encrypt.cr

require "flate"
require "gzip"
require "openssl/cipher"
require "base64"
require "secure_random"

module Flate
  def self.write(str)
    io = IO::Memory.new
    Flate::Writer.new(io) do |flate|
      flate.write str.to_slice
    end
    rstr = io.to_s
    io.close
    rstr
  end

  def self.read(str)
    io = IO::Memory.new(str.to_slice)

    rstr = Flate::Reader.new(io) do |flate|
      flate.gets_to_end
    end
    io.close
    rstr
  end
end

module Gzip
  def self.write(str)
    io = IO::Memory.new
    Gzip::Writer.open(io) do |gzip|
      gzip.write str.to_slice
    end
    rstr = io.to_s
    io.close
    rstr
  end

  def self.read(str)
    io = IO::Memory.new(str.to_slice)

    rstr = Gzip::Reader.open(io) do |gzip|
      gzip.gets_to_end
    end
    io.close
    rstr
  end
end

module Enc
  def self.encrypt(value, secret = "6f65c214-1b26-46fa-a1c1-3f27ffb13802", alg = "aes-256-cbc", iv = SecureRandom.random_bytes(16))
    cipher = OpenSSL::Cipher.new(alg)
    cipher.encrypt
    cipher.key = secret

    cipher.iv = iv

    encrypted_data = IO::Memory.new
    encrypted_data.write(cipher.update(value.to_slice))
    encrypted_data.write(cipher.final)

    # "#{::Base64.strict_encode encrypted_data}--#{::Base64.strict_encode iv}"
    ::Base64.strict_encode encrypted_data
  end

  def self.decrypt(encrypted_message, secret = "6f65c214-1b26-46fa-a1c1-3f27ffb13802", alg = "aes-256-cbc", iv = SecureRandom.random_bytes(16))
    cipher = OpenSSL::Cipher.new(alg)
    encrypted_data = ::Base64.decode(encrypted_message)

    cipher.decrypt
    cipher.key = secret
    cipher.iv = iv

    decrypted_data = IO::Memory.new
    decrypted_data.write cipher.update(encrypted_data)
    decrypted_data.write cipher.final
    decrypted_data.to_s
  end
end
iv = SecureRandom.random_bytes(16)
enc = Enc.encrypt("hey you are now encrypted. That's pretty cool right?", iv: iv)
puts enc
puts Enc.decrypt(enc, iv: iv)

str = Flate.write("We are the world. We are the deflated children.")
puts Flate.read(str)
str2 = Gzip.write("We are the world. We are the gzipped children.")
puts Gzip.read(str2)