import * as repo from './repository.js';
import { HttpError } from '../../utils/http.js';
import { logAudit } from '../../utils/audit.js';

function toTree(flat) {
  const byId = new Map(flat.map((d) => [d.id, { ...d, children: [] }]));
  const roots = [];
  for (const dept of byId.values()) {
    if (dept.parent_id && byId.has(dept.parent_id)) {
      byId.get(dept.parent_id).children.push(dept);
    } else {
      roots.push(dept);
    }
  }
  return roots;
}

export async function listTree() {
  const flat = await repo.findAllFlat();
  return toTree(flat);
}

export async function createDepartment(payload, actorId) {
  if (!payload.name) throw new HttpError(400, 'El nombre es obligatorio');
  const dept = await repo.create(payload);
  await logAudit({ userId: actorId, action: 'create', entityType: 'department', entityId: dept.id });
  return dept;
}

export async function updateDepartment(id, payload, actorId) {
  if (!payload.name) throw new HttpError(400, 'El nombre es obligatorio');
  if (Number(payload.parentId) === Number(id)) throw new HttpError(400, 'Un departamento no puede ser su propio padre');
  const dept = await repo.update(id, payload);
  await logAudit({ userId: actorId, action: 'update', entityType: 'department', entityId: id });
  return dept;
}

export async function deleteDepartment(id, actorId) {
  if (await repo.hasChildren(id)) throw new HttpError(400, 'Tiene sub-departamentos; reasignalos antes de eliminar');
  if (await repo.hasUsers(id)) throw new HttpError(400, 'Tiene usuarios asignados; reasignalos antes de eliminar');
  await repo.remove(id);
  await logAudit({ userId: actorId, action: 'delete', entityType: 'department', entityId: id });
}