Completely untested and totally experimental rate limit feature

KfChatDotNetBot/Models/RateLimitModels.cs

@@ -0,0 +1,83 @@
+namespace KfChatDotNetBot.Models;
+
+public class RateLimitBucketEntryModel
+{
+    /// <summary>
+    /// Database user ID of the user whose entry this belongs to
+    /// </summary>
+    public required int UserId { get; set; }
+    /// <summary>
+    /// When the entry was created in the bucket
+    /// </summary>
+    public required DateTimeOffset EntryCreated { get; set; }
+    /// <summary>
+    /// When the entry is expected to expire based on the command's window
+    /// </summary>
+    public required DateTimeOffset EntryExpires { get; set; }
+    /// <summary>
+    /// String representation of the command using ICommand.GetType().Name
+    /// </summary>
+    public required string CommandInvoked { get; set; }
+    /// <summary>
+    /// Hashed contents of the message for if UseEntireMessage is enabled
+    /// </summary>
+    public required string MessageHash { get; set; }
+}
+
+public class RateLimitOptionsModel
+{
+    /// <summary>
+    /// Window of time to count an invocation towards the rate limit
+    /// </summary>
+    public required TimeSpan Window { get; set; }
+    /// <summary>
+    /// Maximum number of permitted invocations within the window before triggering the rate limit
+    /// </summary>
+    public required int MaxInvocations { get; set; }
+    /// <summary>
+    /// Optional set of flags to configure the behavior of the rate limiter
+    /// </summary>
+    public RateLimitFlags Flags { get; set; }
+}
+
+public class IsRateLimitedModel
+{
+    /// <summary>
+    /// Is the user's request rate limited?
+    /// </summary>
+    public required bool IsRateLimited { get; set; }
+    /// <summary>
+    /// When the oldest entry expires so users know when they can next use the command
+    /// This is set to null if the user is not rate limited
+    /// </summary>
+    public DateTimeOffset? OldestEntryExpires { get; set; }
+}
+
+[Flags]
+public enum RateLimitFlags
+{
+    /// <summary>
+    /// Silently ignore a user when they trigger a rate limit
+    /// </summary>
+    NoResponse,
+    /// <summary>
+    /// The default behavior is to rate limit based on command invoked.
+    /// UseEntireMessage changes it to consider dissimilar messages which invoke
+    /// the same command as being separate for the purposes of rate limiting.
+    /// With this, only identical messages count towards the rate limit.
+    /// </summary>
+    UseEntireMessage,
+    /// <summary>
+    /// The rate limit is global instead of applying per-user
+    /// </summary>
+    Global,
+    /// <summary>
+    /// Exempt users with a higher than default level from rate limiting
+    /// </summary>
+    ExemptPrivilegedUsers,
+    /// <summary>
+    /// Automatically clean up the cooldown response sent to a user
+    /// Mutually exclusive with NoResponse
+    /// </summary>
+    AutoDeleteCooldownResponse
+}