Add initial implementation of API, database, and user management components.

MikrocopApi/Services/JwtTokenService.cs

@@ -0,0 +1,47 @@
+using System.IdentityModel.Tokens.Jwt;
+using System.Security.Claims;
+using System.Text;
+using Microsoft.Extensions.Options;
+using Microsoft.IdentityModel.Tokens;
+using MikrocopApi.Configuration;
+using MikrocopDb.Entities;
+
+namespace MikrocopApi.Services;
+
+public sealed class JwtTokenService : IJwtTokenService
+{
+    private readonly JwtOptions _options;
+
+    public JwtTokenService(IOptions<JwtOptions> options)
+    {
+        _options = options.Value;
+    }
+
+    public (string AccessToken, DateTime ExpiresAtUtc) Generate(UserEntity user)
+    {
+        var now = DateTime.UtcNow;
+        var expires = now.AddMinutes(_options.ExpirationMinutes);
+
+        var claims = new List<Claim>
+        {
+            new(JwtRegisteredClaimNames.Sub, user.Id.ToString()),
+            new(JwtRegisteredClaimNames.UniqueName, user.UserName),
+            new(ClaimTypes.Name, user.UserName),
+            new(ClaimTypes.NameIdentifier, user.Id.ToString())
+        };
+
+        var key = new SymmetricSecurityKey(Encoding.UTF8.GetBytes(_options.SigningKey));
+        var creds = new SigningCredentials(key, SecurityAlgorithms.HmacSha256);
+
+        var token = new JwtSecurityToken(
+            issuer: _options.Issuer,
+            audience: _options.Audience,
+            claims: claims,
+            notBefore: now,
+            expires: expires,
+            signingCredentials: creds);
+
+        var serialized = new JwtSecurityTokenHandler().WriteToken(token);
+        return (serialized, expires);
+    }
+}