Locked changes to a chat while an answer is being written (#1058)

app/MindWork AI Studio/Pages/Chat.razor

@@ -32,7 +32,7 @@
     </MudStack>
 
     <CascadingValue Value="Components.CHAT">
-        <ProviderSelection @bind-ProviderSettings="@this.providerSettings"/>
+        <ProviderSelection @bind-ProviderSettings="@this.providerSettings" Disabled="@this.isAnswerBeingWritten"/>
     </CascadingValue>
     @if (this.AreWorkspacesVisible)
     {
@@ -97,6 +97,7 @@
                 <ChatComponent
                     @bind-ChatThread="@this.chatThread"
                     @bind-Provider="@this.providerSettings"
+                    IsAnswerBeingWrittenChanged="@(isBeingWritten => this.isAnswerBeingWritten = isBeingWritten)"
                     ComposerState="@this.composerState"
                     Workspaces="@this.workspaces"
                     WorkspaceName="name => this.UpdateWorkspaceName(name)"/>
@@ -124,6 +125,7 @@
             <ChatComponent
                 @bind-ChatThread="@this.chatThread"
                 @bind-Provider="@this.providerSettings"
+                IsAnswerBeingWrittenChanged="@(isBeingWritten => this.isAnswerBeingWritten = isBeingWritten)"
                 ComposerState="@this.composerState"
                 Workspaces="@this.workspaces"
                 WorkspaceName="name => this.UpdateWorkspaceName(name)"/>
@@ -135,6 +137,7 @@
         <ChatComponent
             @bind-ChatThread="@this.chatThread"
             @bind-Provider="@this.providerSettings"
+            IsAnswerBeingWrittenChanged="@(isBeingWritten => this.isAnswerBeingWritten = isBeingWritten)"
             ComposerState="@this.composerState"
             Workspaces="@this.workspaces"
             WorkspaceName="name => this.UpdateWorkspaceName(name)"/>

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

@@ -22,6 +22,17 @@ public partial class Chat : MSGComponentBase
     
     private ChatThread? chatThread;
     private AIStudio.Settings.Provider providerSettings = AIStudio.Settings.Provider.NONE;
+
+    /// <summary>
+    /// Whether an answer is being written for the open chat, as the chat component last told.
+    /// </summary>
+    /// <remarks>
+    /// The provider selection is locked meanwhile. Another provider would not reach the answer, which
+    /// keeps the one it started with, but the chat would show the other one while the answer is still
+    /// being written.
+    /// </remarks>
+    private bool isAnswerBeingWritten;
+
     private bool workspaceOverlayVisible;
     private bool workspaceSearchVisible;
     private string currentWorkspaceName = string.Empty;