How to make a Rust team switch cooldown plugin (leave/kick lockout)

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

namespace Oxide.Plugins
{
    [Info("Team Switch Cooldown", "RustPluginGenerator", "1.0.0")]
    [Description("Applies a cooldown after a player leaves or is kicked from a team.")]
    public class TeamSwitchCooldown : RustPlugin
    {
        private const string PermAdmin = "teamswitchcooldown.admin";
        private const string PermBypass = "teamswitchcooldown.bypass";
        private const string DataFile = "TeamSwitchCooldown";

        private PluginConfig config;
        private Dictionary<string, PlayerRecord> records = new Dictionary<string, PlayerRecord>();

        public class PlayerRecord
        {
            public long LeftAtTicks;
            public ulong OldTeamId;
        }

        private class PluginConfig
        {
            [JsonProperty("Cooldown hours")]
            public double CooldownHours = 6.0;

            [JsonProperty("Ignore admins")]
            public bool IgnoreAdmins = true;

            [JsonProperty("Ignore last member leaving")]
            public bool IgnoreLastMemberLeave = true;

            [JsonProperty("Record expiry days")]
            public int RecordExpiryDays = 30;
        }

        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>
            {
                ["Blocked"] = "You cannot join a team for another {0}. You recently left team {1}.",
                ["AdminCheck"] = "Player {0}: old team {1}, remaining {2}.",
                ["AdminCheckNone"] = "No active cooldown for player {0}.",
                ["AdminCleared"] = "Cleared cooldown for player {0}.",
                ["AdminNotFound"] = "No record found for player {0}.",
                ["AdminUsage"] = "Usage: teamcooldown.check <steamid> | teamcooldown.clear <steamid>"
            }, this);
        }

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

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

        private void OnServerInitialized()
        {
            LoadData();
        }

        private void Unload()
        {
            SaveData();
        }

        private void OnServerSave()
        {
            SaveData();
        }

        private void LoadData()
        {
            var stored = Interface.Oxide.DataFileSystem.ReadObject<Dictionary<string, PlayerRecord>>(DataFile);
            records = stored ?? new Dictionary<string, PlayerRecord>();

            if (config.RecordExpiryDays <= 0) return;

            var cutoff = DateTime.UtcNow.AddDays(-config.RecordExpiryDays);
            var stale = new List<string>();

            foreach (var pair in records)
            {
                if (new DateTime(pair.Value.LeftAtTicks, DateTimeKind.Utc) < cutoff)
                    stale.Add(pair.Key);
            }

            foreach (var id in stale) records.Remove(id);
        }

        private void SaveData()
        {
            Interface.Oxide.DataFileSystem.WriteObject(DataFile, records);
        }

        private void ApplyCooldown(ulong userId, ulong teamId)
        {
            if (config.CooldownHours <= 0) return;

            var id = userId.ToString();
            if (permission.UserHasPermission(id, PermBypass)) return;

            var player = BasePlayer.FindByID(userId);
            if (player != null && config.IgnoreAdmins && player.IsAdmin) return;

            records[id] = new PlayerRecord
            {
                LeftAtTicks = DateTime.UtcNow.Ticks,
                OldTeamId = teamId
            };

            SaveData();

            if (player != null)
                player.ChatMessage(string.Format(CultureInfo.InvariantCulture,
                    "Team changed. You cannot join a new team for {0}.", FormatTime(TimeSpan.FromHours(config.CooldownHours))));
        }

        private object OnTeamLeave(RelationshipManager.PlayerTeam playerTeam, BasePlayer player)
        {
            if (playerTeam == null || player == null) return null;
            if (!player.IsConnected) return null;

            if (config.IgnoreLastMemberLeave && playerTeam.members != null && playerTeam.members.Count <= 1)
                return null;

            ApplyCooldown(player.userID, playerTeam.teamID);
            return null;
        }

        private object OnTeamKick(RelationshipManager.PlayerTeam playerTeam, BasePlayer player, ulong uLong)
        {
            if (playerTeam == null) return null;
            if (uLong == playerTeam.teamLeader && player != null) return null;
            if (config.IgnoreLastMemberLeave && playerTeam.members != null && playerTeam.members.Count <= 1)
                return null;

            ApplyCooldown(uLong, playerTeam.teamID);
            return null;
        }

        private object OnTeamAcceptInvite(RelationshipManager.PlayerTeam playerTeam, BasePlayer player)
        {
            if (playerTeam == null || player == null) return null;

            var id = player.UserIDString;
            if (permission.UserHasPermission(id, PermBypass)) return null;
            if (config.IgnoreAdmins && player.IsAdmin) return null;

            PlayerRecord record;
            if (!records.TryGetValue(id, out record)) return null;

            var leftAt = new DateTime(record.LeftAtTicks, DateTimeKind.Utc);
            var endsAt = leftAt.AddHours(config.CooldownHours);
            var remaining = endsAt - DateTime.UtcNow;

            if (remaining <= TimeSpan.Zero) return null;

            player.ChatMessage(string.Format(CultureInfo.InvariantCulture,
                Msg("Blocked", id, FormatTime(remaining), record.OldTeamId)));

            return false;
        }

        private static string FormatTime(TimeSpan span)
        {
            if (span.TotalMinutes < 1) return "less than a minute";
            if (span.TotalHours < 1) return string.Format(CultureInfo.InvariantCulture, "{0} min", (int)span.TotalMinutes);
            return string.Format(CultureInfo.InvariantCulture, "{0} h {1} min", (int)span.TotalHours, span.Minutes);
        }

        [ConsoleCommand("teamcooldown.check")]
        private void CcmdCheck(ConsoleSystem.Arg arg)
        {
            if (!arg.IsAdmin && (arg.Player() == null || !permission.UserHasPermission(arg.Player().UserIDString, PermAdmin)))
            {
                arg.ReplyWith("No permission.");
                return;
            }

            var id = arg.GetString(0, "");
            if (string.IsNullOrEmpty(id))
            {
                arg.ReplyWith(Msg("AdminUsage"));
                return;
            }

            PlayerRecord record;
            if (!records.TryGetValue(id, out record))
            {
                arg.ReplyWith(string.Format(Msg("AdminCheckNone"), id));
                return;
            }

            var endsAt = new DateTime(record.LeftAtTicks, DateTimeKind.Utc).AddHours(config.CooldownHours);
            var remaining = endsAt - DateTime.UtcNow;
            var text = remaining > TimeSpan.Zero ? FormatTime(remaining) : "none";
            arg.ReplyWith(string.Format(Msg("AdminCheck"), id, record.OldTeamId, text));
        }

        [ConsoleCommand("teamcooldown.clear")]
        private void CcmdClear(ConsoleSystem.Arg arg)
        {
            if (!arg.IsAdmin && (arg.Player() == null || !permission.UserHasPermission(arg.Player().UserIDString, PermAdmin)))
            {
                arg.ReplyWith("No permission.");
                return;
            }

            var id = arg.GetString(0, "");
            if (string.IsNullOrEmpty(id))
            {
                arg.ReplyWith(Msg("AdminUsage"));
                return;
            }

            if (!records.Remove(id))
            {
                arg.ReplyWith(string.Format(Msg("AdminNotFound"), id));
                return;
            }

            SaveData();
            arg.ReplyWith(string.Format(Msg("AdminCleared"), id));
        }
    }
}