import java.security.MessageDigest;
import java.security.NoSuchAlgorithmException;
import java.util.HashMap;
import java.util.logging.Logger;

public class StreamAesUtils {
    private static final Logger logger = Logger.getLogger(StreamAesUtils.class.getName());

    public static Aes generateFromExchangeKeyAndSuperSecretKey(String keyExchange, String superSecretKey) throws NoSuchAlgorithmException {
        HashMap<String, String> hashMap = new HashMap<>();
        String[] params = keyExchange.split(" ");
        for (String param : params) {
            String[] keyVal = param.trim().split("=", 2);
            if (!(keyVal.length != 2 || keyVal[0] == null || keyVal[1] == null)) {
                String trim = keyVal[0].trim();
                String trim2 = keyVal[1].replace("\"", "").trim();
                hashMap.put(trim, trim2);
            }
        }
        if (!hashMap.containsKey("nonce")) {
            return null;
        }
        logger.info("cipher=" + (hashMap.get("cipher")));
        logger.info("username=" + (hashMap.get("username")));
        logger.info("padding=" + (hashMap.get("padding")));
        logger.info("algorithm=" + (hashMap.get("algorithm")));
        logger.info("nonce=" + (hashMap.get("nonce")));
        return fromUserNonceSuperSecretKey(hashMap.get("username"), hashMap.get("nonce"), superSecretKey);
    }

    public static Aes fromUserNonceSuperSecretKey(String username, String nonce, String superSecretKey) throws NoSuchAlgorithmException {
        if (GenKey.generateDefaultUsername().equals(username)) {
            logger.info("AES use User Password");
        } else if ("none".equals(username)) {
            superSecretKey = GenKey.generateDefaultPsw();
        } else {
            logger.info("AES key-exchange unknown username");
            return null;
        }
        byte[] md5 = md5Digest(nonce + ":" + superSecretKey);
        return new Aes(md5, md5Digest(username + ":" + nonce));
    }

    private static byte[] md5Digest(String str) throws NoSuchAlgorithmException {
        MessageDigest instance = MessageDigest.getInstance("MD5");
        instance.update(str.getBytes());
        return instance.digest();
    }
}