class JWT::JWA::HmacRbNaCl

def self.from_algorithm(algorithm)
  new(algorithm, ::RbNaCl::HMAC.const_get(algorithm.upcase.gsub('HS', 'SHA')))
end

def initialize(alg, hmac)
  @alg = alg
  @hmac = hmac
end

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 sign(data:, signing_key:)
  Deprecations.warning("The use of the algorithm #{alg} is deprecated and will be removed in the next major version of ruby-jwt")
  hmac.auth(key_for_rbnacl(hmac, signing_key).encode('binary'), data.encode('binary'))
end

def verify(data:, signature:, verification_key:)
  Deprecations.warning("The use of the algorithm #{alg} is deprecated and will be removed in the next major version of ruby-jwt")
  hmac.verify(key_for_rbnacl(hmac, verification_key).encode('binary'), signature.encode('binary'), data.encode('binary'))
rescue ::RbNaCl::BadAuthenticatorError, ::RbNaCl::LengthError
  false
end