import jwt from 'jsonwebtoken'
import { randomUUID } from 'crypto'
import { Resend } from 'resend'
import PreRegistration from '../../../models/preRegistration.js'
import { connectDB } from '../../../utils/mongoose.js'

const resend = new Resend(process.env.RESEND_API_KEY)

export default defineEventHandler(async (event) => {
  await requireAdmin(event)
  const { preRegistrantIds, emailTemplate } = await validateBody(event, preRegistrantInviteSchema)
  await connectDB()

  const baseUrl = process.env.BASE_URL
  if (!baseUrl) {
    throw createError({ statusCode: 500, statusMessage: 'BASE_URL environment variable is not set' })
  }

  const config = useRuntimeConfig(event)
  const preRegs = await PreRegistration.find({ _id: { $in: preRegistrantIds } })

  if (preRegs.length === 0) {
    throw createError({ statusCode: 404, statusMessage: 'No pre-registrants found for the provided IDs' })
  }

  const results = []

  for (const preReg of preRegs) {
    // Only send to pending/selected/invited (allow resend); skip accepted/expired
    if (preReg.status !== 'selected' && preReg.status !== 'pending' && preReg.status !== 'invited') {
      results.push({
        preRegistrantId: preReg._id,
        email: preReg.email,
        success: false,
        error: `Skipped: status is ${preReg.status}`,
      })
      continue
    }

    try {
      const jti = randomUUID()
      const token = jwt.sign(
        { preRegistrationId: preReg._id.toString(), jti, type: 'prereg-invite' },
        config.jwtSecret,
        { expiresIn: '48h' },
      )

      // Token in fragment — never hits server logs
      const acceptLink = `${baseUrl}/accept-invite#${token}`

      const emailText = emailTemplate
        .replace(/\{name\}/g, preReg.name || 'there')
        .replace(/\{acceptLink\}/g, acceptLink)

      // Build HTML version
      const acceptButton = `<a href="${acceptLink}" style="display:inline-block;padding:12px 24px;background-color:#d4a017;color:#1a1a1a;text-decoration:none;border-radius:6px;font-weight:bold;">Accept Your Invitation</a>`
      const emailHtml = emailTemplate
        .replace(/&/g, '&amp;')
        .replace(/</g, '&lt;')
        .replace(/>/g, '&gt;')
        .replace(/\{name\}/g, preReg.name || 'there')
        .replace(/(https?:\/\/[^\s<]+)/g, '<a href="$1">$1</a>')
        .replace(/\n/g, '<br>')
        .replace(/\{acceptLink\}/g, acceptButton)

      const { error: emailError } = await resend.emails.send({
        from: 'Ghost Guild <welcome@babyghosts.org>',
        to: [preReg.email],
        subject: "You're invited to Ghost Guild",
        text: emailText,
        html: emailHtml,
      })

      if (emailError) {
        results.push({ preRegistrantId: preReg._id, email: preReg.email, success: false, error: emailError.message })
        continue
      }

      await PreRegistration.findByIdAndUpdate(preReg._id, {
        $set: {
          magicLinkJti: jti,
          magicLinkJtiUsed: false,
          status: 'invited',
          inviteEmailSentAt: new Date(),
        },
      })

      results.push({ preRegistrantId: preReg._id, email: preReg.email, success: true })
    } catch (err) {
      results.push({ preRegistrantId: preReg._id, email: preReg.email, success: false, error: err.message })
    }
  }

  const sent = results.filter(r => r.success).length
  const failed = results.filter(r => !r.success).length

  return { sent, failed, results }
})