import nodemailer from 'nodemailer'
import * as auth from './auth.js'

const normalize = value => String(value || '').trim().toLowerCase()
const enabled = value => ['1', 'true', 'yes', 'on'].includes(normalize(value))

export function isReviewUser(user) {
  if (!user) return false
  const email = normalize(user.email)
  return normalize(user.accountType) === 'playstore_review' ||
    Boolean(email && email === normalize(process.env.PLAYSTORE_REVIEW_EMAIL))
}

function addresses(values) {
  return values.flat(Infinity).filter(Boolean).flatMap(value => {
    if (typeof value === 'object') return [normalize(value.address)]
    return String(value).split(',').map(part => normalize(part.match(/<([^>]+)>/)?.[1] || part))
  })
}

export async function shouldSuppressMail(event, emails = []) {
  if (enabled(process.env.MAIL_DELIVERY_DISABLED)) return true

  // Use the authenticated account, never a client-provided demo flag.
  if (event) {
    const token = auth.getTokenFromEvent(event)
    if (token && isReviewUser(await auth.getUserFromToken(token))) return true
  }

  const targets = addresses(emails)
  if (!targets.length) return false
  if (targets.includes(normalize(process.env.PLAYSTORE_REVIEW_EMAIL))) return true
  const users = await auth.readUsers()
  return users.some(user => isReviewUser(user) && targets.includes(normalize(user.email)))
}

// All SMTP entry points go through this gate, including newsletter batches.
// Create the real transport lazily so suppressed mail cannot open a connection.
export function createMailTransport(event, options) {
  let transport
  return {
    async sendMail(mail) {
      if (await shouldSuppressMail(event, [mail.to, mail.cc, mail.bcc, mail.replyTo])) {
        return { suppressed: true, messageId: null, accepted: [], rejected: [] }
      }
      transport ||= nodemailer.createTransport(options)
      return transport.sendMail(mail)
    }
  }
}