feat(dashboard): the Connection tile says when the history's size limit cuts it short

docs/features/F1.41-persistent-history.md

@@ -3,7 +3,7 @@
 Status: in progress for 0.8.0 ([#314](https://github.com/APRS-NET/AprsMap/issues/314), maintainer request, 2026-10-27);
 decisions 1–6 by the maintainer, the rest proposed. Built: the store, rotation, the size warning in Settings, the
 settings and the configuration (behaviors 1–6, 12, 13), the restart (7), long tracks and kept packets (8, 9), the
-dashboard's 7 days (10, 11). To come: the Connection tile's note (5).
+dashboard's 7 days (10, 11), the Connection tile's note (5).
 
 ## User story
 
@@ -39,7 +39,8 @@ and how much disk that may take, and I'm told when the disk limit, not the days,
    own limits the same way: **Keep packet history** on or off, **Keep for** 1–30 days, default **7**; **Use at most**
    100–102,400 MB, default **1,024 MB** (decision 2). The gateway's configuration can set both (`[engine.history]
    days = 7`, `max_megabytes = 1024`, `days = 0` for off), and wins on every start, as the configured devices do
-   (#424); Settings then shows them without letting them be changed. Off keeps today's behaviour: memory only, and the history kept so far is deleted after a confirmation.
+   (#424); Settings then shows them without letting them be changed. The file's values are brought into range, as
+   Settings would refuse them. Off keeps today's behaviour: memory only, and the history kept so far is deleted after a confirmation.
 3. **The section says what's kept**: "7 days kept, 412 MB, since 21/10/2026 14:02", and how full the size limit is.
 4. **One file a day** (UTC), `history/2026-10-27.db` in the data folder, so rotating is deleting whole files: no
    rewriting, no pause. Once a minute (with the station sweep) and when the settings change, the engine deletes the days older than **Keep history for**, then

src/AprsMap.Contracts/Dashboard.cs

@@ -74,6 +74,11 @@ public enum DashboardRange
 /// The one source these numbers are for (#454); null for every source. The tiles read from the stations held (farthest
 /// heard, weather, the tables, heard on RF) are every source's either way.
 /// </param>
+/// <param name="History">
+/// What stands in the packet history's way, for the Connection tile (docs/features/F1.41-persistent-history.md, behavior
+/// 5); null when nothing does or no history is kept. Only the size limit's problems, with the days asked for in
+/// <see cref="HistoryStatus.Settings"/> and those that fit in <see cref="HistoryStatus.DaysFit"/>.
+/// </param>
 /// <param name="Comparison">
 /// The sources side by side, for every source's dashboard with two or more (#454); over 7 days, the last 24 hours.
 /// </param>
@@ -107,7 +112,8 @@ public sealed record Dashboard(
     int HeardOnRfTotal = 0,
     TimeSpan? ListsCover = null,
     string? SourceId = null,
-    IReadOnlyList<DashboardSourceRow>? Comparison = null
+    IReadOnlyList<DashboardSourceRow>? Comparison = null,
+    HistoryStatus? History = null
 );
 
 /// <summary>One source against the others over the range (#454).</summary>

src/AprsMap.Core/Engine.DashboardSources.cs

@@ -106,6 +106,7 @@ dashboard with
                 Weather = _stations.WeatherSince(dashboard.Start, include),
                 Tables = _stations.Statistics(include is null ? null : filter, now),
                 Gps = _gpsHistory.Read(dashboard.Start, dashboard.Step, dashboard.Packets.Count, now),
+                History = _history?.SizeProblem(), // F1.41 behavior 5
             }
         );
     }

src/AprsMap.Core/Engine.cs

@@ -2081,6 +2081,7 @@ public async Task<Dashboard> GetDashboardAsync(
             HeardOnRf = heard.Recent, // F3.4 two-way, behavior 7
             HeardOnRfTotal = heard.Total,
             Comparison = CompareSources(range, now), // #454
+            History = _history?.SizeProblem(), // F1.41 behavior 5
         };
     }
 

src/AprsMap.Core/EngineOptions.cs

@@ -183,9 +183,19 @@ public sealed class HistoryOptions
     /// <summary>Whether the configuration sets either.</summary>
     internal bool Configured => Days is not null || MaxMegabytes is not null;
 
-    /// <summary><paramref name="stored"/> with what the configuration sets in place.</summary>
+    /// <summary>
+    /// <paramref name="stored"/> with what the configuration sets in place, brought into range: the file isn't checked
+    /// as Settings is.
+    /// </summary>
     internal HistorySettings Apply(HistorySettings stored) =>
-        new(Days ?? stored.Days, MaxMegabytes ?? stored.MaxMegabytes);
+        new(
+            Math.Clamp(Days ?? stored.Days, 0, HistorySettings.MaxDays),
+            Math.Clamp(
+                MaxMegabytes ?? stored.MaxMegabytes,
+                HistorySettings.MinMegabytes,
+                HistorySettings.MaxMegabytesLimit
+            )
+        );
 }
 
 /// <summary>A first-run gpsd (docs/features/F1.37-gateway-service.md, behavior 4).</summary>

src/AprsMap.Core/PacketHistory.cs

@@ -626,6 +626,25 @@ public async Task MaintainAsync(CancellationToken cancellationToken = default)
         }
     }
 
+    /// <summary>
+    /// The size limit's problem as the last pass found it, without reading the folder: for the dashboard, asked every
+    /// 10 seconds (behavior 5). Null when there's none.
+    /// </summary>
+    public HistoryStatus? SizeProblem()
+    {
+        lock (_lock)
+        {
+            var problem =
+                !_settings.On || _blocked != HistoryProblem.None ? HistoryProblem.None
+                : _fullDay == Day(_time.GetUtcNow()) ? HistoryProblem.TodayFull
+                : _daysFit is not null ? HistoryProblem.SizeLimitShortens
+                : HistoryProblem.None;
+            return problem == HistoryProblem.None
+                ? null
+                : new HistoryStatus(true, _settings, Problem: problem, DaysFit: _daysFit);
+        }
+    }
+
     /// <summary>What the history holds now (behavior 3).</summary>
     public async Task<HistoryStatus> StatusAsync(bool configured, CancellationToken cancellationToken = default)
     {

src/AprsMap.UI/Statistics/DashboardPanel.axaml

@@ -349,6 +349,14 @@
               <TextBlock Classes="title" Text="{l:T Dashboard.Connection}" />
               <ItemsControl ItemsSource="{Binding Connections}" Margin="0,4,0,0" />
               <TextBlock Classes="detail" Text="{Binding ReconnectsText}" Margin="0,4,0,0" />
+              <TextBlock
+                x:Name="HistoryWarning"
+                Text="{Binding HistoryWarning}"
+                IsVisible="{Binding HistoryWarning, Converter={x:Static ObjectConverters.IsNotNull}}"
+                Foreground="{DynamicResource Brush.Warn}"
+                TextWrapping="Wrap"
+                Margin="0,4,0,0"
+              />
             </StackPanel>
           </Border>
 

src/AprsMap.UI/Statistics/DashboardViewModel.cs

@@ -187,6 +187,13 @@ private void ShowScope()
     [ObservableProperty]
     public partial string? ReconnectsText { get; private set; }
 
+    /// <summary>
+    /// That the packet history's size limit is cutting it short, in the Connection tile
+    /// (docs/features/F1.41-persistent-history.md, behavior 5); null otherwise.
+    /// </summary>
+    [ObservableProperty]
+    public partial string? HistoryWarning { get; private set; }
+
     /// <summary>The busiest stations (behavior 4.8), each selectable.</summary>
     public ObservableCollection<CountRow> BusiestStations { get; } = [];
 
@@ -457,6 +464,15 @@ [.. rf.Select((count, i) => dashboard.Packets[i] == 0 ? 0 : 100 * count / dashbo
         ReconnectsText = status is null
             ? null
             : _text.Format("Dashboard.Reconnects", new Dictionary<string, object?> { ["count"] = status.Reconnects });
+        HistoryWarning = dashboard.History switch
+        {
+            { Problem: HistoryProblem.TodayFull } => _text["History.TodayFull"],
+            { Problem: HistoryProblem.SizeLimitShortens } history => _text.Format(
+                "History.SizeLimitShortens",
+                new Dictionary<string, object?> { ["fit"] = history.DaysFit ?? 0, ["wanted"] = history.Settings.Days }
+            ),
+            _ => null,
+        };
 
         ShowExtras(dashboard);
         ShowGps(dashboard, range, Clock);

tests/AprsMap.Core.Tests/PacketHistoryTests.cs

@@ -147,6 +147,7 @@ public async Task WhenTodayAloneReachesTheLimitNothingMoreIsKeptToday()
 
         Assert.Equal(before, (await ReadAll(history)).Count);
         Assert.Equal(HistoryProblem.TodayFull, (await history.StatusAsync(false, Ct)).Problem);
+        Assert.Equal(HistoryProblem.TodayFull, history.SizeProblem()!.Problem); // for the dashboard (behavior 5)
         _time.Advance(TimeSpan.FromDays(1)); // a new day starts again
         history.Record(Record());
         await history.FlushAsync(Ct);
@@ -226,6 +227,16 @@ public async Task TheConfigurationsLengthAndSizeWinAndAreShownAsConfigured()
         Assert.Equal((new HistorySettings(3, 500), true), (status.Settings, status.Configured));
     }
 
+    [Fact]
+    public async Task TheConfigurationsValuesAreBroughtIntoRange()
+    {
+        var options = new HistoryOptions { Days = 90, MaxMegabytes = 1 };
+        await using var history = Store();
+
+        Assert.Equal(new HistorySettings(30, 100), options.Apply(HistorySettings.Default));
+        Assert.Null(history.SizeProblem()); // nothing standing in the way
+    }
+
     [Fact]
     public async Task OutOfRangeSettingsAreRefused()
     {

tests/AprsMap.UI.Tests/DashboardViewModelTests.cs

@@ -73,6 +73,31 @@ public DashboardViewModel Create() =>
             );
     }
 
+    [Fact]
+    public void TheConnectionTileSaysWhenTheHistorysSizeLimitCutsItShort()
+    {
+        // F1.41 behavior 5.
+        var vm = new Harness().Create();
+
+        vm.Show(
+            Sample() with
+            {
+                History = new HistoryStatus(
+                    true,
+                    HistorySettings.Default,
+                    Problem: HistoryProblem.SizeLimitShortens,
+                    DaysFit: 3
+                ),
+            }
+        );
+        Assert.Equal(
+            "The size limit keeps about 3 days of the 7 asked for. Raise it to keep them all.",
+            vm.HistoryWarning
+        );
+        vm.Show(Sample());
+        Assert.Null(vm.HistoryWarning);
+    }
+
     [Fact]
     public async Task WithTwoSourcesOneCanBeShownAndTheyAreCompared()
     {