fix(grid): order startup layout

src/OpenIPC.Viewer.App/Services/Localizer.cs

@@ -217,6 +217,9 @@ private static LangCode DetectSystem()
         ["Settings.Appearance"] = "Appearance",
         ["Settings.Appearance.Language"] = "Language",
         ["Settings.Appearance.ShowSplash"] = "Show animated splash screen on launch",
+        ["Settings.Appearance.StartPage"] = "Start page",
+        ["Settings.Appearance.StartupLayout"] = "Layout at startup",
+        ["Settings.Appearance.StartupLayout.LastUsed"] = "Last used",
         ["Settings.Appearance.CloseToTray"] = "Keep running in the tray when the window is closed",
         ["Settings.Video"] = "Video",
         ["Settings.Recording"] = "Recording",
@@ -708,6 +711,9 @@ private static LangCode DetectSystem()
         ["Settings.Appearance"] = "Внешний вид",
         ["Settings.Appearance.Language"] = "Язык",
         ["Settings.Appearance.ShowSplash"] = "Показывать анимированную заставку при запуске",
+        ["Settings.Appearance.StartPage"] = "Стартовая страница",
+        ["Settings.Appearance.StartupLayout"] = "Раскладка при запуске",
+        ["Settings.Appearance.StartupLayout.LastUsed"] = "Последняя открытая",
         ["Settings.Appearance.CloseToTray"] = "При закрытии окна оставаться в трее",
         ["Settings.Video"] = "Видео",
         ["Settings.Recording"] = "Запись",

src/OpenIPC.Viewer.App/Services/UserSettings.cs

@@ -98,7 +98,12 @@ public sealed record UserSettings(
     // Desktop only: refuse to start a second copy of the app — a repeat launch
     // brings the already-running window to the foreground instead (see
     // Desktop/SingleInstanceGuard). Off = any number of copies may run.
-    bool SingleInstance = false)
+    bool SingleInstance = false,
+    // Page shown when the app starts: "library" (default) or "live" (#70).
+    // With "live", StartupLayoutId picks the layout the grid opens on; 0 = the
+    // one that was active when the app was last closed.
+    string StartupPage = "library",
+    int StartupLayoutId = 0)
 {
     public static UserSettings Default => new();
 }

src/OpenIPC.Viewer.App/ViewModels/GridPageViewModel.cs

@@ -43,6 +43,10 @@ public sealed partial class GridPageViewModel : ViewModelBase,
     private IReadOnlyList<Camera> _allCameras = Array.Empty<Camera>();
     private bool _minimized;
     private bool _suppressSettingsRefresh;
+    private bool _startupLayoutApplied;
+    // Serializes tile-order writes: each is a read-modify-write of LayoutTiles,
+    // so two quick drags must not land out of order.
+    private readonly SemaphoreSlim _reorderGate = new(1, 1);
     private CancellationTokenSource? _graceCts;
 
     public string Title => Localizer.Instance["Nav.Live"];
@@ -156,9 +160,30 @@ public async Task LoadAsync(CancellationToken ct)
         if (_minimized) return;
         _allCameras = await _directory.ListAsync(ct).ConfigureAwait(true);
         await LoadLayoutsAsync(ct).ConfigureAwait(true);
+        await ApplyStartupLayoutOnceAsync().ConfigureAwait(true);
         await RefreshTilesAsync(ct).ConfigureAwait(true);
     }
 
+    // Settings → "Start with Live" + a chosen layout (#70): the first grid load
+    // of the session opens that layout instead of the last active one. Once per
+    // session, so switching tabs afterwards sticks. Persisted as the active
+    // layout too, so the library's "in grid" checkboxes follow the same tab.
+    private async Task ApplyStartupLayoutOnceAsync()
+    {
+        if (_startupLayoutApplied) return;
+        _startupLayoutApplied = true;
+
+        var s = _userSettings.Current;
+        if (s.StartupPage != "live" || s.StartupLayoutId == 0) return;
+        var target = Layouts.FirstOrDefault(l => l.Id.Value == s.StartupLayoutId);
+        if (target is null || (ActiveLayout is { } cur && cur.Id == target.Id)) return;
+
+        ActiveLayout = target;
+        LayoutSize = target.GridSize;
+        CurrentPage = 0;
+        await PersistActiveLayoutAsync(target.Id.Value).ConfigureAwait(true);
+    }
+
     private async Task LoadLayoutsAsync(CancellationToken ct)
     {
         var all = await _layouts.GetAllAsync(ct).ConfigureAwait(true);
@@ -473,6 +498,17 @@ private async Task RefreshTilesAsync(CancellationToken ct)
             catch (Exception ex) { _logger.LogWarning(ex, "Failed to activate tile for {Camera}", camera.Name); }
         }
 
+        // Kept tiles hold their old index and new ones were appended, so after a
+        // layout switch the cameras the two layouts share showed in the previous
+        // layout's order (#69). Put Tiles back into the layout's stored order.
+        for (var i = 0; i < visible.Count; i++)
+        {
+            var j = -1;
+            for (var k = i; k < Tiles.Count; k++)
+                if (Tiles[k].Camera.Id == visible[i].Id) { j = k; break; }
+            if (j > i) Tiles.Move(j, i);
+        }
+
         // Slots fills the *visual* grid (always LayoutSize²), padding with
         // nulls when MaxConcurrentGridSessions is below the layout capacity.
         var visualCapacity = LayoutSize * LayoutSize;
@@ -513,9 +549,8 @@ private StreamQuality DesiredQuality(Camera camera) =>
 
     // Drag-reorder hook called from GridPage code-behind. Both indices are in
     // the *Tiles* collection (live cameras only — empty Slots placeholders are
-    // not draggable and can't be drop targets). Persists SortOrder = newIndex
-    // for the affected tiles; cameras outside the grid keep their existing
-    // SortOrder (so library ordering only shifts grid-included rows).
+    // not draggable and can't be drop targets). Persists the new order into the
+    // active layout's LayoutTiles positions; other layouts are untouched.
     public async Task MoveTileAsync(int fromIndex, int toIndex, CancellationToken ct)
     {
         if (fromIndex < 0 || fromIndex >= Tiles.Count) return;
@@ -532,27 +567,35 @@ public async Task MoveTileAsync(int fromIndex, int toIndex, CancellationToken ct
 
         if (ActiveLayout is not { } a) return;
 
+        // Snapshot before the first await: a layout or page switch while the
+        // repository call is pending replaces Tiles, and its cameras must not be
+        // written into this layout.
+        var layoutId = a.Id;
+        var pageIds = Tiles.Select(t => t.Camera.Id).ToList();
+
+        await _reorderGate.WaitAsync(ct).ConfigureAwait(true);
         try
         {
-            // Tiles holds only the current page's visible prefix; reorder within
-            // the full member list (offset by the page) so cameras on other pages
-            // and beyond the session cap keep their place.
-            var offset = CurrentPage * LayoutSize * LayoutSize;
-            var from = offset + fromIndex;
-            var to = offset + toIndex;
-            var full = (await _layouts.GetTilesAsync(a.Id, ct).ConfigureAwait(true)).ToList();
-            if (from < full.Count && to < full.Count)
-            {
-                var moved = full[from];
-                full.RemoveAt(from);
-                full.Insert(to, moved);
-                await _layouts.SetTilesAsync(a.Id, full, ct).ConfigureAwait(true);
-            }
+            // Tiles holds only the current page's visible cameras. Write their new
+            // order back into the positions those same cameras occupy in the full
+            // member list, so cameras on other pages and beyond the session cap
+            // keep their place. Matching by camera id (not by page offset +
+            // index) stays correct when a closed tile has left a gap in Tiles.
+            var full = (await _layouts.GetTilesAsync(layoutId, ct).ConfigureAwait(true)).ToList();
+            var positions = pageIds.Select(id => full.IndexOf(id)).Where(p => p >= 0).OrderBy(p => p).ToList();
+            if (positions.Count != pageIds.Count) return;
+            for (var i = 0; i < positions.Count; i++)
+                full[positions[i]] = pageIds[i];
+            await _layouts.SetTilesAsync(layoutId, full, ct).ConfigureAwait(true);
         }
         catch (Exception ex)
         {
             _logger.LogWarning(ex, "Persisting layout tile order failed");
         }
+        finally
+        {
+            _reorderGate.Release();
+        }
     }
 
     // Close button on a tile's error cell — drop it from the grid for this

src/OpenIPC.Viewer.App/ViewModels/MainWindowViewModel.cs

@@ -77,6 +77,7 @@ public MainWindowViewModel(
         CameraDirectoryService directory,
         SingleCameraPageFactory singleCameraFactory,
         RecordingPlayerPageFactory playerFactory,
+        UserSettingsService userSettings,
         ILogger<MainWindowViewModel> logger)
     {
         Live = live;
@@ -89,7 +90,8 @@ public MainWindowViewModel(
         _singleCameraFactory = singleCameraFactory;
         _playerFactory = playerFactory;
         _logger = logger;
-        _currentPage = library;
+        // Settings → Start page (#70): open straight into the live grid if asked.
+        _currentPage = userSettings.Current.StartupPage == "live" ? live : library;
 
         WeakReferenceMessenger.Default.Register<OpenCameraMessage>(this);
         WeakReferenceMessenger.Default.Register<GoBackToLibraryMessage>(this);

src/OpenIPC.Viewer.App/ViewModels/SettingsPageViewModel.cs

@@ -8,6 +8,7 @@
 using CommunityToolkit.Mvvm.ComponentModel;
 using CommunityToolkit.Mvvm.Input;
 using CommunityToolkit.Mvvm.Messaging;
+using Microsoft.Extensions.Logging;
 using OpenIPC.Viewer.App.Services;
 using OpenIPC.Viewer.Core.Onvif.Discovery;
 using OpenIPC.Viewer.Core.Platform;
@@ -24,6 +25,8 @@ public sealed partial class SettingsPageViewModel : ViewModelBase
     private readonly OpenIPC.Viewer.Core.Persistence.IConfigBackupService _backup;
     private readonly ConfigSyncService _configSync;
     private readonly OpenIPC.Viewer.Core.Notifications.INotificationService _notifications;
+    private readonly OpenIPC.Viewer.Core.Persistence.ILayoutRepository _layouts;
+    private readonly ILogger<SettingsPageViewModel> _logger;
     private bool _suppressSave;
 
     public string Title => Localizer.Instance["Settings.Title"];
@@ -48,6 +51,17 @@ public sealed partial class SettingsPageViewModel : ViewModelBase
     [ObservableProperty] private bool _closeToTray;
     [ObservableProperty] private bool _singleInstance;
 
+    // Start page + the layout the live grid opens on (#70). The layout list is
+    // filled async from the repository (LoadStartupLayoutsAsync); option 0 is
+    // "last used".
+    [ObservableProperty]
+    [NotifyPropertyChangedFor(nameof(IsStartupLayoutVisible))]
+    private StartPageOption? _startPage;
+    [ObservableProperty] private StartupLayoutOption? _startupLayout;
+    public IReadOnlyList<StartPageOption> StartPageOptions { get; }
+    public System.Collections.ObjectModel.ObservableCollection<StartupLayoutOption> StartupLayoutOptions { get; } = new();
+    public bool IsStartupLayoutVisible => StartPage?.Value == "live";
+
     // Gates the desktop-only toggles (tray) off the shared settings page.
     public bool IsDesktopPlatform { get; } =
         !OperatingSystem.IsAndroid() && !OperatingSystem.IsIOS();
@@ -163,7 +177,9 @@ public SettingsPageViewModel(
         ISshHostKeyStore hostKeys,
         OpenIPC.Viewer.Core.Persistence.IConfigBackupService backup,
         ConfigSyncService configSync,
-        OpenIPC.Viewer.Core.Notifications.INotificationService notifications)
+        OpenIPC.Viewer.Core.Notifications.INotificationService notifications,
+        OpenIPC.Viewer.Core.Persistence.ILayoutRepository layouts,
+        ILogger<SettingsPageViewModel> logger)
     {
         _settings = settings;
         _fs = fs;
@@ -172,6 +188,8 @@ public SettingsPageViewModel(
         _backup = backup;
         _configSync = configSync;
         _notifications = notifications;
+        _layouts = layouts;
+        _logger = logger;
 
         var options = new List<NetworkInterfaceOption>
         {
@@ -188,6 +206,13 @@ public SettingsPageViewModel(
                 m))
             .ToList();
 
+        StartPageOptions = new[]
+        {
+            new StartPageOption(Localizer.Instance["Nav.Library"], "library"),
+            new StartPageOption(Localizer.Instance["Nav.Live"], "live"),
+        };
+        StartupLayoutOptions.Add(new StartupLayoutOption(Localizer.Instance["Settings.Appearance.StartupLayout.LastUsed"], 0));
+
         Load();
     }
 
@@ -218,6 +243,8 @@ private void Load()
             ShowSplash = s.ShowSplash;
             CloseToTray = s.CloseToTray;
             SingleInstance = s.SingleInstance;
+            StartPage = StartPageOptions.FirstOrDefault(o => o.Value == s.StartupPage) ?? StartPageOptions[0];
+            StartupLayout = StartupLayoutOptions.FirstOrDefault(o => o.Id == s.StartupLayoutId);
             SshStrictHostKey = s.SshStrictHostKey;
             SshDefaultPort = s.SshDefaultPort;
             SshTerminalFontSize = s.SshTerminalFontSize;
@@ -251,6 +278,8 @@ private void Load()
     partial void OnShowSplashChanged(bool value) => Persist();
     partial void OnCloseToTrayChanged(bool value) => Persist();
     partial void OnSingleInstanceChanged(bool value) => Persist();
+    partial void OnStartPageChanged(StartPageOption? value) => Persist();
+    partial void OnStartupLayoutChanged(StartupLayoutOption? value) => Persist();
     partial void OnSshStrictHostKeyChanged(bool value) => Persist();
     partial void OnSshDefaultPortChanged(int value) => Persist();
     partial void OnSshTerminalFontSizeChanged(int value) => Persist();
@@ -283,6 +312,9 @@ private void Persist()
             ShowSplash = ShowSplash,
             CloseToTray = CloseToTray,
             SingleInstance = SingleInstance,
+            StartupPage = StartPage?.Value ?? "library",
+            // Null until the layout list has loaded — keep the saved choice.
+            StartupLayoutId = StartupLayout?.Id ?? _settings.Current.StartupLayoutId,
             SshStrictHostKey = SshStrictHostKey,
             SshDefaultPort = SshDefaultPort,
             SshTerminalFontSize = SshTerminalFontSize,
@@ -303,6 +335,33 @@ private void Persist()
         _ = _settings.UpdateAsync(next, CancellationToken.None);
     }
 
+    // Layouts can be added/renamed on the Live page at any time, so the picker
+    // is rebuilt each time the settings page is shown.
+    public async Task LoadStartupLayoutsAsync()
+    {
+        IReadOnlyList<OpenIPC.Viewer.Core.Entities.GridLayout> all;
+        try { all = await _layouts.GetAllAsync(CancellationToken.None).ConfigureAwait(true); }
+        catch (Exception ex)
+        {
+            // Keep the "last used" fallback so the page still works.
+            _logger.LogWarning(ex, "Loading layouts for the startup-layout picker failed");
+            return;
+        }
+
+        _suppressSave = true;
+        try
+        {
+            StartupLayoutOptions.Clear();
+            StartupLayoutOptions.Add(new StartupLayoutOption(Localizer.Instance["Settings.Appearance.StartupLayout.LastUsed"], 0));
+            foreach (var l in all)
+                StartupLayoutOptions.Add(new StartupLayoutOption(l.Name, l.Id.Value));
+            // A deleted layout falls back to "last used" (the grid ignores a stale id too).
+            var id = _settings.Current.StartupLayoutId;
+            StartupLayout = StartupLayoutOptions.FirstOrDefault(o => o.Id == id) ?? StartupLayoutOptions[0];
+        }
+        finally { _suppressSave = false; }
+    }
+
     [RelayCommand]
     private async Task ResetHostKeysAsync()
     {
@@ -502,3 +561,8 @@ public sealed record NetworkInterfaceOption(string Display, string Value);
 // Combo item for Settings → Video idle-pause picker. Display is the localized
 // label ("Off" / "10 min"); Minutes is the persisted threshold (0 = off).
 public sealed record IdleTimeoutOption(string Display, int Minutes);
+
+// Combo items for Settings → Appearance start page / startup layout (#70).
+// Value is the persisted UserSettings.StartupPage; Id is the LayoutId (0 = last used).
+public sealed record StartPageOption(string Display, string Value);
+public sealed record StartupLayoutOption(string Display, int Id);

src/OpenIPC.Viewer.App/Views/Pages/SettingsPage.axaml

@@ -232,6 +232,26 @@
             </ComboBox>
           </Grid>
 
+          <Grid ColumnDefinitions="*,Auto">
+            <TextBlock Grid.Column="0" Classes="field-label"
+                       Text="{Binding [Settings.Appearance.StartPage], Source={x:Static svc:Localizer.Instance}}" />
+            <ComboBox Grid.Column="1"
+                      ItemsSource="{Binding StartPageOptions}"
+                      SelectedItem="{Binding StartPage, Mode=TwoWay}"
+                      DisplayMemberBinding="{Binding Display}"
+                      MinWidth="140" />
+          </Grid>
+
+          <Grid ColumnDefinitions="*,Auto" IsVisible="{Binding IsStartupLayoutVisible}">
+            <TextBlock Grid.Column="0" Classes="field-label"
+                       Text="{Binding [Settings.Appearance.StartupLayout], Source={x:Static svc:Localizer.Instance}}" />
+            <ComboBox Grid.Column="1"
+                      ItemsSource="{Binding StartupLayoutOptions}"
+                      SelectedItem="{Binding StartupLayout, Mode=TwoWay}"
+                      DisplayMemberBinding="{Binding Display}"
+                      MinWidth="140" />
+          </Grid>
+
           <CheckBox IsChecked="{Binding ShowSplash}"
                     Content="{Binding [Settings.Appearance.ShowSplash], Source={x:Static svc:Localizer.Instance}}"
                     Foreground="{StaticResource TextPrimaryBrush}" />

src/OpenIPC.Viewer.App/Views/Pages/SettingsPage.axaml.cs

@@ -21,7 +21,12 @@ public SettingsPage()
     {
         InitializeComponent();
         DataContextChanged += OnDataContextChanged;
-        AttachedToVisualTree += (_, _) => ApplyLayout();
+        AttachedToVisualTree += (_, _) =>
+        {
+            ApplyLayout();
+            // Layouts may have changed on the Live page since the last visit.
+            if (_vm is not null) _ = _vm.LoadStartupLayoutsAsync();
+        };
         SizeChanged += OnSizeChanged;
     }
 
@@ -35,6 +40,7 @@ private void OnDataContextChanged(object? sender, EventArgs e)
             // Hydrate the credential-sync passphrase from the secrets store (async,
             // can't run in the VM's synchronous Load()).
             _ = _vm.LoadConfigSyncSecretAsync();
+            _ = _vm.LoadStartupLayoutsAsync();
             ApplyLayout();
         }
     }