How to make a Rust NPC ignore permission plugin (Oxide/Carbon)

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

namespace Oxide.Plugins
{
    [Info("NpcIgnore", "RustPluginGenerator", "1.0.0")]
    [Description("Lets players and admins opt out of hostile NPC and animal targeting.")]
    public class NpcIgnore : RustPlugin
    {
        private const string PermImmune = "npcignore.immune";
        private const string PermUse = "npcignore.use";
        private const string DataFileName = "NpcIgnore";

        private PluginConfig config;
        private HashSet<ulong> ignored = new HashSet<ulong>();

        private class PluginConfig
        {
            [JsonProperty("Use permission immunity")]
            public bool UsePermission { get; set; } = true;

            [JsonProperty("Allow /npcignore toggle")]
            public bool AllowToggle { get; set; } = true;

            [JsonProperty("Grant immunity to admin group on load")]
            public bool GrantAdmins { get; set; } = true;

            [JsonProperty("Warn player when NPC ignores them")]
            public bool NotifyOnToggle { get; set; } = true;
        }

        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>
            {
                ["Ignored"] = "NPCs and animals will now ignore you.",
                ["NotIgnored"] = "NPCs and animals will now target you again.",
                ["NoPermission"] = "You do not have permission to use this command.",
                ["ToggleDisabled"] = "The /npcignore toggle is disabled on this server."
            }, 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(PermImmune, this);
            permission.RegisterPermission(PermUse, this);
        }

        private void OnServerInitialized()
        {
            ignored = Interface.Oxide.DataFileSystem.ReadObject<HashSet<ulong>>(DataFileName)
                      ?? new HashSet<ulong>();

            if (config.GrantAdmins && !permission.GroupHasPermission("admin", PermImmune))
                permission.GrantGroupPermission("admin", PermImmune, this);
        }

        private void Unload()
        {
            Interface.Oxide.DataFileSystem.WriteObject(DataFileName, ignored);
        }

        private void SaveData()
        {
            Interface.Oxide.DataFileSystem.WriteObject(DataFileName, ignored);
        }

        private bool IsIgnored(BasePlayer player)
        {
            if (player == null) return false;

            if (config.UsePermission && permission.UserHasPermission(player.UserIDString, PermImmune))
                return true;

            return ignored.Contains(player.userID.Get());
        }

        private object HandleTarget(BaseEntity candidate)
        {
            if (!config.UsePermission && !config.AllowToggle) return null;

            var player = candidate as BasePlayer;
            if (player == null || player.IsNpc) return null;
            if (player.IsDead() || player.IsSleeping()) return null;

            return IsIgnored(player) ? (object)true : null;
        }

        private object OnNpcTarget(BaseEntity owner, BaseEntity entity)
        {
            if (owner == null || entity == null) return null;
            return HandleTarget(entity);
        }

        private object OnNpcTarget(HumanNPC humanNPC, BaseEntity entity)
        {
            if (humanNPC == null || entity == null) return null;
            return HandleTarget(entity);
        }

        private object OnNpcTarget(BaseNpc npc, BaseEntity entity)
        {
            if (npc == null || entity == null) return null;
            return HandleTarget(entity);
        }

        [ChatCommand("npcignore")]
        private void CmdNpcIgnore(BasePlayer player, string command, string[] args)
        {
            if (player == null) return;

            if (!config.AllowToggle)
            {
                SendReply(player, Msg("ToggleDisabled", player.UserIDString));
                return;
            }

            if (!permission.UserHasPermission(player.UserIDString, PermUse) && !player.IsAdmin)
            {
                SendReply(player, Msg("NoPermission", player.UserIDString));
                return;
            }

            ulong id = player.userID.Get();
            bool nowIgnored;

            if (ignored.Contains(id))
            {
                ignored.Remove(id);
                nowIgnored = false;
            }
            else
            {
                ignored.Add(id);
                nowIgnored = true;
            }

            SaveData();

            if (config.NotifyOnToggle)
                SendReply(player, Msg(nowIgnored ? "Ignored" : "NotIgnored", player.UserIDString));
        }
    }
}