using JWT;
using JWT.Algorithms;
using JWT.Serializers;
using System;
using System.Collections.Generic;
using System.Linq;
using System.Text;
using System.Threading.Tasks;

namespace JWTDemo
{
    class Program
    {
        static void Main(string[] args)
        {
            //载荷（payload）
            var payload = new Dictionary<string, object>{
                { "iss","terryK"},//发行人
                { "exp", DateTimeOffset.UtcNow.AddSeconds(120).ToUnixTimeSeconds() },//到期时间
                { "sub", "testJWT" }, //主题
                { "aud", "USER" }, //用户
                { "iat", DateTime.Now.ToString() }, //发布时间 
                { "data" ,new { name="Admini",age=20,address="GuangDong"} }
            };

            //生成JWT
            Console.WriteLine("******************生成JWT*******************");
            string JWTString = JwtHelper.CreateJWT(payload);
            Console.WriteLine(JWTString);

            //校验JWT
            Console.WriteLine("*******************校验JWT，获得载荷***************");
            string ResultMessage;//需要解析的消息
            string Payload;//获取负载
            if (JwtHelper.ValidateJWT(JWTString, out Payload, out ResultMessage))
            {
                Console.WriteLine(Payload);
            }

            Console.WriteLine(ResultMessage);//验证结果说明
            Console.WriteLine("*******************END*************************");
            Console.ReadKey();
        }
    }

    class JwtHelper
    {
        static IJwtAlgorithm algorithm = new HMACSHA256Algorithm();//HMACSHA256加密
        static IJsonSerializer serializer = new JsonNetSerializer();//序列化和反序列
        static IBase64UrlEncoder urlEncoder = new JwtBase64UrlEncoder();//Base64编解码
        static IDateTimeProvider provider = new UtcDateTimeProvider();//UTC时间获取
        const string secret = "MIGfMA0GCSqGSIb3DQEBAQUAA4GNADCBiQKBgQC4aKpVo2OHXPwb1R7duLgg";//服务端
        public static string CreateJWT(Dictionary<string, object> payload)
        {
            IJwtEncoder encoder = new JwtEncoder(algorithm, serializer, urlEncoder);
            return encoder.Encode(payload, secret);
        }

        public static bool ValidateJWT(string token, out string payload, out string message)
        {
            bool isValidted = false;
            payload = "";
            try
            {
                IJwtValidator validator = new JwtValidator(serializer, provider);//用于验证JWT的类

                IJwtDecoder decoder = new JwtDecoder(serializer, validator, urlEncoder);//用于解析JWT的类
                payload = decoder.Decode(token, secret, verify: true);

                isValidted = true;
                message = "验证成功";
            }
            catch (TokenExpiredException)//当前时间大于负载过期时间（负荷中的exp），会引发Token过期异常
            {
                message = "过期了！";
            }
            catch (SignatureVerificationException)//如果签名不匹配，引发签名验证异常
            {
                message = "签名错误！";
            }
            return isValidted;
        }

        /*
        /// <summary>
        /// 对header和payload进行base64加密
        /// </summary>
        /// <param name="extraHeaders"></param>
        /// <param name="payload"></param>
        /// <param name="key"></param>
        /// <returns></returns>
        public string Encode(IDictionary<string, object> extraHeaders, object payload, byte[] key)
        {
            if (payload is null)
                throw new ArgumentNullException(nameof(payload));

            var segments = new List<string>(3);

            var header = extraHeaders is null ? new Dictionary<string, object>(StringComparer.OrdinalIgnoreCase) : new Dictionary<string, object>(extraHeaders, StringComparer.OrdinalIgnoreCase);
            header.Add("typ", "JWT");
            header.Add("alg", _algorithm.Name);

            var headerBytes = GetBytes(_jsonSerializer.Serialize(header));
            var payloadBytes = GetBytes(_jsonSerializer.Serialize(payload));

            segments.Add(_urlEncoder.Encode(headerBytes));
            segments.Add(_urlEncoder.Encode(payloadBytes));

            var stringToSign = String.Join(".", segments.ToArray());
            var bytesToSign = GetBytes(stringToSign);

            var signature = _algorithm.Sign(key, bytesToSign);
            segments.Add(_urlEncoder.Encode(signature));

            return String.Join(".", segments.ToArray());
        }
        */
    }
}