CanMountEntity

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

namespace Oxide.Plugins
{
    [Info("VehicleOwnerSeatLock", "RustPluginGenerator", "1.0.0")]
    [Description("Prevents players from mounting a vehicle's driver seat when its owner is offline.")]
    public class VehicleOwnerSeatLock : RustPlugin
    {
        private const string PermBypass = "vehicleownerseatlock.bypass";

        private PluginConfig config;

        private class PluginConfig
        {
            [JsonProperty("Block when owner is offline")]
            public bool BlockWhenOffline = true;

            [JsonProperty("Notify blocked player")]
            public bool Notify = 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>
            {
                ["OwnerOffline"] = "You cannot drive this vehicle while its owner is offline."
            }, this);
        }

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

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

        private object CanMountEntity(BasePlayer player, BaseMountable mountable)
        {
            if (!config.BlockWhenOffline || player == null || mountable == null) return null;
            if (mountable.OwnerID == 0UL) return null;
            if (permission.UserHasPermission(player.UserIDString, PermBypass)) return null;

            var owner = BasePlayer.FindAwakeOrSleeping(mountable.OwnerID.ToString());
            if (owner != null && !owner.IsSleeping()) return null;

            if (config.Notify)
                player.ChatMessage(Msg("OwnerOffline", player.UserIDString));

            return true;
        }
    }
}