add a bunch of authentication stuff

Foxchat.Identity/Authorization/AuthenticationHandler.cs

@@ -1,3 +1,14 @@
+using System.Security.Cryptography;
+using System.Text.Encodings.Web;
+using Foxchat.Core;
+using Foxchat.Core.Utils;
+using Foxchat.Identity.Database;
+using Microsoft.AspNetCore.Authentication;
+using Microsoft.AspNetCore.Authentication.BearerToken;
+using Microsoft.EntityFrameworkCore;
+using Microsoft.Extensions.Options;
+using NodaTime;
+
 namespace Foxchat.Identity.Authorization;
 
 public static class AuthenticationHandlerExtensions
@@ -6,4 +17,34 @@ public static class AuthenticationHandlerExtensions
     {
 
     }
-}
+}
+
+public class FoxchatAuthenticationHandler(
+    IOptionsMonitor<BearerTokenOptions> options,
+    ILoggerFactory logger,
+    UrlEncoder encoder,
+    IdentityContext context,
+    IClock clock
+) : AuthenticationHandler<AuthenticationSchemeOptions>(options, logger, encoder)
+{
+    protected override async Task<AuthenticateResult> HandleAuthenticateAsync()
+    {
+        var header = Request.Headers.Authorization.ToString();
+        if (!header.StartsWith("bearer ", StringComparison.InvariantCultureIgnoreCase))
+            return AuthenticateResult.NoResult();
+        var token = header[7..];
+
+        if (!CryptoUtils.TryFromBase64String(token, out var rawToken))
+            return AuthenticateResult.Fail(new FoxchatError.BadRequest("Invalid token format"));
+
+        var hash = SHA512.HashData(rawToken);
+        var oauthToken = await context.Tokens
+            .Include(t => t.Account)
+            .Include(t => t.Application)
+            .FirstOrDefaultAsync(t => t.Hash == hash && t.Expires > clock.GetCurrentInstant());
+        if (oauthToken == null)
+            return AuthenticateResult.NoResult();
+
+        throw new NotImplementedException();
+    }
+}