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'
    })
  }

  try {
    // Build request body for Brevo Contacts API
    const brevoBody: {
      email: string
      updateEnabled: boolean
      listIds?: number[]
    } = {
      email,
      updateEnabled: true
    }

    // Add list ID if configured
    if (config.brevoNewsletterListId) {
      const listId = parseInt(config.brevoNewsletterListId, 10)
      if (!isNaN(listId)) {
        brevoBody.listIds = [listId]
      }
    }

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

    return {
      success: true,
      id: (response as { id?: number })?.id
    }
  } 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
    if (fetchError.data?.code === 'duplicate_parameter') {
      return {
        success: true,
        message: 'Already subscribed'
      }
    }

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

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