Add project files.

CalendarReminder.Api/Services/TokenService.cs

@@ -0,0 +1,39 @@
+using CalendarReminder.Domain.Entities;
+using Microsoft.IdentityModel.Tokens;
+using System.IdentityModel.Tokens.Jwt;
+using System.Security.Claims;
+using System.Text;
+
+namespace CalendarReminder.Api.Services;
+
+public class TokenService
+{
+    private readonly IConfiguration _config;
+
+    public TokenService(IConfiguration config)
+    {
+        _config = config;
+    }
+
+    public string GenerateToken(User user)
+    {
+        var key = new SymmetricSecurityKey(Encoding.UTF8.GetBytes(_config["Jwt:Secret"]!));
+        var creds = new SigningCredentials(key, SecurityAlgorithms.HmacSha256);
+
+        var claims = new[]
+        {
+            new Claim(ClaimTypes.NameIdentifier, user.Id.ToString()),
+            new Claim(ClaimTypes.Name, user.Username),
+            new Claim(ClaimTypes.Email, user.Email)
+        };
+
+        var token = new JwtSecurityToken(
+            issuer: _config["Jwt:Issuer"],
+            audience: _config["Jwt:Audience"],
+            claims: claims,
+            expires: DateTime.UtcNow.AddDays(7),
+            signingCredentials: creds);
+
+        return new JwtSecurityTokenHandler().WriteToken(token);
+    }
+}