add Twitter/Github button and fix some logic of AbstractDDPDocEventSubscriber

app/src/main/java/chat/rocket/android/fragment/server_config/LoginFragment.java

 package chat.rocket.android.fragment.server_config;
 
+import android.view.View;
 import chat.rocket.android.R;
+import chat.rocket.android.model.MeteorLoginServiceConfiguration;
+import io.realm.Realm;
+import io.realm.RealmResults;
+import java.util.List;
+import jp.co.crowdworks.realm_java_helpers.RealmListObserver;
 
 /**
  * Login screen.
@@ -10,7 +16,39 @@ public class LoginFragment extends AbstractServerConfigFragment {
     return R.layout.fragment_login;
   }
 
+  private RealmListObserver<MeteorLoginServiceConfiguration> authProvidersObserver =
+      new RealmListObserver<MeteorLoginServiceConfiguration>() {
+        @Override protected RealmResults<MeteorLoginServiceConfiguration> queryItems(Realm realm) {
+          return realm.where(MeteorLoginServiceConfiguration.class)
+              .equalTo("serverConfig.id", serverConfigId)
+              .findAll();
+        }
+
+        @Override protected void onCollectionChanged(List<MeteorLoginServiceConfiguration> list) {
+          onRenderAuthProviders(list);
+        }
+      };
+
   @Override protected void onSetupView() {
 
   }
+
+  private void onRenderAuthProviders(List<MeteorLoginServiceConfiguration> authProviders) {
+    final View btnTwitter = rootView.findViewById(R.id.btn_login_with_twitter);
+    final View btnGitHub = rootView.findViewById(R.id.btn_login_with_github);
+
+    boolean hasTwitter = false;
+    boolean hasGitHub = false;
+    for (MeteorLoginServiceConfiguration authProvider : authProviders) {
+      if (!hasTwitter && "twitter".equals(authProvider.getService())) {
+        hasTwitter = true;
+      }
+      if (!hasGitHub && "github".equals(authProvider.getService())) {
+        hasGitHub = true;
+      }
+    }
+
+    btnTwitter.setVisibility(hasTwitter ? View.VISIBLE : View.GONE);
+    btnGitHub.setVisibility(hasGitHub ? View.VISIBLE : View.GONE);
+  }
 }

app/src/main/java/chat/rocket/android/model/MeteorLoginServiceConfiguration.java

@@ -15,4 +15,52 @@ public class MeteorLoginServiceConfiguration
   private String consumerKey; //for Twitter
   private String appId; //for Facebook
   private String clientId; //for other auth providers
+
+  public String getId() {
+    return id;
+  }
+
+  public void setId(String id) {
+    this.id = id;
+  }
+
+  public ServerConfig getServerConfig() {
+    return serverConfig;
+  }
+
+  public void setServerConfig(ServerConfig serverConfig) {
+    this.serverConfig = serverConfig;
+  }
+
+  public String getService() {
+    return service;
+  }
+
+  public void setService(String service) {
+    this.service = service;
+  }
+
+  public String getConsumerKey() {
+    return consumerKey;
+  }
+
+  public void setConsumerKey(String consumerKey) {
+    this.consumerKey = consumerKey;
+  }
+
+  public String getAppId() {
+    return appId;
+  }
+
+  public void setAppId(String appId) {
+    this.appId = appId;
+  }
+
+  public String getClientId() {
+    return clientId;
+  }
+
+  public void setClientId(String clientId) {
+    this.clientId = clientId;
+  }
 }

app/src/main/java/chat/rocket/android/service/RocketChatWebSocketThread.java

@@ -170,8 +170,8 @@ public class RocketChatWebSocketThread extends HandlerThread {
 
     for (Class clazz : REGISTERABLE_CLASSES) {
       try {
-        Constructor ctor = clazz.getConstructor(Context.class, RocketChatWebSocketAPI.class);
-        Object obj = ctor.newInstance(appContext, webSocketAPI);
+        Constructor ctor = clazz.getConstructor(Context.class, String.class, RocketChatWebSocketAPI.class);
+        Object obj = ctor.newInstance(appContext, serverConfigId, webSocketAPI);
 
         if (obj instanceof Registerable) {
           Registerable registerable = (Registerable) obj;

app/src/main/java/chat/rocket/android/service/ddp_subscriber/AbstractDDPDocEventSubscriber.java

@@ -17,12 +17,15 @@ import timber.log.Timber;
 
 abstract class AbstractDDPDocEventSubscriber implements Registerable {
   protected final Context context;
+  protected final String serverConfigId;
   protected final RocketChatWebSocketAPI webSocketAPI;
   private String subscriptionId;
   private Subscription rxSubscription;
 
-  protected AbstractDDPDocEventSubscriber(Context context, RocketChatWebSocketAPI api) {
+  protected AbstractDDPDocEventSubscriber(Context context, String serverConfigId,
+      RocketChatWebSocketAPI api) {
     this.context = context;
+    this.serverConfigId = serverConfigId;
     this.webSocketAPI = api;
   }
 
@@ -90,6 +93,7 @@ abstract class AbstractDDPDocEventSubscriber implements Registerable {
   private void onDocumentAdded(Realm realm, DDPSubscription.Added docEvent) throws JSONException {
     //executed in RealmTransaction
     JSONObject json = new JSONObject().put("id", docEvent.docID);
+    json.put("serverConfig", new JSONObject().put("id", serverConfigId));
     mergeJson(json, docEvent.fields);
     realm.createOrUpdateObjectFromJson(getModelClass(), customizeFieldJson(json));
   }
@@ -105,9 +109,10 @@ abstract class AbstractDDPDocEventSubscriber implements Registerable {
       throws JSONException {
     //executed in RealmTransaction
     JSONObject json = new JSONObject().put("id", docEvent.docID);
+    json.put("serverConfig", new JSONObject().put("id", serverConfigId));
     for (int i = 0; i < docEvent.cleared.length(); i++) {
       String fieldToDelete = docEvent.cleared.getString(i);
-      json.remove(fieldToDelete);
+      json.put(fieldToDelete, JSONObject.NULL);
     }
     mergeJson(json, docEvent.fields);
     realm.createOrUpdateObjectFromJson(getModelClass(), customizeFieldJson(json));

app/src/main/java/chat/rocket/android/service/ddp_subscriber/LoginServiceConfigurationSubscriber.java

@@ -9,8 +9,9 @@ import io.realm.RealmObject;
  * meteor.loginServiceConfiguration subscriber
  */
 public class LoginServiceConfigurationSubscriber extends AbstractDDPDocEventSubscriber {
-  public LoginServiceConfigurationSubscriber(Context context, RocketChatWebSocketAPI api) {
-    super(context, api);
+  public LoginServiceConfigurationSubscriber(Context context, String serverConfigId,
+      RocketChatWebSocketAPI api) {
+    super(context, serverConfigId, api);
   }
 
   @Override protected String getSubscriptionName() {

app/src/main/java/chat/rocket/android/service/observer/AbstractModelObserver.java

@@ -10,10 +10,13 @@ abstract class AbstractModelObserver<T extends RealmObject> extends RealmListObs
     implements Registerable {
 
   protected final Context context;
+  protected final String serverConfigId;
   protected final RocketChatWebSocketAPI webSocketAPI;
 
-  protected AbstractModelObserver(Context context, RocketChatWebSocketAPI api) {
+  protected AbstractModelObserver(Context context, String serverConfigId,
+      RocketChatWebSocketAPI api) {
     this.context = context;
+    this.serverConfigId = serverConfigId;
     webSocketAPI = api;
   }