OnPortalUse

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

namespace Oxide.Plugins
{
    [Info("Portal Combat Block", "RustPluginGenerator", "1.0.0")]
    [Description("Blocks portal use for players who recently dealt or took combat damage")]
    public class PortalCombatBlock : RustPlugin
    {
        private const string PermBypass = "portalcombatblock.bypass";

        private PluginConfig config;
        private readonly Dictionary<ulong, float> lastCombat = new Dictionary<ulong, float>();
        private Timer cleanupTimer;

        private class PluginConfig
        {
            [JsonProperty("Combat lockout seconds")]
            public float CombatSeconds = 20f;
        }

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

        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>
            {
                ["CombatBlocked"] = "You cannot use a portal while in combat."
            }, this);
        }

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

        private void OnServerInitialized()
        {
            cleanupTimer = timer.Every(30f, PruneCombat);
        }

        private void Unload()
        {
            cleanupTimer?.Destroy();
        }

        private void PruneCombat()
        {
            float now = UnityEngine.Time.realtimeSinceStartup;
            var stale = new List<ulong>();
            foreach (var entry in lastCombat)
            {
                if (now - entry.Value > config.CombatSeconds)
                    stale.Add(entry.Key);
            }
            foreach (var id in stale)
                lastCombat.Remove(id);
        }

        private void OnEntityTakeDamage(BaseCombatEntity entity, HitInfo info)
        {
            if (info == null) return;
            var attacker = info.InitiatorPlayer;
            if (attacker == null || attacker.IsNpc) return;
            var victim = entity as BasePlayer;
            if (victim == null || victim.IsNpc) return;
            if (attacker == victim) return;

            float now = UnityEngine.Time.realtimeSinceStartup;
            lastCombat[attacker.userID.Get()] = now;
            lastCombat[victim.userID.Get()] = now;
        }

        private object OnPortalUse(BasePlayer player, BasePortal portal)
        {
            if (player == null || portal == null) return null;
            if (player.IsAdmin || permission.UserHasPermission(player.UserIDString, PermBypass))
                return null;

            float last;
            if (!lastCombat.TryGetValue(player.userID.Get(), out last))
                return null;

            if (UnityEngine.Time.realtimeSinceStartup - last <= config.CombatSeconds)
            {
                player.ChatMessage(Msg("CombatBlocked", player.UserIDString));
                return true;
            }

            return null;
        }
    }
}