WIP: register Slack Preview Deployment agents

packages/eve/src/public/channels/slack/index.ts

@@ -66,6 +66,12 @@ export {
 
 export { defaultSlackAuth } from "#public/channels/slack/defaults.js";
 
+export {
+  slackUserGroupMentions,
+  withoutSlackUserGroupMention,
+  type SlackUserGroupMention,
+} from "#public/channels/slack/user-groups.js";
+
 export {
   describeActionRequest,
   describeActionRequests,

packages/eve/src/public/channels/slack/user-groups.test.ts

@@ -0,0 +1,22 @@
+import { describe, expect, it } from "vitest";
+
+import {
+  slackUserGroupMentions,
+  withoutSlackUserGroupMention,
+} from "#public/channels/slack/user-groups.js";
+
+describe("slackUserGroupMentions", () => {
+  it("returns unique opaque group ids in mention order", () => {
+    expect(
+      slackUserGroupMentions("Ask <!subteam^S123|preview> then <!subteam^S456>. <!subteam^S123>"),
+    ).toEqual([{ id: "S123" }, { id: "S456" }]);
+  });
+});
+
+describe("withoutSlackUserGroupMention", () => {
+  it("removes only the selected group mention", () => {
+    expect(
+      withoutSlackUserGroupMention("<!subteam^S123|preview> check <!subteam^S456>", "S123"),
+    ).toBe("check <!subteam^S456>");
+  });
+});

packages/eve/src/public/channels/slack/user-groups.ts

@@ -0,0 +1,34 @@
+const USER_GROUP_MENTION = /<!subteam\^([A-Z0-9]+)(?:\|[^>]+)?>/gu;
+
+/** One Slack user-group mention found in message text. */
+export interface SlackUserGroupMention {
+  readonly id: string;
+}
+
+/**
+ * Returns unique Slack user-group ids mentioned in text in first-mention
+ * order. The parser deliberately retains Slack's opaque id rather than a
+ * mutable display handle so channel-owned registries can verify ownership.
+ */
+export function slackUserGroupMentions(text: string): readonly SlackUserGroupMention[] {
+  const seen = new Set<string>();
+  const mentions: SlackUserGroupMention[] = [];
+  for (const match of text.matchAll(USER_GROUP_MENTION)) {
+    const id = match[1];
+    if (id === undefined || seen.has(id)) continue;
+    seen.add(id);
+    mentions.push({ id });
+  }
+  return mentions;
+}
+
+/**
+ * Removes one recognized user-group mention using the same whitespace
+ * normalization callers use for an empty Slack app mention.
+ */
+export function withoutSlackUserGroupMention(text: string, userGroupId: string): string {
+  return text
+    .replace(USER_GROUP_MENTION, (mention, id: string) => (id === userGroupId ? "" : mention))
+    .replace(/\s+/gu, " ")
+    .trim();
+}