using System;
using JD.Kernel.StaticHelpers;

namespace JD.Kernel.Classes
{
    public class Scope
    {
        #region Variables

        private int m_level;

        #endregion

        #region Properties

        public bool InScope
        {
            get { return m_level > 0; }
        }

        #endregion

        #region Methods

        public virtual IDisposable Begin()
        {
            return Begin(null, null);
        }

        protected IDisposable Begin(Action begin, Action end)
        {
            ++m_level;

            if (m_level == 1)
            {
                Delegates.SafeExecute(begin);
            }

            return new NotFinalizableHelper(delegate
            {
                System.Diagnostics.Debug.Assert(m_level > 0);

                if (--m_level == 0)
                {
                    Delegates.SafeExecute(end);
                    OnEndScope(EventArgs.Empty);
                }
            });
        }

        #endregion

        #region Event

        public event EventHandler EndScope;

        protected virtual void OnEndScope(EventArgs e)
        {
            EndScope?.Invoke(this, e);
        }

        #endregion
    }
}