OnServerUserRemove

using System;
using System.Collections.Generic;
using Newtonsoft.Json;
using Oxide.Core;
using UnityEngine;

namespace Oxide.Plugins
{
    [Info("ServerUserRemoveLog", "RustPluginGenerator", "1.0.0")]
    [Description("Logs server user record removals and notifies online admins.")]
    public class ServerUserRemoveLog : RustPlugin
    {
        private const string PermSee = "serveruserremovelog.see";

        private PluginConfig config;
        private StoredData data;
        private readonly Dictionary<ulong, string> knownGroups = new Dictionary<ulong, string>();

        private class PluginConfig
        {
            [JsonProperty("Announce removals in chat")]
            public bool Announce { get; set; } = true;

            [JsonProperty("Keep last 200 log entries")]
            public int MaxEntries { get; set; } = 200;
        }

        private class LogEntry
        {
            [JsonProperty("Steam ID")]
            public string UserId { get; set; }

            [JsonProperty("Group")]
            public string Group { get; set; }

            [JsonProperty("Removed at (UTC)")]
            public string RemovedAt { get; set; }
        }

        private class StoredData
        {
            [JsonProperty("Removals")]
            public List<LogEntry> Removals { get; set; } = new List<LogEntry>();
        }

        protected override void LoadDefaultConfig() => config = new PluginConfig();

        protected override void LoadConfig()
        {
            base.LoadConfig();
            try
            {
                config = Config.ReadObject<PluginConfig>();
                if (config == null) throw new Exception();
            }
            catch
            {
                PrintWarning("Configuration file is invalid, using defaults");
                LoadDefaultConfig();
            }
            SaveConfig();
        }

        protected override void SaveConfig() => Config.WriteObject(config);

        protected override void LoadDefaultMessages()
        {
            lang.RegisterMessages(new Dictionary<string, string>
            {
                ["Removed"] = "User record removed: {0} (group: {1})",
                ["UnknownGroup"] = "unknown"
            }, this);
        }

        private void Init()
        {
            permission.RegisterPermission(PermSee, this);
        }

        private void Loaded()
        {
            data = Interface.Oxide.DataFileSystem.ReadObject<StoredData>(Name) ?? new StoredData();
        }

        private string Msg(string key, string userId, params object[] args) =>
            args.Length == 0 ? lang.GetMessage(key, this, userId) : string.Format(lang.GetMessage(key, this, userId), args);

        private void OnServerUserSet(ulong uid, string name, ServerUsers.UserGroup group)
        {
            knownGroups[uid] = group.ToString();
        }

        private void OnServerUserRemove(ulong uid)
        {
            string group;
            if (!knownGroups.TryGetValue(uid, out group))
                group = Msg("UnknownGroup", null);
            knownGroups.Remove(uid);

            data.Removals.Add(new LogEntry
            {
                UserId = uid.ToString(),
                Group = group,
                RemovedAt = DateTime.UtcNow.ToString("yyyy-MM-dd HH:mm:ss")
            });

            while (data.Removals.Count > config.MaxEntries)
                data.Removals.RemoveAt(0);

            if (!config.Announce)
                return;

            string message = Msg("Removed", null, uid, group);
            foreach (var player in BasePlayer.activePlayerList)
            {
                if (player != null && permission.UserHasPermission(player.UserIDString, PermSee))
                    player.ChatMessage(message);
            }
        }

        private void Unload()
        {
            Interface.Oxide.DataFileSystem.WriteObject(Name, data);
        }
    }
}