'use strict';

const User = require('../components/users/userModel');
const Professor = require('../components/professors/professorModel');

/**
 * Generates a unique 10-character placeholder national ID (starting with TMP).
 * @param {string} [seed] - Optional seed like phone number or timestamp
 * @returns {Promise<string>}
 */
const allocatePlaceholderNationalId = async (seed) => {
  const cleanDigits = String(seed || '').replace(/\D/g, '');
  const baseSuffix = (cleanDigits.slice(-7) || Date.now().toString().slice(-7)).padStart(7, '0').slice(0, 7);
  let candidate = `TMP${baseSuffix}`.slice(0, 10);
  let i = 0;
  while ((await User.exists({ nationalIdCode: candidate })) || (await Professor.exists({ nationalIdCode: candidate }))) {
    i += 1;
    candidate = `TMP${String(i).padStart(7, '0')}`.slice(0, 10);
  }
  return candidate;
};

module.exports = {
  allocatePlaceholderNationalId
};