changes

lib/chatStorage.ts

@@ -0,0 +1,135 @@
+/**
+ * Local storage utilities for chat persistence
+ * Provides fast local access while syncing with the database
+ */
+
+interface Message {
+  id: string;
+  role: 'user' | 'assistant';
+  content: string;
+}
+
+interface Chat {
+  id: string;
+  title: string;
+  updatedAt: string;
+  messages: Message[];
+}
+
+const CHATS_STORAGE_KEY = 'chat-gpz-chats';
+
+/**
+ * Get all chats from localStorage
+ */
+export function getLocalChats(): Chat[] {
+  if (typeof window === 'undefined') {
+    return [];
+  }
+  try {
+    const stored = localStorage.getItem(CHATS_STORAGE_KEY);
+    if (!stored) {
+      return [];
+    }
+    return JSON.parse(stored) as Chat[];
+  } catch (e) {
+    console.error('Failed to parse local chats:', e);
+    return [];
+  }
+}
+
+/**
+ * Save all chats to localStorage
+ */
+export function setLocalChats(chats: Chat[]): void {
+  if (typeof window === 'undefined') {
+    return;
+  }
+  try {
+    localStorage.setItem(CHATS_STORAGE_KEY, JSON.stringify(chats));
+  } catch (e) {
+    console.error('Failed to save local chats:', e);
+  }
+}
+
+/**
+ * Get a single chat by ID from localStorage
+ */
+export function getLocalChat(chatId: string): Chat | null {
+  const chats = getLocalChats();
+  return chats.find((c) => c.id === chatId) || null;
+}
+
+/**
+ * Save or update a single chat in localStorage
+ */
+export function saveLocalChat(chat: Chat): void {
+  const chats = getLocalChats();
+  const existingIndex = chats.findIndex((c) => c.id === chat.id);
+
+  if (existingIndex >= 0) {
+    chats[existingIndex] = chat;
+  } else {
+    chats.unshift(chat); // Add to beginning (most recent)
+  }
+
+  setLocalChats(chats);
+}
+
+/**
+ * Add a message to an existing chat in localStorage
+ */
+export function addMessageToLocalChat(chatId: string, message: Message): void {
+  const chats = getLocalChats();
+  const chat = chats.find((c) => c.id === chatId);
+
+  if (chat) {
+    chat.messages.push(message);
+    chat.updatedAt = new Date().toISOString();
+    setLocalChats(chats);
+  }
+}
+
+/**
+ * Delete a chat from localStorage
+ */
+export function deleteLocalChat(chatId: string): void {
+  const chats = getLocalChats();
+  const filtered = chats.filter((c) => c.id !== chatId);
+  setLocalChats(filtered);
+}
+
+/**
+ * Merge remote chats with local chats
+ * Remote chats take precedence for conflicts (based on updatedAt)
+ */
+export function mergeChats(localChats: Chat[], remoteChats: Chat[]): Chat[] {
+  const chatMap = new Map<string, Chat>();
+
+  // Add local chats first
+  for (const chat of localChats) {
+    chatMap.set(chat.id, chat);
+  }
+
+  // Override with remote chats (they're the source of truth)
+  for (const chat of remoteChats) {
+    const local = chatMap.get(chat.id);
+    if (!local || new Date(chat.updatedAt) >= new Date(local.updatedAt)) {
+      chatMap.set(chat.id, chat);
+    }
+  }
+
+  // Sort by updatedAt descending
+  return Array.from(chatMap.values()).sort(
+    (a, b) => new Date(b.updatedAt).getTime() - new Date(a.updatedAt).getTime()
+  );
+}
+
+/**
+ * Clear all local chats (useful for logout)
+ */
+export function clearLocalChats(): void {
+  if (typeof window === 'undefined') {
+    return;
+  }
+  localStorage.removeItem(CHATS_STORAGE_KEY);
+}