+}
+
+let databasePromise: Promise<IDBDatabase> | null = null;
+
+function openDatabase(): Promise<IDBDatabase> {
+  if (typeof window === 'undefined' || !('indexedDB' in window)) {
+    return Promise.reject(new Error('IndexedDB is not available'));
+  }
+
+  if (databasePromise) return databasePromise;
+
+  databasePromise = new Promise((resolve, reject) => {
+    const request = indexedDB.open(DATABASE_NAME, DATABASE_VERSION);
+
+    request.onupgradeneeded = () => {
+      const database = request.result;
+
+      if (!database.objectStoreNames.contains(CHATS_STORE)) {
+        database.createObjectStore(CHATS_STORE, { keyPath: 'id' });
+      }
+
+      if (!database.objectStoreNames.contains(MESSAGES_STORE)) {
+        database.createObjectStore(MESSAGES_STORE, { keyPath: 'chatId' });
+      }
+    };
+
+    request.onsuccess = () => resolve(request.result);
+    request.onerror = () => reject(request.error);
+    request.onblocked = () =>
+      reject(new Error('IndexedDB upgrade was blocked by another tab'));
+  });
+
+  return databasePromise;
+}
+
+function requestToPromise<T>(request: IDBRequest<T>): Promise<T> {
+  return new Promise((resolve, reject) => {
+    request.onsuccess = () => resolve(request.result);
+    request.onerror = () => reject(request.error);
+  });
+}
+
+function transactionToPromise(transaction: IDBTransaction): Promise<void> {
+  return new Promise((resolve, reject) => {
+    transaction.oncomplete = () => resolve();
+    transaction.onerror = () => reject(transaction.error);
+    transaction.onabort = () =>
+      reject(transaction.error ?? new Error('IndexedDB transaction aborted'));
+  });
+}
+
+export async function createChat(id: string, title: string): Promise<StoredChat> {
+  const database = await openDatabase();
+  const now = new Date().toISOString();
+  const chat: StoredChat = {
+    id,
+    title,
+    created_at: now,
+    updated_at: now,
+  };
+  const transaction = database.transaction(CHATS_STORE, 'readwrite');
+  transaction.objectStore(CHATS_STORE).put(chat);
+  await transactionToPromise(transaction);
+  return chat;
+}
+
+export async function listChats(): Promise<StoredChat[]> {
+  const database = await openDatabase();
+  const transaction = database.transaction(CHATS_STORE, 'readonly');
+  const chats = await requestToPromise(
+    transaction.objectStore(CHATS_STORE).getAll() as IDBRequest<StoredChat[]>
+  );
+
+  return chats.sort((a, b) => b.updated_at.localeCompare(a.updated_at));
+}
+
+export async function getMessages(chatId: string): Promise<UIMessage[]> {
+  const database = await openDatabase();
+  const transaction = database.transaction(MESSAGES_STORE, 'readonly');
+  const record = await requestToPromise(
+    transaction.objectStore(MESSAGES_STORE).get(chatId) as IDBRequest<
+      StoredMessages | undefined
+    >
+  );
+
+  return record?.messages ?? [];
+}
+
+export async function saveMessages(
+  chatId: string,
+  messages: UIMessage[]
+): Promise<void> {
+  const database = await openDatabase();
+  const now = new Date().toISOString();
+  const transaction = database.transaction(
+    [CHATS_STORE, MESSAGES_STORE],
+    'readwrite'
+  );
+  const chatsStore = transaction.objectStore(CHATS_STORE);
+
+  const chatRequest = chatsStore.get(chatId) as IDBRequest<
+    StoredChat | undefined
+  >;
+  chatRequest.onsuccess = () => {
+    if (chatRequest.result) {
+      chatsStore.put({ ...chatRequest.result, updated_at: now });
+    }
+  };
+
+  transaction.objectStore(MESSAGES_STORE).put({
+    chatId,
+    messages,
+    updated_at: now,
+  } satisfies StoredMessages);
+
+  await transactionToPromise(transaction);
+}
+
+export async function deleteChat(chatId: string): Promise<void> {
+  const database = await openDatabase();
+  const transaction = database.transaction(
+    [CHATS_STORE, MESSAGES_STORE],
+    'readwrite'
+  );
+  transaction.objectStore(CHATS_STORE).delete(chatId);
+  transaction.objectStore(MESSAGES_STORE).delete(chatId);
+  await transactionToPromise(transaction);
+}