Use Provider.NONE as a default value and refactor provider handling logic across components.

app/MindWork AI Studio/Agents/AgentBase.cs

@@ -54,7 +54,7 @@ public abstract class AgentBase(ILogger<AgentBase> logger, SettingsManager setti
     
     #region Implementation of IAgent
     
-    public abstract AIStudio.Settings.Provider? ProviderSettings { get; set; }
+    public abstract AIStudio.Settings.Provider ProviderSettings { get; set; }
     
     public abstract Task<ChatThread> ProcessContext(ChatThread chatThread, IDictionary<string, string> additionalData);
     
@@ -103,10 +103,9 @@ public abstract class AgentBase(ILogger<AgentBase> logger, SettingsManager setti
     
     protected async Task AddAIResponseAsync(ChatThread thread, IContent lastUserPrompt, DateTimeOffset time)
     {
-        if(this.ProviderSettings is null)
+        if(this.ProviderSettings == Settings.Provider.NONE)
             return;
         
-        var providerSettings = this.ProviderSettings.Value;
         var aiText = new ContentText
         {
             // We have to wait for the remote
@@ -127,6 +126,6 @@ public abstract class AgentBase(ILogger<AgentBase> logger, SettingsManager setti
         // Use the selected provider to get the AI response.
         // By awaiting this line, we wait for the entire
         // content to be streamed.
-        await aiText.CreateFromProviderAsync(providerSettings.CreateProvider(this.Logger), providerSettings.Model, lastUserPrompt, thread);
+        await aiText.CreateFromProviderAsync(this.ProviderSettings.CreateProvider(this.Logger), this.ProviderSettings.Model, lastUserPrompt, thread);
     }
 }

app/MindWork AI Studio/Agents/AgentDataSourceSelection.cs

@@ -86,7 +86,7 @@ public sealed class AgentDataSourceSelection (ILogger<AgentDataSourceSelection>
                                                                       """;
 
     /// <inheritdoc />
-    public override Settings.Provider? ProviderSettings { get; set; }
+    public override Settings.Provider ProviderSettings { get; set; } = Settings.Provider.NONE;
     
     /// <summary>
     /// The data source selection agent does not work with context. Use
@@ -141,6 +141,11 @@ public sealed class AgentDataSourceSelection (ILogger<AgentDataSourceSelection>
 
         // We start with the provider currently selected by the user:
         var agentProvider = this.SettingsManager.GetPreselectedProvider(Tools.Components.AGENT_DATA_SOURCE_SELECTION, provider.Id, true);
+        if (agentProvider == Settings.Provider.NONE)
+        {
+            logger.LogWarning("No provider is selected for the agent. The agent cannot select data sources.");
+            return [];
+        }
 
         // Assign the provider settings to the agent:
         logger.LogInformation($"The agent for the data source selection uses the provider '{agentProvider.InstanceName}' ({agentProvider.UsedLLMProvider.ToName()}, confidence={agentProvider.UsedLLMProvider.GetConfidence(this.SettingsManager).Level.GetName()}).");

app/MindWork AI Studio/Agents/AgentRetrievalContextValidation.cs

@@ -71,7 +71,7 @@ public sealed class AgentRetrievalContextValidation (ILogger<AgentRetrievalConte
                                                                         """;
 
     /// <inheritdoc />
-    public override Settings.Provider? ProviderSettings { get; set; }
+    public override Settings.Provider ProviderSettings { get; set; } = Settings.Provider.NONE;
     
     /// <summary>
     /// The retrieval context validation agent does not work with context. Use
@@ -133,6 +133,11 @@ public sealed class AgentRetrievalContextValidation (ILogger<AgentRetrievalConte
     {
         // We start with the provider currently selected by the user:
         var agentProvider = this.SettingsManager.GetPreselectedProvider(Tools.Components.AGENT_RETRIEVAL_CONTEXT_VALIDATION, provider.Id, true);
+        if (agentProvider == Settings.Provider.NONE)
+        {
+            logger.LogWarning("No provider is selected for the agent.");
+            return;
+        }
         
         // Assign the provider settings to the agent:
         logger.LogInformation($"The agent for the retrieval context validation uses the provider '{agentProvider.InstanceName}' ({agentProvider.UsedLLMProvider.ToName()}, confidence={agentProvider.UsedLLMProvider.GetConfidence(this.SettingsManager).Level.GetName()}).");

app/MindWork AI Studio/Agents/AgentTextContentCleaner.cs

@@ -11,7 +11,7 @@ public sealed class AgentTextContentCleaner(ILogger<AgentBase> logger, SettingsM
     
     #region Overrides of AgentBase
 
-    public override AIStudio.Settings.Provider? ProviderSettings { get; set; }
+    public override AIStudio.Settings.Provider ProviderSettings { get; set; } = AIStudio.Settings.Provider.NONE;
 
     protected override Type Type => Type.SYSTEM;
 

app/MindWork AI Studio/Agents/IAgent.cs

@@ -12,7 +12,7 @@ public interface IAgent
     /// <summary>
     /// The provider to use for this agent.
     /// </summary>
-    public AIStudio.Settings.Provider? ProviderSettings { get; set; }
+    public Settings.Provider ProviderSettings { get; set; }
 
     /// <summary>
     /// Processes a chat thread (i.e., context) and returns the updated thread.

app/MindWork AI Studio/Assistants/AssistantBase.razor.cs

@@ -85,7 +85,7 @@ public abstract partial class AssistantBase<TSettings> : AssistantLowerBase wher
 
     protected virtual IReadOnlyList<IButtonData> FooterButtons => [];
     
-    protected AIStudio.Settings.Provider providerSettings;
+    protected AIStudio.Settings.Provider providerSettings = Settings.Provider.NONE;
     protected MudForm? form;
     protected bool inputIsValid;
     protected Profile currentProfile = Profile.NO_PROFILE;
@@ -352,7 +352,7 @@ public abstract partial class AssistantBase<TSettings> : AssistantLowerBase wher
     private async Task InnerResetForm()
     {
         this.resultingContentBlock = null;
-        this.providerSettings = default;
+        this.providerSettings = Settings.Provider.NONE;
         
         await this.JsRuntime.ClearDiv(RESULT_DIV_ID);
         await this.JsRuntime.ClearDiv(AFTER_RESULT_DIV_ID);

app/MindWork AI Studio/Components/ChatComponent.razor.cs

@@ -20,7 +20,7 @@ public partial class ChatComponent : MSGComponentBase, IAsyncDisposable
     public EventCallback<ChatThread?> ChatThreadChanged { get; set; }
 
     [Parameter]
-    public AIStudio.Settings.Provider Provider { get; set; }
+    public AIStudio.Settings.Provider Provider { get; set; } = AIStudio.Settings.Provider.NONE;
     
     [Parameter]
     public EventCallback<AIStudio.Settings.Provider> ProviderChanged { get; set; }
@@ -634,7 +634,7 @@ public partial class ChatComponent : MSGComponentBase, IAsyncDisposable
             
             default:
             case AddChatProviderBehavior.ADDED_CHATS_USE_LATEST_PROVIDER:
-                if(this.Provider == default)
+                if(this.Provider == AIStudio.Settings.Provider.NONE)
                 {
                     this.Provider = this.SettingsManager.GetPreselectedProvider(Tools.Components.CHAT);
                     await this.ProviderChanged.InvokeAsync(this.Provider);
@@ -797,7 +797,7 @@ public partial class ChatComponent : MSGComponentBase, IAsyncDisposable
                 break;
             
             case LoadingChatProviderBehavior.ALWAYS_USE_LATEST_CHAT_PROVIDER:
-                if(this.Provider == default)
+                if(this.Provider == AIStudio.Settings.Provider.NONE)
                     this.Provider = this.SettingsManager.GetPreselectedProvider(Tools.Components.CHAT);
                 break;
         }

app/MindWork AI Studio/Components/ConfigurationProviderSelection.razor.cs

@@ -42,6 +42,9 @@ public partial class ConfigurationProviderSelection : MSGComponentBase
         foreach (var providerId in this.Data)
         {
             var provider = this.SettingsManager.ConfigurationData.Providers.FirstOrDefault(x => x.Id == providerId.Value);
+            if (provider is null)
+                continue;
+            
             if (provider.UsedLLMProvider.GetConfidence(this.SettingsManager).Level >= minimumLevel)
                 yield return providerId;
         }

app/MindWork AI Studio/Components/ProviderSelection.razor.cs

@@ -13,7 +13,7 @@ public partial class ProviderSelection : MSGComponentBase
     public AssistantBase<NoComponent>? AssistantBase { get; set; }
 
     [Parameter]
-    public AIStudio.Settings.Provider ProviderSettings { get; set; }
+    public AIStudio.Settings.Provider ProviderSettings { get; set; } = AIStudio.Settings.Provider.NONE;
     
     [Parameter]
     public EventCallback<AIStudio.Settings.Provider> ProviderSettingsChanged { get; set; }
@@ -32,6 +32,7 @@ public partial class ProviderSelection : MSGComponentBase
     {
         var minimumLevel = this.SettingsManager.GetMinimumConfidenceLevel(this.AssistantBase?.Component ?? Tools.Components.NONE);
         foreach (var provider in this.SettingsManager.ConfigurationData.Providers)
+            if (provider.UsedLLMProvider != LLMProviders.NONE)
                 if (provider.UsedLLMProvider.GetConfidence(this.SettingsManager).Level >= minimumLevel)
                     yield return provider;
     }

app/MindWork AI Studio/Components/ReadWebContent.razor.cs

@@ -20,7 +20,7 @@ public partial class ReadWebContent : MSGComponentBase
     public EventCallback<string> ContentChanged { get; set; }
     
     [Parameter]
-    public AIStudio.Settings.Provider ProviderSettings { get; set; }
+    public AIStudio.Settings.Provider ProviderSettings { get; set; } = AIStudio.Settings.Provider.NONE;
     
     [Parameter]
     public bool AgentIsRunning { get; set; }
@@ -43,7 +43,7 @@ public partial class ReadWebContent : MSGComponentBase
     private bool urlIsValid;
     private bool isProviderValid;
 
-    private AIStudio.Settings.Provider providerSettings;
+    private AIStudio.Settings.Provider providerSettings = AIStudio.Settings.Provider.NONE;
 
     #region Overrides of ComponentBase
 
@@ -86,7 +86,7 @@ public partial class ReadWebContent : MSGComponentBase
             this.StateHasChanged();
             markdown = this.HTMLParser.ParseToMarkdown(html);
             
-            if (this.useContentCleanerAgent)
+            if (this.useContentCleanerAgent && this.providerSettings != AIStudio.Settings.Provider.NONE)
             {
                 this.AgentTextContentCleaner.ProviderSettings = this.providerSettings;
                 var additionalData = new Dictionary<string, string>
@@ -149,7 +149,7 @@ public partial class ReadWebContent : MSGComponentBase
 
     private string? ValidateProvider(bool shouldUseAgent)
     {
-        if(shouldUseAgent && this.providerSettings == default)
+        if(shouldUseAgent && this.providerSettings == AIStudio.Settings.Provider.NONE)
         {
             this.isProviderValid = false;
             return T("Please select a provider to use the cleanup agent.");

app/MindWork AI Studio/Components/Settings/SettingsPanelProviders.razor.cs

@@ -54,6 +54,9 @@ public partial class SettingsPanelProviders : SettingsPanelBase
     [SuppressMessage("Usage", "MWAIS0001:Direct access to `Providers` is not allowed")]
     private async Task EditLLMProvider(AIStudio.Settings.Provider provider)
     {
+        if(provider == AIStudio.Settings.Provider.NONE)
+            return;
+        
         if (provider.IsEnterpriseConfiguration)
             return;
         

app/MindWork AI Studio/Pages/Chat.razor.cs

@@ -21,7 +21,7 @@ public partial class Chat : MSGComponentBase
     private IDialogService DialogService { get; init; } = null!;
     
     private ChatThread? chatThread;
-    private AIStudio.Settings.Provider providerSettings;
+    private AIStudio.Settings.Provider providerSettings = AIStudio.Settings.Provider.NONE;
     private bool workspaceOverlayVisible;
     private string currentWorkspaceName = string.Empty;
     private Workspaces? workspaces;

app/MindWork AI Studio/Pages/Writer.razor.cs

@@ -18,7 +18,7 @@ public partial class Writer : MSGComponentBase
     private readonly Timer typeTimer = new(TimeSpan.FromMilliseconds(1_500));
     
     private MudTextField<string> textField = null!;
-    private AIStudio.Settings.Provider providerSettings;
+    private AIStudio.Settings.Provider providerSettings = AIStudio.Settings.Provider.NONE;
     private ChatThread? chatThread;
     private bool isStreaming;
     private string userInput = string.Empty;

app/MindWork AI Studio/Settings/Provider.cs

@@ -18,7 +18,7 @@ namespace AIStudio.Settings;
 /// <param name="IsSelfHosted">Whether the provider is self-hosted.</param>
 /// <param name="Hostname">The hostname of the provider. Useful for self-hosted providers.</param>
 /// <param name="Model">The LLM model to use for chat.</param>
-public readonly record struct Provider(
+public record Provider(
     uint Num,
     string Id,
     string InstanceName,
@@ -31,6 +31,21 @@ public readonly record struct Provider(
     Host Host = Host.NONE,
     HFInferenceProvider HFInferenceProvider = HFInferenceProvider.NONE) : ISecretId, IConfigurationObject
 {
+    
+    public static readonly Provider NONE = new();
+
+    public Provider() : this(
+        0,
+        Guid.Empty.ToString(),
+        string.Empty,
+        LLMProviders.NONE,
+        default, 
+        false,
+        false,
+        Guid.Empty)
+    {
+    }
+    
     #region Overrides of ValueType
 
     /// <summary>

app/MindWork AI Studio/Settings/SettingsManager.cs

@@ -215,18 +215,18 @@ public sealed class SettingsManager
             return this.ConfigurationData.Providers[0];
 
         // Is there a current provider with a sufficiently high confidence level?
-        Provider currentProvider = default;
+        var currentProvider = Provider.NONE;
         if (currentProviderId is not null && !string.IsNullOrWhiteSpace(currentProviderId))
         {
             var currentProviderProbe = this.ConfigurationData.Providers.FirstOrDefault(x => x.Id == currentProviderId);
-            if (currentProviderProbe.UsedLLMProvider.GetConfidence(this).Level >= minimumLevel)
+            if (currentProviderProbe is not null && currentProviderProbe.UsedLLMProvider.GetConfidence(this).Level >= minimumLevel)
                 currentProvider = currentProviderProbe;
         }
         
         // Is there a component-preselected provider with a sufficiently high confidence level?
-        Provider preselectedProvider = default;
+        var preselectedProvider = Provider.NONE;
         var preselectedProviderProbe = component.PreselectedProvider(this);
-        if(preselectedProviderProbe != default && preselectedProviderProbe.UsedLLMProvider.GetConfidence(this).Level >= minimumLevel)
+        if(preselectedProviderProbe != Provider.NONE && preselectedProviderProbe.UsedLLMProvider.GetConfidence(this).Level >= minimumLevel)
             preselectedProvider = preselectedProviderProbe;
 
         //
@@ -234,14 +234,14 @@ public sealed class SettingsManager
         //       and the preselected provider is available and has a confidence level
         //       that is high enough.
         //
-        if(usePreselectionBeforeCurrentProvider && preselectedProvider != default)
+        if(usePreselectionBeforeCurrentProvider && preselectedProvider != Provider.NONE)
             return preselectedProvider;
         
         //
         // Case: The current provider is available and has a confidence level that is
         //       high enough.
         //
-        if(currentProvider != default)
+        if(currentProvider != Provider.NONE)
             return currentProvider;
         
         //
@@ -250,11 +250,11 @@ public sealed class SettingsManager
         //       level that is high enough. The preselected provider is available and
         //       has a confidence level that is high enough.
         //
-        if(preselectedProvider != default)
+        if(preselectedProvider != Provider.NONE)
             return preselectedProvider;
 
         // When there is an app-wide preselected provider, and it has a confidence level that is high enough, we return it:
-        return this.ConfigurationData.Providers.FirstOrDefault(x => x.Id == this.ConfigurationData.App.PreselectedProvider && x.UsedLLMProvider.GetConfidence(this).Level >= minimumLevel);
+        return this.ConfigurationData.Providers.FirstOrDefault(x => x.Id == this.ConfigurationData.App.PreselectedProvider && x.UsedLLMProvider.GetConfidence(this).Level >= minimumLevel) ?? Provider.NONE;
     }
 
     public Profile GetPreselectedProfile(Tools.Components component)

app/MindWork AI Studio/Tools/ComponentsExtensions.cs

@@ -113,7 +113,7 @@ public static class ComponentsExtensions
         Components.AGENT_DATA_SOURCE_SELECTION => settingsManager.ConfigurationData.AgentDataSourceSelection.PreselectAgentOptions ? settingsManager.ConfigurationData.Providers.FirstOrDefault(x => x.Id == settingsManager.ConfigurationData.AgentDataSourceSelection.PreselectedAgentProvider) : default,
         Components.AGENT_RETRIEVAL_CONTEXT_VALIDATION => settingsManager.ConfigurationData.AgentRetrievalContextValidation.PreselectAgentOptions ? settingsManager.ConfigurationData.Providers.FirstOrDefault(x => x.Id == settingsManager.ConfigurationData.AgentRetrievalContextValidation.PreselectedAgentProvider) : default,
         
-        _ => default,
+        _ => Settings.Provider.NONE,
     };
 
     public static Profile PreselectedProfile(this Components component, SettingsManager settingsManager) => component switch

app/MindWork AI Studio/Tools/Services/DataSourceService.cs

@@ -37,7 +37,7 @@ public sealed class DataSourceService
         //       does not mean anything. We cannot filter the data sources by any means.
         //       We return an empty list. Better safe than sorry.
         //
-        if (selectedLLMProvider == default)
+        if (selectedLLMProvider == Settings.Provider.NONE)
         {
             this.logger.LogWarning("The selected LLM provider is not set. We cannot filter the data sources by any means.");
             return new([], []);