using Microsoft.Extensions.Options;
using Microsoft.IdentityModel.Tokens;
using System;
using System.Collections.Generic;
using System.IdentityModel.Tokens.Jwt;
using System.Linq;
using System.Security.Claims;
using System.Text;
using System.Threading.Tasks;
using Volo.Abp.DependencyInjection;

namespace Syc.Authorize.JwtBearer
{
    [Dependency(Microsoft.Extensions.DependencyInjection.ServiceLifetime.Transient)]
    public class JwtTokenService : IJwtTokenService
    {
        private JwtBearerAuthenticationOptions JwtSetting { get; set; }
        private JwtSecurityTokenHandler JwtSecurityTokenHandler { get; set; }
        public JwtTokenService(IOptions<JwtBearerAuthenticationOptions> options)
        {
            JwtSetting = options.Value;
            JwtSecurityTokenHandler = new JwtSecurityTokenHandler();
        }

        /// <summary>
        /// 生成 token
        /// </summary>
        /// <param name="obj"></param>
        /// <param name="jwtSetting"></param>
        /// <returns></returns>
        public string GenerateToken(object obj, JwtBearerAuthenticationOptions jwtSetting = null)
        {
            jwtSetting = jwtSetting ?? JwtSetting;

            var dics = GetPropertieValues(obj);

            //组装claims
            var claims = dics.Where(e =>  e.Value is not null).Select(x => new Claim(x.Key, x.Value?.ToString())).ToList();

            var key = new SymmetricSecurityKey(Encoding.UTF8.GetBytes(jwtSetting.SecurityKey));
            var credentials = new SigningCredentials(key, string.IsNullOrWhiteSpace(jwtSetting.Algorithms) ? SecurityAlgorithms.HmacSha256 : jwtSetting.Algorithms);

            var jwtSecurityToken = new JwtSecurityToken(jwtSetting.Issuer, jwtSetting.Audience, claims, null, DateTime.Now.AddMinutes(jwtSetting.ExpiredTime), credentials);

            return JwtSecurityTokenHandler.WriteToken(jwtSecurityToken);
        }

        /// <summary>
        /// 获取对象属性键值对
        /// </summary>
        /// <param name="obj"></param>
        /// <returns></returns>
        public IDictionary<string, object> GetPropertieValues(object obj)
        {
            var t = obj.GetType();
            var props = t.GetProperties();

            IDictionary<string, object> dics = new Dictionary<string, object>();

            if (props is not null && props.Any())
                foreach (var prop in props)
                {
                    dics.Add(prop.Name, prop.GetValue(obj));
                }

            return dics;
        }

        /// <summary>
        /// get claims by token
        /// </summary>
        /// <param name="token"></param>
        /// <returns></returns>
        public IEnumerable<Claim> GetClaims(string token)
        {
            var tokenHandler = new JwtSecurityTokenHandler();

            return tokenHandler.ReadJwtToken(token)?.Claims;
        }

        /// <summary>
        /// 手动验证token
        /// </summary>
        /// <param name="token"></param>
        /// <returns></returns>
        public bool ValidateToken(string token, TokenValidationParameters tokenValidationParameters = null)
        {
            tokenValidationParameters = tokenValidationParameters ?? JwtSetting.TokenValidationParameters;
            SecurityToken validatedToken = null;
            try
            {
                JwtSecurityTokenHandler.ValidateToken(token, tokenValidationParameters, out validatedToken);
            }
            catch (SecurityTokenException stexp)
            {
                return false;
            }
            catch (Exception e)
            {
                return false;
            }

            return validatedToken != null;
        }
    }
}