using Microsoft.Extensions.Caching.Memory;
using Microsoft.Extensions.Configuration;
using Microsoft.IdentityModel.Tokens;
using System;
using System.Collections.Generic;
using System.IdentityModel.Tokens.Jwt;
using System.Reflection;
using System.Security.Claims;
using System.Text;

namespace Common.Helper.Auth
{
    public class AuthHelper
    {

        private readonly IConfiguration _configuration;

        
        /// <param name="configuration"></param>
        public AuthHelper(IConfiguration configuration)
        {
            _configuration = configuration;
        }

        public string GetToken(dynamic userInfo)
        {
            var dynamicProperties =(PropertyInfo[]) userInfo.GetType().GetProperties();
            // token中的claims用于储存自定义信息，如登录之后的用户id等 
            var claims = new Claim[dynamicProperties.Length];
            for (var i = 0; i < dynamicProperties.Length; i++)
            {
                claims[i] = new Claim(dynamicProperties[i].Name, userInfo.GetType().GetProperty(dynamicProperties[i].Name).GetValue(userInfo,null)?.ToString());
            }
            // 获取SecurityKey
            var key = new SymmetricSecurityKey(Encoding.UTF8.GetBytes(_configuration.GetSection("Authentication")["SecurityKey"]));
            var token = new JwtSecurityToken(
                issuer: _configuration.GetSection("Authentication")["IsSure"],                    // 发布者
                audience: _configuration.GetSection("Authentication")["Audience"],                // 接收者
                notBefore: DateTime.Now,                                                          // token签发时间
                expires: DateTime.Now.AddMinutes(30),                                             // token过期时间  
                claims: claims,                                                                   // 该token内存储的自定义字段信息
                signingCredentials: new SigningCredentials(key, SecurityAlgorithms.HmacSha256)    // 用于签发token的秘钥算法
            );
            // 返回成功信息，写出token 
            return new JwtSecurityTokenHandler().WriteToken(token);
        }


    }
}