import type { BookingResponseDto, WaitlistResponseDto, WaitlistStatus } from '@/api/generated/models'
import {
  errorResult,
  handleServiceError,
  type ServiceCallOptions,
  type ServiceResult,
  shouldBubbleErrorToParent,
  successResult,
} from '@/services/errorHandler'
import { unwrapApiData } from '@/services/apiResponse'
import { getBookings } from '@/api/generated/bookings/bookings'
import { getWaitlist } from '@/api/generated/waitlist/waitlist'
import { unwrapApiPayload } from '@/helpers/listResponse'
import { ANALYTICS_EVENTS, trackAnalyticsEventOnce } from '@/lib/analytics'
import { getEventAttribution } from '@/lib/trafficAttribution'
import { texts } from '@/texts'

// Shape mirrors the admin `bookingsColumns` fields used for the same
// underlying entity in app/(dashboard)/users/[id]/page.tsx (bookingCode,
// eventTitle, status, checkedInAt, createdAt) — plus `id`/`eventId`, which
// this self-service list needs for keys and the booking-detail modal.
// The `event*` fields come from bookingSelect's event relation
// (backend/src/modules/bookings/bookings.select.ts) — added alongside this
// service so the list + detail views don't need a second round-trip to
// /events/:id for title/price/fee.
export type MyBooking = BookingResponseDto

export type MyWaitlistEntry = WaitlistResponseDto

// Waitlist entries still considered "in progress" for this event — mirrors
// the DB constraint in waitlist.service.ts (assertNoActiveWaitlist).
const ACTIVE_WAITLIST_STATUSES: WaitlistStatus[] = ['waiting', 'notified', 'accepted']
const bookingsApi = getBookings()
const waitlistApi = getWaitlist()

export const GET_MY_BOOKINGS = async (options?: ServiceCallOptions): Promise<ServiceResult<MyBooking[]>> => {
  try {
    const res = await bookingsApi.bookingsControllerListMine({ page: 1, pageSize: 100 })
    const payload = unwrapApiPayload(res.data)
    const items = Array.isArray(payload) ? payload : Array.isArray(payload.items) ? payload.items : []

    return successResult(items as MyBooking[])
  } catch (error) {
    const normalizedError = handleServiceError(error, options)

    if (shouldBubbleErrorToParent(options)) {
      throw normalizedError
    }

    return errorResult(normalizedError)
  }
}

/** Guest's own active (pending_payment/confirmed) booking for one event, if any — event-booking.md entry checks. */
export const GET_MY_ACTIVE_BOOKING_FOR_EVENT = async (
  eventId: string,
  options?: ServiceCallOptions
): Promise<ServiceResult<MyBooking | null>> => {
  try {
    // At most one active booking per (user, event); list endpoint still
    // requires pagination, so pageSize=1 is enough for this lookup.
    const res = await bookingsApi.bookingsControllerListMine({
      filters: { eventId },
      pageSize: 1,
      sort: '-createdAt',
    })
    const payload = unwrapApiPayload(res.data)
    const items = (Array.isArray(payload) ? payload : Array.isArray(payload.items) ? payload.items : []) as MyBooking[]
    const latest = items[0]
    const active = latest && (latest.status === 'pending_payment' || latest.status === 'confirmed') ? latest : null

    return successResult(active)
  } catch (error) {
    const normalizedError = handleServiceError(error, options)

    if (shouldBubbleErrorToParent(options)) {
      throw normalizedError
    }

    return errorResult(normalizedError)
  }
}

/** Guest's own active waitlist entry for one event, if any — event-booking.md Path B. */
export const GET_MY_WAITLIST_ENTRY_FOR_EVENT = async (
  eventId: string,
  options?: ServiceCallOptions
): Promise<ServiceResult<MyWaitlistEntry | null>> => {
  try {
    // At most one active waitlist row per (user, event); pageSize=1 is enough.
    const res = await waitlistApi.waitlistControllerListMine({
      filters: { eventId },
      pageSize: 1,
      sort: '-createdAt',
    })
    const payload = unwrapApiPayload(res.data)
    const items = (Array.isArray(payload) ? payload : Array.isArray(payload.items) ? payload.items : []) as MyWaitlistEntry[]
    const latest = items[0]
    const active = latest && ACTIVE_WAITLIST_STATUSES.includes(latest.status) ? latest : null

    return successResult(active)
  } catch (error) {
    const normalizedError = handleServiceError(error, options)

    if (shouldBubbleErrorToParent(options)) {
      throw normalizedError
    }

    return errorResult(normalizedError)
  }
}

/** POST /events/:eventId/bookings — direct reserve path (event-booking.md, Path A). */
export const CREATE_BOOKING = async (eventId: string, options?: ServiceCallOptions): Promise<ServiceResult<MyBooking>> => {
  try {
    const attributionSource = getEventAttribution(eventId)
    const res = await bookingsApi.bookingsControllerCreate(eventId, {
      ...(attributionSource ? { attributionSource } : {}),
    })
    const data = res.data.success ? unwrapApiData(res.data) : undefined

    if (data?.id) {
      trackAnalyticsEventOnce(ANALYTICS_EVENTS.BOOKING_CREATED, data.id, {
        booking_id: data.id,
        event_id: eventId,
        booking_status: data.status,
        ...(attributionSource ? { traffic_source: attributionSource } : {}),
      })
    }

    if (!data) {
      throw new Error(texts.bookings.emptyServerResponse)
    }

    return successResult(data)
  } catch (error) {
    const normalizedError = handleServiceError(error, options)

    if (shouldBubbleErrorToParent(options)) {
      throw normalizedError
    }

    return errorResult(normalizedError)
  }
}

/** POST /events/:eventId/waitlist — join waitlist path (event-booking.md, Path B). */
export const JOIN_WAITLIST = async (eventId: string, options?: ServiceCallOptions): Promise<ServiceResult<MyWaitlistEntry>> => {
  try {
    const attributionSource = getEventAttribution(eventId)
    const res = await waitlistApi.waitlistControllerJoin(eventId, {
      ...(attributionSource ? { attributionSource } : {}),
    })
    const data = res.data.success ? unwrapApiData(res.data) : undefined

    if (!data) {
      throw new Error(texts.bookings.emptyServerResponse)
    }

    return successResult(data)
  } catch (error) {
    const normalizedError = handleServiceError(error, options)

    if (shouldBubbleErrorToParent(options)) {
      throw normalizedError
    }

    return errorResult(normalizedError)
  }
}

/**
 * GET /events/:eventId/waitlist — host-only view of the waiting queue for
 * their own event, primarily used to hand-pick who gets an opened seat when
 * `settings.waitlistAutoOffer` is `false`.
 */
export const GET_EVENT_WAITLIST = async (eventId: string, options?: ServiceCallOptions): Promise<ServiceResult<MyWaitlistEntry[]>> => {
  try {
    const res = await waitlistApi.waitlistControllerListForEvent(eventId, { pageSize: 100 })
    const payload = unwrapApiPayload(res.data)
    const items = (Array.isArray(payload) ? payload : Array.isArray(payload.items) ? payload.items : []) as MyWaitlistEntry[]

    return successResult(items)
  } catch (error) {
    const normalizedError = handleServiceError(error, options)

    if (shouldBubbleErrorToParent(options)) {
      throw normalizedError
    }

    return errorResult(normalizedError)
  }
}

/** POST /events/:eventId/waitlist/:entryId/offer — host manually offers a seat to a chosen entry. */
export const OFFER_WAITLIST_SEAT = async (
  eventId: string,
  entryId: string,
  options?: ServiceCallOptions
): Promise<ServiceResult<MyWaitlistEntry>> => {
  try {
    const res = await waitlistApi.waitlistControllerOfferToEntry(eventId, entryId)
    const data = res.data.success ? unwrapApiData(res.data) : undefined

    if (!data) {
      throw new Error(texts.bookings.emptyServerResponse)
    }

    return successResult(data)
  } catch (error) {
    const normalizedError = handleServiceError(error, options)

    if (shouldBubbleErrorToParent(options)) {
      throw normalizedError
    }

    return errorResult(normalizedError)
  }
}

/** PATCH /waitlist/:id/accept — guest accepts a notified offer and receives the pending booking for checkout. */
export const ACCEPT_WAITLIST = async (
  entryId: string,
  options?: ServiceCallOptions
): Promise<ServiceResult<{ waitlistEntryId: string; booking: MyBooking }>> => {
  try {
    const res = await waitlistApi.waitlistControllerAccept(entryId)
    const data = res.data.success ? unwrapApiData(res.data) : undefined

    if (!data?.booking) {
      throw new Error(texts.bookings.emptyServerResponse)
    }

    return successResult({ waitlistEntryId: data.waitlistEntryId, booking: data.booking as MyBooking })
  } catch (error) {
    const normalizedError = handleServiceError(error, options)

    if (shouldBubbleErrorToParent(options)) {
      throw normalizedError
    }

    return errorResult(normalizedError)
  }
}

/** GET /bookings/:id — single booking detail (owner only). */
export const GET_BOOKING = async (id: string, options?: ServiceCallOptions): Promise<ServiceResult<MyBooking>> => {
  try {
    const res = await bookingsApi.bookingsControllerFindOne(id)
    const data = res.data.success ? unwrapApiData(res.data) : undefined

    if (!data) {
      throw new Error(texts.bookings.emptyServerResponse)
    }

    return successResult(data)
  } catch (error) {
    const normalizedError = handleServiceError(error, options)

    if (shouldBubbleErrorToParent(options)) {
      throw normalizedError
    }

    return errorResult(normalizedError)
  }
}

/** PATCH /bookings/:id/cancel — guest-initiated cancel with mandatory reason (booking-cancellation-refund.md). */
export const CANCEL_BOOKING = async (
  id: string,
  cancellationReason: string,
  options?: ServiceCallOptions
): Promise<ServiceResult<MyBooking>> => {
  try {
    const res = await bookingsApi.bookingsControllerCancel(id, { cancellationReason })
    const data = res.data.success ? unwrapApiData(res.data) : undefined

    if (!data) {
      throw new Error(texts.bookings.emptyServerResponse)
    }

    trackAnalyticsEventOnce(ANALYTICS_EVENTS.BOOKING_CANCELLED, data.id, {
      booking_id: data.id,
      event_id: data.eventId,
      booking_status: data.status,
    })

    return successResult(data)
  } catch (error) {
    const normalizedError = handleServiceError(error, options)

    if (shouldBubbleErrorToParent(options)) {
      throw normalizedError
    }

    return errorResult(normalizedError)
  }
}

/**
 * Client-side guest-cancel refund preview — booking-cancellation-refund.md
 * formula: refund = paidGross × (1 - platform commission % - cancellationFeePercent).
 * Mirrors refund.service.ts#refundGuestCancellation exactly (same
 * floor() rounding on each component) so this preview never shows a
 * different number than what's actually credited.
 *
 * `ticketPrice` must be the **amount actually paid** (`payments.total_amount`
 * / `MyBooking.payableAmount`), not the list `eventPrice`. When a discount
 * code was applied, those diverge — using list price overstates commission,
 * host fee, and the toast refund. Callers: `payableAmount ?? eventPrice`.
 *
 * `commissionPercent` must be the booking's resolved rate
 * (`MyBooking.eventEffectiveCommissionPercent` — event override if set, else
 * the platform default; see bookings.service.ts#mapBooking on the backend)
 * and NOT a locally hardcoded constant: the platform default has changed
 * before (COMMISSION_PERCENT, backend/src/common/constants/business.constants.ts)
 * and events can carry their own override, so any constant duplicated here
 * silently drifts from what actually gets charged. Only meaningful for a
 * `confirmed` (paid) booking; `pending_payment` has nothing to refund
 * (never actually paid).
 */
export interface CancellationPreview {
  ticketPrice: number
  platformCommission: number
  /** The rate actually applied, echoed back so callers can label the commission line without re-touching the booking. */
  commissionPercent: number
  hostCancellationFee: number
  refundToGuest: number
}

export const calculateCancellationPreview = (
  ticketPrice: number,
  cancellationFeePercent: number,
  commissionPercent: number
): CancellationPreview => {
  const platformCommission = Math.floor(ticketPrice * (commissionPercent / 100))
  const hostCancellationFee = Math.floor(ticketPrice * (cancellationFeePercent / 100))
  const refundToGuest = ticketPrice - platformCommission - hostCancellationFee

  return { ticketPrice, platformCommission, commissionPercent, hostCancellationFee, refundToGuest }
}

/** Gross base for guest-cancel preview — paid amount after discount, else list price. */
export const resolveCancellationTicketPrice = (booking: Pick<MyBooking, 'eventPrice' | 'payableAmount'>): number =>
  booking.payableAmount ?? booking.eventPrice