/* eslint-disable */
// weapp jwt-decode
const b64 = 'ABCDEFGHIJKLMNOPQRSTUVWXYZabcdefghijklmnopqrstuvwxyz0123456789+/='
const b64re = /^(?:[A-Za-z\d+/]{4})*?(?:[A-Za-z\d+/]{2}(?:==)?|[A-Za-z\d+/]{3}=?)?$/

// btoa
export function weBtoa(string: string) {
  string = String(string)
  let bitmap
  let a
  let b
  let c
  let result = ''
  let i = 0
  const rest = string.length % 3

  for (; i < string.length;) {
    if ((a = string.charCodeAt(i++)) > 255 || (b = string.charCodeAt(i++)) > 255 || (c = string.charCodeAt(i++)) > 255) throw new TypeError('Failed to execute \'btoa\' on \'Window\': The string to be encoded contains characters outside of the Latin1 range.',)

    bitmap = (a << 16) | (b << 8) | c
    result
      += b64.charAt((bitmap >> 18) & 63)
      + b64.charAt((bitmap >> 12) & 63)
      + b64.charAt((bitmap >> 6) & 63)
      + b64.charAt(bitmap & 63)
  }

  return rest ? result.slice(0, rest - 3) + '==='.substring(rest) : result
}
// atob
export const weAtob = function (string: string) {
  string = String(string).replace(/[\t\n\f\r ]+/g, '')
  if (!b64re.test(string)) throw new TypeError('Failed to execute \'atob\' on \'Window\': The string to be decoded is not correctly encoded.')
  string += '=='.slice(2 - (string.length & 3))
  let bitmap
  let result = ''
  let r1
  let r2
  let i = 0
  for (; i < string.length;) {
    bitmap =      (b64.indexOf(string.charAt(i++)) << 18)
      | (b64.indexOf(string.charAt(i++)) << 12)
      | ((r1 = b64.indexOf(string.charAt(i++))) << 6)
      | (r2 = b64.indexOf(string.charAt(i++)))

    result
      += r1 === 64
        ? String.fromCharCode((bitmap >> 16) & 255)
        : r2 === 64
          ? String.fromCharCode((bitmap >> 16) & 255, (bitmap >> 8) & 255)
          : String.fromCharCode((bitmap >> 16) & 255, (bitmap >> 8) & 255, bitmap & 255)
  }
  return result
}

function b64DecodeUnicode(str: string) {
  return decodeURIComponent(weAtob(str).replace(/(.)/g, (p) => {
    let code = p.charCodeAt(0).toString(16)
      .toUpperCase()
    if (code.length < 2) {
      code = `0${code}`
    }
    return `%${code}`
  }),)
}

export function base64_url_decode(str: string) {
  let output = str.replace(/-/g, '+').replace(/_/g, '/')
  switch (output.length % 4) {
    case 0:
      break
    case 2:
      output += '=='
      break
    case 3:
      output += '='
      break
    default:
      throw new Error('Illegal base64url string!')
  }

  try {
    return b64DecodeUnicode(output)
  } catch (err) {
    return weAtob(output)
  }
}

export function weappJwtDecode(token: string, options?: any) {
  if (typeof token !== 'string') {
    throw new Error('Invalid token specified')
  }
  options = options || {}
  const pos = options.header === true ? 0 : 1
  try {
    return JSON.parse(base64_url_decode(token.split('.')[pos]))
  } catch (e) {
    throw new Error(`Invalid token specified: ${e}` ? (e as any).message : '')
  }
}

export function weAppJwtDecodeAll(token: string) {
  if (typeof token !== 'string') {
    throw new Error('Invalid token specified')
  }
  try {
    const parts = token.split('.').map((segment, i) => i === 2 ? segment : JSON.parse(base64_url_decode(segment)))
    return { claims: parts[1], header: parts[0], signature: parts[2]}
  } catch (e) {
    throw new Error(`Invalid token specified: ${e}` ? (e as any).message : '')
  }
}