[parsing] Allow searching for notes by visibility

Iceshrimp.Backend/Core/Extensions/QueryableFtsExtensions.cs

@@ -35,6 +35,7 @@ public static class QueryableFtsExtensions
 			InstanceFilter instanceFilter     => current.ApplyInstanceFilter(instanceFilter, config),
 			MentionFilter mentionFilter       => current.ApplyMentionFilter(mentionFilter, config, db),
 			MiscFilter miscFilter             => current.ApplyMiscFilter(miscFilter, user),
+			VisibilityFilter visibilityFilter => current.ApplyVisibilityFilter(visibilityFilter),
 			ReplyFilter replyFilter           => current.ApplyReplyFilter(replyFilter, config, db),
 			CwFilter cwFilter                 => current.ApplyCwFilter(cwFilter, caseSensitivity, matchType),
 			WordFilter wordFilter             => current.ApplyWordFilter(wordFilter, caseSensitivity, matchType),
@@ -163,6 +164,19 @@ public static class QueryableFtsExtensions
 		};
 	}
 
+	private static IQueryable<Note> ApplyVisibilityFilter(this IQueryable<Note> query, VisibilityFilter filter)
+	{
+		return filter.Value switch
+		{
+			VisibilityFilterType.Public    => query.ApplyPublicFilter(filter.Negated),
+			VisibilityFilterType.Home      => query.ApplyHomeFilter(filter.Negated),
+			VisibilityFilterType.Followers => query.ApplyFollowersOnlyFilter(filter.Negated),
+			VisibilityFilterType.Specified => query.ApplySpecifiedFilter(filter.Negated),
+			VisibilityFilterType.Local     => query.ApplyLocalFilter(filter.Negated),
+			_                              => throw new ArgumentOutOfRangeException(nameof(filter))
+		};
+	}
+
 	[SuppressMessage("ReSharper", "EntityFramework.UnsupportedServerSideFunctionCall", Justification = "Projectables")]
 	private static IQueryable<Note> ApplyFollowersFilter(this IQueryable<Note> query, User user, bool negated)
 		=> query.Where(p => negated ? !p.User.IsFollowing(user) : p.User.IsFollowing(user));
@@ -177,6 +191,21 @@ public static class QueryableFtsExtensions
 	private static IQueryable<Note> ApplyBoostsFilter(this IQueryable<Note> query, bool negated)
 		=> query.Where(p => negated ? !p.IsPureRenote : p.IsPureRenote);
 
+	private static IQueryable<Note> ApplyPublicFilter(this IQueryable<Note> query, bool negated)
+	    => query.Where(p => negated ? p.Visibility != Note.NoteVisibility.Public : p.Visibility == Note.NoteVisibility.Public);
+	
+	private static IQueryable<Note> ApplyHomeFilter(this IQueryable<Note> query, bool negated)
+		=> query.Where(p => negated ? p.Visibility != Note.NoteVisibility.Home : p.Visibility == Note.NoteVisibility.Home);
+	
+	private static IQueryable<Note> ApplyFollowersOnlyFilter(this IQueryable<Note> query, bool negated)
+		=> query.Where(p => negated ? p.Visibility != Note.NoteVisibility.Followers : p.Visibility == Note.NoteVisibility.Followers);
+	
+	private static IQueryable<Note> ApplySpecifiedFilter(this IQueryable<Note> query, bool negated)
+		=> query.Where(p => negated ? p.Visibility != Note.NoteVisibility.Specified : p.Visibility == Note.NoteVisibility.Specified);
+
+	private static IQueryable<Note> ApplyLocalFilter(this IQueryable<Note> query, bool negated)
+		=> query.Where(p => negated ? !p.LocalOnly : p.LocalOnly);
+	
 	private static IQueryable<Note> ApplyAttachmentFilter(this IQueryable<Note> query, AttachmentFilter filter)
 		=> filter.Negated ? query.ApplyNegatedAttachmentFilter(filter) : query.ApplyRegularAttachmentFilter(filter);
 

Iceshrimp.Parsing/SearchQueryFilters.cs

@@ -54,6 +54,42 @@ public record MiscFilter(bool Negated, MiscFilterType Value) : ISearchQueryFilte
 	}
 }
 
+public enum VisibilityFilterType
+{
+	Public,
+	Home,
+	Followers,
+	Specified,
+	Local
+}
+
+public record VisibilityFilter(bool Negated, VisibilityFilterType Value) : ISearchQueryFilter
+{
+	public static bool TryParse(bool negated, ReadOnlySpan<char> value, [NotNullWhen(true)] out VisibilityFilter? result)
+	{
+		VisibilityFilterType? type = value switch
+		{
+			"public"    => VisibilityFilterType.Public,
+			"home"      => VisibilityFilterType.Home,
+			"unlisted"  => VisibilityFilterType.Home,
+			"followers" => VisibilityFilterType.Followers,
+			"direct"    => VisibilityFilterType.Specified,
+			"specified" => VisibilityFilterType.Specified,
+			"local"     => VisibilityFilterType.Local,
+			_           => null
+		};
+		
+		if (!type.HasValue)
+		{
+			result = null;
+			return false;
+		}
+
+		result = new VisibilityFilter(negated, type.Value);
+		return true;
+	}
+}
+
 public enum InFilterType
 {
 	Bookmarks,

Iceshrimp.Parsing/SearchQueryParser.cs

@@ -83,6 +83,7 @@ public static class SearchQueryParser
 			"instance" or "domain" or "host"        => new InstanceFilter(negated, value.ToString()),
 
 			"filter" when MiscFilter.TryParse(negated, value, out var parsed) => parsed,
+			"visibility" when VisibilityFilter.TryParse(negated, value, out var parsed) => parsed,
 			"in" when InFilter.TryParse(negated, value, out var parsed)       => parsed,
 			"has" or "attachment" or "attached" when AttachmentFilter.TryParse(negated, value, out var parsed)
 				=> parsed,