// Apple configuration profile (.mobileconfig) for one-click Mail setup on
// macOS/iOS — the Apple answer to autodiscovery (Apple Mail ignores RFC 6186
// SRV records, and "Microsoft Exchange" needs EWS/EAS which Stalwart doesn't
// speak). The profile carries server settings + the address but NO password:
// profiles are plaintext XML, so Apple prompts for the password on install.
//
// Session-gated like every portal API. The mail host comes from runtime
// config (public.mailUrl), so dev (.local) and prod (.eu) generate correct
// profiles from one build. Includes CalDAV + CardDAV payloads (Traefik
// routes /dav + the well-knowns on the mail host through to Stalwart), so
// one install configures Mail, Calendar and Contacts.

import { getUserSession } from 'nuxt-oidc-auth/runtime/server/utils/session.js'
import { randomUUID } from 'node:crypto'
import { readFileSync } from 'node:fs'
import forge from 'node-forge'

const EMAIL_RE = /^[^\s@]+@[^\s@]+\.[^\s@]+$/

function xmlEscape(s: string): string {
  return s
    .replaceAll('&', '&amp;')
    .replaceAll('<', '&lt;')
    .replaceAll('>', '&gt;')
    .replaceAll('"', '&quot;')
}

export default defineEventHandler(async (event) => {
  const session = await getUserSession(event).catch(() => null)
  if (!(session as { accessToken?: string } | null)?.accessToken) {
    throw createError({ statusCode: 401, statusMessage: 'Not signed in' })
  }

  const q = getQuery(event)
  const email = String(q.email ?? '').trim().toLowerCase()
  const name = String(q.name ?? '').trim() || email
  if (!EMAIL_RE.test(email)) {
    throw createError({ statusCode: 400, statusMessage: 'Invalid email' })
  }

  const mailHost = new URL(useRuntimeConfig().public.mailUrl as string).host
  // The regex above guarantees an @, but noUncheckedIndexedAccess doesn't know.
  const localPart = email.split('@')[0] ?? email
  // All user-visible labels derive from the address's own domain — this is a
  // white-label platform, so neither "dezky" nor "Stalwart" may appear in a
  // customer's account list.
  const domain = email.split('@')[1] ?? mailHost
  const d = xmlEscape(domain)
  const accountUuid = randomUUID()
  const caldavUuid = randomUUID()
  const carddavUuid = randomUUID()
  const profileUuid = randomUUID()
  const e = xmlEscape(email)
  const n = xmlEscape(name)
  const h = xmlEscape(mailHost)

  const profile = `<?xml version="1.0" encoding="UTF-8"?>
<!DOCTYPE plist PUBLIC "-//Apple//DTD PLIST 1.0//EN" "http://www.apple.com/DTDs/PropertyList-1.0.dtd">
<plist version="1.0">
<dict>
  <key>PayloadContent</key>
  <array>
    <dict>
      <key>EmailAccountDescription</key><string>${e}</string>
      <key>EmailAccountName</key><string>${n}</string>
      <key>EmailAccountType</key><string>EmailTypeIMAP</string>
      <key>EmailAddress</key><string>${e}</string>
      <key>IncomingMailServerAuthentication</key><string>EmailAuthPassword</string>
      <key>IncomingMailServerHostName</key><string>${h}</string>
      <key>IncomingMailServerPortNumber</key><integer>993</integer>
      <key>IncomingMailServerUseSSL</key><true/>
      <key>IncomingMailServerUsername</key><string>${e}</string>
      <key>OutgoingMailServerAuthentication</key><string>EmailAuthPassword</string>
      <key>OutgoingMailServerHostName</key><string>${h}</string>
      <key>OutgoingMailServerPortNumber</key><integer>465</integer>
      <key>OutgoingMailServerUseSSL</key><true/>
      <key>OutgoingMailServerUsername</key><string>${e}</string>
      <key>OutgoingPasswordSameAsIncomingPassword</key><true/>
      <key>PreventAppSheet</key><false/>
      <key>PreventMove</key><false/>
      <key>SMIMEEnabled</key><false/>
      <key>PayloadDescription</key><string>Configures the ${e} mail account.</string>
      <key>PayloadDisplayName</key><string>Mail (${d})</string>
      <key>PayloadIdentifier</key><string>eu.dezky.mail.${xmlEscape(localPart)}</string>
      <key>PayloadType</key><string>com.apple.mail.managed</string>
      <key>PayloadUUID</key><string>${accountUuid}</string>
      <key>PayloadVersion</key><integer>1</integer>
    </dict>
    <dict>
      <key>CalDAVAccountDescription</key><string>${d} calendar</string>
      <key>CalDAVHostName</key><string>${h}</string>
      <key>CalDAVPort</key><integer>443</integer>
      <key>CalDAVUseSSL</key><true/>
      <key>CalDAVUsername</key><string>${e}</string>
      <key>PayloadDescription</key><string>Configures the ${e} calendar account.</string>
      <key>PayloadDisplayName</key><string>Calendar (${d})</string>
      <key>PayloadIdentifier</key><string>eu.dezky.caldav.${xmlEscape(localPart)}</string>
      <key>PayloadType</key><string>com.apple.caldav.account</string>
      <key>PayloadUUID</key><string>${caldavUuid}</string>
      <key>PayloadVersion</key><integer>1</integer>
    </dict>
    <dict>
      <key>CardDAVAccountDescription</key><string>${d} contacts</string>
      <key>CardDAVHostName</key><string>${h}</string>
      <key>CardDAVPort</key><integer>443</integer>
      <key>CardDAVUseSSL</key><true/>
      <key>CardDAVUsername</key><string>${e}</string>
      <key>PayloadDescription</key><string>Configures the ${e} contacts account.</string>
      <key>PayloadDisplayName</key><string>Contacts (${d})</string>
      <key>PayloadIdentifier</key><string>eu.dezky.carddav.${xmlEscape(localPart)}</string>
      <key>PayloadType</key><string>com.apple.carddav.account</string>
      <key>PayloadUUID</key><string>${carddavUuid}</string>
      <key>PayloadVersion</key><integer>1</integer>
    </dict>
  </array>
  <key>PayloadDescription</key><string>Sets up ${e} in Apple Mail, Calendar and Contacts. You'll be asked for the mailbox password during installation.</string>
  <key>PayloadDisplayName</key><string>${d} — mail, calendar &amp; contacts (${e})</string>
  <key>PayloadIdentifier</key><string>eu.dezky.profile.${xmlEscape(localPart)}</string>
  <key>PayloadOrganization</key><string>${d}</string>
  <key>PayloadRemovalDisallowed</key><false/>
  <key>PayloadType</key><string>Configuration</string>
  <key>PayloadUUID</key><string>${profileUuid}</string>
  <key>PayloadVersion</key><integer>1</integer>
</dict>
</plist>
`

  setHeader(event, 'Content-Type', 'application/x-apple-aspen-config')
  setHeader(
    event,
    'Content-Disposition',
    `attachment; filename="dezky-mail-${localPart.replace(/[^a-z0-9.-]/gi, '_')}.mobileconfig"`,
  )
  return signProfile(profile)
})

// Sign the profile (PKCS#7 SignedData with embedded content) using the TLS
// cert mounted from cert-manager (PROFILE_SIGN_CERT/KEY in production —
// fleet/apps/portal.yaml). A publicly-trusted signature turns Apple's
// "unsigned profile" warning into a green Verified badge. Unset env (dev)
// → unsigned profile, still installable with the warning.
function signProfile(profileXml: string): Buffer | string {
  const certPath = process.env.PROFILE_SIGN_CERT
  const keyPath = process.env.PROFILE_SIGN_KEY
  if (!certPath || !keyPath) return profileXml
  try {
    const certPem = readFileSync(certPath, 'utf8')
    const keyPem = readFileSync(keyPath, 'utf8')
    // cert-manager's tls.crt is the full chain — leaf first. Include every
    // cert so Apple can build the path to the trusted root.
    const certs = certPem
      .split(/(?=-----BEGIN CERTIFICATE-----)/)
      .filter((c) => c.includes('BEGIN CERTIFICATE'))
      .map((c) => forge.pki.certificateFromPem(c))
    const p7 = forge.pkcs7.createSignedData()
    p7.content = forge.util.createBuffer(profileXml, 'utf8')
    for (const c of certs) p7.addCertificate(c)
    p7.addSigner({
      key: forge.pki.privateKeyFromPem(keyPem) as forge.pki.rsa.PrivateKey,
      certificate: certs[0]!,
      digestAlgorithm: forge.pki.oids.sha256!,
      authenticatedAttributes: [
        { type: forge.pki.oids.contentType!, value: forge.pki.oids.data! },
        { type: forge.pki.oids.messageDigest! },
        { type: forge.pki.oids.signingTime! },
      ],
    })
    p7.sign()
    return Buffer.from(forge.asn1.toDer(p7.toAsn1()).getBytes(), 'binary')
  } catch (err) {
    // Never fail the download over signing — fall back to unsigned.
    console.error('apple-mailconfig: profile signing failed, serving unsigned:', err)
    return profileXml
  }
}
