using Bowin.Common.Cache;
using Bowin.Common.Encoder.DES;
using Bowin.Common.Utility;
using Microsoft.AspNetCore.Mvc.Filters;
using System;
using System.Collections.Generic;
using System.Linq;
using System.Text;

namespace Bowin.Common.ServiceToken.ApiIdentity
{
    /// <summary>
    /// Header：{ auth-key: 密文（系统ID|访问时间(MMyyyyddmmHHss)）, auth-system: 系统ID明文 }
    /// </summary>
    public class ApiIdentityAttribute : ActionFilterAttribute
    {
        public List<string> ScopeList { get; set; }
        public ApiIdentityAttribute(params string[] scopes)
        {
            ScopeList = scopes.ToList();
        }
        public override void OnActionExecuting(ActionExecutingContext context)
        {
            if (!ApiIdentityHelper.IsStarted)
            {
                return;
            }

            var systemService = (ISystemService)HttpHelper.GetService(ApiIdentityHelper.SystemServiceType);
            var systemList = systemService.GetSystemList();
            var systemID = context.HttpContext.Request.Headers["auth-system"].ToString();
            var secret = systemList.Where(x => x.SystemID == systemID).FirstOrDefault()?.Secret;
            if (string.IsNullOrEmpty(secret))
            {
                throw new ServiceException(-1, "无效的auth-system");
            }
            var des = new DesAccessor();
            var key = Encoding.UTF8.GetBytes(secret).Take(8).ToArray();
            var iv = key;

            var encodedText = context.HttpContext.Request.Headers["auth-key"].ToString();
            var decodedString = des.Decrypt(encodedText, key, iv);
            var spliteData = decodedString.Split('|', StringSplitOptions.RemoveEmptyEntries);
            DateTime visitTime;
            if (spliteData.Length != 2 || spliteData[0] != systemID || !DateTime.TryParseExact(spliteData[1], "MMyyyyddmmHHss", null, System.Globalization.DateTimeStyles.None, out visitTime))
            {
                throw new ServiceException(-1, "无效auth-key");
            }
            var passTime = Math.Abs(DateTime.Now.Subtract(visitTime).TotalMinutes);
            if (passTime > 5)
            {
                throw new ServiceException(-1, "auth-key访问超时，请重新生成auth-key");
            }

            var scopeList = systemService.GetScopeList(systemID);

            if (scopeList.Intersect(ScopeList).Count() == 0)
            {
                throw new ServiceException(-2, "未授权的操作。");
            }
            ///考虑如何处理频繁访问，暂时想到是每一次调用接口时记录缓存，一分钟后缓存消失，这时候才可以再次访问，但需要考虑是不是所有将来的接口都需要有这个限制；
            ///另一个方式就是直接记录日志，访问太频繁线下找对方追责
        }
    }
}