preparing to pass error messages to client

Signed-off-by: Stephan Richter <s.richter@srsoftware.de>

de.srsoftware.oidc.api/src/main/java/de/srsoftware/oidc/api/Constants.java

@@ -20,6 +20,9 @@ public class Constants {
 	public static final String DAYS		  = "days";
 	public static final String ENCRYPTION_KEY	  = "encryption_key";
 	public static final String ERROR_DESCRIPTION	  = "error_description";
+	public static final String ERROR_LOCKED	  = "error_locked";
+	public static final String ERROR_LOGIN_FAILED	  = "error_login_failed";
+	public static final String ERROR_NO_USERNAME	  = "error_no_username";
 	public static final String EXPIRATION	  = "expiration";
 	public static final String EXPIRES_IN	  = "expires_in";
 	public static final String GRANT_TYPE	  = "grant_type";

de.srsoftware.oidc.api/src/main/java/de/srsoftware/oidc/api/Error.java

@@ -0,0 +1,36 @@
+/* © SRSoftware 2024 */
+package de.srsoftware.oidc.api;
+
+
+import java.util.HashMap;
+import java.util.Map;
+
+public class Error<T> implements Result<T> {
+	private final String        cause;
+	private Map<String, Object> metadata;
+
+	public Error(String cause) {
+		this.cause = cause;
+	}
+
+	public String cause() {
+		return cause;
+	}
+
+	@Override
+	public boolean isError() {
+		return true;
+	}
+
+	public static <T> Error<T> message(String text) {
+		return new Error<T>(text);
+	}
+
+	public Error<T> metadata(Object... tokens) {
+		metadata = new HashMap<String, Object>();
+		for (int i = 0; i < tokens.length - 1; i += 2) {
+			metadata.put(tokens[i].toString(), tokens[i + 1]);
+		}
+		return this;
+	}
+}

de.srsoftware.oidc.api/src/main/java/de/srsoftware/oidc/api/Payload.java

@@ -0,0 +1,24 @@
+/* © SRSoftware 2024 */
+package de.srsoftware.oidc.api;
+
+
+public class Payload<T> implements Result<T> {
+	private final T object;
+
+	public Payload(T object) {
+		this.object = object;
+	}
+
+	public static <T> Payload<T> of(T object) {
+		return new Payload<>(object);
+	}
+
+	@Override
+	public boolean isError() {
+		return false;
+	}
+
+	public T get() {
+		return object;
+	}
+}

de.srsoftware.oidc.api/src/main/java/de/srsoftware/oidc/api/Result.java

@@ -0,0 +1,6 @@
+/* © SRSoftware 2024 */
+package de.srsoftware.oidc.api;
+
+public interface Result<T> {
+	public boolean isError();
+}

de.srsoftware.oidc.api/src/main/java/de/srsoftware/oidc/api/UserService.java

@@ -26,19 +26,19 @@ public interface UserService {
 	 * @param accessToken
 	 * @return
 	 */
-	public Optional<User>	     forToken(String accessToken);
-	public UserService	     init(User defaultUser);
-	public List<User>	     list();
-	public Set<User>	     find(String idOrEmail);
+	public Optional<User>         forToken(String accessToken);
+	public UserService            init(User defaultUser);
+	public List<User>             list();
+	public Set<User>              find(String idOrEmail);
 	public default Optional<Lock> getLock(String key) {
 		var failedLogin = failedLogins.get(key);
 		if (failedLogin == null || failedLogin.releaseTime().isBefore(Instant.now())) return empty();
 		return Optional.of(failedLogin);
 	}
-	public Optional<User>      load(String id);
-	public Optional<User>      login(String username, String password);
-	public default Lock lock(String key) {
-		return failedLogins.computeIfAbsent(key,k -> new Lock()).count();
+	public Optional<User> load(String id);
+	public Result<User>   login(String username, String password);
+	public default Lock   lock(String key) {
+		  return failedLogins.computeIfAbsent(key, k -> new Lock()).count();
 	}
 	public boolean	           passwordMatches(String plaintextPassword, User user);
 	public UserService         save(User user);

de.srsoftware.oidc.api/src/main/java/de/srsoftware/oidc/api/data/Lock.java

@@ -4,8 +4,8 @@ package de.srsoftware.oidc.api.data;
 import java.time.Instant;
 
 public class Lock {
-	private int	     attempts;
-	private Instant	     releaseTime;
+	private int	attempts;
+	private Instant releaseTime;
 
 	public Lock() {
 		this.attempts = 0;