Singleplayer KERS

using GTA;
using GTA.Math;
using GTA.Native;
using System;
using System.Collections.Generic;
using System.IO;
using System.Windows.Forms;
using System.Xml;

public class KERS : Script
{
    string ScriptName = "KERS for all cars";
    string ScriptVer = "1.0";
    float KERSEnergy;
    int GameTimeRef = Game.GameTime;
    bool BoostActive=false;
    List<Model> Cars = new List<Model>();

    bool KERSNotified = false;
    public KERS()
    {
        Tick += OnTick;



        string ConfigFile = @"scripts\\Kersconfig.xml";

        XmlDocument document = new XmlDocument();
        document.Load(ConfigFile);
        int pat = 0;
        while (document == null && pat < 500)
        {
            document.Load(ConfigFile);
            Script.Wait(0);
        }

        if (document == null)
        {
            UI.Notify("~o~KERS couldn't find the xml file.");

            return;
        }

        XmlElement root = document.DocumentElement;

        foreach (XmlElement e in root.SelectNodes("//model"))
        {
            Model car = e.InnerText;
            if(car.IsValid && car.IsVehicle)
            {
                Cars.Add(car);
                //UI.Notify("[KERS] Added "+car.ToString());
            }
        }
    }
    public static float ForwardSpeed(Entity ent)
    {
        return Function.Call<Vector3>(Hash.GET_ENTITY_SPEED_VECTOR, ent, true).Y;
    }
    void OnTick(object sender, EventArgs e)
    {

        if (GameTimeRef < Game.GameTime)
        {
            GameTimeRef = Game.GameTime + 100;
            if (BoostActive)
            {
                if (KERSEnergy > 0)
                {
                    KERSEnergy--;
                    KERSEnergy--;
                }
                else
                {
                    DisplayHelpTextThisFrame("~b~KERS~w~ discharged.");
                    BoostActive = false;
                }
            }
        }
        if (CanWeUse(Game.Player.Character.CurrentVehicle))
        {
            Vehicle veh = Game.Player.Character.CurrentVehicle;
            if (BoostActive)
            {
                veh.EngineTorqueMultiplier = 4;

            }
            if (Cars.Contains(veh.Model))
            {
                if (!KERSNotified)
                {
                    DisplayHelpTextThisFrame("~b~KERS~w~ is available for this vehicle.");
                    KERSNotified = true;
                }

                if (Game.IsControlPressed(2,GTA.Control.VehicleBrake) && !Game.IsControlPressed(2,GTA.Control.VehicleAccelerate) && veh.IsOnAllWheels && ForwardSpeed(veh)>5)
                {
                    if (KERSEnergy < 100) KERSEnergy += 0.2f;
                }
                if(Game.IsControlJustReleased(2,GTA.Control.VehicleBrake))
                {
                    if(KERSEnergy<100) DisplayHelpTextThisFrame("~b~KERS~w~ charged [" + Math.Round(KERSEnergy, 0).ToString() + "%].");
                    else DisplayHelpTextThisFrame("~b~KERS~w~ charged [~g~" + Math.Round(KERSEnergy, 0).ToString() + "%~w~].~n~Press ~INPUT_CONTEXT~ to release it.");

                }
                if (KERSEnergy>0 && Game.IsControlJustPressed(2, GTA.Control.VehicleHorn))
                {
                    DisplayHelpTextThisFrame("~b~KERS~w~ injected.");
                    BoostActive = true;
                }
            }
        }
        else
        {
            if (KERSNotified) KERSNotified = false;
            if (KERSEnergy!=0) KERSEnergy = 0;
            if (BoostActive) BoostActive = false;
        }
    }
    bool CanWeUse(Entity entity)
    {
        return entity != null && entity.Exists();
    }

    void DisplayHelpTextThisFrame(string text)
    {
        Function.Call(Hash._SET_TEXT_COMPONENT_FORMAT, "STRING");
        Function.Call(Hash._ADD_TEXT_COMPONENT_STRING, text);
        Function.Call(Hash._DISPLAY_HELP_TEXT_FROM_STRING_LABEL, 0, false, true, -1);
    }
}