emoji-change events: add subtype helper (#19)

Author: johnkors

source/src/Slackbot.Net.Endpoints/Models/Events/EmojiChangedEvent.cs

@@ -4,9 +4,45 @@ namespace Slackbot.Net.Endpoints.Models.Events;
 // https://api.slack.com/events/emoji_changed
 public class EmojiChangedEvent : SlackEvent
 {
+    public const string SubTypeAdd = "add";
+    public const string SubTypeRemove = "remove";
+    public const string SubTypeRename = "rename";
+
+    public string SubType { get; init; } = string.Empty; // subtype: add, remove, rename
     public string? Name { get; set; } // subtype: add
     public string[] Names { get; set; } = []; //subtype:  remove
     public string OldName { get; set; } // subtype: rename
     public string NewName { get; set; } // subtype: rename
     public Uri? Value { get; set; }// subtypes: add, rename
+
+    public EmojiChange CreateSubType() => SubType switch
+    {
+        SubTypeAdd => new EmojiAdded { Name = Name!, Value = Value! },
+        SubTypeRemove => new EmojiRemoved { Names = Names },
+        SubTypeRename => new EmojiRenamed { OldName = OldName, NewName = NewName, Value = Value },
+        _ => new UnknownEmojiChange()
+    };
+}
+
+public class EmojiChange();
+
+public class EmojiAdded : EmojiChange
+{
+    public required string Name { get; init; }
+    public Uri Value { get; init; }
+}
+
+public class EmojiRemoved : EmojiChange
+{
+    public string[] Names { get; set; } = [];
 }
+
+public class EmojiRenamed : EmojiChange
+{
+    public string OldName { get; set; } // subtype: rename
+    public string NewName { get; set; } // subtype: rename
+    public Uri? Value { get; set; }// subtypes: add, rename
+}
+
+public class UnknownEmojiChange() : EmojiChange;
+