How to make a Rust building protection plugin (PvE owner-only damage)

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

namespace Oxide.Plugins
{
    [Info("PveBuildingProtection", "RustPluginGenerator", "1.0.0")]
    [Description("Restricts building and deployable damage to the owner or players authorised on the covering tool cupboard.")]
    public class PveBuildingProtection : RustPlugin
    {
        private const string PermAdmin = "pvebuildingprotection.admin";

        private PluginConfig config;

        private class PluginConfig
        {
            [JsonProperty("Enabled")]
            public bool Enabled = true;

            [JsonProperty("ProtectDeployables")]
            public bool ProtectDeployables = true;

            [JsonProperty("AllowNpcDamage")]
            public bool AllowNpcDamage = true;

            [JsonProperty("IgnoreDecayDamage")]
            public bool IgnoreDecayDamage = true;

            [JsonProperty("ProtectedPrefabs")]
            public List<string> ProtectedPrefabs = new List<string>
            {
                "foundation",
                "foundation.triangle",
                "wall",
                "wall.half",
                "wall.low",
                "wall.window",
                "wall.doorway",
                "floor",
                "floor.triangle",
                "floor.frame",
                "roof",
                "block.stair.lshape",
                "block.stair.spiral",
                "block.stair.ushape",
                "wall.external.high",
                "wall.external.high.stone",
                "gates.external.high.wood",
                "gates.external.high.stone",
                "door.hinged.wood",
                "door.hinged.metal",
                "door.double.hinged.wood",
                "door.double.hinged.metal",
                "door.hinged.toptier",
                "door.double.hinged.toptier"
            };
        }

        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>
            {
                ["Report"] = "Building protection: {0} | Decay bypass: {1} | Deployables: {2}",
                ["On"] = "enabled",
                ["Off"] = "disabled",
                ["Toggled"] = "Building protection is now {0}.",
                ["NoPermission"] = "You do not have permission to use this command."
            }, this);
        }

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

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

        private object OnEntityTakeDamage(BaseCombatEntity entity, HitInfo hitInfo)
        {
            if (!config.Enabled || entity == null || hitInfo == null) return null;
            if (entity is BasePlayer || entity is BaseNpc) return null;

            var attacker = hitInfo.InitiatorPlayer;
            if (attacker == null || attacker.IsNpc) return null;

            var damageType = hitInfo.damageTypes.GetMajorityDamageType();
            if (config.IgnoreDecayDamage && damageType == Rust.DamageType.Decay) return null;

            if (!(entity is BuildingBlock) && !(entity is Door) && !(entity is DecayEntity) && !config.ProtectDeployables) return null;
            if (!IsProtected(entity)) return null;

            if (attacker.IsAdmin) return null;
            if (attacker.userID == GetOwner(entity)) return null;

            var privilege = entity.GetBuildingPrivilege();
            if (privilege != null && privilege.IsAuthed(attacker)) return null;

            hitInfo.damageTypes.ScaleAll(0f);
            return true;
        }

        private bool IsProtected(BaseCombatEntity entity)
        {
            var block = entity as BuildingBlock;
            if (block != null)
            {
                var building = block.GetBuilding();
                if (building == null) return config.ProtectDeployables;
                return true;
            }

            if (entity is Door) return config.ProtectDeployables;

            if (entity.ShortPrefabName != null && config.ProtectedPrefabs.Contains(entity.ShortPrefabName))
                return true;

            return config.ProtectDeployables && entity is DecayEntity;
        }

        private ulong GetOwner(BaseCombatEntity entity)
        {
            return entity.OwnerID;
        }

        [ChatCommand("buildingprotect")]
        private void CmdReport(BasePlayer player, string command, string[] args)
        {
            if (player == null) return;
            if (!permission.UserHasPermission(player.UserIDString, PermAdmin))
            {
                player.ChatMessage(Msg("NoPermission", player.UserIDString));
                return;
            }

            player.ChatMessage(Msg("Report", player.UserIDString,
                config.Enabled ? Msg("On", player.UserIDString) : Msg("Off", player.UserIDString),
                config.IgnoreDecayDamage ? "yes" : "no",
                config.ProtectDeployables ? "protected" : "ignored"));
        }

        [ConsoleCommand("pvebuildingprotection.toggle")]
        private void CcmdToggle(ConsoleSystem.Arg arg)
        {
            if (arg == null) return;
            var player = arg.Player();
            if (player != null && !permission.UserHasPermission(player.UserIDString, PermAdmin)) return;
            if (player == null && !arg.IsAdmin) return;

            config.Enabled = !config.Enabled;
            SaveConfig();

            var state = config.Enabled ? Msg("On") : Msg("Off");
            arg.ReplyWith(string.Format(lang.GetMessage("Toggled", this), state));
        }

        private void Unload()
        {
            config = null;
        }
    }
}