Let the listing drop games that are only an address

src/MUI.Catalog/Games/AddressName.cs

@@ -0,0 +1,55 @@
+using System.Globalization;
+using System.Text.RegularExpressions;
+
+namespace MUI.Catalog;
+
+/// <summary>
+/// Whether a game's name is only the address we found it at — <c>mud.example.org:4000</c>,
+/// <c>203.0.113.7:23</c> — because the game told us no name of its own.
+/// </summary>
+/// <remarks>
+/// <para>
+/// <c>CatalogueBinder.NameOf</c> falls back to <c>{host}:{port}</c> when neither MSSP nor a login
+/// command gave a meaningful name, and that name stays until a probe, an owner or staff supplies a
+/// better one. This reads the name rather than a flag, so a rename takes the game out of the set with
+/// nothing else to update.
+/// </para>
+/// <para>
+/// A statement about the name <em>we</em> list the game under, never that the game has no name —
+/// it may well have one it did not publish (rule 5).
+/// </para>
+/// <para>
+/// The host has to look like an address: a dotted name, an IPv4 literal, or an IPv6 literal (bare,
+/// which is how the fallback writes it, or bracketed). A name such as <c>Babylon:5</c> carries no dot
+/// and stays a name.
+/// </para>
+/// </remarks>
+public static partial class AddressName
+{
+    public static bool Is(string? name)
+    {
+        if (string.IsNullOrWhiteSpace(name))
+        {
+            return false;
+        }
+
+        var match = Shape().Match(name.Trim());
+
+        if (!match.Success
+            || !int.TryParse(
+                match.Groups["port"].ValueSpan, NumberStyles.None, CultureInfo.InvariantCulture, out var port)
+            || port is < 1 or > 65535)
+        {
+            return false;
+        }
+
+        var host = match.Groups["host"].Value;
+
+        return host.Contains('.', StringComparison.Ordinal) || host.Contains(':', StringComparison.Ordinal);
+    }
+
+    [GeneratedRegex(
+        @"^(?<host>\[[0-9A-Fa-f:.]+\]|[A-Za-z0-9.-]+|[0-9A-Fa-f:.]+):(?<port>[0-9]{1,5})$",
+        RegexOptions.CultureInvariant)]
+    private static partial Regex Shape();
+}

src/MUI.Catalog/Games/Views.cs

@@ -396,6 +396,14 @@ public sealed record GameFilter
 
     public FacetChoice? Language { get; init; }
 
+    /// <summary>
+    /// The games listed under their address rather than a name (<see cref="FacetKeys.Unnamed"/>).
+    /// </summary>
+    /// <remarks>
+    /// <c>!yes</c> drops them. Unset by default, so every existing caller still gets them.
+    /// </remarks>
+    public FacetChoice? Unnamed { get; init; }
+
     /// <summary>
     /// What order the answer comes back in.
     /// </summary>

src/MUI.Catalog/Search/Facets.FacetedSearch.Choices.cs

@@ -84,5 +84,14 @@ private sealed record ChoiceFacet(
             FacetTokens.GrowthDirections),
         new(FacetKeys.Genre, FacetEvidence.Declared, r => [r.Genre], f => f.Genre),
         new(FacetKeys.Language, FacetEvidence.Declared, r => [r.Language], f => f.Language),
+
+        // Last: it is not a question about the game's character but about the row's label, and a
+        // reader browsing for a game meets it after everything that is.
+        new(
+            FacetKeys.Unnamed,
+            FacetEvidence.Derived,
+            r => [AddressName.Is(r.Summary.Name) ? FacetTokens.Yes : null],
+            f => f.Unnamed,
+            FacetTokens.YesOnly),
     ];
 }

src/MUI.Catalog/Search/Facets.cs

@@ -99,6 +99,17 @@ public static class FacetKeys
     /// </remarks>
     public const string Unreachable = "unreachable";
 
+    /// <summary>
+    /// Games listed under their address because they told us no name — see <see cref="AddressName"/>.
+    /// </summary>
+    /// <remarks>
+    /// What crawlers and API clients reach for to skip rows like <c>mud.example.org:4000</c>:
+    /// <c>?unnamed=!yes</c>. Ours, labelled <see cref="FacetEvidence.Derived"/>: the name is the one
+    /// <em>we</em> list the game under, and a game listed by address may have a name it never
+    /// published, so this never says a game is nameless (rule 5).
+    /// </remarks>
+    public const string Unnamed = "unnamed";
+
     /// <summary>
     /// What order the listing comes back in. A filter parameter by spelling and by plumbing, so the
     /// panel, the page and the read API cannot grow two words for one question.

src/MUI.Web/Api/ApiModels.cs

@@ -278,7 +278,13 @@ public sealed record FilterView(
     GameSort Sort,
 
     /// <summary>The old name for <see cref="Codebase"/>, at the same value. Prefer the new one.</summary>
-    string? CodebaseFamily = null)
+    string? CodebaseFamily = null,
+
+    /// <summary>
+    /// Whether the games listed under their address rather than a name were asked for, or dropped.
+    /// </summary>
+    /// <remarks>Last and defaulted, so the positional shape every earlier field has is unchanged.</remarks>
+    string? Unnamed = null)
 {
     public static FilterView Of(GameFilter filter)
     {
@@ -303,7 +309,8 @@ public static FilterView Of(GameFilter filter)
             filter.Genre?.Token,
             filter.Language?.Token,
             filter.Sort,
-            filter.Codebase?.Token);
+            filter.Codebase?.Token,
+            filter.Unnamed?.Token);
     }
 }
 

src/MUI.Web/Api/GameFilterBinding.cs

@@ -59,6 +59,7 @@ private static bool TryRead(
             || !TryLastSeen(read, out var seen, out error)
             || !TryToggle(read, FacetKeys.Uncounted, out var uncounted, out error)
             || !TryToggle(read, FacetKeys.Unreachable, out var unreachable, out error)
+            || !TryToggle(read, FacetKeys.Unnamed, out var unnamed, out error)
             || !TryTrending(read, out var trending, out error)
             || !TrySort(read, out var sort, out error))
         {
@@ -98,6 +99,7 @@ private static bool TryRead(
             Trending = trending,
             Genre = Choice(read, FacetKeys.Genre),
             Language = Choice(read, FacetKeys.Language),
+            Unnamed = unnamed,
             Sort = sort,
         };
 
@@ -135,7 +137,7 @@ .. read(FacetKeys.Protocol)
     }
 
     /// <summary>
-    /// One of the two measurement switches: <c>yes</c>, <c>!yes</c>, or not asked.
+    /// One of the yes-or-nothing switches (could not count, could not reach, listed by address): <c>yes</c>, <c>!yes</c>, or not asked.
     /// </summary>
     /// <remarks>
     /// Refused rather than ignored: its vocabulary is one word, so anything else is a typo, and a typo

src/MUI.Web/Api/OpenApiDocument.cs

@@ -178,6 +178,12 @@ private static JsonArray ListingParameters()
         {
             parameters.Add(Parameter(key, "yes selects, !yes excludes; ~unknown is an alias for !yes.", values: ["yes", "!yes", "~unknown"]));
         }
+        parameters.Add(Parameter(
+            FacetKeys.Unnamed,
+            "Games listed under their address (host:port) because they published no name of their own. "
+                + "!yes excludes them, yes selects only them; ~unknown is an alias for !yes. "
+                + "Unset, they are included.",
+            values: ["yes", "!yes", "~unknown"]));
         parameters.Add(Parameter(FacetKeys.Trending, "Weekly count trend; prefix ! to exclude, or ~unknown for no trend."));
         return parameters;
     }

src/MUI.Web/Components/Text/FacetWords.cs

@@ -38,6 +38,7 @@ public static class FacetWords
         FacetKeys.Trending => "facet.group.trending",
         FacetKeys.Genre => "facet.group.genre",
         FacetKeys.Language => "facet.group.language",
+        FacetKeys.Unnamed => "facet.group.unnamed",
 
         // Named here, not in the chip builder, so a facet is put into words in one place.
         FacetKeys.Text => "facet.group.search",
@@ -176,6 +177,7 @@ public static string Value(string tag, string key, FacetValue value)
             // the same claim.
             FacetKeys.Uncounted => Messages.For(tag, "state.uncounted"),
             FacetKeys.Unreachable => Messages.For(tag, "state.unreachable"),
+            FacetKeys.Unnamed => Messages.For(tag, "facet.unnamed.yes"),
 
             // Everything else IS the value — a codebase name, version string, protocol acronym — and
             // translating it would destroy the evidence rather than localize anything.
@@ -205,6 +207,7 @@ public static string Excluded(string tag, string key, FacetValue value)
             // say what the reader actually did — hid some rows.
             FacetKeys.Uncounted => Messages.For(tag, "facet.excluded.uncounted"),
             FacetKeys.Unreachable => Messages.For(tag, "facet.excluded.unreachable"),
+            FacetKeys.Unnamed => Messages.For(tag, "facet.excluded.unnamed"),
 
             // A message rather than string concatenation: negation word order varies by language, and
             // concatenating here would fix English's order for every translator.

src/MUI.Web/IndexableFacet.cs

@@ -88,6 +88,7 @@ .. Dimensions.Where(key => key != FacetKeys.Band),
             || filter.LastSeen is not null
             || filter.Uncounted is not null
             || filter.Unreachable is not null
+            || filter.Unnamed is not null
             || filter.CodebaseVersion is not null
             || filter.Family is not null
             || filter.Trending is not null

src/MUI.Web/Localization/Messages.Chrome.cs

@@ -243,6 +243,12 @@ public static partial class Messages
         ["facet.group.genre"] = "genre",
         ["facet.group.language"] = "language",
 
+        // Games listed under host:port because they published no name. The name is ours, so the
+        // words describe our label, never that the game has none (rule 5).
+        ["facet.group.unnamed"] = "name",
+        ["facet.unnamed.yes"] = "listed by address",
+        ["facet.excluded.unnamed"] = "hidden from this listing",
+
         // ── facet values ──────────────────────────────────────────────────────────────────────
         ["facet.band.playersNow"] = "connected now",
         ["facet.band.activeThisWeek"] = "active this week",

src/MUI.Web/Resources/Messages.de.resx

@@ -637,6 +637,15 @@
   <data name="facet.group.language" xml:space="preserve">
     <value>Sprache</value>
   </data>
+  <data name="facet.group.unnamed" xml:space="preserve">
+    <value>Name</value>
+  </data>
+  <data name="facet.unnamed.yes" xml:space="preserve">
+    <value>unter der Adresse gelistet</value>
+  </data>
+  <data name="facet.excluded.unnamed" xml:space="preserve">
+    <value>aus dieser Auflistung ausgeblendet</value>
+  </data>
   <data name="facet.band.playersNow" xml:space="preserve">
     <value>jetzt verbunden</value>
   </data>

src/MUI.Web/Resources/Messages.ja.resx

@@ -637,6 +637,15 @@
   <data name="facet.group.language" xml:space="preserve">
     <value>言語</value>
   </data>
+  <data name="facet.group.unnamed" xml:space="preserve">
+    <value>名前</value>
+  </data>
+  <data name="facet.unnamed.yes" xml:space="preserve">
+    <value>アドレスで掲載</value>
+  </data>
+  <data name="facet.excluded.unnamed" xml:space="preserve">
+    <value>この一覧では非表示</value>
+  </data>
   <data name="facet.band.playersNow" xml:space="preserve">
     <value>現在接続あり</value>
   </data>

src/MUI.Web/Resources/Messages.nl.resx

@@ -637,6 +637,15 @@
   <data name="facet.group.language" xml:space="preserve">
     <value>taal</value>
   </data>
+  <data name="facet.group.unnamed" xml:space="preserve">
+    <value>naam</value>
+  </data>
+  <data name="facet.unnamed.yes" xml:space="preserve">
+    <value>vermeld onder adres</value>
+  </data>
+  <data name="facet.excluded.unnamed" xml:space="preserve">
+    <value>niet getoond in deze lijst</value>
+  </data>
   <data name="facet.band.playersNow" xml:space="preserve">
     <value>nu verbonden</value>
   </data>

src/MUI.Web/Resources/Messages.resx

@@ -808,6 +808,18 @@
     <value>language</value>
     <comment>facet groups</comment>
   </data>
+  <data name="facet.group.unnamed" xml:space="preserve">
+    <value>name</value>
+    <comment>facet over games listed under their host:port because they published no name</comment>
+  </data>
+  <data name="facet.unnamed.yes" xml:space="preserve">
+    <value>listed by address</value>
+    <comment>facet over games listed under their host:port because they published no name</comment>
+  </data>
+  <data name="facet.excluded.unnamed" xml:space="preserve">
+    <value>hidden from this listing</value>
+    <comment>facet over games listed under their host:port because they published no name</comment>
+  </data>
   <data name="facet.band.playersNow" xml:space="preserve">
     <value>connected now</value>
     <comment>facet values</comment>

src/MUI.Web/Resources/Messages.zh-Hans.resx

@@ -637,6 +637,15 @@
   <data name="facet.group.language" xml:space="preserve">
     <value>语言</value>
   </data>
+  <data name="facet.group.unnamed" xml:space="preserve">
+    <value>名称</value>
+  </data>
+  <data name="facet.unnamed.yes" xml:space="preserve">
+    <value>以地址列出</value>
+  </data>
+  <data name="facet.excluded.unnamed" xml:space="preserve">
+    <value>已从此列表中隐藏</value>
+  </data>
   <data name="facet.band.playersNow" xml:space="preserve">
     <value>当前有连接</value>
   </data>

tests/MUI.Catalog.Tests/Persistence/Queries/FacetQueriesPostgresTests.cs

@@ -353,6 +353,7 @@ await Assert.That((await queries.ListAsync(Choose(key, value.Token))).Count)
         FacetKeys.LastSeen => new GameFilter { LastSeen = Seen(token) },
         FacetKeys.Uncounted => new GameFilter { Uncounted = FacetChoice.Parse(token) },
         FacetKeys.Unreachable => new GameFilter { Unreachable = FacetChoice.Parse(token) },
+        FacetKeys.Unnamed => new GameFilter { Unnamed = FacetChoice.Parse(token) },
         FacetKeys.Protocol => new GameFilter { MeasuredProtocols = [token] },
         FacetKeys.Tls => new GameFilter { Tls = true },
         FacetKeys.Charset => new GameFilter { Charset = FacetChoice.Parse(token) },

tests/MUI.Catalog.Tests/Search/AddressNameTests.cs

@@ -0,0 +1,29 @@
+namespace MUI.Catalog.Tests;
+
+/// <summary>
+/// Which names are only the address a game was found at — the fallback <c>CatalogueBinder.NameOf</c>
+/// writes when a game published no name.
+/// </summary>
+public class AddressNameTests
+{
+    [Test]
+    [Arguments("mud.example.org:4000")]
+    [Arguments("203.0.113.7:23")]
+    [Arguments("2001:db8::1:4000")]
+    [Arguments("[2001:db8::1]:4000")]
+    [Arguments("  fs.twkang.net:5555 ")]
+    public async Task AnAddressIsAnAddress(string name) =>
+        await Assert.That(AddressName.Is(name)).IsTrue();
+
+    [Test]
+    [Arguments("Convergence MUSH")]
+    [Arguments("Babylon:5")]
+    [Arguments("Star Wars: 1977")]
+    [Arguments("mud.example.org")]
+    [Arguments("mud.example.org:0")]
+    [Arguments("mud.example.org:70000")]
+    [Arguments("")]
+    [Arguments(null)]
+    public async Task ANameIsNot(string? name) =>
+        await Assert.That(AddressName.Is(name)).IsFalse();
+}

tests/MUI.Catalog.Tests/Search/FacetedSearchTests.cs

@@ -467,12 +467,47 @@ public async Task ASwitchNothingMatchesIsNotDrawnAtAll()
         await Assert.That(listing.Facets.Any(f => f.Key == FacetKeys.Unreachable)).IsFalse();
     }
 
+    [Test]
+    public async Task AGameListedByItsAddressCanBeDroppedFromTheListing()
+    {
+        // What crawlers asked for: rows whose name is only host:port, because the game published
+        // none, are one parameter away from gone — and only on request.
+        GameFacetRow[] rows =
+        [
+            Row("Convergence MUSH"),
+            Row("mud.example.org:4000"),
+            Row("203.0.113.7:23"),
+        ];
+
+        var all = FacetedSearch.Search(rows, new GameFilter());
+        var named = FacetedSearch.Search(rows, new GameFilter { Unnamed = FacetChoice.Not(FacetTokens.Yes) });
+        var unnamed = FacetedSearch.Search(rows, new GameFilter { Unnamed = FacetChoice.Of(FacetTokens.Yes) });
+
+        await Assert.That(all.Games.Count).IsEqualTo(3);
+        await Assert.That(named.Games.Select(g => g.Slug)).IsEquivalentTo(new[] { "Convergence MUSH" });
+        await Assert.That(unnamed.Games.Count).IsEqualTo(2);
+
+        var value = Value(all, FacetKeys.Unnamed, FacetTokens.Yes);
+
+        await Assert.That(value.Count).IsEqualTo(2);
+        await Assert.That(Group(all, FacetKeys.Unnamed).Evidence).IsEqualTo(FacetEvidence.Derived);
+    }
+
+    [Test]
+    public async Task AFullyNamedCatalogueOffersNoUnnamedSwitch()
+    {
+        var listing = FacetedSearch.Search([Row("busy"), Row("also")], new GameFilter());
+
+        await Assert.That(listing.Facets.Any(f => f.Key == FacetKeys.Unnamed)).IsFalse();
+    }
+
     private static GameFilter Choose(string key, string token) => key switch
     {
         FacetKeys.Band => new GameFilter { Band = Band(token) },
         FacetKeys.LastSeen => new GameFilter { LastSeen = Seen(token) },
         FacetKeys.Uncounted => new GameFilter { Uncounted = FacetChoice.Parse(token) },
         FacetKeys.Unreachable => new GameFilter { Unreachable = FacetChoice.Parse(token) },
+        FacetKeys.Unnamed => new GameFilter { Unnamed = FacetChoice.Parse(token) },
         FacetKeys.Protocol => new GameFilter { MeasuredProtocols = [token] },
         FacetKeys.Tls => new GameFilter { Tls = true },
         FacetKeys.Charset => new GameFilter { Charset = FacetChoice.Parse(token) },

tests/MUI.Web.Tests/FacetSurfaceTests.cs

@@ -43,6 +43,7 @@ .. typeof(FacetKeys)
         // narrowing a listing to nothing on a typo.
         FacetKeys.Uncounted => "yes",
         FacetKeys.Unreachable => "yes",
+        FacetKeys.Unnamed => "yes",
         FacetKeys.Protocol => "GMCP",
         FacetKeys.Trending => "up",
         // Not the default. The point of the check below is that the parameter changed something,