hanzo.ai/app/(marketing)/newsletter/confirm/page.tsx

'use client'

import { useEffect, useState, useSyncExternalStore } from 'react'
import { useI18n } from '@hanzo/i18n/react'
import { Text, YStack } from '@hanzo/ui'
import { Action } from '@hanzo/ui/marketing'
import { track } from '@hanzo/app/lib/tags'
import { BAD } from '@hanzo/app/lib/mix'
import { Focus, LARGE } from '@/components/shell/focus'
import { Subscribe } from '@/components/newsletter/Subscribe'
import { confirm, Refused } from '@/lib/newsletter'

/**
 * Where the newsletter's confirmation mail lands: `/newsletter/confirm#t=<token>`.
 * The token rides the fragment, so it reaches neither a server log nor a
 * Referer, and it is spent only by the press below: a mail scanner that opens
 * the link subscribes nobody. Once read, the fragment leaves the address.
 *
 * Events: newsletter_confirmed, newsletter_confirm_refused { status }.
 */
type State = { at: 'ready' | 'busy' | 'done' } | { at: 'refused'; status: number; detail: string }

/** The link's token, read off the fragment the first time it is asked for and kept: the fragment leaves the address once read. */
let kept: string | null = null
const fromHash = () => (kept ??= new URLSearchParams(window.location.hash.slice(1)).get('t') ?? '')
/** Nothing changes the token while the page is open. */
const still = () => () => {}

export default function ConfirmNewsletter() {
  const { t } = useI18n()
  // Null until the page runs: the export cannot know the token.
  const token = useSyncExternalStore(still, fromHash, () => null)
  const [state, setState] = useState<State>({ at: 'ready' })

  useEffect(() => {
    if (window.location.hash) history.replaceState(history.state, '', window.location.pathname)
  }, [])

  const press = async () => {
    setState({ at: 'busy' })
    try {
      await confirm(token ?? '')
      setState({ at: 'done' })
      track('newsletter_confirmed', {})
    } catch (err) {
      const status = err instanceof Refused ? err.status : 0
      track('newsletter_confirm_refused', { status })
      setState({ at: 'refused', status, detail: err instanceof Refused ? err.detail : '' })
    }
  }

  if (state.at === 'done') {
    return (
      <Focus id="confirm-title" title={t('You are subscribed.')} line={t('The next issue comes to your inbox. Every one has a one-click unsubscribe.')}>
        <Action href="/" fill {...LARGE}>
          {t('Back to hanzo.ai')}
        </Action>
      </Focus>
    )
  }

  if (token === '' || (state.at === 'refused' && (state.status === 400 || state.status === 410))) {
    const expired = state.at === 'refused' && state.status === 410
    return (
      <Focus
        id="confirm-title"
        title={expired ? t('This link has expired.') : t('This link does not work.')}
        line={t('Enter your address again and we will send a new one.')}
      >
        <Subscribe source="hanzo.ai/newsletter/confirm" id="again" />
      </Focus>
    )
  }

  return (
    <Focus id="confirm-title" title={t('Confirm your subscription')} line={t('One press and the Hanzo newsletter starts coming to your inbox.')}>
      <YStack gap="$3">
        <Action render="button" fill disabled={!token || state.at === 'busy'} onClick={press} {...LARGE}>
          {state.at === 'busy' ? t('Confirming…') : t('Confirm subscription')}
        </Action>
        {state.at === 'refused' ? (
          <Text role="alert" text="center" fontSize="$2" lineHeight="1.25rem" color={BAD}>
            {state.detail || t('We could not reach our mail service. Try again in a minute.')}
          </Text>
        ) : null}
      </YStack>
    </Focus>
  )
}