Resend RSVP message on dupe submission (#43)

When a user tries to RSVP twice for the same event with the same email,
show them this friendly message and resend their confirmation email:
<img width="804" alt="image"
src="https://github.com/user-attachments/assets/df029817-b01a-4b91-afd2-925cca739fbb">

NOTES.md

@@ -24,7 +24,10 @@
   - [ ] Why are hamburger items missing on Confirm RSVP page?
 - [ ] URL builder helpers
 - [ ] Form to request resend link(s) for email address
+      <<<<<<< HEAD
+- [ ] # Add Sentry to frontend
 - [ ] Resend confirmation if an RSVP enters an existing email
+  > > > > > > > origin/main
 - [ ] Diff dates in `notify` so that they are omitted when unchanged
 - [ ] Investigate why some emailed URLs use incorrect hosts for Netlify Deploy Preview
 - [ ] Stably sort RSVP list
@@ -39,11 +42,13 @@
 - [ ] Consensually gather user emails for mailing list
 - [ ] Add pretty error messages for 404s (e.g. clicked an expired/tidied link)
 - [ ] Redirect old slugs on slug change
+- [ ] Add sticky bit to "sent you a confirmation email for your RSVP"
 - [ ] Site-wide announcement feature
 - [ ] Unify email templates (header, unsub footer, etc.)
 - [ ] Unify email and Discord notifications
 - [ ] "Serious mode" for LoadingBuddy for e.g. unsubscribe requests
 - [ ] Notification when target email is denylisted on record creation
+- [x] Resend confirmation if an RSVP enters an existing email
 - [x] Captcha
 - [x] Hold RSVP locally with cookie
 - [x] **Scheduler engine**

api/src/services/responses/responses.ts

@@ -94,10 +94,23 @@ export const createResponse: MutationResolvers['createResponse'] = async ({
 
   const { captchaResponse, ...input } = _input
   const valid = await validateCaptcha(captchaResponse)
-  if (!valid)
+  if (!valid) {
     throw new RedwoodError(
       'Could not validate reCAPTCHA. Please refresh the page and try again.'
     )
+  }
+
+  const existingResponse = await db.response.findFirst({
+    where: { eventId, email: input.email },
+  })
+  if (existingResponse) {
+    await sendResponseConfirmation({ event, response: existingResponse })
+    throw new RedwoodError(
+      `You have already RSVPed to this event. ` +
+        `We've resent your confirmation email to ${input.email}.`,
+      { forbidResubmitForEmail: input.email }
+    )
+  }
 
   const reminders: { sendAt: Date }[] = []
   if (input.remindPriorSec) {

web/src/components/ResponseForm/ResponseForm.tsx

@@ -62,7 +62,11 @@ const ResponseForm = (props: Props) => {
     onCaptchaResponse,
     onSubmit,
   } = props
-  const { formState } = formMethods
+  const { formState, getValues } = formMethods
+
+  const { email } = getValues()
+  const forbidResubmit =
+    email === error?.cause?.extensions?.['forbidResubmitForEmail']
 
   const [exampleName, setExampleName] = useState('')
   useEffect(() => {
@@ -172,7 +176,12 @@ const ResponseForm = (props: Props) => {
 
         <Submit
           className="button is-success mt-3"
-          disabled={loading || !formState.isValid || !formState.isDirty}
+          disabled={
+            loading ||
+            !formState.isValid ||
+            !formState.isDirty ||
+            forbidResubmit
+          }
         >
           {mode === 'CREATE'
             ? loading