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

/** Function: UpdateWorkerInput
 * Description: Corrects mutable personal attributes (workerCode) on an existing Worker */
export type UpdateWorkerInput = {
  id: string;
} & {
  workerCode?: string;
};

/** Function: run
 * Description: Update mutable personal attributes on a Worker without affecting employment or assignment history */
export async function run<CF extends Record<string, unknown>>(
  db: Transaction,
  input: UpdateWorkerInput & Partial<CF>,
  _ctx: CommandContext,
) {
  const { id, workerCode, ...customFields } = input;

  const worker = await db
    .selectFrom("Worker")
    .selectAll()
    .where("id", "=", id)
    .forUpdate()
    .executeTakeFirst();

  if (!worker) return err(new WorkerNotFoundError(id));

  if (workerCode !== undefined && workerCode !== worker.workerCode) {
    const existing = await db
      .selectFrom("Worker")
      .select("id")
      .where("workerCode", "=", workerCode)
      .where("id", "!=", id)
      .executeTakeFirst();

    if (existing) return err(new WorkerCodeTakenError(workerCode));
  }

  // Host-defined custom fields are updated alongside the builtin workerCode; a builtin column
  // provided in the input always wins over a custom field of the same name.
  const updates: Record<string, unknown> = { ...(customFields as Record<string, unknown>) };
  if (workerCode !== undefined) updates.workerCode = workerCode;

  if (Object.keys(updates).length === 0) {
    return ok({ worker });
  }

  const updated = await db
    .updateTable("Worker")
    .set(updates)
    .where("id", "=", id)
    .returningAll()
    .executeTakeFirstOrThrow();

  return ok({ worker: updated });
}