Add filter, virtualization, and export UI to DebugLogModal and unify file save

src/EventLogExpert.Components.Tests/TestUtils/Constants/Constants.DebugLog.cs

@@ -0,0 +1,15 @@
+// // Copyright (c) Microsoft Corporation.
+// // Licensed under the MIT License.
+
+namespace EventLogExpert.Components.Tests.TestUtils.Constants;
+
+public sealed partial class Constants
+{
+    public const string DebugLogErrorMessage = "Error message";
+    public const string DebugLogFirstMessage = "First message";
+    public const string DebugLogSecondMessage = "Second message";
+    public const string DebugLogTestMessage = "Test message";
+    public const int DebugLogTestThreadId = 12;
+    public const string DebugLogTestTimestamp = "2026-04-29T07:53:20.9321852-04:00";
+    public const string DebugLogThirdMessage = "Third message";
+}

src/EventLogExpert.Components.Tests/TestUtils/DebugLogUtils.cs

@@ -0,0 +1,34 @@
+// // Copyright (c) Microsoft Corporation.
+// // Licensed under the MIT License.
+
+using Microsoft.Extensions.Logging;
+
+namespace EventLogExpert.Components.Tests.TestUtils;
+
+public static class DebugLogUtils
+{
+    public static string BuildLine(LogLevel level, string message) =>
+        $"[{Constants.Constants.DebugLogTestTimestamp}] [{Constants.Constants.DebugLogTestThreadId}] [{level}] {message}";
+
+    public static async IAsyncEnumerable<string> ToAsyncEnumerable(IEnumerable<string> lines)
+    {
+        foreach (var line in lines)
+        {
+            yield return line;
+
+            await Task.Yield();
+        }
+    }
+
+    public static async IAsyncEnumerable<string> YieldThenThrow(IEnumerable<string> lines, Exception exception)
+    {
+        foreach (var line in lines)
+        {
+            yield return line;
+
+            await Task.Yield();
+        }
+
+        throw exception;
+    }
+}

src/EventLogExpert.Components/Filters/FilterCategoryEditor.razor

@@ -27,6 +27,7 @@
 else if (Data.Evaluator == FilterEvaluator.MultiSelect)
 {
     <ValueSelect AriaLabelledBy="@($"{Id}_Value")" CssClass="input filter-multiselect-dropdown" T="string" @bind-Values="Data.Values" IsMultiSelect
+        EmptyText="All"
         ToStringFunc="@(x => string.IsNullOrWhiteSpace(x) ? "All" : x)">
         <ValueSelectItem T="string" ClearItem>All</ValueSelectItem>
         @foreach (var item in Items)

src/EventLogExpert.Components/Inputs/ValueSelect.razor.cs

@@ -45,6 +45,14 @@ public ValueSelectItem<T>? HighlightedItem
     [Parameter]
     public bool IsMultiSelect { get; set; }
 
+    /// <summary>
+    /// Text shown by a multi-select <see cref="ValueSelect{T}"/> when no values are selected.
+    /// Defaults to "Empty"; consumers should override with a domain-appropriate label such as
+    /// "All" when an empty selection means "no filter applied".
+    /// </summary>
+    [Parameter]
+    public string EmptyText { get; set; } = "Empty";
+
     private string? DisplayString
     {
         get
@@ -56,7 +64,7 @@ private string? DisplayString
                 return converter is null ? $"{Value}" : converter.Set(Value);
             }
 
-            if (Values.Count <= 0) { return "Empty"; }
+            if (Values.Count <= 0) { return EmptyText; }
 
             return converter is null ?
                 string.Join(", ", Values.Select(x => $"{x}")) :
@@ -105,6 +113,8 @@ public async ValueTask DisposeAsync()
         }
     }
 
+    public bool HasAnySelection => _selectedValues.Count > 0;
+
     public bool IsItemSelected(T value) => _selectedValues.Contains(value);
 
     public async Task OpenDropDown() => await JSRuntime.InvokeVoidAsync("openDropdown", _selectComponent);

src/EventLogExpert.Components/Inputs/ValueSelectItem.razor.cs

@@ -41,7 +41,7 @@ private string? DisplayString
 
     private bool IsHighlighted => _parent.HighlightedItem?.Equals(this) ?? false;
 
-    private bool IsSelected => _parent.IsItemSelected(Value);
+    private bool IsSelected => ClearItem ? !_parent.HasAnySelection : _parent.IsItemSelected(Value);
 
     [CascadingParameter]
     private ValueSelect<T> ValueSelect

src/EventLogExpert.Components/Modals/DebugLogModal.razor

@@ -1,35 +1,107 @@
 @inherits ModalBase<bool>
+@using EventLogExpert.UI
+@using Microsoft.Extensions.Logging
 
 <ModalChrome AriaLabel="Debug Log"
     CloseLabel="Exit"
     Footer="FooterPreset.CloseOnly"
     Height="60%"
     InlineAlert="@CurrentInlineAlert"
-    MinWidth="50rem"
+    MaxWidth="100rem"
+    MinWidth="100rem"
     OnClose="OnCancelAsync"
     OnDialogClosedByUser="HandleDialogClosedByUserAsync"
     OnInlineAlertResolved="HandleInlineAlertResolvedAsync"
     @ref="ChromeRef">
     <ChildContent>
-        <div aria-busy="@(_hasLoaded ? "false" : "true")" aria-label="Debug log entries" aria-live="polite" class="flex-column-scroll" role="log">
-            @if (_data.Count > 0)
+        <div aria-label="Filters" class="debug-log-filter-bar" role="group">
+            <label>Level</label>
+            <ValueSelect AriaLabel="Level operator"
+                CssClass="input filter-dropdown"
+                T="FilterEvaluator"
+                Value="_levelOperator"
+                ValueChanged="HandleLevelOperatorChanged"
+                ToStringFunc="@(x => x.ToFullString())">
+                <ValueSelectItem T="FilterEvaluator" Value="FilterEvaluator.Equals" />
+                <ValueSelectItem T="FilterEvaluator" Value="FilterEvaluator.NotEqual" />
+                <ValueSelectItem T="FilterEvaluator" Value="FilterEvaluator.MultiSelect" />
+            </ValueSelect>
+            @if (_levelOperator == FilterEvaluator.MultiSelect)
             {
-                @for (var i = _data.Count - 1; i >= 0; i--)
-                {
-                    <text>@_data[i]</text>
-                    <br />
-                }
+                <ValueSelect AriaLabel="Levels"
+                    CssClass="input filter-dropdown debug-log-level-multi"
+                    EmptyText="All"
+                    IsMultiSelect
+                    T="LogLevel"
+                    Values="_multiLevels"
+                    ValuesChanged="HandleMultiLevelsChanged"
+                    ToStringFunc="@(x => x.ToString())">
+                    <ValueSelectItem T="LogLevel" ClearItem>All</ValueSelectItem>
+                    @foreach (var level in s_logLevels)
+                    {
+                        <ValueSelectItem T="LogLevel" Value="level" />
+                    }
+                </ValueSelect>
             }
-            else if (_hasLoaded)
+            else
             {
-                <text>Log is Empty...</text>
+                <ValueSelect AriaLabel="Level"
+                    CssClass="input filter-dropdown"
+                    T="LogLevel?"
+                    Value="_singleLevel"
+                    ValueChanged="HandleSingleLevelChanged"
+                    ToStringFunc="@(x => x?.ToString() ?? "All")">
+                    <ValueSelectItem T="LogLevel?" ClearItem>All</ValueSelectItem>
+                    @foreach (var level in s_logLevels)
+                    {
+                        <ValueSelectItem T="LogLevel?" Value="level" />
+                    }
+                </ValueSelect>
             }
+            <input aria-label="Filter messages"
+                class="input debug-log-text-filter"
+                @oninput="HandleStringFilterInput"
+                placeholder="Filter messages..."
+                type="text"
+                value="@_pendingStringFilter" />
+        </div>
+        <div aria-busy="@(_hasLoaded ? "false" : "true")" aria-label="Debug log entries" class="debug-log-viewport" role="region" tabindex="0">
+            <Virtualize Items="_displayedView" Context="line" ItemSize="@RowHeightPx" OverscanCount="20">
+                <ItemContent>
+                    <div class="debug-log-row">@line</div>
+                </ItemContent>
+                <EmptyContent>
+                    @if (_hasLoaded)
+                    {
+                        <span>@(_entries.Count == 0 ? "Log is Empty..." : "No entries match filters.")</span>
+                    }
+                </EmptyContent>
+            </Virtualize>
         </div>
     </ChildContent>
     <ExtraFooterContent>
-        <div class="button-group">
-            <button class="button" @onclick="Refresh" type="button">Refresh</button>
-            <button class="button" @onclick="Clear" type="button">Clear</button>
+        <div class="debug-log-footer">
+            <div class="debug-log-footer-actions debug-log-footer-left">
+                <button class="button"
+                    disabled="@(!_hasLoaded || _filteredEntryCount == 0)"
+                    @onclick="HandleExportAsync"
+                    type="button">
+                    Export
+                </button>
+                <button class="button"
+                    disabled="@(!_hasLoaded || _filteredEntryCount == 0)"
+                    @onclick="HandleCopyAsync"
+                    type="button">
+                    Copy
+                </button>
+            </div>
+            <span aria-atomic="true" aria-live="polite" class="debug-log-footer-counter" role="status">
+                @($"{_filteredEntryCount:N0} of {_entries.Count:N0} {(_entries.Count == 1 ? "entry" : "entries")}")
+            </span>
+            <div class="debug-log-footer-actions debug-log-footer-right">
+                <button class="button" @onclick="Refresh" type="button">Refresh</button>
+                <button class="button" @onclick="Clear" type="button">Clear</button>
+            </div>
         </div>
     </ExtraFooterContent>
 </ModalChrome>