// Copyright (c) Mysten Labs, Inc.
// SPDX-License-Identifier: Apache-2.0

/* eslint-disable */

/*
|*  Base64 / binary data / UTF-8 strings utilities
|*  https://developer.mozilla.org/en-US/docs/Web/JavaScript/Base64_encoding_and_decoding
\*

/* Array of bytes to Base64 string decoding */

function b64ToUint6(nChr: number) {
  return nChr > 64 && nChr < 91
    ? nChr - 65
    : nChr > 96 && nChr < 123
    ? nChr - 71
    : nChr > 47 && nChr < 58
    ? nChr + 4
    : nChr === 43
    ? 62
    : nChr === 47
    ? 63
    : 0
}

export function fromB64(sBase64: string, nBlocksSize?: number): Uint8Array {
  var sB64Enc = sBase64.replace(/[^A-Za-z0-9+/]/g, ''),
    nInLen = sB64Enc.length,
    nOutLen = nBlocksSize
      ? Math.ceil(((nInLen * 3 + 1) >> 2) / nBlocksSize) * nBlocksSize
      : (nInLen * 3 + 1) >> 2,
    taBytes = new Uint8Array(nOutLen)

  for (var nMod3, nMod4, nUint24 = 0, nOutIdx = 0, nInIdx = 0; nInIdx < nInLen; nInIdx++) {
    nMod4 = nInIdx & 3
    nUint24 |= b64ToUint6(sB64Enc.charCodeAt(nInIdx)) << (6 * (3 - nMod4))
    if (nMod4 === 3 || nInLen - nInIdx === 1) {
      for (nMod3 = 0; nMod3 < 3 && nOutIdx < nOutLen; nMod3++, nOutIdx++) {
        taBytes[nOutIdx] = (nUint24 >>> ((16 >>> nMod3) & 24)) & 255
      }
      nUint24 = 0
    }
  }

  return taBytes
}

/* Base64 string to array encoding */

function uint6ToB64(nUint6: number) {
  return nUint6 < 26
    ? nUint6 + 65
    : nUint6 < 52
    ? nUint6 + 71
    : nUint6 < 62
    ? nUint6 - 4
    : nUint6 === 62
    ? 43
    : nUint6 === 63
    ? 47
    : 65
}

export function toB64(aBytes: Uint8Array): string {
  var nMod3 = 2,
    sB64Enc = ''

  for (var nLen = aBytes.length, nUint24 = 0, nIdx = 0; nIdx < nLen; nIdx++) {
    nMod3 = nIdx % 3
    nUint24 |= aBytes[nIdx] << ((16 >>> nMod3) & 24)
    if (nMod3 === 2 || aBytes.length - nIdx === 1) {
      sB64Enc += String.fromCodePoint(
        uint6ToB64((nUint24 >>> 18) & 63),
        uint6ToB64((nUint24 >>> 12) & 63),
        uint6ToB64((nUint24 >>> 6) & 63),
        uint6ToB64(nUint24 & 63),
      )
      nUint24 = 0
    }
  }

  return (
    sB64Enc.slice(0, sB64Enc.length - 2 + nMod3) + (nMod3 === 2 ? '' : nMod3 === 1 ? '=' : '==')
  )
}