import 'server-only'
import { Resend } from 'resend'
import { asAdmin } from '@/lib/db/with-user'
import { capaActions, incidents, users } from '@/lib/db/schema'
import { and, eq, inArray, isNotNull, lt } from 'drizzle-orm'
import { sendWhatsAppMessage } from '@/lib/notifications/whatsapp'
import { getApiKey } from '@/lib/settings'

const ROUND_LABELS = ['30-day', '60-day', '90-day'] as const
const NEXT_INTERVAL_DAYS: (number | null)[] = [60, 90, null]

export function getRoundLabel(round: number): string {
  return ROUND_LABELS[round] ?? '90-day'
}

export function getNextRecheckDate(verifiedAt: string, currentRound: number): string | null {
  const days = NEXT_INTERVAL_DAYS[currentRound]
  if (days === null || days === undefined) return null
  const base = new Date(verifiedAt)
  base.setUTCDate(base.getUTCDate() + days)
  return base.toISOString().split('T')[0]
}

export function shouldSendRecheck(
  recheckDate: string | null,
  round: number,
  today: string = new Date().toISOString().split('T')[0],
): boolean {
  if (!recheckDate || round >= 3) return false
  return recheckDate <= today
}

export async function sendEffectivenessRecheckNotifications(): Promise<{ notified: number }> {
  const today = new Date().toISOString().split('T')[0]

  const capas = await asAdmin(db =>
    db.select({
      id: capaActions.id,
      description: capaActions.description,
      effectivenessRecheckDate: capaActions.effectivenessRecheckDate,
      effectivenessRecheckRound: capaActions.effectivenessRecheckRound,
      verifiedAt: capaActions.verifiedAt,
      incidentId: capaActions.incidentId,
      incidentRef: incidents.referenceNo,
      verifierEmail: users.email,
      verifierName: users.name,
      verifierPhone: users.phone,
    })
    .from(capaActions)
    .leftJoin(incidents, eq(capaActions.incidentId, incidents.id))
    .leftJoin(users, eq(capaActions.verifiedBy, users.id))
    .where(and(
      inArray(capaActions.status, ['verified', 'closed']),
      isNotNull(capaActions.effectivenessRecheckDate),
      lt(capaActions.effectivenessRecheckRound, 3),
    ))
  )

  if (!capas || capas.length === 0) return { notified: 0 }

  const resend = new Resend(process.env.RESEND_API_KEY)
  const from = process.env.RESEND_FROM_EMAIL ?? 'onboarding@resend.dev'
  const siteUrl = process.env.NEXT_PUBLIC_SITE_URL ?? 'http://localhost:3000'

  let whatsappPhoneId: string | null = null
  let whatsappToken: string | null = null
  try {
    whatsappPhoneId = await getApiKey('META_WHATSAPP_PHONE_NUMBER_ID')
    whatsappToken = await getApiKey('META_WHATSAPP_ACCESS_TOKEN')
  } catch {
    // WhatsApp not configured — email only
  }

  let notified = 0

  for (const capa of capas) {
    const recheckDate = capa.effectivenessRecheckDate
    const round = capa.effectivenessRecheckRound

    if (!shouldSendRecheck(recheckDate, round, today)) continue

    const verifierEmail = capa.verifierEmail
    const verifierName = capa.verifierName ?? 'HSE Officer'
    const verifierPhone = capa.verifierPhone ?? ''
    if (!verifierEmail) continue

    const incidentRef = capa.incidentRef ?? capa.incidentId
    const roundLabel = getRoundLabel(round)
    const capaDesc = capa.description
    const capaUrl = `${siteUrl}/ims/hse/capa/${capa.id}`

    const subject = `[IMS] ${roundLabel} effectiveness check — ${incidentRef}`
    const html = `
      <p>Hi ${verifierName},</p>
      <p>This is the <strong>${roundLabel} effectiveness check</strong> for a corrective action you verified on incident <strong>${incidentRef}</strong>.</p>
      <p><strong>Action:</strong> ${capaDesc}</p>
      <p>Please confirm the corrective action is still in place and effective.</p>
      <p><a href="${capaUrl}">View CAPA</a></p>
    `
    const text = `${roundLabel} effectiveness check for ${incidentRef}\nAction: ${capaDesc}\n${capaUrl}`

    const { error } = await resend.emails.send({ from, to: [verifierEmail], subject, html, text })
    if (error) {
      console.error('Effectiveness recheck email error:', error)
      continue
    }

    // WhatsApp (non-blocking, best-effort)
    if (whatsappPhoneId && whatsappToken && verifierPhone) {
      sendWhatsAppMessage(
        verifierPhone,
        'ims_effectiveness_recheck',
        [roundLabel, incidentRef ?? '', capaDesc],
        whatsappPhoneId,
        whatsappToken,
      ).catch(err => console.error('WhatsApp recheck error:', err))
    }

    // Advance round
    const nextDate = getNextRecheckDate(capa.verifiedAt!.toISOString(), round)
    await asAdmin(db =>
      db.update(capaActions)
        .set({
          effectivenessRecheckRound: round + 1,
          effectivenessRecheckDate: nextDate ?? null,
        })
        .where(eq(capaActions.id, capa.id))
    )

    notified++
  }

  return { notified }
}