using System;
using System.Collections.Generic;
using System.Linq;
using System.Web;
using JWT;
using JWT.Algorithms;
using JWT.Exceptions;
using JWT.Serializers;
using Newtonsoft.Json;
using VueWebCoreApi.Models;

namespace VueWebCoreApi.Tools
{
    public static class JwtTools
    {
        public static ToMessage mes = new ToMessage(); //定义全局返回信息对象
        public static string Key = AppSetting.GetAppSetting("SigningKey");
        public static double time =double.Parse(AppSetting.GetAppSetting("RedisKeyTimeCont"));
        //public static string Key { get; set; } = "Hello World"; //不要泄密
        //加密
        public static ToMessage Encode(Dictionary<string, object> payLoad, string key = null)
        {
            if (string.IsNullOrEmpty(key))
            {
                key = Key;
            }

            IJwtAlgorithm algorithm = new HMACSHA256Algorithm();
            IJsonSerializer serializer = new JsonNetSerializer();
            IBase64UrlEncoder urlEncoder = new JwtBase64UrlEncoder();
            IJwtEncoder encoder = new JwtEncoder(algorithm, serializer, urlEncoder);
            //添加一个Jwt时效串
            payLoad.Add("timeout", DateTime.Now.AddSeconds(time));
            mes.code = "200";
            mes.Message = "获取token成功!";
            mes.data= encoder.Encode(payLoad, key);
            return mes;
        }

        //解密(数据类型1)
        public static Dictionary<string, object> Decode(string jwtstr, string key = null)
        {
            if (string.IsNullOrEmpty(key))
            {
                key = Key;
            }
            try
            {
                IJsonSerializer serializer = new JsonNetSerializer();
                IDateTimeProvider provider = new UtcDateTimeProvider();
                IJwtValidator validator = new JwtValidator(serializer, provider);
                IBase64UrlEncoder urlEncoder = new JwtBase64UrlEncoder();
                IJwtAlgorithm algorithm = new HMACSHA256Algorithm();
                IJwtDecoder decoder = new JwtDecoder(serializer, validator, urlEncoder, algorithm);

                var json = decoder.Decode(jwtstr, key, verify: true);//token为之前生成的字符串

                //string---->Dictionary
                //把一个字符串反向生成对应的对象内容 
                var result = JsonConvert.DeserializeObject<Dictionary<string, object>>(json);
                if ((DateTime)result["timeout"] < DateTime.Now)
                {
                    throw new Exception(message: "token已过期,请重新登录");
                }
                result.Remove(key: "timeout");
                return result;
            }
            catch (TokenExpiredException)
            {

                throw;  //请求超时
            }
            catch (SignatureVerificationException)
            {
                throw; //签名验证失败，数据可能被篡改
            }
        }
        //解密(数据类型2)
        public static User Denocode(string jwtstr, string key = null)
        {
            if (string.IsNullOrEmpty(key))
            {
                key = Key;
            }
            try
            {
                IJsonSerializer serializer = new JsonNetSerializer();
                IDateTimeProvider provider = new UtcDateTimeProvider();
                IJwtValidator validator = new JwtValidator(serializer, provider);
                IBase64UrlEncoder urlEncoder = new JwtBase64UrlEncoder();
                IJwtAlgorithm algorithm = new HMACSHA256Algorithm();
                IJwtDecoder decoder = new JwtDecoder(serializer, validator, urlEncoder, algorithm);

                var json = decoder.Decode(jwtstr, key, verify: true);//token为之前生成的字符串

                //string---->Dictionary
                //把一个字符串反向生成对应的对象内容 
                User loginUser = JsonConvert.DeserializeObject<User>(json);
                return loginUser;
            }
            catch (TokenExpiredException)
            {

                throw;  //请求超时
            }
            catch (SignatureVerificationException)
            {
                throw; //签名验证失败，数据可能被篡改
            }
        }

        //根据给定值获取键名
        public static K FindFirstValueByKey<K, V>(this Dictionary<K, V> dict, V val)
        {
            return dict.FirstOrDefault(entry =>
                EqualityComparer<V>.Default.Equals(entry.Value, val)).Key;
        }

        //根据给定键名获取值
        public static V FindFirstKeyByValue<K,V>(this Dictionary<K, V> dict, K val)
        {
            return dict.FirstOrDefault(entry =>EqualityComparer<K>.Default.Equals(entry.Key, val)).Value;
        }
        //校验登录
        //public static string key = "123456";
        //public static string ValideLogined(HttpRequest req)
        //{
        //    if (req.Headers["token"] == null)
        //        throw new Exception(message: "请登录!");
        //    return Decode(token: req.Headers["token"], key);
        //}
    }
}