// Phase 5: Payment service — single owner of the payment_requests table + Xendit integration.
//
// Public API surface (the future microservice contract):
//
//   requestPayment({ productType, productMetadata, customerId, amount, ttlMinutes, ... })
//     → inserts row, optionally creates Xendit invoice, returns row (with invoice_url if Xendit on)
//
//   confirmPayment(paymentRequestId, xenditMeta = {})
//     → pending → confirmed; emits 'payment_request.confirmed'
//
//   expirePayment(paymentRequestId)
//     → pending → expired (webhook-callable, no customer check); emits 'payment_request.expired'
//
//   cancelPayment(paymentRequestId, customerId)
//     → customer-initiated pending → abandoned; emits 'payment_request.cancelled'
//
//   markDeliveryFailed(paymentRequestId, causeTag)
//     → confirmed → failed_delivery; writes pairing_failures row; emits 'payment_request.delivery_failed'
//
//   consumePayment(paymentRequestId)
//     → confirmed → consumed; no event (terminal success)
//
//   getPayment(id) → row or null
//   getCustomerPendingPayments(customerId) → { items, total }
//   expireStalePaymentRequests() → background sweeper + reconciliation
//
//   on(eventName, handler) → subscribe to lifecycle events
//   verifyWebhookToken(headerToken) → constant-time compare for webhook auth (used by route)
//
//   registerPairingSubscriber() → wires pairing.service as a subscriber to payment_request.confirmed
//   recordIntermediateFailure(...) → audit-only failure for flows with a fallback path
//
// Internals (NOT exported):
//   createXenditInvoice() — wraps xendit-node SDK
//   emit() / emitter — EventEmitter setup
//
// Events emit AFTER the DB transition commits. Subscribers run on the next tick
// (handlers wrapped fire-and-forget) so the publisher is never blocked.
//
// Durability story: events are in-process EventEmitter; lost on process death.
// The reconciliation sweeper (expireStalePaymentRequests) re-derives missed work
// from DB state every minute + on startup. Subscribers MUST be idempotent.
// See requirement/phase5-xendit-plan.md "Event durability" section.

import { EventEmitter } from 'node:events'
import { Xendit } from 'xendit-node'
import { getDb } from '../db/client.js'
import { PaymentRequestStatus, PairingFailureCause, UserType, WsMessage, SessionMode } from '../constants.js'
import { recordFailure } from './pairing-failure.service.js'
import { sendToUser } from '../plugins/websocket.js'
import { sendPushNotification } from './notification.service.js'
import {
  getPaymentRequestTimeoutMinutes as readPaymentRequestTimeoutMinutes,
  getXenditConfig,
} from './config.service.js'

const sql = getDb()

// --- EventEmitter setup ---

const emitter = new EventEmitter()
// Bump default 10-listener cap so future product subscribers don't trigger the leak warning
emitter.setMaxListeners(50)

export const on = (eventName, handler) => {
  emitter.on(eventName, (payload) => {
    // Wrap every handler so an unhandled throw doesn't kill the process AND so handlers
    // run async-fire-and-forget (don't block the publisher's emit() return). Errors are
    // logged; recovery is the sweeper's job.
    Promise.resolve()
      .then(() => handler(payload))
      .catch((err) => console.error(`[payment event ${eventName}] handler failed`, err))
  })
}

const emit = (eventName, payload) => emitter.emit(eventName, payload)

// --- Internal Xendit client (lazy + re-creatable for test env stubbing) ---

let _xenditClient = null
let _xenditKey = null
const xenditClient = () => {
  const { secretKey } = getXenditConfig()
  if (_xenditClient && _xenditKey === secretKey) return _xenditClient
  _xenditClient = new Xendit({ secretKey })
  _xenditKey = secretKey
  return _xenditClient
}

const createXenditInvoice = async ({ paymentRequestId, amount, ttlMinutes, description }) => {
  const { successRedirectUrl, failureRedirectUrl } = getXenditConfig()
  const inv = await xenditClient().Invoice.createInvoice({
    data: {
      externalId: paymentRequestId,             // D4 — our UUID is the Xendit external_id
      amount,
      description,
      invoiceDuration: Math.floor(ttlMinutes * 60),    // D5 — TTL mirrors session timeout
      currency: 'IDR',
      successRedirectUrl: successRedirectUrl || undefined,
      failureRedirectUrl: failureRedirectUrl || undefined,
      // Stamped so a shared webhook router (no DB access) can route v1 vs v2 traffic
      // purely from the echoed payload. Keep this string stable — it is a routing key.
      metadata: { app: 'halobestie_v2' },
      // paymentMethods omitted → honor dashboard config (operator picks methods without a deploy)
    },
  })
  return { invoiceId: inv.id, invoiceUrl: inv.invoiceUrl }
}

// Used by the webhook route to authenticate Xendit's x-callback-token header.
export const verifyWebhookToken = (headerToken) => {
  const { webhookToken } = getXenditConfig()
  if (!headerToken || !webhookToken) return false
  if (typeof headerToken !== 'string') return false
  if (headerToken.length !== webhookToken.length) return false
  let mismatch = 0
  for (let i = 0; i < headerToken.length; i++) {
    mismatch |= headerToken.charCodeAt(i) ^ webhookToken.charCodeAt(i)
  }
  return mismatch === 0
}

// Test-only — drop cached client so vi.stubEnv changes take effect.
export const _resetXenditClientForTest = () => {
  _xenditClient = null
  _xenditKey = null
}

// --- Helpers ---

const getPaymentRequestTimeoutMinutes = async () => {
  const { payment_request_timeout_minutes } = await readPaymentRequestTimeoutMinutes()
  return payment_request_timeout_minutes
}

const buildEventPayload = (row) => ({
  paymentRequestId: row.id,
  productType: row.product_type ?? 'chat_session',
  productMetadata: row.product_metadata ?? {},
  customerId: row.customer_id,
  amount: row.amount,
  xenditInvoiceId: row.xendit_invoice_id ?? null,
  xenditPaymentMethod: row.xendit_payment_method ?? null,
})

const buildInvoiceDescription = (row) => {
  if (row.product_type === 'chat_session') {
    return row.is_extension
      ? `Perpanjangan sesi ${row.duration_minutes} menit`
      : `Sesi ${row.duration_minutes} menit`
  }
  // Generic fallback — future products can build their own descriptions and pass via productMetadata
  return row.product_metadata?.description ?? `Pembayaran ${row.product_type}`
}

// --- requestPayment: insert pending row + (if Xendit on) mint invoice ---

/**
 * Create a new payment request in `pending` status. When XENDIT_ENABLED=true, also
 * creates a Xendit Invoice and stamps invoice_id + invoice_url on the row.
 *
 * Product-agnostic: callers stamp `productType` + `productMetadata`. The legacy
 * top-level chat-specific args (durationMinutes, mode, isExtension, targetedMitraId,
 * isFirstSessionDiscount) are accepted for backward compat with existing chat code,
 * and also written into product_metadata when productType === 'chat_session'.
 */
export const requestPayment = async ({
  productType = 'chat_session',
  productMetadata = {},
  customerId,
  amount,
  ttlMinutes,
  // Chat-specific legacy fields (still written to top-level columns for now)
  durationMinutes,
  mode = SessionMode.CHAT,
  isFirstSessionDiscount = false,
  isExtension = false,
  targetedMitraId = null,
  // Customer's pre-picked payment method from the catalog. Optional;
  // upper-cased Xendit channel code (e.g. `OVO`). Stamped onto
  // product_metadata for analytics + future use as a Xendit `paymentMethods`
  // filter. Not currently passed to Xendit invoice creation — the customer
  // re-picks on Xendit's checkout page.
  preferredPaymentCode = null,
}) => {
  if (!customerId) {
    throw Object.assign(new Error('customerId is required'), { code: 'VALIDATION_ERROR', statusCode: 422 })
  }
  if (typeof amount !== 'number' || amount < 0) {
    throw Object.assign(new Error('amount must be a non-negative number'), { code: 'VALIDATION_ERROR', statusCode: 422 })
  }
  if (productType === 'chat_session') {
    if (typeof durationMinutes !== 'number' || durationMinutes <= 0) {
      throw Object.assign(new Error('durationMinutes must be a positive number for chat_session'), { code: 'VALIDATION_ERROR', statusCode: 422 })
    }
    if (mode !== SessionMode.CHAT && mode !== SessionMode.CALL) {
      throw Object.assign(new Error('mode must be chat or call'), { code: 'VALIDATION_ERROR', statusCode: 422 })
    }
  }

  const ttl = ttlMinutes ?? await getPaymentRequestTimeoutMinutes()

  // For chat_session, fold legacy args into product_metadata so the canonical
  // location is the JSONB blob. Subscribers read from product_metadata.
  const meta = productType === 'chat_session'
    ? {
        duration_minutes: durationMinutes,
        mode,
        is_extension: isExtension,
        targeted_mitra_id: targetedMitraId,
        is_first_session_discount: isFirstSessionDiscount,
        preferred_payment_code: preferredPaymentCode,
        ...productMetadata,
      }
    : { preferred_payment_code: preferredPaymentCode, ...productMetadata }

  const [row] = await sql`
    INSERT INTO payment_requests (
      customer_id, amount, duration_minutes, is_first_session_discount, is_extension,
      status, targeted_mitra_id, mode, expires_at, product_type, product_metadata
    )
    VALUES (
      ${customerId}, ${amount}, ${durationMinutes ?? 0}, ${isFirstSessionDiscount}, ${isExtension},
      ${PaymentRequestStatus.PENDING}, ${targetedMitraId}, ${mode},
      NOW() + (${ttl} || ' minutes')::interval,
      ${productType}, ${sql.json(meta)}
    )
    RETURNING *
  `

  // If Xendit is on, create the invoice + stamp the row. If creation fails, mark
  // the row as `failed` (NOT `expired` — distinct: "we never got an invoice at all"
  // vs. "TTL elapsed unpaid") and surface a 502 to the caller.
  const xc = getXenditConfig()
  if (xc.enabled) {
    try {
      const { invoiceId, invoiceUrl } = await createXenditInvoice({
        paymentRequestId: row.id,
        amount: row.amount,
        ttlMinutes: ttl,
        description: buildInvoiceDescription(row),
      })
      await sql`
        UPDATE payment_requests
        SET xendit_invoice_id = ${invoiceId}, xendit_invoice_url = ${invoiceUrl}
        WHERE id = ${row.id}
      `
      row.xendit_invoice_id = invoiceId
      row.xendit_invoice_url = invoiceUrl
    } catch (err) {
      console.error('[xendit] createInvoice failed; marking payment_request failed', { paymentRequestId: row.id, err })
      const [failed] = await sql`
        UPDATE payment_requests
        SET status = ${PaymentRequestStatus.FAILED}
        WHERE id = ${row.id} AND status = ${PaymentRequestStatus.PENDING}
        RETURNING *
      `
      if (failed) emit('payment_request.failed', buildEventPayload(failed))
      throw Object.assign(new Error('Payment provider error'), {
        code: 'PAYMENT_PROVIDER_ERROR',
        statusCode: 502,
        cause: err,
      })
    }
  }

  return row
}

// --- confirmPayment ---

/**
 * Transition pending → confirmed. Customer-facing callers (the legacy
 * /payment-requests/:id/confirm route) verify customer ownership themselves before
 * calling. Webhook caller does not check ownership (Xendit's authority).
 *
 * Optional xenditMeta stamps payment-time data from the webhook body:
 *   { invoiceId, paymentMethod, amount }
 *
 * Throws on missing row / wrong status / expiry. Webhook handler swallows
 * INVALID_STATE (already confirmed) and EXPIRED (raced sweeper) and ACKs.
 *
 * Emits 'payment_request.confirmed' after commit.
 */
export const confirmPayment = async (paymentRequestId, xenditMeta = {}) => {
  const [existing] = await sql`
    SELECT id, customer_id, status, expires_at
    FROM payment_requests
    WHERE id = ${paymentRequestId}
  `
  if (!existing) {
    throw Object.assign(new Error('Payment request not found'), { code: 'NOT_FOUND', statusCode: 404 })
  }
  if (existing.status !== PaymentRequestStatus.PENDING) {
    throw Object.assign(new Error(`Payment request is ${existing.status}, cannot confirm`), {
      code: 'INVALID_STATE', statusCode: 409,
    })
  }
  if (new Date(existing.expires_at) <= new Date()) {
    // Inline expiry check (sweeper hasn't run yet)
    await sql`
      UPDATE payment_requests SET status = ${PaymentRequestStatus.EXPIRED}
      WHERE id = ${paymentRequestId} AND status = ${PaymentRequestStatus.PENDING}
    `
    throw Object.assign(new Error('Payment request has expired'), { code: 'EXPIRED', statusCode: 409 })
  }

  const [updated] = await sql`
    UPDATE payment_requests
    SET status = ${PaymentRequestStatus.CONFIRMED},
        confirmed_at = NOW(),
        xendit_invoice_id = COALESCE(${xenditMeta.invoiceId ?? null}, xendit_invoice_id),
        xendit_payment_method = COALESCE(${xenditMeta.paymentMethod ?? null}, xendit_payment_method),
        xendit_paid_amount = COALESCE(${xenditMeta.amount ?? null}, xendit_paid_amount)
    WHERE id = ${paymentRequestId} AND status = ${PaymentRequestStatus.PENDING}
    RETURNING *
  `
  if (!updated) {
    throw Object.assign(new Error('Payment request state changed during confirm'), { code: 'CONFLICT', statusCode: 409 })
  }

  emit('payment_request.confirmed', buildEventPayload(updated))
  return updated
}

// Customer-facing wrapper used by the legacy /payment-requests/:id/confirm route
// (kept only for dev/Maestro — production gates the route on XENDIT_ENABLED).
// Verifies customer ownership before delegating to the internal confirmPayment.
export const confirmPaymentForCustomer = async (paymentRequestId, customerId) => {
  const [existing] = await sql`SELECT customer_id FROM payment_requests WHERE id = ${paymentRequestId}`
  if (!existing) {
    throw Object.assign(new Error('Payment request not found'), { code: 'NOT_FOUND', statusCode: 404 })
  }
  if (existing.customer_id !== customerId) {
    throw Object.assign(new Error('Payment request does not belong to this customer'), { code: 'FORBIDDEN', statusCode: 403 })
  }
  return confirmPayment(paymentRequestId)
}

// --- expirePayment (webhook-callable; no ownership check) ---

/**
 * Transition pending → expired. Called by the Xendit EXPIRED webhook handler
 * and by the background sweeper. Idempotent — if already terminal, no-op.
 * Emits 'payment_request.expired' if a transition occurred.
 */
export const expirePayment = async (paymentRequestId) => {
  const [updated] = await sql`
    UPDATE payment_requests
    SET status = ${PaymentRequestStatus.EXPIRED}
    WHERE id = ${paymentRequestId} AND status = ${PaymentRequestStatus.PENDING}
    RETURNING *
  `
  if (updated) emit('payment_request.expired', buildEventPayload(updated))
  return updated ?? null
}

// --- consumePayment ---

/**
 * Transition confirmed → consumed. Called by product code (pairing service for chat)
 * after successful delivery. No event — terminal success.
 */
export const consumePayment = async (paymentRequestId) => {
  const [updated] = await sql`
    UPDATE payment_requests
    SET status = ${PaymentRequestStatus.CONSUMED}, consumed_at = NOW()
    WHERE id = ${paymentRequestId} AND status = ${PaymentRequestStatus.CONFIRMED}
    RETURNING id, status, consumed_at
  `
  return updated ?? null
}

// --- markDeliveryFailed ---

/**
 * TERMINAL: mark a confirmed payment as failed_delivery + write a pairing_failures
 * audit row. Idempotent: no-op if not currently confirmed.
 *
 * Use only when no fallback is possible (no mitra available, all rejected, etc.).
 * For intermediate failures with a fallback (targeted reject during returning-chat),
 * use recordIntermediateFailure() which keeps the payment confirmed.
 *
 * Emits 'payment_request.delivery_failed' on transition.
 */
export const markDeliveryFailed = async (paymentRequestId, causeTag) => {
  if (!Object.values(PairingFailureCause).includes(causeTag)) {
    throw Object.assign(new Error(`Unknown cause_tag: ${causeTag}`), { code: 'VALIDATION_ERROR', statusCode: 422 })
  }

  const [existing] = await sql`
    SELECT id, customer_id, targeted_mitra_id, amount, status, product_type, product_metadata, xendit_invoice_id, xendit_payment_method
    FROM payment_requests
    WHERE id = ${paymentRequestId}
  `
  if (!existing) return null
  if (existing.status !== PaymentRequestStatus.CONFIRMED) return existing   // idempotent

  const [updated] = await sql`
    UPDATE payment_requests
    SET status = ${PaymentRequestStatus.FAILED_DELIVERY}
    WHERE id = ${paymentRequestId} AND status = ${PaymentRequestStatus.CONFIRMED}
    RETURNING *
  `
  if (!updated) return existing

  await recordFailure({
    paymentRequestId,
    customerId: existing.customer_id,
    targetedMitraId: existing.targeted_mitra_id,
    causeTag,
    amount: existing.amount,
  })

  emit('payment_request.delivery_failed', { ...buildEventPayload(updated), causeTag })
  return updated
}

// Backward-compat alias — pairing.service still calls failPaymentSession by name.
// TODO follow-up phase: rename call sites and drop this alias.
export const failPaymentSession = markDeliveryFailed

// --- recordIntermediateFailure (audit only; doesn't terminate) ---

/**
 * INTERMEDIATE: write a pairing_failures audit row WITHOUT terminating the payment.
 * Used inside flows with a fallback path (targeted "Curhat lagi" reject can fall back
 * to general blast on the same payment). One payment_request may have many audit rows.
 *
 * Returns the inserted pairing_failures row, or null if the payment is missing.
 */
export const recordIntermediateFailure = async ({
  paymentRequestId,
  customerId,
  targetedMitraId = null,
  causeTag,
  amount,
}) => {
  if (!Object.values(PairingFailureCause).includes(causeTag)) {
    throw Object.assign(new Error(`Unknown cause_tag: ${causeTag}`), { code: 'VALIDATION_ERROR', statusCode: 422 })
  }
  const [existing] = await sql`SELECT id FROM payment_requests WHERE id = ${paymentRequestId}`
  if (!existing) return null
  return recordFailure({ paymentRequestId, customerId, targetedMitraId, causeTag, amount })
}

// --- cancelPayment (customer-initiated abandonment) ---

/**
 * Customer-initiated abandonment of a pending payment (closed payment screen).
 * No pairing_failures row (no money moved). Idempotent.
 *
 * Emits 'payment_request.cancelled' on transition.
 */
export const cancelPayment = async (paymentRequestId, customerId) => {
  const [existing] = await sql`
    SELECT id, customer_id, status FROM payment_requests WHERE id = ${paymentRequestId}
  `
  if (!existing) {
    throw Object.assign(new Error('Payment request not found'), { code: 'NOT_FOUND', statusCode: 404 })
  }
  if (existing.customer_id !== customerId) {
    throw Object.assign(new Error('Payment request does not belong to this customer'), { code: 'FORBIDDEN', statusCode: 403 })
  }
  if (existing.status !== PaymentRequestStatus.PENDING) {
    return existing      // idempotent
  }

  const [updated] = await sql`
    UPDATE payment_requests SET status = ${PaymentRequestStatus.ABANDONED}
    WHERE id = ${paymentRequestId} AND status = ${PaymentRequestStatus.PENDING}
    RETURNING *
  `
  if (updated) emit('payment_request.cancelled', buildEventPayload(updated))
  return updated ?? existing
}

// --- Background sweeper + reconciliation ---

/**
 * Runs every 60s from server.js + once at startup.
 *
 * Three jobs:
 *   1. Pending past expires_at → expired (no failure row; emits .expired)
 *   2. Confirmed past expires_at AND not consumed → failed_delivery (writes pairing_failures, emits .delivery_failed)
 *   3. Confirmed-with-no-chat-session-yet → re-invoke pairing subscriber (lost-event recovery)
 *
 * Job 3 is the durability backstop — if a process restart lost the in-process
 * EventEmitter notification before pairing started, the sweeper re-triggers it
 * on the next tick. Subscribers MUST be idempotent (the pairing subscriber checks
 * "chat_sessions WHERE payment_request_id = ?" before doing work).
 */
export const expireStalePaymentRequests = async () => {
  // 1) pending → expired (emit event for each)
  const expired = await sql`
    UPDATE payment_requests
    SET status = ${PaymentRequestStatus.EXPIRED}
    WHERE status = ${PaymentRequestStatus.PENDING}
      AND expires_at <= NOW()
    RETURNING *
  `
  for (const row of expired) emit('payment_request.expired', buildEventPayload(row))

  // 2) confirmed-but-stale → failed_delivery
  const flipped = await sql`
    UPDATE payment_requests
    SET status = ${PaymentRequestStatus.FAILED_DELIVERY}
    WHERE status = ${PaymentRequestStatus.CONFIRMED}
      AND expires_at <= NOW()
    RETURNING *
  `
  await Promise.all(flipped.map(async (row) => {
    await recordFailure({
      paymentRequestId: row.id,
      customerId: row.customer_id,
      targetedMitraId: row.targeted_mitra_id,
      causeTag: PairingFailureCause.PAYMENT_REQUEST_EXPIRED,
      amount: row.amount,
    })
    // Customer-facing: push terminal PAIRING_FAILED via WS; FCM fallback if not connected.
    try {
      const wsSent = sendToUser(UserType.CUSTOMER, row.customer_id, {
        type: WsMessage.PAIRING_FAILED,
        payment_request_id: row.id,
        cause_tag: PairingFailureCause.PAYMENT_REQUEST_EXPIRED,
        is_terminal: true,
      })
      if (!wsSent) {
        await sendPushNotification(UserType.CUSTOMER, row.customer_id, {
          title: 'Sesi gagal',
          body: 'Sesi pembayaranmu telah berakhir. Silakan mulai ulang.',
          data: {
            type: WsMessage.PAIRING_FAILED,
            payment_request_id: row.id,
            cause_tag: PairingFailureCause.PAYMENT_REQUEST_EXPIRED,
          },
        })
      }
    } catch (err) {
      console.error('expireStalePaymentRequests: failed to notify customer', {
        paymentRequestId: row.id, customerId: row.customer_id, err,
      })
    }
    emit('payment_request.delivery_failed', {
      ...buildEventPayload(row),
      causeTag: PairingFailureCause.PAYMENT_REQUEST_EXPIRED,
    })
  }))

  // 3) Reconciliation — confirmed payments that should have started product work but didn't.
  //    For chat_session: no chat_sessions row exists AND no pairing_failures row exists.
  //    The 30-second buffer avoids racing with happy-path subscribers mid-flight.
  const orphans = await sql`
    SELECT *
    FROM payment_requests pr
    WHERE pr.status = ${PaymentRequestStatus.CONFIRMED}
      AND pr.confirmed_at < NOW() - INTERVAL '30 seconds'
      AND pr.product_type = 'chat_session'
      AND NOT EXISTS (SELECT 1 FROM chat_sessions       cs WHERE cs.payment_request_id = pr.id)
      AND NOT EXISTS (SELECT 1 FROM pairing_failures    pf WHERE pf.payment_request_id = pr.id)
    LIMIT 100
  `
  let reconciled = 0
  for (const row of orphans) {
    try {
      // Re-emit the event the subscriber missed. Subscriber's idempotency check
      // makes this safe even if the subscriber did actually run (just slow).
      emit('payment_request.confirmed', buildEventPayload(row))
      reconciled++
    } catch (err) {
      console.error('[reconciler] re-emit failed', { paymentRequestId: row.id, err })
    }
  }

  return { expired: expired.length, failed: flipped.length, reconciled }
}

// Backward-compat alias — server.js previously called expireStalePaymentSessions
export const expireStalePaymentSessions = expireStalePaymentRequests

// --- getPayment ---

export const getPayment = async (id) => {
  const [row] = await sql`SELECT * FROM payment_requests WHERE id = ${id}`
  return row ?? null
}

// Backward-compat aliases (legacy callers — to be migrated in a follow-up pass)
export const createPaymentSession = (args) => requestPayment(args)
export const confirmPaymentSession = confirmPaymentForCustomer
export const consumePaymentSession = consumePayment
export const abandonPaymentSession = cancelPayment
export const getPaymentSession = getPayment

// --- getCustomerPendingPayments (unchanged shape) ---

/**
 * Phase 4 Stage 10 — Chat Tab Pembayaran feed.
 * Returns the customer's pending payment requests (initial + extension) that
 * haven't paid AND haven't expired.
 */
export const getCustomerPendingPayments = async (customerId) => {
  const items = await sql`
    SELECT
      ps.id,
      ps.is_extension,
      ps.amount,
      ps.duration_minutes,
      ps.mode,
      ps.created_at,
      ps.expires_at,
      COALESCE(ext_m.id, tgt_m.id)              AS mitra_id,
      COALESCE(ext_m.display_name, tgt_m.display_name) AS mitra_display_name
    FROM payment_requests ps
    LEFT JOIN session_extensions se ON se.payment_request_id = ps.id
    LEFT JOIN chat_sessions cs ON cs.id = se.session_id
    LEFT JOIN mitras ext_m ON ext_m.id = cs.mitra_id
    LEFT JOIN mitras tgt_m ON tgt_m.id = ps.targeted_mitra_id
    WHERE ps.customer_id = ${customerId}
      AND ps.status = ${PaymentRequestStatus.PENDING}
      AND ps.expires_at > NOW()
    ORDER BY ps.created_at DESC
  `
  return { items, total: items.length }
}

// --- Pairing subscriber wiring (called from server.js at startup) ---

/**
 * Wires pairing.service as a subscriber to payment_request.confirmed.
 * Filters on productType so future product subscribers can coexist.
 * Subscriber implements its own idempotency (skip if chat_sessions row exists).
 *
 * Imported lazily to avoid a circular import: pairing.service imports payment.service
 * for failPaymentSession + consumePayment + getPayment.
 */
export const registerPairingSubscriber = () => {
  on('payment_request.confirmed', async (evt) => {
    if (evt.productType !== 'chat_session') return
    const { startPairingFromPaymentRequest } = await import('./pairing.service.js')
    await startPairingFromPaymentRequest({
      paymentRequestId: evt.paymentRequestId,
      productMetadata: evt.productMetadata,
      customerId: evt.customerId,
    })
  })
}