smartstring/ts/smartstring.create.ts

import * as plugins from './smartstring.plugins.js';

/**
 * Cross-platform random number generator
 * Uses crypto.getRandomValues in browser and Math.random as fallback
 */
const getRandomInt = (min: number, max: number): number => {
  if (typeof globalThis !== 'undefined' && globalThis.crypto && globalThis.crypto.getRandomValues) {
    // Browser environment with crypto API
    const range = max - min;
    const array = new Uint32Array(1);
    globalThis.crypto.getRandomValues(array);
    return min + (array[0] % range);
  } else {
    // Fallback to Math.random for environments without crypto
    return Math.floor(Math.random() * (max - min)) + min;
  }
};

/**
 * Custom implementation of randomatic pattern-based string generator
 * Pattern characters:
 * A - Uppercase letter
 * a - Lowercase letter  
 * 0 - Number (0-9)
 * ! - Special character
 * * - Any character (A, a, 0, or !)
 */
const customRandomatic = (pattern: string, length?: number, options?: any): string => {
  const charSets = {
    'A': 'ABCDEFGHIJKLMNOPQRSTUVWXYZ',
    'a': 'abcdefghijklmnopqrstuvwxyz',
    '0': '0123456789',
    '!': '!@#$%^&*()_+-=[]{}|;:,.<>?',
    '*': 'ABCDEFGHIJKLMNOPQRSTUVWXYZabcdefghijklmnopqrstuvwxyz0123456789!@#$%^&*()_+-=[]{}|;:,.<>?'
  };

  // If length is provided, repeat the pattern to match length
  let actualPattern = pattern;
  if (length && length > pattern.length) {
    actualPattern = pattern.repeat(Math.ceil(length / pattern.length)).slice(0, length);
  } else if (length) {
    actualPattern = pattern.slice(0, length);
  }

  let result = '';
  for (const char of actualPattern) {
    if (charSets[char]) {
      const charSet = charSets[char];
      const randomIndex = getRandomInt(0, charSet.length);
      result += charSet[randomIndex];
    } else {
      // If not a pattern character, use it literally
      result += char;
    }
  }

  return result;
};

/**
 * creates a random string
 *
 * ```ts
 * createRandomString('AAAA')
 * //=> 'AGHR'
 * ```
 *
 * @param patternArg the pattern argument to use, Aa0!* are viable pattern descritors
 * @param lengthArg  the length of the random string
 * @param optionsArg options
 */
export const createRandomString = (
  patternArg: string,
  lengthArg?: number,
  optionsArg?: any
): string => {
  return customRandomatic(patternArg, lengthArg, optionsArg);
};

/**
 * creates a crytic string in the speicifed length
 * @param lengthArg the length of the crypto string
 */
export const createCryptoRandomString = (): string => {
  return plugins.isounique.uni();
};