module JWT::Algos::HmacRbNaCl

def key_for_rbnacl(hmac, key)
  key ||= ''
  raise JWT::DecodeError, 'HMAC key expected to be a String' unless key.is_a?(String)
  return padded_empty_key(hmac.key_bytes) if key == ''
  key
end

def padded_empty_key(length)
  Array.new(length, 0x0).pack('C*').encode('binary')
end

def resolve_algorithm(algorithm)
  MAPPING.fetch(algorithm)
end

def sign(algorithm, msg, key)
  warn("[DEPRECATION] The use of the algorithm #{algorithm} is deprecated and will be removed in the next major version of ruby-jwt")
  if (hmac = resolve_algorithm(algorithm))
    hmac.auth(key_for_rbnacl(hmac, key).encode('binary'), msg.encode('binary'))
  else
    Hmac.sign(algorithm, msg, key)
  end
end

def verify(algorithm, key, signing_input, signature)
  warn("[DEPRECATION] The use of the algorithm #{algorithm} is deprecated and will be removed in the next major version of ruby-jwt")
  if (hmac = resolve_algorithm(algorithm))
    hmac.verify(key_for_rbnacl(hmac, key).encode('binary'), signature.encode('binary'), signing_input.encode('binary'))
  else
    Hmac.verify(algorithm, key, signing_input, signature)
  end
rescue ::RbNaCl::BadAuthenticatorError, ::RbNaCl::LengthError
  false
end