feat: resend RSVP message on dupe submission

NOTES.md

@@ -25,7 +25,6 @@
   - [ ] Why are hamburger items missing on Confirm RSVP page?
 - [ ] URL builder helpers
 - [ ] Form to request resend link(s) for email address
-- [ ] Resend confirmation if an RSVP enters an existing email
 - [ ] Add Sentry to frontend
 - [ ] Diff dates in `notify` so that they are omitted when unchanged
 - [ ] Investigate why some emailed URLs use incorrect hosts for Netlify Deploy Preview
@@ -41,6 +40,8 @@
 - [ ] 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"
+- [x] Resend confirmation if an RSVP enters an existing email
 - [x] Hold RSVP locally with cookie
 - [x] **Scheduler engine**
   - [x] Send reminders

api/src/services/responses/responses.ts

@@ -5,6 +5,8 @@ import type {
   Reminder,
 } from 'types/graphql'
 
+import { RedwoodError } from '@redwoodjs/api'
+
 import { db } from 'src/lib/db'
 import {
   sendNewResponseReceived,
@@ -96,6 +98,18 @@ export const createResponse: MutationResolvers['createResponse'] = async ({
   const event = await db.event.findUnique({ where: { id: eventId } })
   if (!event) throw new Error(`Event not found: ${eventId}`)
 
+  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) {
     const sendAt = dayjs(event.start)

web/src/components/ResponseForm/ResponseForm.tsx

@@ -50,7 +50,11 @@ function random<T>(choices: T[]): T {
 
 const ResponseForm = (props: Props) => {
   const { mode, event, error, loading, formMethods, onChange, onSubmit } = props
-  const { formState } = formMethods
+  const { formState, getValues } = formMethods
+
+  const { email } = getValues()
+  const forbidResubmit =
+    email === error?.cause?.extensions?.['forbidResubmitForEmail']
 
   const [exampleName, setExampleName] = useState('')
   useEffect(() => {
@@ -153,7 +157,12 @@ 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