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

export interface CreateWorkerInput {
  userId: string;
  workerCode: string;
}

export async function run<CF extends Record<string, unknown>>(
  db: Transaction,
  input: CreateWorkerInput & CF,
  _ctx: CommandContext,
) {
  const { userId, workerCode, ...customFields } = input;
  // NOTE: user-management (vendored erp-kit) exposes no `getUser` query, so there is no
  // injected query available to validate that `userId` refers to an existing User. Following
  // the vendored `approval` module's precedent (node_modules/@tailor-platform/erp-kit/src/modules/approval),
  // we do not invent a fictitious cross-module existence check here — referential integrity for
  // userId is enforced by the DB-level FK constraint set up via DB type injection in module.ts.

  const existingWorkerForUser = await db
    .selectFrom("Worker")
    .selectAll()
    .where("userId", "=", userId)
    .forUpdate()
    .executeTakeFirst();
  if (existingWorkerForUser) {
    return err(new WorkerAlreadyExistsError(userId));
  }

  const existingWorkerCode = await db
    .selectFrom("Worker")
    .selectAll()
    .where("workerCode", "=", workerCode)
    .forUpdate()
    .executeTakeFirst();
  if (existingWorkerCode) {
    return err(new WorkerCodeTakenError(workerCode));
  }

  const worker = await db
    .insertInto("Worker")
    .values({
      // Host-defined custom fields first; the builtin columns always win.
      ...(customFields as Record<string, unknown>),
      userId,
      workerCode,
    })
    .returningAll()
    .executeTakeFirstOrThrow();

  return ok({ worker });
}