// SPDX-License-Identifier: Apache-2.0
pragma solidity 0.8.18;

/**
 * @title Library for string manipulation operations
 * @notice This library contains functions for manipulating strings in Solidity.
 */
library LibString {
  bytes private constant ALPHABET_HEX_16 = '0123456789abcdef';
  bytes private constant ALPHABET_32 = 'abcdefghijklmnopqrstuvwxyz234567';

  /**
   * @notice Prefixes a hexadecimal string with "0x".
   * @param _hex The hexadecimal string to prefix.
   * @return The prefixed hexadecimal string.
   */
  function prefixHexadecimal(string memory _hex) internal pure returns (string memory) {
    return string(abi.encodePacked('0x', _hex));
  }

  /**
   * @notice Prefixes a base32 string with "b".
   * @param _base32 The base32 string to prefix.
   * @return The prefixed base32 string.
   */
  function prefixBase32(string memory _base32) internal pure returns (string memory) {
    return string(abi.encodePacked('b', _base32));
  }

  /**
   * @notice Converts a byte array to a hexadecimal string.
   * @param _bytes The byte array to convert.
   * @return The resulting hexadecimal string.
   */
  function bytesToHexadecimal(bytes memory _bytes) internal pure returns (string memory) {
    uint256 bytesLength = _bytes.length;
    bytes memory bytesArray = new bytes(bytesLength << 1);

    unchecked {
      for (uint256 i = 0; i < bytesLength; i++) {
        uint256 word = uint8(_bytes[i]);
        uint256 ib = i << 1;
        bytesArray[ib] = bytes1(ALPHABET_HEX_16[word >> 4]);
        bytesArray[ib + 1] = bytes1(ALPHABET_HEX_16[word & 0xf]);
      }
    }

    return string(bytesArray);
  }

  /**
   * @notice Converts a byte array to a base32 string.
   * @param _bytes The byte array to convert.
   * @return The resulting base32 string.
   */
  function bytesToBase32(bytes memory _bytes) internal pure returns (string memory) {
    uint256 bytesLength = _bytes.length;

    uint256 t1 = bytesLength << 3;

    unchecked {
      // base32-encoded length = ceil(# of bits / 5)
      bytes memory bytesArray = new bytes((t1 + 4) / 5);

      uint256 bits = 0;
      uint256 buffer = 0;
      uint256 pointer = 0;

      for (uint256 i = 0; i < bytesLength; i++) {
        buffer = (buffer << 8) | uint8(_bytes[i]);
        bits += 8;

        while (bits >= 5) {
          bits -= 5;
          bytesArray[pointer] = bytes1(ALPHABET_32[(buffer >> bits) & 0x1f]);
          pointer++;
        }
      }

      if (bits > 0) {
        bytesArray[pointer] = bytes1(ALPHABET_32[(buffer << (5 - bits)) & 0x1f]);
      }

      return string(bytesArray);
    }
  }
}