yep

Shogi.UI/Pages/Home/PromotePrompt.cs

@@ -0,0 +1,58 @@
+using Shogi.Contracts.Api;
+using Shogi.UI.Pages.Home.Api;
+
+namespace Shogi.UI.Pages.Home;
+
+public class PromotePrompt
+{
+  private readonly IShogiApi shogiApi;
+  private string? sessionName;
+  private MovePieceCommand? command;
+
+  public PromotePrompt(IShogiApi shogiApi)
+  {
+    this.shogiApi = shogiApi;
+    IsVisible = false;
+    OnClickCancel = Hide;
+  }
+
+  public bool IsVisible { get; private set; }
+  public Action OnClickCancel;
+  public Func<Task>? OnClickNo;
+  public Func<Task>? OnClickYes;
+
+  public void Show(string sessionName, MovePieceCommand command)
+  {
+    this.sessionName = sessionName;
+    this.command = command;
+    IsVisible = true;
+    OnClickNo = Move;
+    OnClickYes = MoveAndPromote;
+  }
+
+  public void Hide()
+  {
+    IsVisible = false;
+    OnClickNo = null;
+    OnClickYes = null;
+  }
+
+  private Task Move()
+  {
+    if (command != null && sessionName != null)
+    {
+      command.IsPromotion = false;
+      return shogiApi.PostMove(sessionName, command);
+    }
+    return Task.CompletedTask;
+  }
+  private Task MoveAndPromote()
+  {
+    if (command != null && sessionName != null)
+    {
+      command.IsPromotion = true;
+      return shogiApi.PostMove(sessionName, command);
+    }
+    return Task.CompletedTask;
+  }
+}