import { Resend } from 'resend'
import { escapeHtml } from '../helpers.js'
import { getResendFromAddress, getResendInboxAddress, sendResendEmailWithRetry } from '../email.js'

// A visitor who finished the /salvation page can tell us they prayed to receive Christ.
// Nothing is stored on the server: the response is emailed once to the site inbox and that is all.
const hits = new Map()

function rateLimit(req, res, next) {
  const ip = req.ip ?? 'unknown'
  const now = Date.now()
  const windowMs = 10 * 60 * 1000
  const entry = hits.get(ip) ?? { count: 0, start: now }
  if (now - entry.start > windowMs) { entry.count = 0; entry.start = now }
  entry.count += 1
  hits.set(ip, entry)
  if (hits.size > 2000) {
    for (const [k, v] of hits) { if (now - v.start > windowMs) hits.delete(k) }
  }
  if (entry.count > 3) {
    res.status(429).json({ message: 'Please wait a few minutes before trying again.' })
    return
  }
  next()
}

function clean(value, max) {
  return typeof value === 'string' ? value.trim().replace(/\s+/g, ' ').slice(0, max) : ''
}

export function register(app) {
  app.post('/api/salvation-response', rateLimit, async (req, res) => {
    const { name, email, message, _honey } = req.body ?? {}
    if (_honey) { res.json({ ok: true }); return }

    const safeName = clean(name, 100)
    const safeEmail = clean(email, 200)
    const safeMessage = typeof message === 'string' ? message.trim().slice(0, 2000) : ''
    if (safeEmail && !/^[a-zA-Z0-9._%+\-]{1,64}@[a-zA-Z0-9.\-]{1,253}\.[a-zA-Z]{2,}$/.test(safeEmail)) {
      res.status(400).json({ message: 'That email address does not look right. You can also leave it blank.' })
      return
    }

    if (!process.env.RESEND_API_KEY) {
      console.error('[salvation] RESEND_API_KEY env var not set')
      res.status(503).json({ message: 'We could not send this right now.' })
      return
    }

    const when = new Date().toLocaleString('en-US', { dateStyle: 'medium', timeStyle: 'short' })
    const nameLine = safeName || 'Name not given'
    const emailLine = safeEmail || 'Email not given'
    const text = [
      'Someone responded to the gospel on the /salvation page (the courtroom presentation) and says they pleaded guilty, accepted the pardon, and prayed to receive Jesus as Savior.',
      '',
      `Name: ${nameLine}`,
      `Email: ${emailLine}`,
      `When: ${when}`,
      '',
      safeMessage ? `Their message:\n${safeMessage}` : 'They did not leave a message.',
      '',
      safeEmail ? 'You can reply directly to this email to reach them.' : 'They did not leave an email address, so there is no way to reply.',
    ].join('\n')
    const html = `<div style="font-family:Georgia,serif;max-width:560px;line-height:1.6;color:#1a1208">
<p><strong>Someone responded to the gospel</strong> on the /salvation page and says they prayed to receive Jesus as Savior.</p>
<p><strong>Name:</strong> ${escapeHtml(nameLine)}<br><strong>Email:</strong> ${escapeHtml(emailLine)}<br><strong>When:</strong> ${escapeHtml(when)}</p>
${safeMessage ? `<p><strong>Their message:</strong></p><blockquote style="margin:0;padding-left:12px;border-left:3px solid #b8860b">${escapeHtml(safeMessage).replace(/\n/g, '<br>')}</blockquote>` : '<p><em>They did not leave a message.</em></p>'}
<p style="color:#6b5a30">${safeEmail ? 'You can reply directly to this email to reach them.' : 'They did not leave an email address, so there is no way to reply.'}</p>
</div>`

    try {
      const resend = new Resend(process.env.RESEND_API_KEY)
      await sendResendEmailWithRetry({
        resend,
        context: 'salvation-response',
        payload: {
          from: getResendFromAddress(),
          to: [getResendInboxAddress()],
          ...(safeEmail ? { replyTo: safeEmail } : {}),
          subject: 'Someone prayed to receive Christ on your salvation page',
          tags: [{ name: 'flow', value: 'salvation-response' }],
          text,
          html,
        },
      })
      res.json({ ok: true })
    } catch (err) {
      console.error('[salvation] email failed:', err?.message ?? err)
      res.status(502).json({ message: 'We could not send this right now.' })
    }
  })
}