using System;
using System.Collections;
using System.Collections.Generic;
using System.Linq;

namespace BITKit.Modification
{
	/// <summary>
	/// 不兼容的改装
	/// </summary>
	public class IncompatibleModifyException : InGameException
	{
		public IncompatibleModifyException(IModifyElement[] errorElements) : base()
		{
		}
	}
	/// <summary>
	/// 没有前置改装
	/// </summary>
	public class NotRequireModifyException : InGameException
	{
		public NotRequireModifyException(IModifyElement[] errorElements) : base()
		{
		}
	}
	/// <summary>
	/// 不支持的改装
	/// </summary>
	public class NotSupportModifyException : InGameException
	{
		public NotSupportModifyException(IModifyElement[] errorElements) : base()
		{
		}
	}
	/// <summary>
	/// 改装元素
	/// </summary>
	public interface IModifyElement
	{
		IModifyElement[] Require => Array.Empty<IModifyElement>();
		IModifyElement[] Incompatible => Array.Empty<IModifyElement>();
	}
	/// <summary>
	/// 改装管理器
	/// </summary>
	public interface IModifyManager
	{
		/// <summary>
		/// 获取所有改装
		/// </summary>
		IDictionary<IModifyElement,object> Modifies { get; }
		/// <summary>
		/// 获取所有已改装
		/// </summary>
		IDictionary<IModifyElement,object> Modified { get; }
		/// <summary>
		/// 添加改装
		/// </summary>
		/// <param name="modify"></param>
		void Add(IModifyElement modify,object obj);
		/// <summary>
		/// 移除改装
		/// </summary>
		/// <param name="modify"></param>
		void Remove(IModifyElement modify,out object obj);
	}
	public class ModifyManager : IModifyManager
	{
		public virtual IDictionary<IModifyElement, object> Modifies { get; } =new Dictionary<IModifyElement,object>();
		public virtual IDictionary<IModifyElement, object> Modified { get; } = new Dictionary<IModifyElement, object>();

		public virtual void Add(IModifyElement modify, object obj)
		{
			if(Modified.ContainsKey(modify))
				throw new NotSupportModifyException(new[]{modify});
			
			var list = new List<IModifyElement>();
			list.AddRange(Modified.Keys);
			list.Add(modify);
			

			foreach (var x in list)
			{
				if(x.Require is null or {Length:0})continue;

				foreach (var _x in x.Require)
				{
					if (list.Contains(_x) is false)
						throw new NotRequireModifyException(x.Require);
				}
			}
			
			//你知道怎么做,帮我做一下
			
			
			var incompatible = list.Where(x=>x.Incompatible is not null).SelectMany(x => x.Incompatible).ToArray();
			if(MathE.Contains(incompatible,list))
				throw new IncompatibleModifyException(incompatible);
			
			Modified.Add(modify,obj);
		}

		public virtual void Remove(IModifyElement modify,out object obj)
		{
			var list = new List<IModifyElement>();
			list.AddRange(Modified.Keys);
			list.Remove(modify);

			var requires = list.Where(x=>x.Require is not null).SelectMany(x => x.Require).ToArray();
			if(requires.Contains(modify))
				throw new NotRequireModifyException(requires);
			
			obj = Modified[modify];
			Modified.Remove(modify);
		}
	}
}