import { randomUUID } from 'crypto'
import { pool, getSetting } from '../db.js'
import {
  fetchBooking, updateGuestContactDetails, setBookingCustomFields,
  buildContactDetails, pickPrimaryGuest, isRelayEmail,
  formatGuestAddress, getContactByType,
} from '../lib/newbook.js'
import { generateRegcardPdf } from '../lib/pdf.js'
import { saveRegcardPdf } from '../lib/uploads.js'
import { queueMarketingSync } from '../lib/marketing/index.js'
import { pushIdle } from '../lib/device-stream.js'

const DEFAULT_TERMS = 'No terms & conditions text has been configured yet — set one under Settings.'

// Public/token-gated — deliberately NOT behind requireAuth. The
// checkin_sessions.token itself (short-lived, single-use, minted only by an
// already-authenticated staff push or, later, the online matcher) is the
// authorization here, same as every other app's write routes are gated by a
// capability — this route group is gated by "possession of a live token"
// instead. See project_checkin's "Submission flow sequencing + schema".
export async function checkinRoutes(app) {
  app.get('/api/checkin/:token', async (req, reply) => {
    const session = await loadSession(req.params.token)
    if (!session.ok) return reply.status(session.status).send({ error: session.error })

    let booking
    try {
      booking = await fetchBooking(session.row.booking_id)
    } catch (err) {
      return reply.status(502).send({ error: `Could not reach NewBook: ${err.message}` })
    }
    if (!booking) return reply.status(404).send({ error: 'Booking not found' })

    const guest = pickPrimaryGuest(booking)
    const contactDetails = Array.isArray(guest?.contact_details) ? guest.contact_details : []
    const excludedDomains = await getExcludedDomains()
    // Matches the legacy system's confirmed behaviour (2026-09-01, see
    // project_checkin_legacy_plugin): excluded-domain emails aren't shown as
    // "on file" at all, not just flagged — hadExcludedEmail tells the
    // frontend whether to explain *why* nothing (or fewer than expected)
    // showed up, without exposing the actual excluded address.
    const allEmails = contactDetails.filter(d => d.type === 'email')
    const existingEmails = allEmails
      .filter(d => !isRelayEmail(d.content, excludedDomains))
      .map(d => ({ content: d.content }))
    const hadExcludedEmail = allEmails.length > existingEmails.length
    const existingCarRegos = contactDetails.filter(d => d.type === 'car_rego').map(d => d.content)

    return {
      booking: {
        booking_id: booking.booking_id ?? session.row.booking_id,
        arrival: booking.booking_arrival ?? null,
        departure: booking.booking_departure ?? null,
        site_name: booking.site_name ?? null,
        tariff_total: booking.tariff_total ?? null,
        tariff_names: extractTariffNames(booking),
        nights: booking.booking_length ?? null,
      },
      guest: {
        guest_id: guest?.guest_id ?? null,
        name: [guest?.firstname, guest?.lastname].filter(Boolean).join(' ') || '',
        address: formatGuestAddress(guest),
        phone: getContactByType(contactDetails, ['mobile', 'phone']),
        existing_emails: existingEmails,
        had_excluded_email: hadExcludedEmail,
        car_regos: existingCarRegos,
      },
      terms_text: await getSetting('terms_and_conditions_text', DEFAULT_TERMS),
    }
  })

  app.post('/api/checkin/:token/submit', async (req, reply) => {
    const { email, car_regos, opted_in, signature_png_base64, accepted_terms } = req.body || {}
    if (!signature_png_base64 || !accepted_terms) {
      return reply.status(400).send({ error: 'Signature and accepted terms are required' })
    }

    // Step 1 — atomic claim. Both double-submit AND a token that expired
    // between page-load and submit are rejected here outright.
    const { rows: claimedRows } = await pool.query(
      `UPDATE checkin_sessions SET used_at = now()
       WHERE token = $1 AND used_at IS NULL AND expires_at > now()
       RETURNING *`,
      [req.params.token]
    )
    if (!claimedRows.length) {
      return reply.status(409).send({ error: 'This check-in link has already been used or has expired.' })
    }
    const session = claimedRows[0]

    let booking, guest
    try {
      booking = await fetchBooking(session.booking_id)
      guest = pickPrimaryGuest(booking)
      if (!guest) throw new Error('Could not resolve a guest for this booking')
    } catch (err) {
      await failCheckin(session, `Could not re-fetch booking from NewBook: ${err.message}`)
      return reply.status(502).send({ error: 'Could not load your booking — please ask a member of staff for help.' })
    }

    const contactDetails = buildContactDetails(guest.contact_details, {
      email: email?.trim() || null,
      carRegos: Array.isArray(car_regos) ? car_regos : [],
      optedIn: !!opted_in,
    })

    // Step 2 — NewBook write-back first. Only the guest's own contact details
    // are treated as business-critical (must succeed or the check-in fails
    // outright) — that's real guest data with no fallback. online_checkin_complete
    // is a per-hotel custom field, same shape of problem as regcard_link below
    // (its numeric field_id varies per hotel and may not be configured yet) —
    // non-fatal for the same reason: a missing admin setting shouldn't block a
    // guest from actually checking in.
    try {
      await retry(() => updateGuestContactDetails(guest.guest_id, contactDetails), 2)
    } catch (err) {
      await failCheckin(session, `NewBook update failed: ${err.message}`)
      return reply.status(502).send({ error: 'Could not save your details — please ask a member of staff for help.' })
    }

    const checkinCompleteFieldId = await getSetting('online_checkin_complete_custom_field_id', '')
    if (checkinCompleteFieldId) {
      await retry(() => setBookingCustomFields(session.booking_id, [
        { field_id: checkinCompleteFieldId, field_value: 1 },
      ]), 2).catch(err => {
        app.log.warn(`[checkin] online_checkin_complete write-back failed: ${err.message}`)
      })
    }

    // Local audit row, inserted now that the business-critical write has
    // landed — status starts 'pending' and only flips to 'complete' once the
    // PDF is generated below, so a PDF failure never loses the record.
    const guestName = [guest.firstname, guest.lastname].filter(Boolean).join(' ') || guest.name || ''
    const { rows: checkinRows } = await pool.query(
      `INSERT INTO checkins (booking_id, guest_id, hotel_id, device_id, guest_name, guest_email, opted_in, status)
       VALUES ($1,$2,$3,$4,$5,$6,$7,'pending') RETURNING *`,
      [session.booking_id, guest.guest_id, session.hotel_id, session.device_id, guestName, email || null, !!opted_in]
    )
    const checkin = checkinRows[0]

    // Step 3 — PDF generation (synchronous, pure-JS — no headless browser).
    try {
      const buffer = await generateRegcardPdf({
        hotelName: process.env.HOTEL_NAME || 'Hotel',
        booking,
        guest: { name: guestName, address: formatGuestAddress(guest), phone: getContactByType(guest.contact_details, ['mobile', 'phone']) },
        contactEmail: email,
        carRegos: Array.isArray(car_regos) ? car_regos : [],
        optedIn: !!opted_in,
        termsText: await getSetting('terms_and_conditions_text', DEFAULT_TERMS),
        signaturePngBase64: signature_png_base64,
      })
      const pdfPath = await saveRegcardPdf(randomUUID(), buffer)
      await pool.query(`UPDATE checkins SET pdf_path = $1, status = 'complete' WHERE id = $2`, [pdfPath, checkin.id])
      checkin.pdf_path = pdfPath
      checkin.status = 'complete'

      // Step 4 — write the PDF link back to NewBook, non-fatal if it fails
      // (the guest is still checked in either way — reception can find the
      // PDF from this app's own Checkins page regardless).
      const fieldId = await getSetting('regcard_custom_field_id', '')
      if (fieldId) {
        const publicUrl = `${(process.env.PUBLIC_BASE_URL || '').replace(/\/$/, '')}/tablet-checkin/api/checkins/${checkin.id}/pdf`
        await setBookingCustomFields(session.booking_id, [
          { field_id: fieldId, field_value: publicUrl },
        ]).catch(err => {
          app.log.warn(`[checkin] regcard_link custom field write-back failed: ${err.message}`)
        })
      }
    } catch (err) {
      await pool.query(`UPDATE checkins SET status = 'pending', error = $1 WHERE id = $2`, [err.message, checkin.id])
      app.log.error(`[checkin] PDF generation failed for checkin ${checkin.id}: ${err.message}`)
    }

    // Step 6 — marketing push, fire-and-forget, never blocks the response.
    if (opted_in) {
      queueMarketingSync(checkin.id, { email, name: guestName }).catch(err => {
        app.log.error(`[checkin] queueMarketingSync failed for checkin ${checkin.id}: ${err.message}`)
      })
    }

    // Step 7 — flip the device back to idle so the next guest can be pushed.
    await pool.query(`UPDATE devices SET status = 'idle' WHERE device_id = $1`, [session.device_id])
    pushIdle(session.device_id)

    return { ok: true, checkin_id: checkin.id, pdf_generated: checkin.status === 'complete' }
  })
}

async function getExcludedDomains() {
  const raw = await getSetting('excluded_email_domains', '')
  return raw.split(',').map(d => d.trim().toLowerCase()).filter(Boolean)
}

// "Rate type name(s)" for the booking-confirm step — a stay can run across
// more than one tariff if the rate changed mid-stay, so this surfaces every
// distinct label actually charged rather than just the single top-level
// tariff_name (which reflects whichever tariff applies to the first night).
// Falls back to that single field if tariffs_quoted isn't present at all.
function extractTariffNames(booking) {
  const quoted = Array.isArray(booking?.tariffs_quoted) ? booking.tariffs_quoted : []
  const labels = [...new Set(quoted.map(t => t.label).filter(Boolean))]
  if (labels.length) return labels
  return booking?.tariff_name ? [booking.tariff_name] : []
}

async function loadSession(token) {
  const { rows } = await pool.query('SELECT * FROM checkin_sessions WHERE token = $1', [token])
  if (!rows.length) return { ok: false, status: 404, error: 'Check-in link not found' }
  const row = rows[0]
  if (row.used_at) return { ok: false, status: 410, error: 'This check-in link has already been used' }
  if (new Date(row.expires_at) < new Date()) return { ok: false, status: 410, error: 'This check-in link has expired' }
  return { ok: true, row }
}

async function failCheckin(session, errorMessage) {
  await pool.query(
    `INSERT INTO checkins (booking_id, guest_id, hotel_id, device_id, status, error)
     VALUES ($1, NULL, $2, $3, 'failed', $4)`,
    [session.booking_id, session.hotel_id, session.device_id, errorMessage]
  )
  await pool.query(`UPDATE devices SET status = 'idle' WHERE device_id = $1`, [session.device_id])
  pushIdle(session.device_id)
}

async function retry(fn, times) {
  let lastErr
  for (let i = 0; i <= times; i++) {
    try {
      return await fn()
    } catch (err) {
      lastErr = err
    }
  }
  throw lastErr
}