class JWT::JWA::HmacRbNaClFixed

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 padded_key_bytes(key, bytesize)
  key.bytes.fill(0, key.bytesize...bytesize).pack('C*')
end

def sign(data:, signing_key:)
  signing_key ||= ''
  Deprecations.warning("The use of the algorithm #{alg} is deprecated and will be removed in the next major version of ruby-jwt")
  raise JWT::DecodeError, 'HMAC key expected to be a String' unless signing_key.is_a?(String)
  hmac.auth(padded_key_bytes(signing_key, hmac.key_bytes), data.encode('binary'))
end

def verify(data:, signature:, verification_key:)
  verification_key ||= ''
  Deprecations.warning("The use of the algorithm #{alg} is deprecated and will be removed in the next major version of ruby-jwt")
  raise JWT::DecodeError, 'HMAC key expected to be a String' unless verification_key.is_a?(String)
  hmac.verify(padded_key_bytes(verification_key, hmac.key_bytes), signature.encode('binary'), data.encode('binary'))
rescue ::RbNaCl::BadAuthenticatorError, ::RbNaCl::LengthError
  false
end