Adds keyboard shortcut for editing last message sent

ts/util/canEditMessage.ts

@@ -0,0 +1,24 @@
+// Copyright 2023 Signal Messenger, LLC
+// SPDX-License-Identifier: AGPL-3.0-only
+
+import type { MessageAttributesType } from '../model-types.d';
+import { HOUR } from './durations';
+import { canEditMessages } from './canEditMessages';
+import { isMoreRecentThan } from './timestamp';
+import { isOutgoing } from '../messages/helpers';
+import { isSent, someSendStatus } from '../messages/MessageSendState';
+
+const MAX_EDIT_COUNT = 10;
+const THREE_HOURS = 3 * HOUR;
+
+export function canEditMessage(message: MessageAttributesType): boolean {
+  return (
+    canEditMessages() &&
+    !message.deletedForEveryone &&
+    isOutgoing(message) &&
+    isMoreRecentThan(message.sent_at, THREE_HOURS) &&
+    (message.editHistory?.length ?? 0) <= MAX_EDIT_COUNT &&
+    someSendStatus(message.sendStateByConversationId, isSent) &&
+    Boolean(message.body)
+  );
+}