'use strict'

const crc = require('crc')
const zlib = require('zlib')
const crypto = require('crypto')

const AES_SECRET = 'eagleye_9fd&fwfl'

class EagleEye {
  static hexToBytes (hex) {
    for (var bytes = [], c = 0; c < hex.length; c += 2) { bytes.push(parseInt(hex.substr(c, 2), 16)) }
    return bytes
  }

  static bytesToHex (bytes) {
    for (var hex = [], i = 0; i < bytes.length; i++) {
      hex.push((bytes[i] >>> 4).toString(16))
      hex.push((bytes[i] & 0xF).toString(16))
    }
    return hex.join('')
  }

  static encrypt (payload) {
    var key128 = [0, 1, 2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12, 13, 14, 15]
    var iv = Buffer.from(key128)
    let key = Buffer.from(AES_SECRET)
    let cipher = crypto.createCipheriv('aes-128-cfb', key, iv)
    cipher.setAutoPadding(false)
    let encrypted = cipher.update(payload)
    return encrypted
  }

  static decrypt (hex) {
    var key128 = [0, 1, 2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12, 13, 14, 15]
    var iv = Buffer.from(key128)
    let key = Buffer.from(AES_SECRET)
    let decipher = crypto.createDecipheriv('aes-128-cfb', key, iv)
    decipher.setAutoPadding(false)
    var deciphered = decipher.update(hex)
    decipher.final()
    return deciphered.toString('utf8')
  }

  static encode (pl) {
    let str = this.encrypt(pl)
    let woo = this.bytesToHex(str)
    let hash = crc.crc32(woo.toString())
    woo = woo + ',' + hash
    let output = zlib.gzipSync(Buffer.from(woo))
    return output
  }

  static decode (hexString) {
    var output = zlib.gunzipSync(Buffer.from(hexString, 'hex'))
    let woo = this.hexToBytes(output.toString().split(',')[0])
    let out = EagleEye.decrypt(Buffer.from(woo))
    return out.toString()
  }
}

module.exports = EagleEye