OnSprayRemove

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

namespace Oxide.Plugins
{
    [Info("SprayClearGuard", "RustPluginGenerator", "1.0.0")]
    [Description("Restricts who can clear spray decals, optionally to owners and permitted players.")]
    public class SprayClearGuard : RustPlugin
    {
        private const string PermUse = "sprayclearguard.use";

        private PluginConfig config;

        public class PluginConfig
        {
            [JsonProperty("Allow admins to bypass")]
            public bool AllowAdmins { get; set; } = true;

            [JsonProperty("Require ownership when permission is held")]
            public bool RequireOwnershipForPermission { 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>
            {
                ["NotAllowed"] = "You are not allowed to clear this spray.",
                ["NotOwner"] = "Only the owner of this spray can clear it."
            }, 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(PermUse, this);
        }

        private object OnSprayRemove(SprayCanSpray sprayCanSpray, BasePlayer player)
        {
            if (sprayCanSpray == null || player == null) return null;

            if (config.AllowAdmins && player.IsAdmin) return null;

            bool hasPerm = permission.UserHasPermission(player.UserIDString, PermUse);
            if (!hasPerm)
            {
                player.ChatMessage(Msg("NotAllowed", player.UserIDString));
                return true;
            }

            if (config.RequireOwnershipForPermission && sprayCanSpray.OwnerID != 0 && sprayCanSpray.OwnerID != player.userID.Get())
            {
                player.ChatMessage(Msg("NotOwner", player.UserIDString));
                return true;
            }

            return null;
        }
    }
}