import type { PrismaClient } from "@/generated/prisma/client";
import { NotificationType } from "@/generated/prisma/enums";
import { notifySafely } from "@/services/notifications/notification.service";
import { getOwnerUserIds } from "@/services/notifications/recipients";
import type { Appointment } from "./booking.service";
import { scheduleAppointmentReminders } from "./reminder-scheduling";

/**
 * Builds and queues the Notification rows a booking-domain event
 * produces — called by booking.service.ts strictly AFTER the appointment
 * transaction has already committed, using notifySafely so a notification
 * failure can never roll back or fail an otherwise-successful booking.
 * Owns only "who gets told what, in what words" — the actual email/push
 * send happens later, out of process (see reminder-worker.ts).
 */

function formatDateLabel(date: Date, timezone: string): string {
  return date.toLocaleDateString("en-GB", { weekday: "short", day: "numeric", month: "short", timeZone: timezone });
}

function formatTimeLabel(date: Date, timezone: string): string {
  return date.toLocaleTimeString("en-GB", { hour: "2-digit", minute: "2-digit", timeZone: timezone });
}

async function getBusinessTimezone(prisma: PrismaClient, businessId: string): Promise<string> {
  const business = await prisma.business.findUnique({ where: { id: businessId }, select: { timezone: true } });
  return business?.timezone ?? "Europe/London";
}

function serviceNames(appointment: Appointment): string {
  return appointment.services.map((s) => s.service.name).join(", ");
}

export async function notifyBookingCreated(
  prisma: PrismaClient,
  appointment: Appointment,
  options: { guestAccessToken?: string } = {},
): Promise<void> {
  const timezone = await getBusinessTimezone(prisma, appointment.businessId);
  const dateLabel = formatDateLabel(appointment.startAt, timezone);
  const timeLabel = formatTimeLabel(appointment.startAt, timezone);
  const services = serviceNames(appointment);
  const isPending = appointment.status === "PENDING";
  const customerDeepLink = `/appointments/${appointment.id}${options.guestAccessToken ? `?token=${options.guestAccessToken}` : ""}`;

  await notifySafely(prisma, {
    businessId: appointment.businessId,
    type: isPending ? NotificationType.BOOKING_PENDING_APPROVAL : NotificationType.BOOKING_CONFIRMED,
    recipientUserId: appointment.customer.userId ?? undefined,
    recipientCustomerId: appointment.customer.id,
    appointmentId: appointment.id,
    subject: isPending ? "Booking request received" : "Booking confirmed",
    bodyText: isPending
      ? `Your request for ${services} with ${appointment.staff.user.name} on ${dateLabel} at ${timeLabel} is awaiting approval.`
      : `Your appointment for ${services} with ${appointment.staff.user.name} on ${dateLabel} at ${timeLabel} is confirmed.`,
    deepLinkPath: customerDeepLink,
    idempotencyKey: `notify:booking-created:${appointment.id}`,
  });

  await notifySafely(prisma, {
    businessId: appointment.businessId,
    type: NotificationType.STAFF_NEW_APPOINTMENT,
    recipientUserId: appointment.staff.userId,
    appointmentId: appointment.id,
    subject: "New appointment",
    bodyText: `New appointment: ${services} with ${appointment.customer.firstName} ${appointment.customer.lastName} on ${dateLabel} at ${timeLabel}.`,
    deepLinkPath: `/staff/appointments/${appointment.id}`,
    idempotencyKey: `notify:staff-new-appointment:${appointment.id}`,
  });

  const ownerUserIds = await getOwnerUserIds(prisma, appointment.businessId);
  for (const ownerUserId of ownerUserIds) {
    await notifySafely(prisma, {
      businessId: appointment.businessId,
      type: NotificationType.OWNER_NEW_BOOKING,
      recipientUserId: ownerUserId,
      appointmentId: appointment.id,
      subject: "New booking",
      bodyText: `${appointment.customer.firstName} ${appointment.customer.lastName} booked ${services} with ${appointment.staff.user.name} on ${dateLabel} at ${timeLabel}.`,
      deepLinkPath: `/owner/appointments/${appointment.id}`,
      idempotencyKey: `notify:owner-new-booking:${appointment.id}:${ownerUserId}`,
    });
  }
}

export async function notifyBookingRescheduled(prisma: PrismaClient, appointment: Appointment): Promise<void> {
  const timezone = await getBusinessTimezone(prisma, appointment.businessId);
  const dateLabel = formatDateLabel(appointment.startAt, timezone);
  const timeLabel = formatTimeLabel(appointment.startAt, timezone);
  const services = serviceNames(appointment);
  // Included in the key so a second reschedule creates a fresh notification
  // rather than being deduped against the first one's key.
  const versionSuffix = appointment.startAt.getTime();

  await notifySafely(prisma, {
    businessId: appointment.businessId,
    type: NotificationType.BOOKING_RESCHEDULED,
    recipientUserId: appointment.customer.userId ?? undefined,
    recipientCustomerId: appointment.customer.id,
    appointmentId: appointment.id,
    subject: "Booking rescheduled",
    bodyText: `Your appointment for ${services} with ${appointment.staff.user.name} has been moved to ${dateLabel} at ${timeLabel}.`,
    deepLinkPath: `/appointments/${appointment.id}`,
    idempotencyKey: `notify:booking-rescheduled:${appointment.id}:${versionSuffix}`,
  });

  await notifySafely(prisma, {
    businessId: appointment.businessId,
    type: NotificationType.STAFF_APPOINTMENT_RESCHEDULED,
    recipientUserId: appointment.staff.userId,
    appointmentId: appointment.id,
    subject: "Appointment rescheduled",
    bodyText: `${appointment.customer.firstName} ${appointment.customer.lastName}'s appointment (${services}) has moved to ${dateLabel} at ${timeLabel}.`,
    deepLinkPath: `/staff/appointments/${appointment.id}`,
    idempotencyKey: `notify:staff-appointment-rescheduled:${appointment.id}:${versionSuffix}`,
  });
}

export async function notifyBookingCancelled(
  prisma: PrismaClient,
  appointment: Appointment,
  options: { wasLateCancellation?: boolean; reason?: string } = {},
): Promise<void> {
  const timezone = await getBusinessTimezone(prisma, appointment.businessId);
  const dateLabel = formatDateLabel(appointment.startAt, timezone);
  const timeLabel = formatTimeLabel(appointment.startAt, timezone);
  const services = serviceNames(appointment);
  const lateNote = options.wasLateCancellation ? " This was a late cancellation." : "";

  await notifySafely(prisma, {
    businessId: appointment.businessId,
    type: NotificationType.BOOKING_CANCELLED,
    recipientUserId: appointment.customer.userId ?? undefined,
    recipientCustomerId: appointment.customer.id,
    appointmentId: appointment.id,
    subject: "Booking cancelled",
    bodyText: `Your appointment for ${services} with ${appointment.staff.user.name} on ${dateLabel} at ${timeLabel} has been cancelled.${lateNote}`,
    deepLinkPath: `/appointments/${appointment.id}`,
    idempotencyKey: `notify:booking-cancelled:${appointment.id}`,
  });

  await notifySafely(prisma, {
    businessId: appointment.businessId,
    type: NotificationType.STAFF_APPOINTMENT_CANCELLED,
    recipientUserId: appointment.staff.userId,
    appointmentId: appointment.id,
    subject: "Appointment cancelled",
    bodyText: `${appointment.customer.firstName} ${appointment.customer.lastName}'s appointment (${services}) on ${dateLabel} at ${timeLabel} was cancelled.`,
    deepLinkPath: `/staff/appointments/${appointment.id}`,
    idempotencyKey: `notify:staff-appointment-cancelled:${appointment.id}`,
  });

  const ownerUserIds = await getOwnerUserIds(prisma, appointment.businessId);
  for (const ownerUserId of ownerUserIds) {
    await notifySafely(prisma, {
      businessId: appointment.businessId,
      type: NotificationType.OWNER_BOOKING_CANCELLED,
      recipientUserId: ownerUserId,
      appointmentId: appointment.id,
      subject: "Booking cancelled",
      bodyText: `${appointment.customer.firstName} ${appointment.customer.lastName}'s appointment with ${appointment.staff.user.name} on ${dateLabel} at ${timeLabel} was cancelled.${lateNote}`,
      deepLinkPath: `/owner/appointments/${appointment.id}`,
      idempotencyKey: `notify:owner-booking-cancelled:${appointment.id}:${ownerUserId}`,
    });
  }
}

/** A PENDING booking (requireApproval) is approved — see AppointmentService.confirm, only ever reachable from PENDING. */
export async function notifyBookingApproved(prisma: PrismaClient, appointment: Appointment): Promise<void> {
  const timezone = await getBusinessTimezone(prisma, appointment.businessId);
  await notifySafely(prisma, {
    businessId: appointment.businessId,
    type: NotificationType.BOOKING_APPROVED,
    recipientUserId: appointment.customer.userId ?? undefined,
    recipientCustomerId: appointment.customer.id,
    appointmentId: appointment.id,
    subject: "Booking approved",
    bodyText: `Your appointment for ${serviceNames(appointment)} with ${appointment.staff.user.name} on ${formatDateLabel(appointment.startAt, timezone)} at ${formatTimeLabel(appointment.startAt, timezone)} has been approved.`,
    deepLinkPath: `/appointments/${appointment.id}`,
    idempotencyKey: `notify:booking-approved:${appointment.id}`,
  });
  // Approval is the first point a PENDING (requireApproval) booking becomes
  // CONFIRMED — reminders were never scheduled at creation time for it (see
  // scheduleAppointmentReminders' own CONFIRMED-only guard), so this is
  // where that has to happen instead.
  await scheduleAppointmentReminders(prisma, appointment);
}

/** The owner reassigns an appointment to a different staff member — distinct from a plain time reschedule (see notifyBookingRescheduled, which still also fires for a reassignment since the underlying rescheduleBooking() call can't distinguish "why", see ownerRescheduleAppointmentAction). This tells the customer specifically who they're now booked with. */
export async function notifyBookingBarberChanged(prisma: PrismaClient, appointment: Appointment): Promise<void> {
  await notifySafely(prisma, {
    businessId: appointment.businessId,
    type: NotificationType.BOOKING_BARBER_CHANGED,
    recipientUserId: appointment.customer.userId ?? undefined,
    recipientCustomerId: appointment.customer.id,
    appointmentId: appointment.id,
    subject: "Your barber has changed",
    bodyText: `Your appointment for ${serviceNames(appointment)} is now with ${appointment.staff.user.name}.`,
    deepLinkPath: `/appointments/${appointment.id}`,
    idempotencyKey: `notify:booking-barber-changed:${appointment.id}:${appointment.staffId}`,
  });
}

/** The appointment reaches COMPLETED — a distinct, non-loyalty "thanks for visiting" notice (see LoyaltyService for the separate stamp/reward notifications, which fire independently). */
export async function notifyBookingCompleted(prisma: PrismaClient, appointment: Appointment): Promise<void> {
  await notifySafely(prisma, {
    businessId: appointment.businessId,
    type: NotificationType.BOOKING_COMPLETED,
    recipientUserId: appointment.customer.userId ?? undefined,
    recipientCustomerId: appointment.customer.id,
    appointmentId: appointment.id,
    subject: "Thanks for visiting",
    bodyText: `Thanks for visiting ${appointment.staff.user.name ? `and seeing ${appointment.staff.user.name}` : ""} — hope you loved your ${serviceNames(appointment)}!`,
    deepLinkPath: `/appointments/${appointment.id}`,
    idempotencyKey: `notify:booking-completed:${appointment.id}`,
  });
}

/** Customer marked NO_SHOW — owner-facing only (the barber already knows, they're the one who marked it). */
export async function notifyAppointmentNoShow(prisma: PrismaClient, appointment: Appointment): Promise<void> {
  const timezone = await getBusinessTimezone(prisma, appointment.businessId);
  const ownerUserIds = await getOwnerUserIds(prisma, appointment.businessId);
  for (const ownerUserId of ownerUserIds) {
    await notifySafely(prisma, {
      businessId: appointment.businessId,
      type: NotificationType.OWNER_NO_SHOW,
      recipientUserId: ownerUserId,
      appointmentId: appointment.id,
      subject: "No-show recorded",
      bodyText: `${appointment.customer.firstName} ${appointment.customer.lastName} didn't show up for their appointment with ${appointment.staff.user.name} on ${formatDateLabel(appointment.startAt, timezone)} at ${formatTimeLabel(appointment.startAt, timezone)}.`,
      deepLinkPath: `/owner/appointments/${appointment.id}`,
      idempotencyKey: `notify:owner-no-show:${appointment.id}:${ownerUserId}`,
    });
  }
}