import nodemailer from 'nodemailer'

const SETTINGS_URL = process.env.SETTINGS_URL || 'http://10.10.10.106:3080'
const SETTINGS_SECRET = process.env.SETTINGS_SECRET || ''

let _smtpCache = null  // { config, expires_at }
let _transporter = null

async function getSmtpConfig() {
  if (_smtpCache && Date.now() < _smtpCache.expires_at) return _smtpCache.config
  const res = await fetch(`${SETTINGS_URL}/settings/api/internal/integration/smtp`, {
    headers: { Authorization: `Bearer ${SETTINGS_SECRET}` },
    signal: AbortSignal.timeout(5000),
  })
  if (!res.ok) throw new Error(`Failed to fetch SMTP config from settings: ${res.status}`)
  const config = await res.json()
  if (!config.host) throw new Error('SMTP not configured in settings')
  _smtpCache = { config, expires_at: Date.now() + 5 * 60_000 }
  _transporter = null  // force transporter rebuild on next send
  return config
}

async function getTransporter() {
  if (_transporter) return _transporter
  const config = await getSmtpConfig()
  const port = parseInt(config.port || '587')
  _transporter = nodemailer.createTransport({
    host: config.host,
    port,
    secure: port === 465,
    auth: config.user ? { user: config.user, pass: config.pass } : undefined,
  })
  return _transporter
}

export async function sendPinEmail(to, name, pin) {
  const config = await getSmtpConfig()
  const transport = await getTransporter()
  const from = config.from || '"Hotel Number Four" <noreply@hotelnumberfour.com>'

  await transport.sendMail({
    from,
    to,
    subject: 'Your Hotel Number Four verification code',
    text: `Hi ${name},\n\nYour staff portal verification code is: ${pin}\n\nThis code expires in 15 minutes.\n\nIf you did not request this, please ignore this email.`,
    html: `
      <div style="font-family:sans-serif;max-width:480px;margin:0 auto;padding:2rem">
        <h2 style="color:#1e3a5f;margin:0 0 1rem">Hotel Number Four</h2>
        <p>Hi ${name},</p>
        <p>Your staff portal verification code is:</p>
        <div style="font-size:2.5rem;font-weight:700;letter-spacing:0.3em;color:#1e3a5f;
                    background:#f3f4f6;padding:1rem 2rem;border-radius:8px;
                    text-align:center;margin:1.5rem 0">${pin}</div>
        <p style="color:#6b7280;font-size:0.875rem">
          This code expires in 15 minutes.<br>
          If you did not request access to the staff portal, please ignore this email.
        </p>
      </div>
    `,
  })
}