using Microsoft.AspNetCore.Mvc.Controllers;
using Microsoft.AspNetCore.Mvc.Filters;
using Microsoft.Extensions.DependencyInjection;
using Microsoft.Extensions.Logging;
using Serilog;
using System;
using System.Collections.Generic;
using System.Linq;
using System.Reflection;
using System.Text;
using System.Threading.Tasks;
using System.Transactions;

namespace Wood.Data.Repository
{
	/// <summary>
	/// 工作单元配置特性
	/// </summary>
	[AttributeUsage(AttributeTargets.Method)]
	public sealed class UnitOfWorkAttribute : Attribute, IAsyncActionFilter, IOrderedFilter
	{
		/// <summary>
		///  MiniProfiler 分类名
		/// </summary>
		private const string MiniProfilerCategory = "unitOfWork";

		/// <summary>
		/// 过滤器排序
		/// </summary>
		private const int FilterOrder = 9999;

		/// <summary>
		/// 排序属性
		/// </summary>
		public int Order => FilterOrder;

		/// <summary>
		/// 构造函数
		/// </summary>
		public UnitOfWorkAttribute()
		{
		}

		/// <summary>
		/// 拦截请求
		/// </summary>
		/// <param name="context">动作方法上下文</param>
		/// <param name="next">中间件委托</param>
		/// <returns></returns>
		public async Task OnActionExecutionAsync(ActionExecutingContext context, ActionExecutionDelegate next)
		{
			// 获取动作方法描述器
			var actionDescriptor = context.ActionDescriptor as ControllerActionDescriptor;
			var method = actionDescriptor?.MethodInfo;
			IUnitOfWork? unitOfWork = null;
			try
			{

				// 开始事务
				BeginTransaction(context, method, out unitOfWork);

				// 获取执行 Action 结果
				var resultContext = await next();

				// 提交事务
				CommitTransaction( unitOfWork, resultContext);
			}
			catch (Exception ex)
			{
				//logger.LogError(ex, "Transaction Failed.");
				Log.Error(ex, "事务执行失败！URL({url})",context.HttpContext.Request);
				throw;
			}
		}

		/// <summary>
		/// 开始事务
		/// </summary>
		/// <param name="context"></param>
		/// <param name="method"></param>
		/// <param name="_unitOfWork"></param>
		/// <param name="unitOfWorkAttribute"></param>
		private static void BeginTransaction(FilterContext context, MethodInfo? method, out IUnitOfWork _unitOfWork)
		{
			// 解析工作单元服务
			_unitOfWork = context.HttpContext.RequestServices.GetRequiredService<IUnitOfWork>();

			// 获取工作单元特性
			//unitOfWorkAttribute = method.GetCustomAttribute<UnitOfWorkAttribute>();

			// 调用开启事务方法
			_unitOfWork.BeginTransaction();

		}

		/// <summary>
		/// 提交事务
		/// </summary>
		/// <param name="context"></param>
		/// <param name="_unitOfWork"></param>
		/// <param name="unitOfWorkAttribute"></param>
		/// <param name="resultContext"></param>
		private static void CommitTransaction(IUnitOfWork _unitOfWork, FilterContext resultContext)
		{
			// 获取动态结果上下文
			dynamic dynamicResultContext = resultContext;

			if (dynamicResultContext.Exception == null)
			{
				// 调用提交事务方法
				_unitOfWork.CommitTransaction();
			}
			else
			{
				// 调用回滚事务方法
				_unitOfWork.RollbackTransaction();
			}

			// 调用执行完毕方法
			_unitOfWork.OnCompleted();
		}
	}
}