using Microsoft.AspNetCore.Mvc;
using Microsoft.AspNetCore.Mvc.Filters;
using Newtonsoft.Json.Linq;
using Newtonsoft.Json;
using System;
using System.Collections.Generic;
using System.Linq;
using System.Text;
using System.Threading.Tasks;
using Utility.Tools;
using static System.Net.Mime.MediaTypeNames;

namespace Utility
{
    /// <summary>
    /// 验签
    /// </summary>
    [AttributeUsage(AttributeTargets.Class | AttributeTargets.Method, AllowMultiple = false)]
    public class VerificationAttribute : ActionFilterAttribute
    {
        private static readonly string appKey = SignConfig.AppKey;
        private static readonly double Minutes = SignConfig.Minutes;//时间戳必须5分钟内的，否则不通过
        public VerificationAttribute()
        {

        }

        public override async Task OnActionExecutionAsync(ActionExecutingContext context, ActionExecutionDelegate next)
        {
            var request = context.HttpContext.Request;

            // 获取请求中的时间戳和签名
            var timestamp = request.Headers["Timestamp"].FirstOrDefault();
            var signature = request.Headers["Signature"].FirstOrDefault();
            //var timestamp = "1718873584";
            //var signature = "1718873584";

            if (string.IsNullOrEmpty(timestamp) || string.IsNullOrEmpty(signature))
            {
                context.Result = new UnauthorizedResult();
                return;
            }

            // 验证时间戳是否在允许的时间范围内
            if (!IsTimestampValid(timestamp))
            {
                context.Result = new UnauthorizedResult();
                return;
            }

            // 读取请求体中的 JSON 参数
            string jsonParams;
            using (var reader = new System.IO.StreamReader(request.Body, Encoding.UTF8, true, 1024, true))
            {
                // 将请求体流位置重置到起始位置
                request.Body.Seek(0, System.IO.SeekOrigin.Begin);
                jsonParams = await reader.ReadToEndAsync();
            }

            // 反序列化 JSON 参数为 JObject
            JObject jObject = null;
            Dictionary<string, string> filteredProperties = new Dictionary<string, string>();
            if (jsonParams != null)
            {
                try
                {
                    jObject = JObject.Parse(jsonParams);
                    // 过滤掉数组类型的属性
                    filteredProperties = jObject.Properties()
                        .Where(p => p.Value.Type != JTokenType.Array)
                        .ToDictionary(p => p.Name, p => p.Value.ToString());
                }
                catch (JsonReaderException)
                {
                    // JSON 格式错误，返回未经授权
                    context.Result = new UnauthorizedResult();
                    return;
                }
            }
            filteredProperties.Add("timestamp", timestamp);
            filteredProperties.Add("appKey", appKey);

            // 构建待签名字符串
            var signatureBaseString = string.Join("&", filteredProperties.OrderBy(p => p.Key).Select(p => p.Key + "=" + p.Value));

            // 计算 MD5 值
            var computedSignature = Md5Tools.CalcMd5(Encoding.UTF8.GetBytes(signatureBaseString));

            // 验证签名
            if (computedSignature != signature)
            {
                context.Result = new UnauthorizedResult();
                return;
            }

            await base.OnActionExecutionAsync(context, next);
        }

        private bool IsTimestampValid(string timestamp)
        {
            //var logs = long.Parse(timestamp);
            //var logs2 = int.Parse(timestamp);
            if (long.TryParse(timestamp, out var timestampSeconds))
            {
                var requestDateTime = DateTimeOffset.FromUnixTimeSeconds(timestampSeconds);
                var currentDateTime = DateTimeOffset.UtcNow;

                // 计算时间差
                var timeDifference = currentDateTime - requestDateTime;

                // 比较时间差是否在允许的范围内
                return timeDifference.TotalMinutes <= Minutes;

            }
            return false;

        }
    }
    public class SignConfig
    {
        public static string AppKey { get; set; }
        public static double Minutes { get; set; }
    }

}