# frozen_string_literal: true

require 'openssl'
require 'digest'
require 'base64'
require 'models/client_token'

class EncryptionUtils
  def self.padding_key(key, length)
    if key.length == length
      key
    else
      if key.length > length
        key.slice(0, length)
      else
        (length - key.length).times { key << '0' }
        key
      end
    end
  end

  def self.encrypt(plain_text, secret_key)
    begin
      cipher = OpenSSL::Cipher.new('aes-256-cbc')
      cipher.encrypt
      iv = cipher.random_iv
      cipher.key = padding_key(secret_key, 32)
      encrypted = cipher.update(plain_text) + cipher.final
      (iv + encrypted).unpack1('H*')
    rescue StandardError
      ''
    end
  end

  def self.decrypt(cipher_text, secret_key)
    begin
      cipher = OpenSSL::Cipher.new('aes-256-cbc')
      cipher.decrypt
      raw_data = [cipher_text].pack('H*')
      cipher.iv = raw_data.slice(0, 16)
      cipher.key = padding_key(secret_key, 32)
      decrypted = JSON.parse(cipher.update(raw_data.slice(16, raw_data.length)) + cipher.final)

      return ClientToken.new(decrypted['cid'], decrypted['vid'], decrypted['fp'])
    rescue StandardError
      ClientToken.new('', '','')
    end
  end
end