"use server";

import { auth } from "@/auth";
import { prisma } from "@/lib/db/prisma";
import { Permission } from "@/generated/prisma/enums";
import { assertOwnerPermission, OwnerPermissionDeniedError } from "@/features/owner/authorization";
import { writeAuditLog } from "@/lib/audit/write-audit-log";
import { getActingBusinessContext } from "@/lib/business/get-acting-business-context";
import {
  createBusinessHoliday,
  deleteBusinessHoliday,
  findHolidayConflicts,
  validateHolidayInput,
} from "@/services/business/holiday.service";
import type { HolidayInput } from "@/services/business/holiday.service";

export interface HolidayActionResult {
  success: boolean;
  error?: string;
  /** Appointments already booked inside the range — shown for review, never cancelled automatically. */
  conflicts?: {
    id: string;
    customerName: string;
    serviceNames: string;
    startAt: string;
    staffName: string;
  }[];
}

/** Holidays change when the whole business can be booked, so they share Business Details' permission. */
async function requireBusinessManager() {
  const session = await auth();
  if (!session?.user) return { staff: null, error: "You must be signed in." } as const;

  try {
    await assertOwnerPermission(session.user.id, Permission.MANAGE_BUSINESS_PROFILE);
  } catch (error) {
    if (error instanceof OwnerPermissionDeniedError)
      return { staff: null, error: error.message } as const;
    throw error;
  }

  const context = await getActingBusinessContext();
  if (!context) return { staff: null, error: "You must be signed in as staff." } as const;

  return {
    staff: { businessId: context.businessId, userId: context.userId },
    error: null,
  } as const;
}

export async function addHolidayAction(
  holiday: HolidayInput,
  acknowledgeConflicts?: boolean,
): Promise<HolidayActionResult> {
  const { staff, error } = await requireBusinessManager();
  if (!staff) return { success: false, error: error ?? "Not authorized." };

  const validation = validateHolidayInput(holiday);
  if (!validation.valid) return { success: false, error: validation.issues[0]?.message };

  if (!acknowledgeConflicts) {
    const business = await prisma.business.findUnique({
      where: { id: staff.businessId },
      select: { timezone: true },
    });
    if (!business) return { success: false, error: "Business not found." };

    const conflicts = await findHolidayConflicts(prisma, {
      businessId: staff.businessId,
      businessTimezone: business.timezone,
      startDate: holiday.startDate,
      endDate: holiday.endDate,
    });
    if (conflicts.length > 0) {
      return {
        success: false,
        error: "Some appointments are already booked on these dates.",
        conflicts: conflicts.map((c) => ({
          id: c.id,
          customerName: `${c.customer.firstName} ${c.customer.lastName}`,
          serviceNames: c.services.map((s) => s.service.name).join(" + "),
          startAt: c.startAt.toISOString(),
          staffName: c.staff.user.name ?? "Staff",
        })),
      };
    }
  }

  const result = await createBusinessHoliday(prisma, { businessId: staff.businessId, holiday });
  if (!result.success) return { success: false, error: result.validation.issues[0]?.message };

  await writeAuditLog(prisma, {
    actorUserId: staff.userId,
    action: "BUSINESS_HOLIDAY_CREATED",
    entityType: "BusinessHoliday",
    entityId: result.id,
    metadata: { name: holiday.name.trim(), startDate: holiday.startDate, endDate: holiday.endDate },
  });

  return { success: true };
}

export async function deleteHolidayAction(holidayId: string): Promise<HolidayActionResult> {
  const { staff, error } = await requireBusinessManager();
  if (!staff) return { success: false, error: error ?? "Not authorized." };

  const deleted = await deleteBusinessHoliday(prisma, { businessId: staff.businessId, holidayId });
  if (!deleted) return { success: false, error: "That holiday no longer exists." };

  await writeAuditLog(prisma, {
    actorUserId: staff.userId,
    action: "BUSINESS_HOLIDAY_DELETED",
    entityType: "BusinessHoliday",
    entityId: holidayId,
  });

  return { success: true };
}