import { Hex } from 'viem';

export function hexToBase64(hex: Hex): string {
  if (hex.length % 2 !== 0) {
    throw new Error('Hex string must have an even number of characters');
  }
  const hexStr = hex.startsWith('0x') ? hex.slice(2) : hex;
  if (hexStr.length === 0) {
    return '';
  }
  const bytes = new Uint8Array(
    hexStr.match(/.{1,2}/g)!.map((byte) => parseInt(byte, 16))
  );
  const base64 = btoa(String.fromCharCode(...bytes));
  return base64.replace(/\+/g, '-').replace(/\//g, '_').replace(/=+$/, '');
}

export function base64ToHex(base64: string): Hex {
  if (base64.length === 0) {
    return '0x';
  }
  const urlSafeBase64 = base64.replace(/-/g, '+').replace(/_/g, '/');
  const binaryStr = atob(urlSafeBase64);
  const hexArray = Array.from(binaryStr, (char) =>
    char.charCodeAt(0).toString(16).padStart(2, '0')
  );
  return `0x${hexArray.join('')}` as Hex;
}