Add more comments and make some additional updates

Author: daxian-dbw

shell/agents/AIShell.Ollama.Agent/Command.cs

@@ -59,7 +59,7 @@ private void ListPresetAction(string name)
 
             settings.ShowOnePreset(host, name);
         }
-        catch (InvalidOperationException ex)
+        catch (Exception ex)
         {
             string availablePresetNames = PresetNamesAsString();
             host.WriteErrorLine($"{ex.Message} Available preset(s): {availablePresetNames}.");
@@ -98,7 +98,7 @@ private async Task UsePresetAction(string name)
             await setting.UsePreset(host, chosenPreset);
             host.MarkupLine($"Using the preset [green]{chosenPreset.Name}[/]:");
         }
-        catch (InvalidOperationException ex)
+        catch (Exception ex)
         {
             string availablePresetNames = PresetNamesAsString();
             host.WriteErrorLine($"{ex.Message} Available presets: {availablePresetNames}.");
@@ -153,7 +153,7 @@ private void ShowSystemPromptAction()
         {
             settings.ShowSystemPrompt(host);
         }
-        catch (InvalidOperationException ex)
+        catch (Exception ex)
         {
             host.WriteErrorLine(ex.Message);
         }
@@ -179,7 +179,7 @@ private void SetSystemPromptAction(string prompt)
         {
             settings.SetSystemPrompt(host, prompt);
         }
-        catch (InvalidOperationException ex)
+        catch (Exception ex)
         {
             host.WriteErrorLine(ex.Message);
         }
@@ -239,7 +239,7 @@ private async Task ListModelAction(string name)
 
             await settings.ShowOneModel(host, name);
         }
-        catch (InvalidOperationException ex)
+        catch (Exception ex)
         {
             host.WriteErrorLine(ex.Message);
         }
@@ -282,14 +282,28 @@ private async Task UseModelAction(string name)
                     CancellationToken.None);
             }
 
-            await settings.UseModel(host: null, name);
+            await settings.UseModel(host, name);
             host.MarkupLine($"Using the model [green]{name}[/]");
         }
-        catch (InvalidOperationException ex)
+        catch (Exception ex)
         {
             host.WriteErrorLine(ex.Message);
         }
     }
 
-    private IEnumerable<string> ModelNameCompleter(CompletionContext context) => _agnet.Settings?.GetAllModels().GetAwaiter().GetResult() ?? [];
+    private IEnumerable<string> ModelNameCompleter(CompletionContext context)
+    {
+        try
+        {
+            // Model retrieval may throw.
+            var results = _agnet.Settings?.GetAllModels().Result;
+            if (results is not null)
+            {
+                return results;
+            }
+        }
+        catch (Exception) { }
+
+        return [];
+    }
 }

shell/agents/AIShell.Ollama.Agent/Settings.cs

@@ -45,14 +45,23 @@ public Settings(ConfigData configData)
         }
     }
 
+    /// <summary>
+    /// Retrieve available models from the Ollama endpoint.
+    /// </summary>
+    /// <param name="host">Used for writing error to host when it's a local endpoint but the Ollama server is not started. The endpoint check will be skipped if a `null` is specified.</param>
+    /// <param name="cancellationToken">Used for cancel the operation.</param>
+    /// <returns></returns>
     private async Task<bool> EnsureModelsInitialized(IHost host, CancellationToken cancellationToken = default)
     {
         if (_initialized)
         {
             return true;
         }
 
-        // Skip the self check when host is null.
+        // The endpoint check is supposed to be interactive and can be skipped in some cases, such as when
+        // the `PerformSelfcheck` method was already called right before entering this method.
+        // So, we will simply skip the endpoint check when the passed-in host is null. If there's something
+        // wrong with the endpoint, the subsequent calls to retrieve models will fail and throw anyway.
         if (host is not null)
         {
             bool success = await PerformSelfcheck(host, checkEndpointOnly: true);
@@ -183,6 +192,7 @@ internal async Task<bool> PerformSelfcheck(IHost host, bool checkEndpointOnly =
 
         if (!checkEndpointOnly && !_runningConfigChecked)
         {
+            // Skip the endpoint check in 'EnsureModelsInitialized' as we already did it.
             await EnsureModelsInitialized(host: null).ConfigureAwait(false);
             if (string.IsNullOrEmpty(RunningConfig.ModelName))
             {