source: ChapterX.Infrastructure/Services/JwtTokenService.cs@ 0b502c2

using ChapterX.Application.Auth;
using ChapterX.Domain.Entities;
using Microsoft.Extensions.Configuration;
using Microsoft.IdentityModel.Tokens;
using System.IdentityModel.Tokens.Jwt;
using System.Security.Claims;
using System.Text;

namespace ChapterX.Infrastructure.Services
{
    public class JwtTokenService : IJwtTokenService
    {
        private readonly IConfiguration _configuration;

        public JwtTokenService(IConfiguration configuration)
        {
            _configuration = configuration;
        }

        public string GenerateToken(User user)
        {
            var key = new SymmetricSecurityKey(Encoding.UTF8.GetBytes(_configuration["Jwt:Key"]!));
            var credentials = new SigningCredentials(key, SecurityAlgorithms.HmacSha256);

            var role = user.Admin != null ? "Admin"
                : user.Writer != null ? "Writer"
                : "RegularUser";

            var claims = new[]
            {
                new Claim(JwtRegisteredClaimNames.Sub, user.Id.ToString()),
                new Claim(JwtRegisteredClaimNames.Email, user.Email),
                new Claim(JwtRegisteredClaimNames.UniqueName, user.Username),
                new Claim(JwtRegisteredClaimNames.Jti, Guid.NewGuid().ToString()),
                new Claim(ClaimTypes.Role, role)
            };

            var token = new JwtSecurityToken(
                issuer: _configuration["Jwt:Issuer"],
                audience: _configuration["Jwt:Audience"],
                claims: claims,
                expires: DateTime.UtcNow.AddDays(7),
                signingCredentials: credentials
            );

            return new JwtSecurityTokenHandler().WriteToken(token);
        }
    }
}