import { err, ok, type CommandContext } from "@tailor-platform/erp-kit/core";
import type { Transaction } from "../generated/kysely-tailordb";
import { DuplicateHolidayDateError, InvalidHolidayKindError } from "../lib/errors.generated";

const HOLIDAY_KINDS = ["STATUTORY", "PRESCRIBED"] as const;

export interface CreateCompanyHolidayInput {
  calendarId: string;
  holidayDate: Date;
  holidayKind: string;
  name: string;
}

/**
 * Function: createCompanyHoliday
 * Description: Registers a new dated holiday fact — a calendar, a date, its
 * holidayKind, and a name — in a HolidayCalendar. This is the data-driven
 * replacement for the legacy hardcoded holiday list. holidayDate is unique
 * per calendar, so the same date can be a holiday in one calendar and a
 * working day in another.
 */
export async function run(db: Transaction, input: CreateCompanyHolidayInput, _ctx: CommandContext) {
  const existing = await db
    .selectFrom("CompanyHoliday")
    .selectAll()
    .where("calendarId", "=", input.calendarId)
    .where("holidayDate", "=", input.holidayDate)
    .forUpdate()
    .executeTakeFirst();
  if (existing) {
    return err(
      new DuplicateHolidayDateError(`${input.calendarId}:${input.holidayDate.toISOString()}`),
    );
  }

  if (!(HOLIDAY_KINDS as readonly string[]).includes(input.holidayKind)) {
    return err(new InvalidHolidayKindError(input.holidayKind));
  }

  const companyHoliday = await db
    .insertInto("CompanyHoliday")
    .values({
      calendarId: input.calendarId,
      holidayDate: input.holidayDate,
      holidayKind: input.holidayKind as (typeof HOLIDAY_KINDS)[number],
      name: input.name,
    })
    .returningAll()
    .executeTakeFirstOrThrow();

  return ok({ companyHoliday });
}