module CWT

# File lib/cwt.rb, line 15
def self.decode(token, cose_key)
  decoded = CBOR.decode(token)

  case decoded.tag
  when CBOR_TAG
    decode(CBOR.encode(decoded.value), cose_key)
  when COSE::Sign1.tag
    key = COSE::Key.deserialize(cose_key)
    sign1 = COSE::Sign1.deserialize(token)

    if sign1.verify(key)
      CWT::ClaimsSet.from_cbor(sign1.payload)
    else
      raise(CWT::Error, "Verification failed")
    end
  when COSE::Mac0.tag
    key = COSE::Key.deserialize(cose_key)
    mac0 = COSE::Mac0.deserialize(token)

    if mac0.verify(key)
      CWT::ClaimsSet.from_cbor(mac0.payload)
    else
      raise(CWT::Error, "Verification failed")
    end
  else
    raise(CWT::Error, "Unsupported tag #{decoded.tag}")
  end
end