using System;
using System.Reflection;

namespace AibisDream.Utility
{
    public abstract class SingletonBase<T> where T : SingletonBase<T>
    {
        private static T _instance;

        public static T Instance
        {
            get
            {
                if (_instance != null) return _instance;
                // 先获取所有非public的构造方法
                var ctors = typeof(T).GetConstructors(BindingFlags.Instance | BindingFlags.NonPublic);
                // 从ctors中获取无参的构造方法
                var ctor = Array.Find(ctors, c => c.GetParameters().Length == 0);
                if (ctor == null)
                    throw new Exception("Non-public ctor() not found!");
                // 调用构造方法
                _instance = ctor.Invoke(null) as T;

                return _instance;
            }
        }
    }
}