polkadot-js/common

// Copyright 2017-2024 @polkadot/util-crypto authors & contributors
// SPDX-License-Identifier: Apache-2.0

import { BN, bnToU8a, compactAddLength, hexToU8a, isBigInt, isBn, isHex, isNumber, isString, stringToU8a } from '@polkadot/util';

import { blake2AsU8a } from '../blake2/asU8a.js';
import { BN_LE_256_OPTS } from '../bn.js';

const RE_NUMBER = /^\d+$/;

const JUNCTION_ID_LEN = 32;

export class DeriveJunction {
  readonly #chainCode: Uint8Array = new Uint8Array(32);

  #isHard = false;

  public static from (value: string): DeriveJunction {
    const result = new DeriveJunction();
    const [code, isHard] = value.startsWith('/')
      ? [value.substring(1), true]
      : [value, false];

    result.soft(
      RE_NUMBER.test(code)
        ? new BN(code, 10)
        : code
    );

    return isHard
      ? result.harden()
      : result;
  }

  public get chainCode (): Uint8Array {
    return this.#chainCode;
  }

  public get isHard (): boolean {
    return this.#isHard;
  }

  public get isSoft (): boolean {
    return !this.#isHard;
  }

  public hard (value: number | string | bigint | BN | Uint8Array): DeriveJunction {
    return this.soft(value).harden();
  }

  public harden (): DeriveJunction {
    this.#isHard = true;

    return this;
  }

  public soft (value: number | string | bigint | BN | Uint8Array): DeriveJunction {
    if (isNumber(value) || isBn(value) || isBigInt(value)) {
      return this.soft(bnToU8a(value, BN_LE_256_OPTS));
    } else if (isHex(value)) {
      return this.soft(hexToU8a(value));
    } else if (isString(value)) {
      return this.soft(compactAddLength(stringToU8a(value)));
    } else if (value.length > JUNCTION_ID_LEN) {
      return this.soft(blake2AsU8a(value));
    }

    this.#chainCode.fill(0);
    this.#chainCode.set(value, 0);

    return this;
  }

  public soften (): DeriveJunction {
    this.#isHard = false;

    return this;
  }
}