/**
 * @file yaml.js
 * @description js-yaml 5 with js-yaml 4's loading rules, for the YAML files
 * AgentHub reads from a user (a repo's docker-compose file, omp's
 * `models.yml`/`config.yml`). js-yaml 5's `load` uses the bare YAML 1.2 core
 * schema — no `<<` merge keys, no timestamps, `!!binary`/`!!set` refused — and
 * throws on an empty document; 4's default schema was core plus exactly those
 * tags, and an empty document loaded as `undefined`. A member's file that
 * loaded before must load the same now (and `mergedModels` rewrites it).
 * @author Nguyễn Ngọc Trí Vĩ <vinnt@smartgift.vn>
 */

const yaml = require("js-yaml");

/** js-yaml 4's DEFAULT_SCHEMA. */
const V4_SCHEMA = yaml.CORE_SCHEMA.withTags([
  yaml.mergeTag,
  yaml.timestampTag,
  yaml.binaryTag,
  yaml.omapTag,
  yaml.pairsTag,
  yaml.setTag,
]);

/** `yaml.load` as js-yaml 4 did it: undefined for a document-less text. */
function load(text) {
  try {
    return yaml.load(text, { schema: V4_SCHEMA });
  } catch (err) {
    if (err && /input is empty/.test(err.reason || "")) return undefined;
    throw err;
  }
}

module.exports = { load, dump: yaml.dump, V4_SCHEMA };