import { err, ok, type ReadonlyDB } from "@tailor-platform/erp-kit/core";
import type { DB } from "../generated/kysely-tailordb";
import { WorkRuleNotFoundError } from "../lib/errors.generated";

export interface GetWorkRuleInput {
  id: string;
}

/**
 * Function: getWorkRule
 * Description: Retrieves a single WorkRule generation by its surrogate id,
 * returning the rounding configuration, break deduction, daily overtime
 * threshold, night-work window, and premium-category pins, along with
 * effective-dating fields.
 */
export async function run(db: ReadonlyDB<DB>, input: GetWorkRuleInput) {
  const workRule = await db
    .selectFrom("WorkRule")
    .selectAll()
    .where("id", "=", input.id)
    .executeTakeFirst();

  if (!workRule) {
    return err(new WorkRuleNotFoundError(input.id));
  }

  return ok({ workRule });
}