Refactor connectors

1) Remove unnecessary access token emptiness check. We have only two states of user in connectors: null and authorized (with id, email and tokens).
2) Simplify authorized client creation based on two states of a user: login if there's no user, update tokens if needed and finally initialize client with up-to-date access token.
3) Move token up-to-date check to Stepik client and create separate client for the request, because it simplifies logic of client authorization

python/educational-core/course-creator/src/com/jetbrains/edu/coursecreator/stepik/CCStepicConnector.java

@@ -73,7 +73,7 @@ public class CCStepicConnector {
       LOG.warn("Http client is null");
       return;
     }
-    final StepicUser currentUser = EduStepicAuthorizedClient.getCurrentUser(client);
+    final StepicUser currentUser = EduStepicAuthorizedClient.getCurrentUser();
     if (currentUser != null) {
       final List<StepicUser> courseAuthors = course.getAuthors();
       for (int i = 0; i < courseAuthors.size(); i++) {

python/educational-core/student/src/com/jetbrains/edu/learning/StudyUtils.java

@@ -72,6 +72,7 @@ import com.jetbrains.edu.learning.courseFormat.tasks.TheoryTask;
 import com.jetbrains.edu.learning.courseGeneration.StudyProjectGenerator;
 import com.jetbrains.edu.learning.editor.StudyEditor;
 import com.jetbrains.edu.learning.stepic.StepicUpdateSettings;
+import com.jetbrains.edu.learning.stepic.StepicUser;
 import com.jetbrains.edu.learning.ui.StudyToolWindow;
 import com.jetbrains.edu.learning.ui.StudyToolWindowFactory;
 import com.petebevin.markdown.MarkdownProcessor;
@@ -612,9 +613,12 @@ public class StudyUtils {
   public static File getCourseDirectory(Course course) {
     final File courseDirectory;
     if (course.isAdaptive()) {
+      StepicUser user = StepicUpdateSettings.getInstance().getUser();
+      String email = user == null ? "" : user.getEmail();
+
       courseDirectory = new File(StudyProjectGenerator.OUR_COURSES_DIR,
                                  StudyProjectGenerator.ADAPTIVE_COURSE_PREFIX + course.getName()
-                                 + "_" + StepicUpdateSettings.getInstance().getUser().getEmail());
+                                 + "_" + email);
     }
     else {
       courseDirectory = new File(StudyProjectGenerator.OUR_COURSES_DIR, course.getName());

python/educational-core/student/src/com/jetbrains/edu/learning/checker/StudyCheckTask.java

@@ -109,7 +109,8 @@ public class StudyCheckTask extends com.intellij.openapi.progress.Task.Backgroun
       runAfterTaskCheckedActions();
       final Course course = StudyTaskManager.getInstance(myProject).getCourse();
       if (course != null && EduNames.STUDY.equals(course.getCourseMode())) {
-        if (StepicUpdateSettings.getInstance().getUser().getAccessToken() != null) {
+        StepicUser user = StepicUpdateSettings.getInstance().getUser();
+        if (user != null) {
           EduStepicConnector.postSolution(myTask, testsOutput.isSuccess(), myProject);
         }
       }
@@ -155,9 +156,18 @@ public class StudyCheckTask extends com.intellij.openapi.progress.Task.Backgroun
     else if (myTask instanceof TheoryTask) {
       final int lessonId = myTask.getLesson().getId();
       final StepicUser user = StepicUpdateSettings.getInstance().getUser();
-      final boolean reactionPosted = EduAdaptiveStepicConnector.postRecommendationReaction(String.valueOf(lessonId),
-                                                                              String.valueOf(user.getId()),
-                                                                              EduAdaptiveStepicConnector.NEXT_RECOMMENDATION_REACTION);
+
+      final boolean reactionPosted;
+      if (user == null) {
+        LOG.warn("User is null");
+        reactionPosted = false;
+      }
+      else {
+        reactionPosted = EduAdaptiveStepicConnector.postRecommendationReaction(String.valueOf(lessonId),
+                                                                               String.valueOf(user.getId()),
+                                                                               EduAdaptiveStepicConnector.NEXT_RECOMMENDATION_REACTION);
+      }
+
       if (reactionPosted) {
         if (myStatusBeforeCheck != StudyStatus.Solved) {
           myTask.setStatus(StudyStatus.Solved);

python/educational-core/student/src/com/jetbrains/edu/learning/courseFormat/Course.java

@@ -100,7 +100,7 @@ public class Course {
     for (String name : authors) {
       final List<String> firstLast = StringUtil.split(name, " ");
       if (!firstLast.isEmpty()) {
-        final StepicUser stepicUser = new StepicUser();
+        final StepicUser stepicUser = StepicUser.createEmptyUser();
         stepicUser.setFirstName(firstLast.remove(0));
         if (firstLast.size() > 0) {
           stepicUser.setLastName(StringUtil.join(firstLast, " "));

python/educational-core/student/src/com/jetbrains/edu/learning/courseGeneration/StudyProjectGenerator.java

@@ -66,7 +66,7 @@ public class StudyProjectGenerator {
 
   public boolean isLoggedIn() {
     final StepicUser user = StepicUpdateSettings.getInstance().getUser();
-    return user.getAccessToken() != null;
+    return user != null;
   }
 
   public void setEnrolledCoursesIds(@NotNull final List<Integer> coursesIds) {
@@ -122,7 +122,7 @@ public class StudyProjectGenerator {
     }
     else {
       final StepicUser user = StepicUpdateSettings.getInstance().getUser();
-      if (user.getAccessToken() != null) {
+      if (user != null) {
         final File adaptiveCourseFile = new File(new File(OUR_COURSES_DIR, ADAPTIVE_COURSE_PREFIX +
                                                                            mySelectedCourseInfo.getName() + "_" +
                                                                            user.getEmail()), EduNames.COURSE_META_FILE);
@@ -617,7 +617,7 @@ public class StudyProjectGenerator {
         final ArrayList<StepicUser> authors = new ArrayList<>();
         for (JsonElement author : courseAuthors) {
           final JsonObject authorAsJsonObject = author.getAsJsonObject();
-          final StepicUser stepicUser = new StepicUser();
+          final StepicUser stepicUser = StepicUser.createEmptyUser();
           stepicUser.setFirstName(authorAsJsonObject.get("first_name").getAsString());
           stepicUser.setLastName(authorAsJsonObject.get("last_name").getAsString());
           authors.add(stepicUser);

python/educational-core/student/src/com/jetbrains/edu/learning/stepic/EduAdaptiveStepicConnector.java

@@ -207,6 +207,7 @@ public class EduAdaptiveStepicConnector {
   @Nullable
   private static StepicWrappers.AdaptiveAttemptWrapper.Attempt getAttemptForStep(int id) {
     final StepicUser user = StepicUpdateSettings.getInstance().getUser();
+    if (user == null) return null;
     try {
       final List<StepicWrappers.AdaptiveAttemptWrapper.Attempt> attempts = getAttempts(user, id);
       if (attempts != null && attempts.size() > 0) {
@@ -296,7 +297,10 @@ public class EduAdaptiveStepicConnector {
     if (course != null && editor != null && editor.getTaskFile() != null) {
       indicator.checkCanceled();
       final StepicUser user = StepicUpdateSettings.getInstance().getUser();
-
+      if (user == null) {
+        LOG.warn("Can't get next recommendation: user is null");
+        return;
+      }
       final boolean recommendationReaction = postRecommendationReaction(String.valueOf(editor.getTaskFile().getTask().getLesson().getId()),
                                                                         String.valueOf(user.getId()), reaction);
       if (recommendationReaction) {
@@ -553,7 +557,7 @@ public class EduAdaptiveStepicConnector {
     if (client != null) {
       final StepicUser user = StepicUpdateSettings.getInstance().getUser();
       StepicWrappers.ResultSubmissionWrapper wrapper = postResultsForCheck(client, submission);
-      if (wrapper != null) {
+      if (wrapper != null && user != null) {
         wrapper = getCheckResults(client, wrapper, attemptId, user.getId());
         if (wrapper.submissions.length > 0) {
           final String status = wrapper.submissions[0].status;
@@ -565,6 +569,9 @@ public class EduAdaptiveStepicConnector {
           LOG.warn("Got a submission wrapper with incorrect submissions number: " + wrapper.submissions.length);
         }
       }
+      else {
+        LOG.warn("Can't do adaptive check: " + (wrapper == null ? "wrapper is null" : "user is null"));
+      }
     }
 
     return Pair.create(false, "");

python/educational-core/student/src/com/jetbrains/edu/learning/stepic/EduStepicAuthorizedClient.java

@@ -5,7 +5,6 @@ import com.google.gson.Gson;
 import com.google.gson.GsonBuilder;
 import com.intellij.openapi.application.ApplicationManager;
 import com.intellij.openapi.diagnostic.Logger;
-import com.intellij.openapi.util.text.StringUtil;
 import org.apache.http.*;
 import org.apache.http.client.entity.UrlEncodedFormEntity;
 import org.apache.http.client.methods.CloseableHttpResponse;
@@ -36,27 +35,37 @@ public class EduStepicAuthorizedClient {
     if (ourClient != null) {
       return ourClient;
     }
-    else {
-      final StepicUser stepicUser = StepicUpdateSettings.getInstance().getUser();
-      ourClient = initializeClient(stepicUser);
-      if (ourClient == null || !isTokenUpToDate(ourClient, stepicUser.getId())) {
-        ourClient = loginAndInitializeClient(stepicUser);
+
+    StepicUpdateSettings stepicUpdateSettings = StepicUpdateSettings.getInstance();
+
+
+    if (stepicUpdateSettings.getUser() == null) {
+      final StepicUser user = showLoginDialog();
+      if (user != null) {
+        stepicUpdateSettings.setUser(user);
+      }
+      else {
+        LOG.warn("Unable to login");
+        return null;
       }
     }
-    return ourClient;
-  }
 
-  @Nullable
-  private static CloseableHttpClient loginAndInitializeClient(@NotNull StepicUser stepicUser) {
-    final StepicUser user = login(stepicUser);
-    if (user != null) {
-      StepicUpdateSettings.getInstance().setUser(user);
-      return initializeClient(stepicUser);
-    }
-    else {
-      LOG.warn("Couldn't initialize client: user is null");
-      return null;
+    StepicUser stepicUser = stepicUpdateSettings.getUser();
+    assert stepicUser != null;
+
+    if (!EduStepicClient.isTokenUpToDate(stepicUser.getAccessToken())) {
+      StepicWrappers.TokenInfo tokens = getUpdatedTokens(stepicUser.getRefreshToken());
+      if (tokens != null) {
+        stepicUser.setTokenInfo(tokens);
+      }
+      else {
+        return null;
+      }
     }
+
+    ourClient = createInitializedClient(stepicUser.getAccessToken());
+
+    return ourClient;
   }
 
   @Nullable
@@ -74,17 +83,19 @@ public class EduStepicAuthorizedClient {
     if (ourClient != null) {
       return ourClient;
     }
-    ourClient = initializeClient(stepicUser);
-    if (ourClient == null || !isTokenUpToDate(ourClient, stepicUser.getId())) {
-      final StepicUser user = login(stepicUser);
-      if (user != null) {
-        StepicUpdateSettings.getInstance().setUser(user);
-        ourClient = initializeClient(stepicUser);
+
+    if (!EduStepicClient.isTokenUpToDate(stepicUser.getAccessToken())) {
+      StepicWrappers.TokenInfo tokenInfo = getUpdatedTokens(stepicUser.getRefreshToken());
+      if (tokenInfo != null) {
+        stepicUser.setTokenInfo(tokenInfo);
+      }
+      else {
+        return EduStepicClient.getHttpClient();
       }
     }
-    if (ourClient == null) {
-      ourClient = EduStepicClient.getHttpClient();
-    }
+
+    ourClient = createInitializedClient(stepicUser.getAccessToken());
+
     return ourClient;
   }
 
@@ -96,36 +107,12 @@ public class EduStepicAuthorizedClient {
     return EduStepicClient.getFromStepic(link, container, getHttpClient(stepicUser));
   }
 
-  @Nullable
-  private static CloseableHttpClient initializeClient(@NotNull final StepicUser stepicUser) {
+  @NotNull
+  private static CloseableHttpClient createInitializedClient(@NotNull String accessToken) {
     final List<BasicHeader> headers = new ArrayList<>();
-    final String accessToken = stepicUser.getAccessToken();
-    if (accessToken != null && !accessToken.isEmpty()) {
-      headers.add(new BasicHeader("Authorization", "Bearer " + accessToken));
-      headers.add(new BasicHeader("Content-type", EduStepicNames.CONTENT_TYPE_APP_JSON));
-      return getBuilder().setDefaultHeaders(headers).build();
-    }
-    return null;
-  }
-
-  private static StepicUser login(@NotNull final StepicUser user) {
-    final String login = user.getEmail();
-    final String refreshToken = user.getRefreshToken();
-    if (StringUtil.isEmptyOrSpaces(login)) {
-      return showLoginDialog();
-    }
-    else if (StringUtil.isNotEmpty(refreshToken)) {
-      final StepicWrappers.TokenInfo tokenInfo = login(refreshToken);
-      if (tokenInfo != null) {
-        user.setupTokenInfo(tokenInfo);
-        final StepicUser currentUser = getCurrentUser(getHttpClient());
-        if (currentUser != null) {
-          user.setId(currentUser.getId());
-        }
-        return user;
-      }
-    }
-    return null;
+    headers.add(new BasicHeader("Authorization", "Bearer " + accessToken));
+    headers.add(new BasicHeader("Content-type", EduStepicNames.CONTENT_TYPE_APP_JSON));
+    return getBuilder().setDefaultHeaders(headers).build();
   }
 
   private static StepicUser showLoginDialog() {
@@ -148,28 +135,28 @@ public class EduStepicAuthorizedClient {
     parameters.add(new BasicNameValuePair("username", email));
     parameters.add(new BasicNameValuePair("password", password));
 
-    final StepicUser user = new StepicUser(email, password);
     final StepicWrappers.TokenInfo tokenInfo = getTokens(parameters);
     if (tokenInfo != null) {
-      user.setupTokenInfo(tokenInfo);
-      final CloseableHttpClient client = getHttpClient(user);
-      final StepicUser currentUser = getCurrentUser(client);
+      final StepicUser user = new StepicUser(email, password, tokenInfo);
+      final StepicUser currentUser = getCurrentUser();
       if (currentUser != null) {
         user.setId(currentUser.getId());
       }
+      ourClient = createInitializedClient(user.getAccessToken());
+
+      return user;
     }
-    ourClient = initializeClient(user);
-    return user;
+
+    return null;
   }
 
   public static void invalidateClient() {
     ourClient = null;
   }
 
-  private static StepicWrappers.TokenInfo login(@NotNull final String refreshToken) {
+  @Nullable
+  private static StepicWrappers.TokenInfo getUpdatedTokens(@NotNull final String refreshToken) {
     final List<NameValuePair> parameters = new ArrayList<>();
-
-    if (refreshToken.isEmpty()) return null;
     parameters.add(new BasicNameValuePair("client_id", ourClientId));
     parameters.add(new BasicNameValuePair("content-type", "application/json"));
     parameters.add(new BasicNameValuePair("grant_type", "refresh_token"));
@@ -179,17 +166,20 @@ public class EduStepicAuthorizedClient {
   }
 
   @Nullable
-  public static StepicUser getCurrentUser(CloseableHttpClient client) {
-    try {
-      final StepicWrappers.AuthorWrapper wrapper = EduStepicClient.getFromStepic(EduStepicNames.CURRENT_USER, 
-                                                                                 StepicWrappers.AuthorWrapper.class, 
-                                                                                 client);
-      if (wrapper != null && !wrapper.users.isEmpty()) {
-        return wrapper.users.get(0);
+  public static StepicUser getCurrentUser() {
+    CloseableHttpClient client = getHttpClient();
+    if (client != null) {
+      try {
+        final StepicWrappers.AuthorWrapper wrapper = EduStepicClient.getFromStepic(EduStepicNames.CURRENT_USER,
+                                                                                   StepicWrappers.AuthorWrapper.class,
+                                                                                   client);
+        if (wrapper != null && !wrapper.users.isEmpty()) {
+          return wrapper.users.get(0);
+        }
+      }
+      catch (IOException e) {
+        LOG.warn("Couldn't get a current user");
       }
-    }
-    catch (IOException e) {
-      LOG.warn("Couldn't get author info");
     }
     return null;
   }
@@ -212,7 +202,7 @@ public class EduStepicAuthorizedClient {
         return gson.fromJson(responseString, StepicWrappers.TokenInfo.class);
       }
       else {
-        LOG.warn("Failed to Login: " + statusLine.getStatusCode() + statusLine.getReasonPhrase());
+        LOG.warn("Failed to get tokens: " + statusLine.getStatusCode() + statusLine.getReasonPhrase());
       }
     }
     catch (IOException e) {
@@ -220,9 +210,4 @@ public class EduStepicAuthorizedClient {
     }
     return null;
   }
-  
-  private static boolean isTokenUpToDate(@NotNull CloseableHttpClient client, int userId) {
-    final StepicUser user = getCurrentUser(client);
-    return user != null && userId == user.getId() && userId != -1;
-  }
 }

python/educational-core/student/src/com/jetbrains/edu/learning/stepic/EduStepicClient.java

@@ -18,6 +18,7 @@ import org.apache.http.impl.DefaultConnectionReuseStrategy;
 import org.apache.http.impl.client.CloseableHttpClient;
 import org.apache.http.impl.client.HttpClientBuilder;
 import org.apache.http.impl.client.HttpClients;
+import org.apache.http.message.BasicHeader;
 import org.apache.http.util.EntityUtils;
 import org.jetbrains.annotations.NotNull;
 
@@ -30,6 +31,7 @@ import java.net.URI;
 import java.security.KeyManagementException;
 import java.security.NoSuchAlgorithmException;
 import java.security.SecureRandom;
+import java.util.ArrayList;
 import java.util.List;
 
 public class EduStepicClient {
@@ -102,4 +104,28 @@ public class EduStepicClient {
     }
     return builder;
   }
+
+  static boolean isTokenUpToDate(@NotNull String token) {
+    if (token.isEmpty()) return false;
+
+    final List<BasicHeader> headers = new ArrayList<>();
+    headers.add(new BasicHeader("Authorization", "Bearer " + token));
+    headers.add(new BasicHeader("Content-type", EduStepicNames.CONTENT_TYPE_APP_JSON));
+    CloseableHttpClient httpClient = getBuilder().setDefaultHeaders(headers).build();
+
+    try {
+      final StepicWrappers.AuthorWrapper wrapper = getFromStepic(EduStepicNames.CURRENT_USER, StepicWrappers.AuthorWrapper.class, httpClient);
+      if (wrapper != null && !wrapper.users.isEmpty()) {
+        StepicUser user = wrapper.users.get(0);
+        return user != null && !user.isGuest();
+      }
+      else {
+        throw new IOException(wrapper == null ? "Got a null current user" : "Got an empty wrapper");
+      }
+    }
+    catch (IOException e) {
+      LOG.warn(e.getMessage());
+      return false;
+    }
+  }
 }

python/educational-core/student/src/com/jetbrains/edu/learning/stepic/EduStepicConnector.java

@@ -42,8 +42,8 @@ public class EduStepicConnector {
   private EduStepicConnector() {
   }
 
-  public static boolean enrollToCourse(final int courseId, final StepicUser stepicUser) {
-    if (stepicUser == null || stepicUser.getAccessToken() == null) return false;
+  public static boolean enrollToCourse(final int courseId, @Nullable final StepicUser stepicUser) {
+    if (stepicUser == null) return false;
     HttpPost post = new HttpPost(EduStepicNames.STEPIC_API_URL + EduStepicNames.ENROLLMENTS);
     try {
       final StepicWrappers.EnrollmentWrapper enrollment = new StepicWrappers.EnrollmentWrapper(String.valueOf(courseId));
@@ -131,7 +131,7 @@ public class EduStepicConnector {
       return false;
     }
     final StepicWrappers.CoursesContainer coursesContainer;
-    if (user != null && user.getAccessToken() != null) {
+    if (user != null) {
       coursesContainer = EduStepicAuthorizedClient.getFromStepic(url.toString(), StepicWrappers.CoursesContainer.class, user);
     }
     else {
@@ -256,7 +256,7 @@ public class EduStepicConnector {
 
   private static <T> T getFromStepic(String link, final Class<T> container) throws IOException{
     final StepicUser user = StepicUpdateSettings.getInstance().getUser();
-    final boolean isAuthorized = user.getAccessToken() != null;
+    final boolean isAuthorized = user != null;
     if (isAuthorized) {
       return EduStepicAuthorizedClient.getFromStepic(link, container, user);
     }
@@ -351,7 +351,7 @@ public class EduStepicConnector {
 
   public static String postAttempt(int id) throws IOException {
     final CloseableHttpClient client = EduStepicAuthorizedClient.getHttpClient();
-    if (client == null || StepicUpdateSettings.getInstance().getUser().getAccessToken() == null) return "";
+    if (client == null || StepicUpdateSettings.getInstance().getUser() == null) return "";
     final HttpPost attemptRequest = new HttpPost(EduStepicNames.STEPIC_API_URL + EduStepicNames.ATTEMPTS);
     String attemptRequestBody = new Gson().toJson(new StepicWrappers.AttemptWrapper(id));
     attemptRequest.setEntity(new StringEntity(attemptRequestBody, ContentType.APPLICATION_JSON));

python/educational-core/student/src/com/jetbrains/edu/learning/stepic/LoginDialog.java

@@ -43,7 +43,7 @@ public class LoginDialog extends DialogWrapper {
   protected void doOKAction() {
     if (!validateLoginAndPasswordFields()) return;
     myStepicUser = EduStepicAuthorizedClient.login(myLoginPanel.getLogin(), myLoginPanel.getPassword());
-    if (myStepicUser != null && myStepicUser.getId() > 0 && myStepicUser.getAccessToken() != null) {
+    if (myStepicUser != null && myStepicUser.getId() > 0) {
       doJustOkAction();
     }
     else {

python/educational-core/student/src/com/jetbrains/edu/learning/stepic/StepicStudyOptions.java

@@ -82,8 +82,10 @@ public class StepicStudyOptions implements StudyOptionsProvider {
     final StepicUpdateSettings stepikSettings = StepicUpdateSettings.getInstance();
     myEnableTestingFromSamples.setSelected(stepikSettings.isEnableTestingFromSamples());
     final StepicUser user = stepikSettings.getUser();
-    setLogin(user.getEmail());
-    setPassword(user.getPassword());
+    if (user != null) {
+      setLogin(user.getEmail());
+      setPassword(user.getPassword());
+    }
   }
 
   @Override
@@ -99,7 +101,9 @@ public class StepicStudyOptions implements StudyOptionsProvider {
     }
 
     final StepicUser user = stepikSettings.getUser();
-    final boolean isCredentialsModified = !getLogin().equals(user.getEmail()) || !getPassword().equals(user.getPassword());
+    String savedEmail = user == null ? "" : user.getEmail();
+    String savedPassword = user == null ? "" : user.getPassword();
+    final boolean isCredentialsModified = !getLogin().equals(savedEmail) || !getPassword().equals(savedPassword);
     if (isCredentialsModified) {
       final String login = getLogin();
       final String password = getPassword();
@@ -113,7 +117,7 @@ public class StepicStudyOptions implements StudyOptionsProvider {
           }, "Logging In", true,
           null);
 
-        if (stepicUser[0] != null && stepicUser[0].getAccessToken() != null) {
+        if (stepicUser[0] != null) {
           stepikSettings.setUser(stepicUser[0]);
         }
         else {
@@ -127,7 +131,7 @@ public class StepicStudyOptions implements StudyOptionsProvider {
   }
 
   private static void removeCredentials() {
-    StepicUpdateSettings.getInstance().setUser(new StepicUser());
+    StepicUpdateSettings.getInstance().setUser(null);
     EduStepicAuthorizedClient.invalidateClient();
   }
 
@@ -142,8 +146,11 @@ public class StepicStudyOptions implements StudyOptionsProvider {
     boolean isTestOptionModified = !isTestingFromSamplesEnabled() == stepikSettings.isEnableTestingFromSamples();
     final StepicUser user = stepikSettings.getUser();
 
-    return !getLogin().equals(user.getEmail())
-           || !getPassword().equals(user.getPassword())
+    String email = user == null ? "" : user.getEmail();
+    String password = user == null ? "" : user.getPassword();
+
+    return !getLogin().equals(email)
+           || !getPassword().equals(password)
            || isTestOptionModified;
   }
 

python/educational-core/student/src/com/jetbrains/edu/learning/stepic/StepicUpdateSettings.java

@@ -5,7 +5,6 @@ import com.intellij.openapi.components.ServiceManager;
 import com.intellij.openapi.components.State;
 import com.intellij.openapi.components.Storage;
 import com.intellij.util.xmlb.XmlSerializerUtil;
-import org.jetbrains.annotations.NotNull;
 import org.jetbrains.annotations.Nullable;
 
 @State(name = "StepicUpdateSettings", storages = @Storage("other.xml"))
@@ -39,15 +38,13 @@ public class StepicUpdateSettings implements PersistentStateComponent<StepicUpda
   public static StepicUpdateSettings getInstance() {
     return ServiceManager.getService(StepicUpdateSettings.class);
   }
-  @NotNull
+
+  @Nullable
   public StepicUser getUser() {
-    if (myUser == null) {
-      myUser = new StepicUser();
-    }
     return myUser;
   }
 
-  public void setUser(@NotNull final StepicUser user) {
+  public void setUser(@Nullable final StepicUser user) {
     myUser = user;
   }
 

python/educational-core/student/src/com/jetbrains/edu/learning/stepic/StepicUser.java

@@ -14,16 +14,24 @@ public class StepicUser {
   private String myEmail;
   private String myAccessToken;
   private String myRefreshToken;
+  private boolean isGuest;
 
-  public StepicUser() {
+  private StepicUser() {
     myFirstName = "";
     myLastName = "";
     myEmail = "";
+    myAccessToken = "";
+    myRefreshToken = "";
+  }
+
+  public static StepicUser createEmptyUser() {
+    return new StepicUser();
   }
   
-  public StepicUser(@NotNull final String email, @NotNull final String password) {
+  public StepicUser(@NotNull final String email, @NotNull final String password, @NotNull StepicWrappers.TokenInfo tokenInfo) {
     this.myEmail = email;
     setPassword(password);
+    setTokenInfo(tokenInfo);
   }
 
   public int getId() {
@@ -77,6 +85,7 @@ public class StepicUser {
     return StringUtil.join(new String[]{myFirstName, myLastName}, " ");
   }
 
+  @NotNull
   public String getAccessToken() {
     return myAccessToken;
   }
@@ -85,6 +94,7 @@ public class StepicUser {
     this.myAccessToken = accessToken;
   }
 
+  @NotNull
   public String getRefreshToken() {
     return myRefreshToken;
   }
@@ -93,8 +103,16 @@ public class StepicUser {
     this.myRefreshToken = refreshToken;
   }
 
-  public void setupTokenInfo(@NotNull final StepicWrappers.TokenInfo tokenInfo) {
+  public void setTokenInfo(@NotNull final StepicWrappers.TokenInfo tokenInfo) {
     myAccessToken = tokenInfo.getAccessToken();
     myRefreshToken = tokenInfo.getRefreshToken();
   }
+
+  public boolean isGuest() {
+    return isGuest;
+  }
+
+  public void setGuest(boolean guest) {
+    isGuest = guest;
+  }
 }

python/educational-core/student/src/com/jetbrains/edu/learning/stepic/StepicWrappers.java

@@ -423,14 +423,6 @@ public class StepicWrappers {
     }
   }
 
-  static class UserWrapper {
-    StepicUser user;
-
-    public UserWrapper(String user, String password) {
-      this.user = new StepicUser(user, password);
-    }
-  }
-
   static class RecommendationReaction {
     int reaction;
     String user;

python/educational-core/student/src/com/jetbrains/edu/learning/ui/LoginPanel.java

@@ -50,8 +50,10 @@ public class LoginPanel {
       }
     });
     final StepicUser user = StepicUpdateSettings.getInstance().getUser();
-    myLoginField.setText(user.getEmail());
-    myPasswordField.setText(user.getPassword());
+    if (user != null) {
+      myLoginField.setText(user.getEmail());
+      myPasswordField.setText(user.getPassword());
+    }
   }
 
   public JPanel getContentPanel() {

python/educational-core/student/src/com/jetbrains/edu/learning/ui/StudyNewProjectPanel.java

@@ -358,7 +358,7 @@ public class StudyNewProjectPanel extends JPanel implements PanelWithAnchor {
 
         final StepicUser stepicUser = StudyUtils.execCancelable(() -> EduStepicAuthorizedClient.login(myLoginPanel.getLogin(),
                                                                                                       myLoginPanel.getPassword()));
-        if (stepicUser != null && stepicUser.getAccessToken() != null) {
+        if (stepicUser != null) {
           stepicUser.setEmail(myLoginPanel.getLogin());
           stepicUser.setPassword(myLoginPanel.getPassword());
           StepicUpdateSettings.getInstance().setUser(stepicUser);