import * as u8a from 'uint8arrays';

/**
 * Encoding | Decoding functionality provided by TrackBack
 */
export class Encoding {
  /**
   * Base64Encode
   * @param buffer string |Buffer|Uint8Array
   * @returns string
   */
  static base64Encode(buffer: string | Buffer | Uint8Array): string {
    return Buffer.from(buffer).toString('base64').replace(/=+$/g, '');
  }

  /**
   * Base64Decode
   * @param st string
   * @returns string
   */
  static base64Decode(st: string): string {
    return Buffer.from(st, 'base64').toString('utf8');
  }

  /**
   * Base58BTC
   * Reference :- https://en.bitcoin.it/wiki/Base58Check_encoding
   * @param key Uint8Array | reference :- https://developer.mozilla.org/en-US/docs/Web/JavaScript/Reference/Global_Objects/Uint8Array
   * @returns 
   */
  static base58BTC(key: Uint8Array) {
    return u8a.toString(key, 'base58btc');
  }

  /**
   * Convert public key to mulibase key
   * @param {Uint8Array} publicKey public key arry
   * @param {string} encoding encoding type must be one of base58btc, base64url
   * @returns {string} encoded public key
   */
  static encodeED25519Key(publicKey: Uint8Array, encoding: string): string {
    if (!encoding) {
      throw new Error('encoding required');
    }
    const buffer = new Uint8Array(2 + publicKey.length);
    buffer[0] = 0xec;
    buffer[1] = 0x01;
    buffer.set(publicKey, 2);

    if (encoding === 'base58btc') {
      return `z${u8a.toString(publicKey, 'base58btc')}`;
    }
    if (encoding === 'base64url') {
      return `u${u8a.toString(publicKey, 'base64url')}`;
    }

    throw new Error('Encoding not supported: ' + encoding);
  }

  static toBase58btc(publicKey: Uint8Array): string {
    return u8a.toString(publicKey, 'base58btc');
  }
  // Reference :- https://medium.com/swlh/json-web-signature-jws-and-jws-detached-for-a-five-year-old-88729b7b1a68
  static toBase64url(data: any): string {
    return Buffer.from(data || '')
      .toString('base64')
      .replace(/\+/g, '-')
      .replace(/\//g, '_')
      .replace(/=+$/g, '');
  }

  static decodeBase64Url(data: string): string {
    const fixed = data.replace(/-/g, '+').replace(/_/g, '/');
    const decoded = Buffer.from(fixed, 'base64').toString('utf8');
    return decoded;
  }
}