class Argon2::Engine

def self.hash_argon2i(password, salt, t_cost, m_cost)
  result = ''
  FFI::MemoryPointer.new(:char, Constants::OUT_LEN) do |buffer|
    ret = Ext.hash_argon2i(buffer, Constants::OUT_LEN, password, password.length, salt, salt.length, t_cost, (1<<m_cost))
    raise ArgonHashFail.new(ERRORS[ret]) unless ret == 0
    result = buffer.read_string(Constants::OUT_LEN)
  end
   result.unpack('H*').join
end

def self.hash_argon2i_encode(password, salt, t_cost, m_cost)
  result = ''
  if salt.length != Constants::SALT_LEN
    raise ArgonHashFail.new("Invalid salt size") 
  end
  FFI::MemoryPointer.new(:char, 300) do |buffer|
    ret = Ext.argon2_wrap(buffer, password, salt, t_cost, (1<<m_cost), 1)
    raise ArgonHashFail.new(ERRORS[ret]) unless ret == 0
    result = buffer.read_string(300)
  end
  result.gsub("\0", '')
end

def self.saltgen
  SecureRandom.random_bytes(Argon2::Constants::SALT_LEN)
end