import { z } from 'zod'

const subscribeSchema = z.object({
  email: z.string().email()
})

export default defineEventHandler(async (event) => {
  const config = useRuntimeConfig()

  // Validate request body
  const body = await readBody(event)
  const result = subscribeSchema.safeParse(body)

  if (!result.success) {
    throw createError({
      statusCode: 400,
      statusMessage: 'Invalid email address'
    })
  }

  const { email } = result.data

  // Check if API key is configured
  if (!config.brevoApiKey) {
    console.error('BREVO_API_KEY is not configured')
    throw createError({
      statusCode: 500,
      statusMessage: 'Newsletter service is not configured'
    })
  }

  // Check if DOI template ID is configured
  if (!config.brevoDoiTemplateId) {
    console.error('BREVO_DOI_TEMPLATE_ID is not configured')
    throw createError({
      statusCode: 500,
      statusMessage: 'Newsletter service is not configured'
    })
  }

  console.log('DOI_TEMPLATE_ID', config.brevoDoiTemplateId)

  // Check if public site URL is configured (for DOI redirect)
  if (!config.public.siteUrl) {
    console.error('NUXT_PUBLIC_SITE_URL is not configured')
    throw createError({
      statusCode: 500,
      statusMessage: 'Newsletter service is not configured'
    })
  }

  // Check if newsletter list ID is configured
  if (!config.brevoNewsletterListId) {
    console.error('BREVO_NEWSLETTER_LIST_ID is not configured')
    throw createError({
      statusCode: 500,
      statusMessage: 'Newsletter service is not configured'
    })
  }

  const templateId = parseInt(config.brevoDoiTemplateId, 10)
  if (isNaN(templateId)) {
    console.error('BREVO_DOI_TEMPLATE_ID is not a valid number')
    throw createError({
      statusCode: 500,
      statusMessage: 'Newsletter service is not configured'
    })
  }

  const listId = parseInt(config.brevoNewsletterListId, 10)
  if (isNaN(listId)) {
    console.error('BREVO_NEWSLETTER_LIST_ID is not a valid number')
    throw createError({
      statusCode: 500,
      statusMessage: 'Newsletter service is not configured'
    })
  }

  // Build the redirection URL to the confirmation page
  const redirectionUrl = `${config.public.siteUrl}/newsletter-bestaetigt`

  try {
    // Build request body for Brevo Double Opt-In API
    const brevoBody = {
      email,
      templateId,
      redirectionUrl,
      includeListIds: [listId]
    }

    console.log('Brevo DOI request body:', brevoBody)

    await $fetch('https://api.brevo.com/v3/contacts/doubleOptinConfirmation', {
      method: 'POST',
      headers: {
        accept: 'application/json',
        'api-key': config.brevoApiKey,
        'content-type': 'application/json'
      },
      body: brevoBody
    })

    return {
      success: true
    }
  } catch (error: unknown) {
    // Handle Brevo API errors
    const fetchError = error as { statusCode?: number; data?: { code?: string; message?: string } }

    // Contact already exists (duplicate_parameter error) - treat as success
    // User will receive another confirmation email
    if (fetchError.data?.code === 'duplicate_parameter') {
      return {
        success: true,
        message: 'Confirmation email sent'
      }
    }

    console.error('Brevo API error:', fetchError.data || error)

    throw createError({
      statusCode: fetchError.statusCode || 500,
      statusMessage: fetchError.data?.message || 'Failed to subscribe to newsletter'
    })
  }
})