fix: Show error when signing in with unregistered email

.changeset/polite-monkeys-travel.md

@@ -0,0 +1,5 @@
+---
+"namesake": minor
+---
+
+fix: Show error when signing in with unregistered email

src/routes/_unauthenticated/signin.tsx

@@ -30,39 +30,82 @@ export const Route = createFileRoute("/_unauthenticated/signin")({
 });
 
 const SignIn = () => {
-  const { signIn } = useAuthActions();
+  const { signIn} = useAuthActions();
   const [flow, setFlow] = useState<Key>("signIn");
   const [email, setEmail] = useState<string>("");
   const [password, setPassword] = useState<string>("");
   const [isSubmitting, setIsSubmitting] = useState(false);
-  const [error, setError] = useState<string | null>(null);
+  const [error, setError] = useState<string | React.ReactNode | null>(null);
   const navigate = useNavigate({ from: "/signin" });
   const isClosed = process.env.NODE_ENV === "production";
 
+  const checkUserExists = async (email: string): Promise<boolean> => {
+    try {
+      const response = await convex.query('checkUserExists', { email });
+
+      return response.exists;
+    } catch (err) {
+      if (err instanceof ConvexError && err.message === 'User does not exist') {
+        return false; 
+      }
+      console.error(err);
+      return false;
+    }
+  };
+
   const handleSubmit = async (event: React.FormEvent<HTMLFormElement>) => {
     event.preventDefault();
     setIsSubmitting(true);
     setError(null);
 
-    await signIn("password", {
-      flow,
-      email,
-      password,
-      redirectTo: "/quests",
-    })
-      .catch((error) =>
-        error instanceof ConvexError
-          ? setError(error.message)
-          : setError(error),
-      )
-      .then(() => navigate({ to: "/" }))
-      .finally(() => setIsSubmitting(false));
+    try {
+      if (flow === "signIn") {
+        const userExists = await checkUserExists(email);
+        if (!userExists) {
+          setError(
+            <>
+              There isn't an account for this email. Would you like to{" "}
+              <button
+                type="button"
+                onClick={() => setFlow("signUp")}
+                style={{
+                  color: "blue",
+                  textDecoration: "underline",
+                  background: "none",
+                  border: "none",
+                  padding: 0,
+                  cursor: "pointer",
+                }}
+              >
+                register a new account
+              </button>
+              ?
+            </>
+          );
+          setIsSubmitting(false);
+          return;
+        }
+      }
+
+      await signIn("password", {
+        flow,
+        email,
+        password,
+        redirectTo: "/quests",
+      });
+      navigate({ to: "/" });
+    } catch (err) {
+      setError('An unexpected error occurred. Please try again.');
+      setIsSubmitting(false);
+      console.error(err);
+    }
   };
 
-  if (flow === "reset")
+  if (flow === "reset") {
     return (
       <ForgotPassword onBack={() => setFlow("signIn")} defaultEmail={email} />
     );
+  }
 
   return (
     <Tabs selectedKey={flow} onSelectionChange={setFlow}>