import { NextRequest, NextResponse } from 'next/server'
import { getCampaign, updateCampaignStatus, getCampaignRecipients } from '../../../../../server/db/campaigns'
import { emailSendQueue } from '../../../../../queues/email-send.queue'
import { hashEmail } from '../../../../../lib/crypto'
import { checkSuppression } from '../../../../../server/suppression/check'
import { getTenantId } from '../../../../../lib/tenant-header'

export async function POST(req: NextRequest, { params }: { params: { id: string } }) {
  let tenantId: string
  try { tenantId = getTenantId(req) } catch {
    return NextResponse.json({ error: 'Tenant nicht identifizierbar' }, { status: 401 })
  }

  const campaignResult = await getCampaign(tenantId, params.id)
  if (!campaignResult.ok) {
    return NextResponse.json({ error: campaignResult.error.message }, { status: 404 })
  }
  if (campaignResult.data.status !== 'draft') {
    return NextResponse.json({ error: 'Nur Draft-Kampagnen können versendet werden' }, { status: 400 })
  }

  const statusResult = await updateCampaignStatus(tenantId, params.id, 'sending')
  if (!statusResult.ok) {
    return NextResponse.json({ error: statusResult.error.message }, { status: 500 })
  }

  const recipientsResult = await getCampaignRecipients(tenantId, params.id)
  if (!recipientsResult.ok) {
    // Rollback auf draft — verhindert verwaisten 'sending'-Status
    await updateCampaignStatus(tenantId, params.id, 'draft')
    return NextResponse.json({ error: 'Empfänger konnten nicht geladen werden' }, { status: 500 })
  }
  const recipients = recipientsResult.data

  // Suppression-Check PFLICHT — kein Opt-out-Empfänger darf in die Queue
  const unsuppressedRecipients = await Promise.all(
    recipients.map(async (r) => {
      const suppressed = await checkSuppression(tenantId, r.email)
      return suppressed ? null : r
    })
  ).then((results) => results.filter((r): r is { email: string } => r !== null))

  let addedJobs: { id?: string }[]
  try {
    addedJobs = await emailSendQueue.addBulk(
      unsuppressedRecipients.map((recipient) => ({
        name: 'send',
        data: {
          tenantId,
          campaignId: params.id,
          recipientEmail: recipient.email,
          recipientHash: hashEmail(recipient.email),
        },
        opts: {
          attempts: 3,
          backoff: { type: 'exponential' as const, delay: 2000 },
          removeOnComplete: 100,
          removeOnFail: { count: 500 },
        },
      }))
    )
  } catch (e) {
    // Rollback auf draft — Queue-Fehler darf nicht zu verwaisten Kampagnen führen
    await updateCampaignStatus(tenantId, params.id, 'draft')
    return NextResponse.json({ error: 'Jobs konnten nicht eingestellt werden' }, { status: 500 })
  }

  return NextResponse.json({ queued: addedJobs.length })
}