add a bunch of authentication stuff

Foxchat.Identity/Database/Models/Application.cs

@@ -0,0 +1,46 @@
+using System.Security.Cryptography;
+using Microsoft.AspNetCore.WebUtilities;
+
+namespace Foxchat.Identity.Database.Models;
+
+public class Application : BaseModel
+{
+    public required string ClientId { get; init; }
+    public required string ClientSecret { get; init; }
+    public required string Name { get; init; }
+    public required string[] Scopes { get; init; }
+
+    public static Application Create(string name, string[] scopes)
+    {
+        var clientId = RandomNumberGenerator.GetHexString(16, true);
+        var clientSecretBytes = RandomNumberGenerator.GetBytes(48);
+        var clientSecret = WebEncoders.Base64UrlEncode(clientSecretBytes);
+
+        if (!scopes.All(s => Scope.ValidScopes.Contains(s)))
+        {
+            throw new ArgumentException("Invalid scopes passed to Application.Create", nameof(scopes));
+        }
+
+        return new Application
+        {
+            ClientId = clientId,
+            ClientSecret = clientSecret,
+            Name = name,
+            Scopes = scopes,
+        };
+    }
+}
+
+public static class Scope
+{
+    /// <summary>
+    /// OAuth scope for identifying a user and nothing else.
+    /// </summary>
+    public const string Identity = "identity";
+    /// <summary>
+    /// OAuth scope for a full chat client. This grants *full access* to an account.
+    /// </summary>
+    public const string ChatClient = "chat_client";
+
+    public static readonly string[] ValidScopes = [Identity, ChatClient];
+}