fix default workspace creation bug. fix no workspace message

src/app/workspace/workspace.less

@@ -14,6 +14,15 @@
     border-radius: 8px;
     transition: width 0.2s ease;
     margin-bottom: 0.5em;
+
+    .center-message {
+        display: flex;
+        align-items: center;
+        justify-content: center;
+        height: 100%;
+        width: 100%;
+        color: @text-secondary;
+    }
 }
 .collapsed + .session-view {
     max-width: calc(100% - 6.7em);

src/app/workspace/workspaceview.tsx

@@ -25,7 +25,11 @@ class WorkspaceView extends React.Component<{}, {}> {
         let model = GlobalModel;
         let session = model.getActiveSession();
         if (session == null) {
-            return <div className="session-view">(no active session)</div>;
+            return (
+                <div className="session-view">
+                    <div className="center-message"><div>(no active workspace)</div></div>
+                </div>
+            );
         }
         let activeScreen = session.getActiveScreen();
         let cmdInputHeight = model.inputModel.cmdInputHeight.get();

wavesrv/cmd/main-server.go

@@ -825,7 +825,7 @@ func main() {
 		log.Printf("[error] ensuring local remote: %v\n", err)
 		return
 	}
-	_, err = sstore.EnsureDefaultSession(context.Background())
+	err = sstore.EnsureOneSession(context.Background())
 	if err != nil {
 		log.Printf("[error] ensuring default session: %v\n", err)
 		return

wavesrv/pkg/sstore/dbops.go

@@ -507,6 +507,15 @@ func GetSessionById(ctx context.Context, id string) (*SessionType, error) {
 	return nil, nil
 }
 
+// counts non-archived sessions
+func GetSessionCount(ctx context.Context) (int, error) {
+	return WithTxRtn(ctx, func(tx *TxWrap) (int, error) {
+		query := `SELECT COALESCE(count(*), 0) FROM session WHERE NOT archived`
+		numSessions := tx.GetInt(query)
+		return numSessions, nil
+	})
+}
+
 func GetSessionByName(ctx context.Context, name string) (*SessionType, error) {
 	var session *SessionType
 	txErr := WithTx(ctx, func(tx *TxWrap) error {

wavesrv/pkg/sstore/sstore.go

@@ -1197,19 +1197,19 @@ func EnsureLocalRemote(ctx context.Context) error {
 	return nil
 }
 
-func EnsureDefaultSession(ctx context.Context) (*SessionType, error) {
-	session, err := GetSessionByName(ctx, DefaultSessionName)
+func EnsureOneSession(ctx context.Context) error {
+	numSessions, err := GetSessionCount(ctx)
 	if err != nil {
-		return nil, err
+		return err
 	}
-	if session != nil {
-		return session, nil
+	if numSessions > 0 {
+		return nil
 	}
 	_, err = InsertSessionWithName(ctx, DefaultSessionName, true)
 	if err != nil {
-		return nil, err
+		return err
 	}
-	return GetSessionByName(ctx, DefaultSessionName)
+	return nil
 }
 
 func createClientData(tx *TxWrap) error {