Fixing issues with topic selection autocomplete

Author: Damien LEROY

Pages/Tester.razor

@@ -37,7 +37,7 @@
                     <label for="topic" class="col-2 col-form-label text-right">Topic</label>
                     <div class="col-10">
                         <div class="input-group autocomplete">
-                            <input type="text" class="form-control" id="topic" placeholder="topic" @bind="_setting.Topic" @oninput="OnTypeTopic">
+                            <input type="text" class="form-control" id="topic" placeholder="topic" @bind="_setting.Topic" @oninput="OnTypeTopic" @onfocusout="OnLostTopicFocus" @onfocusin="OnGetTopicFocus">
                             @if (_filteredTopics is not null)
                             {
                                 <ul class="options">

Pages/Tester.razor.cs

@@ -180,14 +180,33 @@ private void OnSelectSetting(ChangeEventArgs e)
 
         async Task OnTypeTopic(ChangeEventArgs e)
         {
-            var filter = e.Value?.ToString();
+            if (e != null)
+            {
+                _setting.Topic = e.Value.ToString();
+            }
+
+            var filter = _setting.Topic;
+            await JsRuntime.InvokeVoidAsync("console.log", filter);
             await LoadTopics(null);
-            _filteredTopics = _topics.Where(t => t.Contains(filter ?? string.Empty)).ToList();
+            _filteredTopics = _topics?.Where(t => t.Contains(filter ?? string.Empty)).ToList();
+
+            if (_filteredTopics?.Count == 1 && filter.Equals(_filteredTopics.First(), StringComparison.InvariantCultureIgnoreCase))
+                _filteredTopics = null;
+        }
+
+        async Task OnLostTopicFocus(FocusEventArgs e)
+        {
+            await Task.Delay(200).ContinueWith(t => _filteredTopics = null);
+        }
+
+        async Task  OnGetTopicFocus(FocusEventArgs e)
+        {
+            await OnTypeTopic(null);
         }
 
         private async Task LoadTopics(MouseEventArgs e)
         {
-            if (_topics != null || _isTopicLoading)
+            if (_topics != null || _isTopicLoading || string.IsNullOrWhiteSpace(_setting.Brokers))
                 return;
 
             _isTopicLoading = true;

Service/KafkaTesterService.cs

@@ -85,8 +85,8 @@ public async Task<List<string>> GetTopicsAsync(string servers)
             }
             catch (Exception e)
             {
-                Console.WriteLine(e);
-                return new List<string>();
+                _logger.LogError($"Error occured: {e.Message}");
+                return null;
             }
         }
 

wwwroot/css/autocomplete/autocomplete.css

@@ -13,6 +13,8 @@
         border: 1px solid #ced4da;
         border-radius: 0.5rem;
         box-shadow: 0 30px 25px 8px rgba(0, 0, 0, 0.1);
+        max-height: 500px;
+        overflow: auto;
     }
 
     .autocomplete .option {