Extract hosts file filter into GroupedSelectDropdown and builder

Add shared Models.Ui grouped-select model, IGroupedSelectBuilder, optional
trigger summary API, and GroupedSelectDropdown component. Hosts page uses
HostsFileFilterBuilder and hosts-specific option row styling for full paths.

Remove HostsSourcePathDisplay and file filter menu records in favor of the
builder. Bump version to 0.0.8.

src/DnsmasqWebUI.Tests/Models/Hosts/HostsFileFilterBuilderTests.cs

@@ -0,0 +1,111 @@
+using DnsmasqWebUI.Models.Hosts;
+using DnsmasqWebUI.Models.Ui;
+
+namespace DnsmasqWebUI.Tests.Models.Hosts;
+
+public sealed class HostsFileFilterBuilderTests
+{
+    private static HostsPageRow Row(HostsRowSourceKind kind, string path, bool isComment = false) =>
+        new(
+            Id: "id",
+            SourceKind: kind,
+            SourcePath: path,
+            IsEditable: false,
+            IsActive: true,
+            InactiveReason: null,
+            Address: "127.0.0.1",
+            Names: [],
+            EffectiveNames: [],
+            IsComment: isComment,
+            LineNumber: 1);
+
+    [Fact]
+    public void Build_InjectsManagedPath_WhenNotInRows()
+    {
+        var managed = "/data/managed.hosts";
+        var builder = new HostsFileFilterBuilder([], managed);
+        var model = builder.Build();
+
+        Assert.NotNull(model.AllOption);
+        var managedSection = model.Sections.Single();
+        Assert.Equal("Managed hosts", managedSection.Label);
+        Assert.Equal("managed", managedSection.Kind);
+        Assert.Single(managedSection.Options);
+        Assert.Equal(managed, managedSection.Options[0].Value);
+        Assert.Equal(0, managedSection.Options[0].Count);
+    }
+
+    [Fact]
+    public void Build_OrdersGroupsManagedSystemAddn_AndCountsNonComments()
+    {
+        var rows = new[]
+        {
+            Row(HostsRowSourceKind.SystemHosts, "/etc/hosts"),
+            Row(HostsRowSourceKind.Managed, "/m/a.hosts"),
+            Row(HostsRowSourceKind.Managed, "/m/a.hosts", isComment: true),
+            Row(HostsRowSourceKind.AddnHosts, "/extra/b.hosts"),
+        };
+
+        var builder = new HostsFileFilterBuilder(rows, managedHostsPath: null);
+        var model = builder.Build();
+
+        Assert.Equal(3, model.Sections.Count);
+        Assert.Equal("managed", model.Sections[0].Kind);
+        Assert.Equal("system", model.Sections[1].Kind);
+        Assert.Equal("addn", model.Sections[2].Kind);
+
+        Assert.Single(model.Sections[0].Options);
+        Assert.Equal(1, model.Sections[0].Options[0].Count);
+    }
+
+    [Fact]
+    public void GetSummaryText_AllFiles_ShowsRecordCount()
+    {
+        var rows = new[] { Row(HostsRowSourceKind.Managed, "/m/x.hosts") };
+        var builder = new HostsFileFilterBuilder(rows, null);
+        Assert.Equal("All files · 1 records", builder.GetSummaryText(""));
+        Assert.Equal("All files · 1 records", builder.GetSummaryText("   "));
+    }
+
+    [Fact]
+    public void GetSummaryText_SelectedFile_UsesShortLabelAndPrefix()
+    {
+        var rows = new[] { Row(HostsRowSourceKind.Managed, "/m/my.hosts") };
+        var builder = new HostsFileFilterBuilder(rows, null);
+        Assert.Equal("Managed · my.hosts (1)", builder.GetSummaryText("/m/my.hosts"));
+    }
+
+    [Fact]
+    public void GetSummaryText_UnknownPath_FallsBackToShortLabel()
+    {
+        var builder = new HostsFileFilterBuilder([], null);
+        Assert.Equal("orphan.txt", builder.GetSummaryText("/tmp/orphan.txt"));
+    }
+
+    [Fact]
+    public void GetTriggerSummary_SingleSource_SplitsPrefixPrimaryAndCount()
+    {
+        var rows = new[] { Row(HostsRowSourceKind.AddnHosts, "/etc/extra.d/hosts") };
+        var builder = new HostsFileFilterBuilder(rows, null);
+        var s = builder.GetTriggerSummary("/etc/extra.d/hosts");
+
+        Assert.Equal(GroupedSelectTriggerSummaryKind.SingleSource, s.Kind);
+        Assert.Equal("Additional", s.CategoryPrefix);
+        Assert.Equal("hosts", s.PrimaryLabel);
+        Assert.Equal("1", s.SecondaryMeta);
+        Assert.Equal("Additional · hosts (1)", s.AccessibleFullText);
+    }
+
+    [Fact]
+    public void GetTriggerSummary_AllSources_WithRecords_HasSecondaryMeta()
+    {
+        var rows = new[] { Row(HostsRowSourceKind.Managed, "/m/x.hosts") };
+        var builder = new HostsFileFilterBuilder(rows, null);
+        var s = builder.GetTriggerSummary("");
+
+        Assert.Equal(GroupedSelectTriggerSummaryKind.AllSources, s.Kind);
+        Assert.Null(s.CategoryPrefix);
+        Assert.Equal("All files", s.PrimaryLabel);
+        Assert.Equal("1 records", s.SecondaryMeta);
+    }
+}

src/DnsmasqWebUI.Tests/Models/Hosts/HostsSourcePathDisplayTests.cs

@@ -1,55 +0,0 @@
-using DnsmasqWebUI.Models.Hosts;
-
-namespace DnsmasqWebUI.Tests.Models.Hosts;
-
-public sealed class HostsSourcePathDisplayTests
-{
-    private static HostsPageRow Row(HostsRowSourceKind kind, string path, bool isComment = false) =>
-        new(
-            Id: "id",
-            SourceKind: kind,
-            SourcePath: path,
-            IsEditable: false,
-            IsActive: true,
-            InactiveReason: null,
-            Address: "127.0.0.1",
-            Names: [],
-            EffectiveNames: [],
-            IsComment: isComment,
-            LineNumber: 1);
-
-    [Fact]
-    public void BuildFileFilterMenuGroups_InjectsManagedPath_WhenNotInRows()
-    {
-        var managed = "/data/managed.hosts";
-        var groups = HostsSourcePathDisplay.BuildFileFilterMenuGroups([], managed);
-
-        Assert.Single(groups);
-        Assert.Equal(HostsRowSourceKind.Managed, groups[0].SourceKind);
-        Assert.Single(groups[0].Files);
-        Assert.Equal(managed, groups[0].Files[0].Path);
-        Assert.Equal(0, groups[0].Files[0].RecordCount);
-    }
-
-    [Fact]
-    public void BuildFileFilterMenuGroups_OrdersGroupsManagedSystemAddn_AndCountsNonComments()
-    {
-        var rows = new[]
-        {
-            Row(HostsRowSourceKind.SystemHosts, "/etc/hosts"),
-            Row(HostsRowSourceKind.Managed, "/m/a.hosts"),
-            Row(HostsRowSourceKind.Managed, "/m/a.hosts", isComment: true),
-            Row(HostsRowSourceKind.AddnHosts, "/extra/b.hosts"),
-        };
-
-        var groups = HostsSourcePathDisplay.BuildFileFilterMenuGroups(rows, managedHostsPathAlwaysShow: null);
-
-        Assert.Equal(3, groups.Count);
-        Assert.Equal(HostsRowSourceKind.Managed, groups[0].SourceKind);
-        Assert.Equal(HostsRowSourceKind.SystemHosts, groups[1].SourceKind);
-        Assert.Equal(HostsRowSourceKind.AddnHosts, groups[2].SourceKind);
-
-        Assert.Single(groups[0].Files);
-        Assert.Equal(1, groups[0].Files[0].RecordCount);
-    }
-}

src/DnsmasqWebUI/Components/Pages/Hosts.razor

@@ -5,6 +5,7 @@
 @using DnsmasqWebUI.Models.Dnsmasq.EffectiveConfig
 @using DnsmasqWebUI.Models.Dnsmasq.PageStates
 @using DnsmasqWebUI.Models.Hosts
+@using DnsmasqWebUI.Models.Ui
 @using DnsmasqWebUI.Infrastructure.Services.EffectiveConfig.Abstractions
 @using DnsmasqWebUI.Infrastructure.Services.Dnsmasq.Hosts.Abstractions
 @using DnsmasqWebUI.Infrastructure.Serialization.Parsers.DnsmasqConfig
@@ -78,63 +79,31 @@ else
                            @bind="_search"
                            @bind:event="oninput" />
                     <label class="visually-hidden" for="hosts-file-filter-trigger">Hosts file</label>
-                    <div class="hosts-file-filter-wrap @(_fileFilterMenuOpen ? "hosts-file-filter-wrap--open" : null)">
+                    <div class="hosts-file-filter-wrap">
-                        @if (_fileFilterMenuOpen)
+                        <GroupedSelectDropdown TValue="string"
-                        {
+                                               @ref="_hostsFileFilterDropdown"
-                            <div class="hosts-file-filter-backdrop" @onclick="CloseFileFilterMenu" aria-hidden="true"></div>
+                                               Builder="HostsFileFilterBuilder"
-                        }
+                                               @bind-Value="_sourceFileFilter"
-                        <button type="button"
+                                               @bind-Value:after="OnSourceFileFilterChangedAfterBind"
-                                id="hosts-file-filter-trigger"
+                                               TriggerId="hosts-file-filter-trigger"
-                                class="hosts-file-filter-toggle hosts-toolbar-file-filter"
+                                               MenuId="hosts-file-filter-menu"
-                                title="Show entries from all loaded hosts files, or only one file"
+                                               TriggerClass="hosts-toolbar-file-filter">
-                                aria-label="Filter by hosts file"
+                            <OptionTemplate Context="ctx">
-                                aria-haspopup="listbox"
-                                aria-expanded="@(_fileFilterMenuOpen ? "true" : "false")"
-                                aria-controls="hosts-file-filter-menu"
-                                @onclick="ToggleFileFilterMenu"
-                                @onclick:stopPropagation="true">
-                            <span class="hosts-file-filter-toggle-label text-truncate">@FileFilterSummaryText</span>
-                            <i class="bi bi-chevron-down hosts-file-filter-chevron flex-shrink-0" aria-hidden="true"></i>
-                        </button>
-                        @if (_fileFilterMenuOpen)
-                        {
-                            <div id="hosts-file-filter-menu"
-                                 class="hosts-file-filter-panel shadow"
-                                 role="listbox"
-                                 aria-label="Hosts files"
-                                 @onclick:stopPropagation="true">
                                 <button type="button"
-                                        class="hosts-file-filter-option hosts-file-filter-option--all @(string.IsNullOrWhiteSpace(_sourceFileFilter) ? "hosts-file-filter-option--active" : null)"
+                                        class="hosts-file-filter-option @(ctx.IsSelected ? "hosts-file-filter-option--active" : null)"
                                         role="option"
-                                        aria-selected="@(string.IsNullOrWhiteSpace(_sourceFileFilter) ? "true" : "false")"
+                                        aria-selected="@(ctx.IsSelected ? "true" : "false")"
-                                        @onclick="@(() => SelectSourceFileFilter(""))">
+                                        title="@(ctx.Option.Title ?? ctx.Option.Label)"
-                                    <span class="hosts-file-filter-option-main">All files</span>
+                                        @onclick="ctx.OnSelect">
-                                    <span class="hosts-file-filter-count">@HostsTotalDataRowCount</span>
+                                    <span class="hosts-file-filter-option-main hosts-file-filter-option-path"
+                                          title="@(ctx.Option.Title ?? ctx.Option.Label)">@(ctx.Option.Title ?? ctx.Option.Label)</span>
+                                    @if (ctx.Option.Count is not null)
+                                    {
+                                        <span class="hosts-file-filter-count">@ctx.Option.Count</span>
+                                    }
                                 </button>
-                                @foreach (var group in FileFilterMenuGroups)
+                            </OptionTemplate>
-                                {
+                        </GroupedSelectDropdown>
-                                    <div class="hosts-file-filter-group hosts-file-filter-group--@FileFilterGroupKindClass(group.SourceKind)">
-                                        <div class="hosts-file-filter-group-header" role="presentation">
-                                            <span class="hosts-file-filter-group-title">@group.Title</span>
-                                        </div>
-                                        @foreach (var file in group.Files)
-                                        {
-                                            var path = file.Path;
-                                            var active = IsSourceFilePathSelected(path);
-                                            <button type="button"
-                                                    class="hosts-file-filter-option @(active ? "hosts-file-filter-option--active" : null)"
-                                                    role="option"
-                                                    aria-selected="@(active ? "true" : "false")"
-                                                    title="@path"
-                                                    @onclick="@(() => SelectSourceFileFilter(path))">
-                                                <span class="hosts-file-filter-option-main hosts-file-filter-path" title="@path">@path</span>
-                                                <span class="hosts-file-filter-count">@file.RecordCount</span>
-                                            </button>
-                                        }
-                                    </div>
-                                }
-                            </div>
-                        }
                     </div>
                 </div>
             </div>
@@ -619,72 +588,19 @@ else
             ActiveFilter: null);
     }
 
-    private bool _fileFilterMenuOpen;
+    private GroupedSelectDropdown<string>? _hostsFileFilterDropdown;
 
-    private IReadOnlyList<HostsFileFilterMenuGroup> FileFilterMenuGroups =>
+    private IGroupedSelectBuilder<string> HostsFileFilterBuilder =>
-        HostsSourcePathDisplay.BuildFileFilterMenuGroups(_unifiedRows, _status?.ManagedHostsFilePath);
+        new HostsFileFilterBuilder(_unifiedRows, _status?.ManagedHostsFilePath);
-
-    private int HostsTotalDataRowCount => _unifiedRows.Count(r => !r.IsComment);
-
-    private string FileFilterSummaryText
-    {
-        get
-        {
-            if (string.IsNullOrWhiteSpace(_sourceFileFilter))
-            {
-                var n = HostsTotalDataRowCount;
-                return n == 0 ? "All files" : $"All files · {n} records";
-            }
-
-            var trimmed = _sourceFileFilter.Trim();
-            foreach (var g in FileFilterMenuGroups)
-            {
-                foreach (var f in g.Files)
-                {
-                    if (string.Equals(f.Path, trimmed, StringComparison.OrdinalIgnoreCase))
-                    {
-                        var prefix = HostsSourcePathDisplay.GroupSummaryPrefix(g.SourceKind);
-                        return $"{prefix} · {f.FileName} ({f.RecordCount})";
-                    }
-                }
-            }
-
-            return HostsSourcePathDisplay.FormatOptionLabel(trimmed);
-        }
-    }
-
-    private void ToggleFileFilterMenu() => _fileFilterMenuOpen = !_fileFilterMenuOpen;
-
-    private void CloseFileFilterMenu() => _fileFilterMenuOpen = false;
-
-    private void SelectSourceFileFilter(string path)
-    {
-        _sourceFileFilter = path ?? "";
-        CloseFileFilterMenu();
-        OnSourceFileFilterChangedAfterBind();
-    }
 
     private async Task OnHostsToolbarKeyDown(KeyboardEventArgs e)
     {
-        if (!_fileFilterMenuOpen || e.Key != "Escape")
+        if (e.Key != "Escape")
             return;
-        CloseFileFilterMenu();
+        if (_hostsFileFilterDropdown?.CloseMenu() == true)
-        await InvokeAsync(StateHasChanged);
+            await InvokeAsync(StateHasChanged);
     }
 
-    private bool IsSourceFilePathSelected(string path) =>
-        !string.IsNullOrWhiteSpace(_sourceFileFilter)
-        && string.Equals(_sourceFileFilter.Trim(), path.Trim(), StringComparison.OrdinalIgnoreCase);
-
-    private static string FileFilterGroupKindClass(HostsRowSourceKind kind) => kind switch
-    {
-        HostsRowSourceKind.Managed => "managed",
-        HostsRowSourceKind.SystemHosts => "system",
-        HostsRowSourceKind.AddnHosts => "addn",
-        HostsRowSourceKind.Hostsdir => "hostsdir",
-        _ => "other"
-    };
-
     private void OnSourceFileFilterChangedAfterBind()
     {
         InvalidateVisibleGroupsCache();
@@ -950,9 +866,8 @@ else
         if (_showRemoveHostsModal || _showInvalidHostEditModal)
             return;
 
-        if (_fileFilterMenuOpen && e.Key == "Escape")
+        if (e.Key == "Escape" && (_hostsFileFilterDropdown?.CloseMenu() ?? false))
         {
-            CloseFileFilterMenu();
             await InvokeAsync(StateHasChanged);
             return;
         }

src/DnsmasqWebUI/Components/Pages/Hosts.razor.css

@@ -74,85 +74,23 @@
     max-width: none;
 }
 
-/* File filter: wrapper keeps toolbar flex slot; menu layers above table when open. */
+/* Flex slot for file filter; inner GroupedSelectDropdown fills width (matches pre-extract layout). */
 .hosts-file-filter-wrap {
     position: relative;
-    flex: 0 0 auto;
+    flex: 0 1 22rem;
-    min-width: 13.5rem;
+    min-width: min(13.5rem, 100%);
-    max-width: 22rem;
+    max-width: min(22rem, 100%);
     width: auto;
 }
 
-.hosts-file-filter-wrap--open {
+.hosts-file-filter-wrap ::deep .grouped-select {
-    z-index: 1080;
+    display: block;
-}
-
-.hosts-file-filter-backdrop {
-    position: fixed;
-    inset: 0;
-    z-index: 1070;
-    background: transparent;
-}
-
-.hosts-file-filter-toggle {
-    display: flex;
-    align-items: center;
-    justify-content: space-between;
-    gap: 0.35rem;
     width: 100%;
-    padding: 0.25rem 0.55rem;
-    font-size: 0.875rem;
-    line-height: 1.5;
-    text-align: left;
-    color: var(--bs-body-color);
-    background-color: var(--bs-body-bg);
-    border: 1px solid var(--bs-border-color);
-    border-radius: var(--bs-border-radius-sm);
-    transition: border-color 0.12s ease, box-shadow 0.12s ease;
-}
-
-.hosts-file-filter-toggle:hover {
-    border-color: #bfc7d4;
-}
-
-.hosts-file-filter-wrap--open .hosts-file-filter-toggle {
-    border-color: #86b7fe;
-    box-shadow: 0 0 0 0.2rem rgba(13, 110, 253, 0.2);
-}
-
-.hosts-file-filter-toggle-label {
     min-width: 0;
+    max-width: none;
 }
 
-.hosts-file-filter-chevron {
+.hosts-file-filter-wrap ::deep .hosts-file-filter-option {
-    font-size: 0.75rem;
-    opacity: 0.65;
-    transition: transform 0.15s ease;
-}
-
-.hosts-file-filter-wrap--open .hosts-file-filter-chevron {
-    transform: rotate(180deg);
-}
-
-.hosts-file-filter-panel {
-    position: absolute;
-    top: calc(100% + 4px);
-    right: 0;
-    left: auto;
-    min-width: 100%;
-    width: max-content;
-    max-width: min(26rem, 92vw);
-    max-height: min(22rem, 55vh);
-    overflow-x: hidden;
-    overflow-y: auto;
-    z-index: 1085;
-    padding: 0.35rem;
-    background: var(--bs-body-bg, #fff);
-    border: 1px solid var(--bs-border-color, #e2e8f0);
-    border-radius: 10px;
-}
-
-.hosts-file-filter-option {
     display: flex;
     align-items: center;
     justify-content: space-between;
@@ -170,32 +108,26 @@
     cursor: pointer;
 }
 
-.hosts-file-filter-option:hover {
+.hosts-file-filter-wrap ::deep .hosts-file-filter-option:hover {
     background: rgba(15, 23, 42, 0.06);
 }
 
-.hosts-file-filter-option--active {
+.hosts-file-filter-wrap ::deep .hosts-file-filter-option--active {
     background: rgba(13, 110, 253, 0.12);
     font-weight: 600;
 }
 
-.hosts-file-filter-option--active:hover {
+.hosts-file-filter-wrap ::deep .hosts-file-filter-option--active:hover {
     background: rgba(13, 110, 253, 0.18);
 }
 
-.hosts-file-filter-option--all {
+.hosts-file-filter-wrap ::deep .hosts-file-filter-option-main {
-    margin-bottom: 0.25rem;
-    border: 1px solid #e7ebf0;
-    background: linear-gradient(180deg, #fbfcfe 0%, #f4f6f9 100%);
-}
-
-.hosts-file-filter-option-main {
     flex: 1 1 0%;
     min-width: 0;
 }
 
-/* Full path when width allows; when truncated, keep the end (usually the filename) visible. Full path in title for hover. */
+/* Hosts-specific menu rows show the full path, but truncate from the left so the filename stays visible. */
-.hosts-file-filter-path {
+.hosts-file-filter-wrap ::deep .hosts-file-filter-option-path {
     display: block;
     overflow: hidden;
     white-space: nowrap;
@@ -205,7 +137,7 @@
     unicode-bidi: plaintext;
 }
 
-.hosts-file-filter-count {
+.hosts-file-filter-wrap ::deep .hosts-file-filter-count {
     flex-shrink: 0;
     padding: 0.1rem 0.45rem;
     font-size: 0.7rem;
@@ -217,57 +149,11 @@
     border-radius: 999px;
 }
 
-.hosts-file-filter-option--active .hosts-file-filter-count {
+.hosts-file-filter-wrap ::deep .hosts-file-filter-option--active .hosts-file-filter-count {
     color: #0d47a1;
     background: rgba(13, 110, 253, 0.2);
 }
 
-.hosts-file-filter-group {
-    margin-top: 0.35rem;
-    padding: 0.3rem 0.35rem 0.45rem;
-    border-radius: 8px;
-    border: 1px solid rgba(15, 23, 42, 0.08);
-}
-
-.hosts-file-filter-group:first-of-type {
-    margin-top: 0;
-}
-
-.hosts-file-filter-group--managed {
-    background: linear-gradient(180deg, #e8f4fd 0%, #dceef9 100%);
-    border-color: #b8d4ee;
-}
-
-.hosts-file-filter-group--system {
-    background: linear-gradient(180deg, #f1f5f9 0%, #e8edf3 100%);
-    border-color: #cbd5e1;
-}
-
-.hosts-file-filter-group--addn {
-    background: linear-gradient(180deg, #fff8e6 0%, #fff0cc 100%);
-    border-color: #e9d48a;
-}
-
-.hosts-file-filter-group--hostsdir {
-    background: linear-gradient(180deg, #ecfdf3 0%, #dff6e8 100%);
-    border-color: #a7e3c0;
-}
-
-.hosts-file-filter-group--other {
-    background: #f8fafc;
-}
-
-.hosts-file-filter-group-header {
-    padding: 0.2rem 0.35rem 0.45rem;
-    font-size: 0.65rem;
-    font-weight: 700;
-    letter-spacing: 0.04em;
-    text-transform: uppercase;
-    color: #334155;
-    border-bottom: 1px solid rgba(15, 23, 42, 0.08);
-    margin-bottom: 0.15rem;
-}
-
 .hosts-toolbar-select {
     min-width: 9rem;
     max-width: 14rem;

src/DnsmasqWebUI/Components/Shared/GroupedSelectDropdown.razor

@@ -0,0 +1,187 @@
+@typeparam TValue
+@using DnsmasqWebUI.Models.Ui
+
+<div class="grouped-select @(_open ? "grouped-select--open" : null)"
+     @onkeydown="OnKeyDown">
+    @if (_open)
+    {
+        <div class="grouped-select__backdrop" @onclick="Close" aria-hidden="true"></div>
+    }
+    @{
+        var triggerSummaryProvider = Builder as IGroupedSelectTriggerSummary<TValue>;
+        var triggerSummary = triggerSummaryProvider?.GetTriggerSummary(Value);
+        var summaryText = triggerSummary?.AccessibleFullText ?? Builder.GetSummaryText(Value);
+        var triggerKindClass = triggerSummary?.Kind switch
+        {
+            GroupedSelectTriggerSummaryKind.SingleSource => "grouped-select__trigger--filtered",
+            GroupedSelectTriggerSummaryKind.UnknownSource => "grouped-select__trigger--unknown",
+            _ => null
+        };
+    }
+    <button type="button"
+            id="@TriggerId"
+            class="grouped-select__trigger @TriggerClass @triggerKindClass"
+            title="@($"{Builder.TriggerTitle} — {summaryText}")"
+            aria-label="@($"{Builder.TriggerAriaLabel}. Current: {summaryText}")"
+            aria-haspopup="listbox"
+            aria-expanded="@(_open ? "true" : "false")"
+            aria-controls="@MenuId"
+            @onclick="Toggle"
+            @onclick:stopPropagation="true">
+        @if (triggerSummary is not null)
+        {
+            <span class="grouped-select__trigger-label grouped-select__trigger-label--rich">
+                @if (!string.IsNullOrEmpty(triggerSummary.CategoryPrefix))
+                {
+                    <span class="grouped-select__trigger-prefix">@triggerSummary.CategoryPrefix</span>
+                    <span class="grouped-select__trigger-sep" aria-hidden="true">·</span>
+                }
+                <span class="grouped-select__trigger-primary text-truncate">@triggerSummary.PrimaryLabel</span>
+                @if (!string.IsNullOrEmpty(triggerSummary.SecondaryMeta))
+                {
+                    @if (triggerSummary.Kind == GroupedSelectTriggerSummaryKind.SingleSource)
+                    {
+                        <span class="grouped-select__trigger-count" aria-hidden="true">@triggerSummary.SecondaryMeta</span>
+                    }
+                    else
+                    {
+                        <span class="grouped-select__trigger-meta" aria-hidden="true">· @triggerSummary.SecondaryMeta</span>
+                    }
+                }
+            </span>
+        }
+        else
+        {
+            <span class="grouped-select__trigger-label text-truncate">@Builder.GetSummaryText(Value)</span>
+        }
+        <i class="bi bi-chevron-down grouped-select__chevron flex-shrink-0" aria-hidden="true"></i>
+    </button>
+    @if (_open)
+    {
+        var model = Builder.Build();
+        <div id="@MenuId"
+             class="grouped-select__panel shadow"
+             role="listbox"
+             aria-label="@Builder.MenuAriaLabel"
+             @onclick:stopPropagation="true">
+            @if (model.AllOption is not null)
+            {
+                var allSelected = IsSelected(model.AllOption.Value);
+                @if (AllOptionTemplate is not null)
+                {
+                    @AllOptionTemplate(new GroupedSelectAllOptionContext<TValue>(
+                        model.AllOption,
+                        allSelected,
+                        EventCallback.Factory.Create(this, () => Select(model.AllOption!.Value))))
+                }
+                else
+                {
+                    var option = model.AllOption;
+                    <button type="button"
+                            class="grouped-select__option grouped-select__option--all @(allSelected ? "grouped-select__option--active" : null)"
+                            role="option"
+                            aria-selected="@(allSelected ? "true" : "false")"
+                            @onclick="async () => await Select(option.Value)">
+                        <span class="grouped-select__option-main">@option.Label</span>
+                        @if (option.Count is not null)
+                        {
+                            <span class="grouped-select__count">@option.Count</span>
+                        }
+                    </button>
+                }
+            }
+            @foreach (var grp in model.Sections.OrderBy(s => s.Order))
+            {
+                <div class="grouped-select__group grouped-select__group--@(grp.Kind ?? "other")">
+                    @if (GroupHeaderTemplate is not null)
+                    {
+                        @GroupHeaderTemplate(grp)
+                    }
+                    else
+                    {
+                        <div class="grouped-select__group-header" role="presentation">@grp.Label</div>
+                    }
+                    @foreach (var option in grp.Options)
+                    {
+                        <div @key="option.Value">
+                            @if (OptionTemplate is not null)
+                            {
+                                var active = IsSelected(option.Value);
+                                @OptionTemplate(new GroupedSelectOptionSelectContext<TValue>(
+                                    option,
+                                    active,
+                                    EventCallback.Factory.Create(this, () => Select(option.Value))))
+                            }
+                            else
+                            {
+                                var active = IsSelected(option.Value);
+                                <button type="button"
+                                        class="grouped-select__option @(active ? "grouped-select__option--active" : null)"
+                                        role="option"
+                                        aria-selected="@(active ? "true" : "false")"
+                                        title="@(option.Title ?? option.Label)"
+                                        @onclick="async () => await Select(option.Value)">
+                                    <span class="grouped-select__option-main"
+                                          title="@(option.Title ?? option.Label)">@option.Label</span>
+                                    @if (option.Count is not null)
+                                    {
+                                        <span class="grouped-select__count">@option.Count</span>
+                                    }
+                                </button>
+                            }
+                        </div>
+                    }
+                </div>
+            }
+        </div>
+    }
+</div>
+
+@code {
+    [Parameter, EditorRequired] public IGroupedSelectBuilder<TValue> Builder { get; set; } = default!;
+    [Parameter] public TValue? Value { get; set; }
+    [Parameter] public EventCallback<TValue?> ValueChanged { get; set; }
+    [Parameter] public string TriggerId { get; set; } = "grouped-select-trigger";
+    [Parameter] public string MenuId { get; set; } = "grouped-select-menu";
+    [Parameter] public string TriggerClass { get; set; } = "";
+    [Parameter] public RenderFragment<GroupedSelectSection<TValue>>? GroupHeaderTemplate { get; set; }
+    [Parameter] public RenderFragment<GroupedSelectOptionSelectContext<TValue>>? OptionTemplate { get; set; }
+    [Parameter] public RenderFragment<GroupedSelectAllOptionContext<TValue>>? AllOptionTemplate { get; set; }
+
+    private bool _open;
+
+    public bool CloseMenu()
+    {
+        if (!_open)
+            return false;
+        _open = false;
+        StateHasChanged();
+        return true;
+    }
+
+    private void Toggle() => _open = !_open;
+
+    private void Close()
+    {
+        _open = false;
+    }
+
+    private async Task Select(TValue? value)
+    {
+        _open = false;
+        await ValueChanged.InvokeAsync(value);
+    }
+
+    private bool IsSelected(TValue? candidate) =>
+        EqualityComparer<TValue?>.Default.Equals(Value, candidate);
+
+    private Task OnKeyDown(KeyboardEventArgs e)
+    {
+        if (_open && e.Key == "Escape")
+        {
+            _open = false;
+            StateHasChanged();
+        }
+        return Task.CompletedTask;
+    }
+}

src/DnsmasqWebUI/Components/Shared/GroupedSelectDropdown.razor.css

@@ -0,0 +1,259 @@
+/* Sizing is owned by the parent (e.g. Hosts .hosts-file-filter-wrap); default fills container width. */
+.grouped-select {
+    position: relative;
+    width: 100%;
+    box-sizing: border-box;
+}
+
+.grouped-select--open {
+    z-index: 1080;
+}
+
+.grouped-select__backdrop {
+    position: fixed;
+    inset: 0;
+    z-index: 1070;
+    background: transparent;
+}
+
+.grouped-select__trigger {
+    display: flex;
+    align-items: center;
+    justify-content: space-between;
+    gap: 0.45rem;
+    width: 100%;
+    min-height: calc(1.5em + 0.75rem);
+    padding: 0.375rem 0.65rem;
+    font-size: 0.8125rem;
+    line-height: 1.4;
+    text-align: left;
+    color: var(--bs-body-color);
+    background: linear-gradient(180deg, #ffffff 0%, #f8fafc 100%);
+    border: 1px solid #d8dee9;
+    border-radius: 10px;
+    box-shadow: inset 0 1px 0 rgba(255, 255, 255, 0.75);
+    transition: border-color 0.12s ease, box-shadow 0.12s ease, background 0.12s ease;
+}
+
+.grouped-select__trigger:hover {
+    border-color: #b8c4d4;
+    background: linear-gradient(180deg, #ffffff 0%, #f1f5f9 100%);
+}
+
+.grouped-select__trigger--filtered {
+    border-color: #93b9f0;
+    background: linear-gradient(180deg, #f6f9ff 0%, #eef4fc 100%);
+    box-shadow: inset 0 1px 0 rgba(255, 255, 255, 0.9);
+}
+
+.grouped-select__trigger--filtered:hover {
+    border-color: #7aa8e8;
+}
+
+.grouped-select__trigger--unknown {
+    border-color: #e9c46c;
+    background: linear-gradient(180deg, #fffdf8 0%, #fff6e5 100%);
+}
+
+.grouped-select--open .grouped-select__trigger {
+    border-color: #86b7fe;
+    box-shadow: 0 0 0 0.2rem rgba(13, 110, 253, 0.2), inset 0 1px 0 rgba(255, 255, 255, 0.85);
+}
+
+.grouped-select__trigger-label {
+    min-width: 0;
+    flex: 1 1 auto;
+}
+
+.grouped-select__trigger-label--rich {
+    display: flex;
+    align-items: center;
+    gap: 0.28rem;
+    min-width: 0;
+}
+
+.grouped-select__trigger-prefix {
+    flex-shrink: 0;
+    font-size: 0.7rem;
+    font-weight: 700;
+    letter-spacing: 0.03em;
+    text-transform: uppercase;
+    color: #64748b;
+}
+
+.grouped-select__trigger--filtered .grouped-select__trigger-prefix {
+    color: #2563eb;
+}
+
+.grouped-select__trigger-sep {
+    flex-shrink: 0;
+    opacity: 0.45;
+    font-weight: 500;
+    color: #64748b;
+}
+
+.grouped-select__trigger-primary {
+    flex: 1 1 auto;
+    min-width: 0;
+    font-weight: 600;
+    color: #0f172a;
+}
+
+.grouped-select__trigger-meta {
+    flex-shrink: 0;
+    font-size: 0.75rem;
+    font-weight: 500;
+    color: #64748b;
+    font-variant-numeric: tabular-nums;
+}
+
+.grouped-select__trigger-count {
+    flex-shrink: 0;
+    min-width: 1.35rem;
+    padding: 0.12rem 0.4rem;
+    font-size: 0.68rem;
+    font-weight: 700;
+    font-variant-numeric: tabular-nums;
+    line-height: 1.2;
+    text-align: center;
+    color: #1e40af;
+    background: rgba(37, 99, 235, 0.12);
+    border-radius: 999px;
+}
+
+.grouped-select__chevron {
+    font-size: 0.8rem;
+    opacity: 0.55;
+    transition: transform 0.15s ease, opacity 0.12s ease;
+}
+
+.grouped-select__trigger:hover .grouped-select__chevron {
+    opacity: 0.85;
+}
+
+.grouped-select--open .grouped-select__chevron {
+    transform: rotate(180deg);
+}
+
+.grouped-select__panel {
+    position: absolute;
+    top: calc(100% + 4px);
+    right: 0;
+    left: auto;
+    min-width: 100%;
+    width: max-content;
+    max-width: min(26rem, 92vw);
+    max-height: min(22rem, 55vh);
+    overflow-x: hidden;
+    overflow-y: auto;
+    z-index: 1085;
+    padding: 0.35rem;
+    background: var(--bs-body-bg, #fff);
+    border: 1px solid var(--bs-border-color, #e2e8f0);
+    border-radius: 10px;
+}
+
+.grouped-select__option {
+    display: flex;
+    align-items: center;
+    justify-content: space-between;
+    gap: 0.65rem;
+    width: 100%;
+    padding: 0.4rem 0.55rem;
+    margin: 0;
+    font-size: 0.8125rem;
+    line-height: 1.35;
+    text-align: left;
+    color: #1e293b;
+    background: transparent;
+    border: none;
+    border-radius: 6px;
+    cursor: pointer;
+}
+
+.grouped-select__option:hover {
+    background: rgba(15, 23, 42, 0.06);
+}
+
+.grouped-select__option--active {
+    background: rgba(13, 110, 253, 0.12);
+    font-weight: 600;
+}
+
+.grouped-select__option--active:hover {
+    background: rgba(13, 110, 253, 0.18);
+}
+
+.grouped-select__option--all {
+    margin-bottom: 0.25rem;
+    border: 1px solid #e7ebf0;
+    background: linear-gradient(180deg, #fbfcfe 0%, #f4f6f9 100%);
+}
+
+.grouped-select__option-main {
+    flex: 1 1 0%;
+    min-width: 0;
+}
+
+.grouped-select__count {
+    flex-shrink: 0;
+    padding: 0.1rem 0.45rem;
+    font-size: 0.7rem;
+    font-weight: 600;
+    font-variant-numeric: tabular-nums;
+    line-height: 1.3;
+    color: #475569;
+    background: rgba(15, 23, 42, 0.06);
+    border-radius: 999px;
+}
+
+.grouped-select__option--active .grouped-select__count {
+    color: #0d47a1;
+    background: rgba(13, 110, 253, 0.2);
+}
+
+.grouped-select__group {
+    margin-top: 0.35rem;
+    padding: 0.3rem 0.35rem 0.45rem;
+    border-radius: 8px;
+    border: 1px solid rgba(15, 23, 42, 0.08);
+}
+
+.grouped-select__group:first-of-type {
+    margin-top: 0;
+}
+
+.grouped-select__group--managed {
+    background: linear-gradient(180deg, #e8f4fd 0%, #dceef9 100%);
+    border-color: #b8d4ee;
+}
+
+.grouped-select__group--system {
+    background: linear-gradient(180deg, #f1f5f9 0%, #e8edf3 100%);
+    border-color: #cbd5e1;
+}
+
+.grouped-select__group--addn {
+    background: linear-gradient(180deg, #fff8e6 0%, #fff0cc 100%);
+    border-color: #e9d48a;
+}
+
+.grouped-select__group--hostsdir {
+    background: linear-gradient(180deg, #ecfdf3 0%, #dff6e8 100%);
+    border-color: #a7e3c0;
+}
+
+.grouped-select__group--other {
+    background: #f8fafc;
+}
+
+.grouped-select__group-header {
+    padding: 0.2rem 0.35rem 0.45rem;
+    font-size: 0.65rem;
+    font-weight: 700;
+    letter-spacing: 0.04em;
+    text-transform: uppercase;
+    color: #334155;
+    border-bottom: 1px solid rgba(15, 23, 42, 0.08);
+    margin-bottom: 0.15rem;
+}

src/DnsmasqWebUI/DnsmasqWebUI.csproj

@@ -3,7 +3,7 @@
   <PropertyGroup>
     <TargetFramework>net10.0</TargetFramework>
     <Nullable>enable</Nullable>
-    <Version>0.0.7</Version>
+    <Version>0.0.8</Version>
     <ImplicitUsings>enable</ImplicitUsings>
     <!-- Avoid pre-compressed .br/.gz so MapStaticAssets serves uncompressed files (fixes 0-byte/empty response bug). -->
     <DisableBuildCompression>true</DisableBuildCompression>

src/DnsmasqWebUI/Models/Hosts/HostsFileFilterBuilder.cs

@@ -0,0 +1,174 @@
+using DnsmasqWebUI.Models.Ui;
+
+namespace DnsmasqWebUI.Models.Hosts;
+
+public sealed class HostsFileFilterBuilder : IGroupedSelectBuilder<string>, IGroupedSelectTriggerSummary<string>
+{
+    private readonly IReadOnlyList<HostsPageRow> _rows;
+    private readonly string? _managedHostsPath;
+
+    public HostsFileFilterBuilder(IReadOnlyList<HostsPageRow> rows, string? managedHostsPath)
+    {
+        _rows = rows;
+        _managedHostsPath = managedHostsPath;
+    }
+
+    public string TriggerTitle =>
+        "Show entries from all loaded hosts files, or only one file";
+
+    public string TriggerAriaLabel => "Filter by hosts file";
+
+    public string MenuAriaLabel => "Hosts files";
+
+    public GroupedSelectModel<string> Build()
+    {
+        var byPath = _rows
+            .Where(r => !string.IsNullOrWhiteSpace(r.SourcePath))
+            .GroupBy(r => r.SourcePath.Trim(), StringComparer.OrdinalIgnoreCase)
+            .Select(g => new
+            {
+                Path = g.Key,
+                SourceKind = g.First().SourceKind,
+                Count = g.Count(r => !r.IsComment)
+            })
+            .ToList();
+
+        var managed = _managedHostsPath?.Trim();
+        if (!string.IsNullOrWhiteSpace(managed)
+            && !byPath.Any(x => string.Equals(x.Path, managed, StringComparison.OrdinalIgnoreCase)))
+        {
+            byPath.Add(new
+            {
+                Path = managed,
+                SourceKind = HostsRowSourceKind.Managed,
+                Count = 0
+            });
+        }
+
+        var sections = byPath
+            .GroupBy(x => x.SourceKind)
+            .OrderBy(g => SourceOrder(g.Key))
+            .Select(g => new GroupedSelectSection<string>(
+                Label: GroupTitle(g.Key),
+                Kind: GroupKind(g.Key),
+                Order: SourceOrder(g.Key),
+                Options: g
+                    .OrderBy(x => x.Path, StringComparer.OrdinalIgnoreCase)
+                    .Select(x => new GroupedSelectOption<string>(
+                        Value: x.Path,
+                        Label: FormatOptionLabel(x.Path),
+                        Count: x.Count,
+                        Title: x.Path))
+                    .ToList()))
+            .ToList();
+
+        return new GroupedSelectModel<string>(
+            AllOption: new GroupedSelectOption<string>(
+                Value: "",
+                Label: "All files",
+                Count: _rows.Count(r => !r.IsComment),
+                Title: null),
+            Sections: sections);
+    }
+
+    public string GetSummaryText(string? selectedValue) =>
+        GetTriggerSummary(selectedValue).AccessibleFullText;
+
+    public GroupedSelectTriggerSummary GetTriggerSummary(string? selectedValue)
+    {
+        var model = Build();
+        if (string.IsNullOrWhiteSpace(selectedValue))
+        {
+            var count = model.AllOption?.Count ?? 0;
+            if (count == 0)
+            {
+                return new GroupedSelectTriggerSummary(
+                    AccessibleFullText: "All files",
+                    Kind: GroupedSelectTriggerSummaryKind.AllSources,
+                    CategoryPrefix: null,
+                    PrimaryLabel: "All files",
+                    SecondaryMeta: null);
+            }
+
+            return new GroupedSelectTriggerSummary(
+                AccessibleFullText: $"All files · {count} records",
+                Kind: GroupedSelectTriggerSummaryKind.AllSources,
+                CategoryPrefix: null,
+                PrimaryLabel: "All files",
+                SecondaryMeta: $"{count} records");
+        }
+
+        var selected = selectedValue.Trim();
+        foreach (var section in model.Sections)
+        {
+            foreach (var option in section.Options)
+            {
+                if (string.Equals(option.Value, selected, StringComparison.OrdinalIgnoreCase))
+                {
+                    var count = option.Count ?? 0;
+                    var prefix = SummaryPrefix(section.Kind);
+                    return new GroupedSelectTriggerSummary(
+                        AccessibleFullText: $"{prefix} · {option.Label} ({count})",
+                        Kind: GroupedSelectTriggerSummaryKind.SingleSource,
+                        CategoryPrefix: prefix,
+                        PrimaryLabel: option.Label,
+                        SecondaryMeta: count.ToString());
+                }
+            }
+        }
+
+        var fallback = FormatOptionLabel(selected);
+        return new GroupedSelectTriggerSummary(
+            AccessibleFullText: fallback,
+            Kind: GroupedSelectTriggerSummaryKind.UnknownSource,
+            CategoryPrefix: null,
+            PrimaryLabel: fallback,
+            SecondaryMeta: null);
+    }
+
+    private static string FormatOptionLabel(string path)
+    {
+        if (string.IsNullOrWhiteSpace(path))
+            return path;
+
+        var trimmed = path.TrimEnd(Path.DirectorySeparatorChar, Path.AltDirectorySeparatorChar);
+        var name = Path.GetFileName(trimmed);
+        return string.IsNullOrEmpty(name) ? path : name;
+    }
+
+    private static int SourceOrder(HostsRowSourceKind kind) => kind switch
+    {
+        HostsRowSourceKind.Managed => 0,
+        HostsRowSourceKind.SystemHosts => 1,
+        HostsRowSourceKind.AddnHosts => 2,
+        HostsRowSourceKind.Hostsdir => 3,
+        _ => 99
+    };
+
+    private static string GroupTitle(HostsRowSourceKind kind) => kind switch
+    {
+        HostsRowSourceKind.Managed => "Managed hosts",
+        HostsRowSourceKind.SystemHosts => "System hosts",
+        HostsRowSourceKind.AddnHosts => "Additional hosts",
+        HostsRowSourceKind.Hostsdir => "Hosts directory",
+        _ => "Hosts files"
+    };
+
+    private static string GroupKind(HostsRowSourceKind kind) => kind switch
+    {
+        HostsRowSourceKind.Managed => "managed",
+        HostsRowSourceKind.SystemHosts => "system",
+        HostsRowSourceKind.AddnHosts => "addn",
+        HostsRowSourceKind.Hostsdir => "hostsdir",
+        _ => "other"
+    };
+
+    private static string SummaryPrefix(string? kind) => kind switch
+    {
+        "managed" => "Managed",
+        "system" => "System",
+        "addn" => "Additional",
+        "hostsdir" => "Hosts dir",
+        _ => "Hosts"
+    };
+}

src/DnsmasqWebUI/Models/Hosts/HostsFileFilterMenuModels.cs

@@ -1,10 +0,0 @@
-namespace DnsmasqWebUI.Models.Hosts;
-
-/// <summary>One hosts file row in the filter menu (path, short name, non-comment line count).</summary>
-public sealed record HostsFileFilterMenuItem(string Path, string FileName, int RecordCount);
-
-/// <summary>A source-kind section in the hosts file filter menu.</summary>
-public sealed record HostsFileFilterMenuGroup(
-    HostsRowSourceKind SourceKind,
-    string Title,
-    IReadOnlyList<HostsFileFilterMenuItem> Files);

src/DnsmasqWebUI/Models/Hosts/HostsSourcePathDisplay.cs

@@ -1,81 +0,0 @@
-namespace DnsmasqWebUI.Models.Hosts;
-
-/// <summary>Labels for hosts <see cref="HostsPageRow.SourcePath"/> in UI (e.g. file filter dropdown).</summary>
-public static class HostsSourcePathDisplay
-{
-    public static string FormatOptionLabel(string path)
-    {
-        if (string.IsNullOrWhiteSpace(path))
-            return path;
-
-        var trimmed = path.TrimEnd(Path.DirectorySeparatorChar, Path.AltDirectorySeparatorChar);
-        var name = Path.GetFileName(trimmed);
-        return string.IsNullOrEmpty(name) ? path : name;
-    }
-
-    /// <summary>
-    /// Builds grouped menu data: paths grouped by <see cref="HostsRowSourceKind"/> with per-file record counts
-    /// (non-comment lines). Ensures <paramref name="managedHostsPathAlwaysShow"/> appears even when there are no managed rows yet.
-    /// </summary>
-    public static IReadOnlyList<HostsFileFilterMenuGroup> BuildFileFilterMenuGroups(
-        IReadOnlyList<HostsPageRow> rows,
-        string? managedHostsPathAlwaysShow)
-    {
-        var byPath = rows
-            .Where(r => !string.IsNullOrWhiteSpace(r.SourcePath))
-            .GroupBy(r => r.SourcePath.Trim(), StringComparer.OrdinalIgnoreCase)
-            .Select(g => (
-                Path: g.Key,
-                Kind: g.First().SourceKind,
-                Count: g.Count(r => !r.IsComment)))
-            .ToList();
-
-        var managedTrim = managedHostsPathAlwaysShow?.Trim();
-        if (!string.IsNullOrEmpty(managedTrim)
-            && !byPath.Any(e => string.Equals(e.Path, managedTrim, StringComparison.OrdinalIgnoreCase)))
-            byPath.Add((managedTrim, HostsRowSourceKind.Managed, 0));
-
-        return byPath
-            .GroupBy(e => e.Kind)
-            .OrderBy(g => SourceKindOrder(g.Key))
-            .Select(g =>
-            {
-                var files = g.OrderBy(e => e.Path, StringComparer.OrdinalIgnoreCase)
-                    .Select(e => new HostsFileFilterMenuItem(e.Path, FormatOptionLabel(e.Path), e.Count))
-                    .ToList();
-                return new HostsFileFilterMenuGroup(
-                    g.Key,
-                    GroupMenuTitle(g.Key),
-                    files);
-            })
-            .ToList();
-    }
-
-    public static string GroupMenuTitle(HostsRowSourceKind kind) => kind switch
-    {
-        HostsRowSourceKind.Managed => "Managed hosts",
-        HostsRowSourceKind.SystemHosts => "System hosts",
-        HostsRowSourceKind.AddnHosts => "Additional hosts",
-        HostsRowSourceKind.Hostsdir => "Hosts directory",
-        _ => "Hosts files"
-    };
-
-    public static string GroupSummaryPrefix(HostsRowSourceKind kind) => kind switch
-    {
-        HostsRowSourceKind.Managed => "Managed",
-        HostsRowSourceKind.SystemHosts => "System",
-        HostsRowSourceKind.AddnHosts => "Additional",
-        HostsRowSourceKind.Hostsdir => "Hosts dir",
-        _ => "Hosts"
-    };
-
-    private static int SourceKindOrder(HostsRowSourceKind kind) => kind switch
-    {
-        HostsRowSourceKind.Managed => 0,
-        HostsRowSourceKind.SystemHosts => 1,
-        HostsRowSourceKind.AddnHosts => 2,
-        HostsRowSourceKind.Hostsdir => 3,
-        _ => 99
-    };
-
-}

src/DnsmasqWebUI/Models/Ui/GroupedSelectModels.cs

@@ -0,0 +1,26 @@
+namespace DnsmasqWebUI.Models.Ui;
+
+public sealed record GroupedSelectOption<TValue>(
+    TValue Value,
+    string Label,
+    int? Count = null,
+    string? Title = null);
+
+public sealed record GroupedSelectSection<TValue>(
+    string Label,
+    IReadOnlyList<GroupedSelectOption<TValue>> Options,
+    string? Kind = null,
+    int Order = 0);
+
+public sealed record GroupedSelectModel<TValue>(
+    GroupedSelectOption<TValue>? AllOption,
+    IReadOnlyList<GroupedSelectSection<TValue>> Sections);
+
+public interface IGroupedSelectBuilder<TValue>
+{
+    GroupedSelectModel<TValue> Build();
+    string GetSummaryText(TValue? selectedValue);
+    string TriggerTitle { get; }
+    string TriggerAriaLabel { get; }
+    string MenuAriaLabel { get; }
+}

src/DnsmasqWebUI/Models/Ui/GroupedSelectTemplateContexts.cs

@@ -0,0 +1,13 @@
+using Microsoft.AspNetCore.Components;
+
+namespace DnsmasqWebUI.Models.Ui;
+
+public sealed record GroupedSelectAllOptionContext<TValue>(
+    GroupedSelectOption<TValue> Option,
+    bool IsSelected,
+    EventCallback OnSelect);
+
+public sealed record GroupedSelectOptionSelectContext<TValue>(
+    GroupedSelectOption<TValue> Option,
+    bool IsSelected,
+    EventCallback OnSelect);

src/DnsmasqWebUI/Models/Ui/GroupedSelectTriggerSummary.cs

@@ -0,0 +1,22 @@
+namespace DnsmasqWebUI.Models.Ui;
+
+public enum GroupedSelectTriggerSummaryKind
+{
+    AllSources,
+    SingleSource,
+    UnknownSource
+}
+
+/// <summary>Optional structured lines for the collapsed trigger; use with <see cref="IGroupedSelectTriggerSummary{TValue}"/>.</summary>
+public sealed record GroupedSelectTriggerSummary(
+    string AccessibleFullText,
+    GroupedSelectTriggerSummaryKind Kind,
+    string? CategoryPrefix,
+    string PrimaryLabel,
+    string? SecondaryMeta);
+
+/// <summary>Builders that can supply structured trigger content for richer styling.</summary>
+public interface IGroupedSelectTriggerSummary<TValue>
+{
+    GroupedSelectTriggerSummary GetTriggerSummary(TValue? selectedValue);
+}