feat: add ability to share chats (#594)

hooks/use-chat-visibility.ts

@@ -0,0 +1,62 @@
+'use client';
+
+import { updateChatVisibility } from '@/app/(chat)/actions';
+import { VisibilityType } from '@/components/visibility-selector';
+import { Chat } from '@/lib/db/schema';
+import { useMemo } from 'react';
+import useSWR, { useSWRConfig } from 'swr';
+
+export function useChatVisibility({
+  chatId,
+  initialVisibility,
+}: {
+  chatId: string;
+  initialVisibility: VisibilityType;
+}) {
+  const { mutate, cache } = useSWRConfig();
+  const history: Array<Chat> = cache.get('/api/history')?.data;
+
+  const { data: localVisibility, mutate: setLocalVisibility } = useSWR(
+    `${chatId}-visibility`,
+    null,
+    {
+      fallbackData: initialVisibility,
+    },
+  );
+
+  const visibilityType = useMemo(() => {
+    if (!history) return localVisibility;
+    const chat = history.find((chat) => chat.id === chatId);
+    if (!chat) return 'private';
+    return chat.visibility;
+  }, [history, chatId, localVisibility]);
+
+  const setVisibilityType = (updatedVisibilityType: VisibilityType) => {
+    setLocalVisibility(updatedVisibilityType);
+
+    mutate<Array<Chat>>(
+      '/api/history',
+      (history) => {
+        return history
+          ? history.map((chat) => {
+              if (chat.id === chatId) {
+                return {
+                  ...chat,
+                  visibility: updatedVisibilityType,
+                };
+              }
+              return chat;
+            })
+          : [];
+      },
+      { revalidate: false },
+    );
+
+    updateChatVisibility({
+      chatId: chatId,
+      visibility: updatedVisibilityType,
+    });
+  };
+
+  return { visibilityType, setVisibilityType };
+}