/**
 * @fileoverview Common utils for regular expressions.
 * @author Josh Goldberg
 * @author Toru Nagashima
 */

'use strict';

const { RegExpValidator } = require('@eslint-community/regexpp');

const REGEXPP_LATEST_ECMA_VERSION = 2025;

/**
 * Checks if the given regular expression pattern would be valid with the `u` flag.
 * @param {number} ecmaVersion ECMAScript version to parse in.
 * @param {string} pattern The regular expression pattern to verify.
 * @param {"u"|"v"} flag The type of Unicode flag
 * @returns {boolean} `true` if the pattern would be valid with the `u` flag.
 * `false` if the pattern would be invalid with the `u` flag or the configured
 * ecmaVersion doesn't support the `u` flag.
 */
function isValidWithUnicodeFlag(ecmaVersion, pattern, flag = 'u') {
  if (flag === 'u' && ecmaVersion <= 5) {
    // ecmaVersion <= 5 doesn't support the 'u' flag
    return false;
  }
  if (flag === 'v' && ecmaVersion <= 2023) {
    return false;
  }

  const validator = new RegExpValidator({
    ecmaVersion: Math.min(ecmaVersion, REGEXPP_LATEST_ECMA_VERSION),
  });

  try {
    validator.validatePattern(
      pattern,
      void 0,
      void 0,
      flag === 'u' ?
        {
          unicode: /* uFlag = */ true,
        }
      : {
          unicodeSets: true,
        }
    );
  } catch {
    return false;
  }

  return true;
}

module.exports = {
  isValidWithUnicodeFlag,
  REGEXPP_LATEST_ECMA_VERSION,
};