Refactor: migrate Core -> Domain and reorganize projects

Large refactor that renames/moves core types into a new Govor.Domain surface and reorganizes the Application layer. Models, configurations, migrations and many files moved from Govor.Core/Govor.Data to Govor.Domain; numerous Application services, interfaces and implementations were relocated or added (authentication, friends, messages, medias, push notifications, user sessions, storage, synching, private chats, etc.). Tests updated to use Govor.Domain namespaces and adjusted project references (removed Govor.Data reference from API tests). Also updated API, Hub and mapping code and project files to reflect the new structure and naming. This is primarily a codebase-wide namespace and module reorganization to establish a Domain project and restructure application services.

Govor.Application/Authentication/JWT/IJwtService.cs

@@ -0,0 +1,11 @@
+using System.Security.Claims;
+using Govor.Domain.Models.Users;
+
+namespace Govor.Application.Authentication.JWT;
+
+public interface IJwtService
+{
+    Task<string> GenerateAccessTokenAsync(User user, Guid sessionId);
+    Task<string> GenerateRefreshTokenAsync(User user);
+    ClaimsPrincipal GetPrincipalFromExpiredToken(string token);
+}

Govor.Application/Authentication/JWT/IJwtTokenHasher.cs

@@ -0,0 +1,7 @@
+namespace Govor.Application.Authentication.JWT;
+
+public interface IJwtTokenHasher
+{
+    string HashToken(string token);
+    bool VerifyToken(string token, string storedHash);
+}

Govor.Application/Authentication/JWT/JwtAccessOption.cs

@@ -0,0 +1,6 @@
+namespace Govor.Application.Authentication.JWT;
+public class JwtAccessOption
+{
+    public string SecretKey {get; set;}
+    public int Minutes { get; set; }
+}

Govor.Application/Authentication/JWT/JwtRefreshOption.cs

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+namespace Govor.Application.Authentication.JWT;
+
+public class JwtRefreshOption
+{
+    public int RefreshTokenLifetimeDays { get; set; }
+}

Govor.Application/Authentication/JWT/JwtService.cs

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+using System.IdentityModel.Tokens.Jwt;
+using System.Security.Claims;
+using System.Text;
+using Govor.Domain.Models.Users;
+using Microsoft.Extensions.Options;
+using Microsoft.IdentityModel.Tokens;
+
+namespace Govor.Application.Authentication.JWT;
+
+public class JwtService : IJwtService
+{
+    private JwtAccessOption _jwtAccessOption;
+    private JwtRefreshOption _refreshOptions;
+    private IInvitesService _invitesService;
+    
+    public JwtService(IOptions<JwtAccessOption> options, IOptions<JwtRefreshOption> refreshOptions, IInvitesService invitesService)
+    {
+        _refreshOptions = refreshOptions.Value;
+        _jwtAccessOption = options.Value;
+        _invitesService = invitesService;
+    }
+    
+    public async Task<string> GenerateAccessTokenAsync(User user, Guid sessionId)
+    {
+        var claims = new[]
+        {
+            new Claim("userId", user.Id.ToString()),
+            new Claim("sid", sessionId.ToString()),
+            new Claim(ClaimTypes.Role, await _invitesService.GetRoleNameAsync(user), ClaimValueTypes.String)
+        };
+        
+        var singing = new SigningCredentials(
+            new SymmetricSecurityKey(Encoding.UTF8.GetBytes(_jwtAccessOption.SecretKey)),
+            SecurityAlgorithms.HmacSha256Signature);
+
+        var token = new JwtSecurityToken(
+            expires: DateTime.UtcNow.AddMinutes(_jwtAccessOption.Minutes),
+            signingCredentials: singing,
+            claims: claims);
+        
+        return new JwtSecurityTokenHandler().WriteToken(token);
+    }
+    
+    public async Task<string> GenerateRefreshTokenAsync(User user)
+    {
+        var key = new SymmetricSecurityKey(Encoding.UTF8.GetBytes(_jwtAccessOption.SecretKey));
+        var creds = new SigningCredentials(key, SecurityAlgorithms.HmacSha256);
+
+        var claims = new[]
+        {
+            new Claim("userId", user.Id.ToString()),
+            new Claim("tokenType", "refresh")
+        };
+
+        var token = new JwtSecurityToken(
+            expires: DateTime.UtcNow.AddDays(_refreshOptions.RefreshTokenLifetimeDays),
+            signingCredentials: creds,
+            claims: claims
+        );
+
+        return new JwtSecurityTokenHandler().WriteToken(token);
+    }
+    
+    public ClaimsPrincipal GetPrincipalFromExpiredToken(string token)
+    {
+        var tokenValidationParameters = new TokenValidationParameters
+        {
+            ValidateAudience = false,
+            ValidateIssuer = false,
+            ValidateIssuerSigningKey = true,
+            IssuerSigningKey = new SymmetricSecurityKey(Encoding.UTF8.GetBytes(_jwtAccessOption.SecretKey)),
+            ValidateLifetime = false // << important 
+        };
+        
+        var handler = new JwtSecurityTokenHandler();
+        var principal = handler.ValidateToken(token, tokenValidationParameters, out var securityToken);
+
+        if (securityToken is not JwtSecurityToken jwtToken || jwtToken.Header.Alg != SecurityAlgorithms.HmacSha256)
+            throw new SecurityTokenException("Invalid token");
+
+        return principal;
+    }
+
+}

Govor.Application/Authentication/JWT/JwtTokenHasher.cs

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+using System.Security.Cryptography;
+using System.Text;
+using Microsoft.Extensions.Configuration;
+
+namespace Govor.Application.Authentication.JWT;
+
+public class JwtTokenHasher : IJwtTokenHasher
+{
+    private readonly byte[] _pepperBytes;
+
+    public JwtTokenHasher(IConfiguration config)
+    {
+        var pepper = config["EncryptionOption:Secret"]
+                     ?? throw new InvalidOperationException("Pepper is missing");
+
+        _pepperBytes = Encoding.UTF8.GetBytes(pepper);
+    }
+
+    public string HashToken(string token)
+    {
+        using var hmac = new HMACSHA256(_pepperBytes);
+
+        var tokenBytes = Encoding.UTF8.GetBytes(token);
+        var hash = hmac.ComputeHash(tokenBytes);
+
+        return Convert.ToBase64String(hash);
+    }
+
+    public bool VerifyToken(string token, string storedHash)
+    {
+        using var hmac = new HMACSHA256(_pepperBytes);
+
+        var tokenBytes = Encoding.UTF8.GetBytes(token);
+        var computedHash = hmac.ComputeHash(tokenBytes);
+
+        var storedHashBytes = Convert.FromBase64String(storedHash);
+
+        return CryptographicOperations.FixedTimeEquals(computedHash, storedHashBytes);
+    }
+}