CanSwapToSeat

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

namespace Oxide.Plugins
{
    [Info("Seat Swap Guard", "RustPluginGenerator", "1.0.0")]
    [Description("Blocks other players from swapping into an occupied driver seat on modular cars")]
    public class SeatSwapGuard : RustPlugin
    {
        private const string PermBypass = "seatswapguard.bypass";

        private PluginConfig config;

        private class PluginConfig
        {
            [JsonProperty("Notify blocked players")]
            public bool NotifyPlayers { get; set; } = true;

            [JsonProperty("Allow players with bypass permission")]
            public bool AllowBypass { 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 System.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>
            {
                ["DriverOccupied"] = "You cannot take the driver seat while it is occupied."
            }, 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(PermBypass, this);
        }

        private object CanSwapToSeat(BasePlayer player, ModularCarSeat seat)
        {
            if (player == null || seat == null) return null;

            var car = seat.GetParentEntity() as ModularCar;
            if (car == null) return null;

            BasePlayer currentDriver = car.GetDriver();

            // Only guard the driver seat: it is the seat currently held by the driver.
            if (currentDriver == null || currentDriver == player) return null;
            if (seat.GetMounted() != currentDriver) return null;

            if (config.AllowBypass && permission.UserHasPermission(player.UserIDString, PermBypass)) return null;

            if (config.NotifyPlayers)
                player.ChatMessage(Msg("DriverOccupied", player.UserIDString));

            return false;
        }
    }
}