Desktop: stop the status bar's session timer when the shell ends

src/DodoSSH.Client.Shell/ViewModels/MainWindowViewModel.cs

@@ -4518,7 +4518,7 @@ internal sealed partial class MainWindowViewModel : ObservableObject, IAsyncDisp
     {
         if (Tabs.FirstOrDefault(tab => tab.SessionId == e.SessionId) is { } tab)
         {
-            tab.Ended(e.Outcome.End, e.Outcome.Description);
+            tab.Ended(e.Outcome.End, e.Outcome.Description, clock.GetUtcNow());
 
             // Only for the tab being looked at, which is what these three already ask. The rectangle does not
             // change — a dead tab keeps its pane and its scrollback — but the status bar under it does, and
@@ -4998,7 +4998,12 @@ internal sealed partial class MainWindowViewModel : ObservableObject, IAsyncDisp
                 return null;
             }
 
-            var elapsed = clock.GetUtcNow() - started;
+            // Up to the end, for a shell that has one: how long it ran, not how long ago it started.
+            var until = Surface is ShellSurface.Terminal && SelectedTab?.EndedAt is { } ended
+                ? ended
+                : clock.GetUtcNow();
+
+            var elapsed = until - started;
 
             if (elapsed < TimeSpan.Zero)
             {

src/DodoSSH.Client.Shell/ViewModels/TerminalTabViewModel.cs

@@ -274,6 +274,15 @@ internal sealed partial class TerminalTabViewModel : ObservableObject
     /// </remarks>
     internal DateTimeOffset? StartedAt { get; set; }
 
+    /// <summary>When the session behind this tab ended, or null while it has not.</summary>
+    /// <remarks>
+    /// What stops the status bar's timer. It used to go on counting from <see cref="StartedAt"/> to now over a
+    /// shell that had exited an hour earlier, which made "how long that shell ran" — the fact the remark above
+    /// keeps <see cref="StartedAt"/> for — the one thing it no longer said. Stamped by <see cref="Ended"/> from
+    /// the shell's clock, and cleared whenever a new session takes the tab.
+    /// </remarks>
+    internal DateTimeOffset? EndedAt { get; private set; }
+
     /// <summary>
     /// The negotiated server-to-client cipher, for the status bar — or null while there is no session.
     /// </summary>
@@ -620,6 +629,7 @@ internal sealed partial class TerminalTabViewModel : ObservableObject
         // stale-fact failure this pair exists to remove.
         EndReason = null;
         EndDescription = null;
+        EndedAt = null;
 
         IsLive = true;
         State = TerminalTabState.Open;
@@ -679,13 +689,14 @@ internal sealed partial class TerminalTabViewModel : ObservableObject
     /// live attempt dead. <see cref="Advance"/> guards its own reports for the same reason.
     /// </para>
     /// </remarks>
-    internal void Ended(SshSessionEnd end, string description)
+    internal void Ended(SshSessionEnd end, string description, DateTimeOffset at)
     {
         if (State is not TerminalTabState.Open)
         {
             return;
         }
 
+        EndedAt ??= at;
         EndReason = end;
         EndDescription = description;
         IsLive = false;
@@ -733,6 +744,7 @@ internal sealed partial class TerminalTabViewModel : ObservableObject
         // Cleared with the session they were facts about. Keeping them would put the previous connection's
         // cipher in the status bar beside a handshake that has not negotiated one yet.
         StartedAt = null;
+        EndedAt = null;
         Cipher = null;
         HostKeyAlgorithm = null;
         IdentityLabel = null;

tests/DodoSSH.Client.App.Tests/ShellFlowTests.cs

@@ -2075,6 +2075,15 @@ public sealed partial class ShellFlowTests : IAsyncLifetime
         // Still worth offering, because the tab and the machine are both still there — what it is not is an
         // alarm.
         shell.CanReconnectSelectedTab.ShouldBeTrue();
+
+        // And the timer stopped with it: how long that shell ran, rather than how long ago it started. The
+        // shell's clock here is the system's, so the second has to actually pass for the two to differ.
+        await Task.Delay(TimeSpan.FromSeconds(1.2), Token);
+
+        var ran = tab.EndedAt.ShouldNotBeNull() - tab.StartedAt.ShouldNotBeNull();
+
+        shell.SessionElapsedText.ShouldBe(string.Create(
+            CultureInfo.InvariantCulture, $"session {(int)ran.TotalHours:00}:{ran.Minutes:00}:{ran.Seconds:00}"));
     }
 
     /// <remarks>