Whisper 0.1.0: private messages between players

/pm (/w) with names, #userid, SteamIDs, @me, @aim, @random, @randomt and
@randomct, /r to reply, and /block, /blocklist, /unblock. Lines use
CS2-Tags' rank prefixes and colours: >[[M] Kalus -> me] message. Gagged
players can't send; blocks stop everyone but staff. Messages are kept in
CS2-SimpleAdmin's database while History is on (css_whisper_history).

Tags.cs

@@ -0,0 +1,97 @@
+using System.Reflection;
+using System.Text.Json;
+using CounterStrikeSharp.API.Core;
+using CounterStrikeSharp.API.Modules.Admin;
+using CounterStrikeSharp.API.Modules.Utils;
+
+namespace Whisper;
+
+// Reads CS2-Tags' tags.json so private messages show the same rank prefix and colours as chat, and
+// picks a player's tag the way CS2-Tags does: their SteamID64 first, then the first "#group" or
+// "@permission" key they match in file order, then "everyone". Reread when the file changes.
+public sealed class Tags(string path, Action<string> warn)
+{
+    public sealed record Tag(string Prefix, string NickColor, string MessageColor);
+
+    private List<KeyValuePair<string, Tag>> _tags = [];
+    private DateTime _loadedWrite;
+
+    public Tag? Find(CCSPlayerController player)
+    {
+        Refresh();
+        if (player.IsBot || player.IsHLTV || player.AuthorizedSteamID == null)
+            return null;
+
+        var steamid = player.AuthorizedSteamID.SteamId64.ToString();
+        foreach (var (key, tag) in _tags)
+            if (key == steamid)
+                return tag;
+        foreach (var (key, tag) in _tags)
+        {
+            if (key.StartsWith('#') && AdminManager.PlayerInGroup(player, key)) return tag;
+            if (key.StartsWith('@') && AdminManager.PlayerHasPermissions(player, key)) return tag;
+        }
+        foreach (var (key, tag) in _tags)
+            if (key == "everyone")
+                return tag;
+        return null;
+    }
+
+    private void Refresh()
+    {
+        DateTime written;
+        try
+        {
+            written = File.GetLastWriteTimeUtc(path);
+        }
+        catch (Exception)
+        {
+            return;
+        }
+        // GetLastWriteTimeUtc gives 1601 for a missing file.
+        if (written == _loadedWrite || written.Year < 1700)
+        {
+            if (written.Year < 1700 && _tags.Count > 0)
+                _tags = [];
+            _loadedWrite = written;
+            return;
+        }
+        _loadedWrite = written;
+        try
+        {
+            using var doc = JsonDocument.Parse(File.ReadAllText(path),
+                new JsonDocumentOptions { CommentHandling = JsonCommentHandling.Skip, AllowTrailingCommas = true });
+            var tags = new List<KeyValuePair<string, Tag>>();
+            if (doc.RootElement.TryGetProperty("tags", out var section))
+                foreach (var entry in section.EnumerateObject())
+                    tags.Add(new(entry.Name, new Tag(Str(entry.Value, "prefix"), Str(entry.Value, "nick_color"), Str(entry.Value, "message_color"))));
+            _tags = tags;
+        }
+        catch (Exception ex)
+        {
+            // Keep the tags from before, as CS2-Tags does with a broken file.
+            warn($"Couldn't read {path}: {ex.Message}; keeping the previous tags");
+        }
+    }
+
+    private static string Str(JsonElement e, string name) =>
+        e.TryGetProperty(name, out var v) && v.ValueKind == JsonValueKind.String ? v.GetString() ?? "" : "";
+
+    public static string TeamColor(int team) => team switch
+    {
+        (int)CsTeam.Terrorist => ChatColors.Gold.ToString(),
+        (int)CsTeam.CounterTerrorist => ChatColors.Blue.ToString(),
+        _ => "",
+    };
+
+    // Colour tags in config strings only, never in names or messages: {Red}, {Default}, {TEAMCOLOR}.
+    public static string Colors(string text, int team = 0)
+    {
+        if (!text.Contains('{'))
+            return text;
+        foreach (var field in typeof(ChatColors).GetFields(BindingFlags.Public | BindingFlags.Static))
+            if (field.FieldType == typeof(char))
+                text = text.Replace($"{{{field.Name}}}", field.GetValue(null)!.ToString(), StringComparison.OrdinalIgnoreCase);
+        return text.Replace("{TEAMCOLOR}", TeamColor(team), StringComparison.OrdinalIgnoreCase);
+    }
+}