CanHideStash

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

namespace Oxide.Plugins
{
    [Info("Stash Owner Only", "RustPluginGenerator", "1.0.0")]
    [Description("Only allow players to hide stashes they placed themselves.")]
    public class StashOwnerOnly : RustPlugin
    {
        private const string PermAdmin = "stashowneronly.admin";

        private PluginConfig config;

        private class PluginConfig
        {
            [JsonProperty("Only owner may hide stash")]
            public bool OwnerOnly { 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 System.Collections.Generic.Dictionary<string, string>
            {
                ["NotOwner"] = "You can only hide a stash that you placed.",
                ["AdminDenied"] = "Only the owner can hide this stash."
            }, this);
        }

        private string Msg(string key, string userId = null) => lang.GetMessage(key, this, userId);

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

        private object CanHideStash(BasePlayer player, StashContainer stashContainer)
        {
            if (!config.OwnerOnly || player == null || stashContainer == null) return null;

            ulong ownerId = stashContainer.OwnerID;
            if (ownerId == 0) return null;

            if (stashContainer is BaseEntity entity && entity.OwnerID == player.userID.Get()) return null;

            if (permission.UserHasPermission(player.UserIDString, PermAdmin)) return null;

            player.ChatMessage(Msg("NotOwner", player.UserIDString));
            return true;
        }
    }
}