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 { get; }
		IModifyElement[] Incompatible { get; }
	}
	/// <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;private set; } =new Dictionary<IModifyElement,object>();
		public virtual IDictionary<IModifyElement, object> Modified => new Dictionary<IModifyElement, object>(Modifies.Where(x=>x.Value is not null));

		public virtual void Add(IModifyElement modify, object obj)
		{
			var list = new List<IModifyElement>();
			list.AddRange(Modified.Keys);
			list.Add(modify);
			
			if(list.All(x=>x.Require?.Any(y=>list.Contains(y)) is false))
				throw new NotRequireModifyException(list.ToArray());
			
			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);
		}
	}
}