Slack: add some fixes and connect it all up

src/slack/probe.ts

@@ -0,0 +1,59 @@
+import { WebClient } from "@slack/web-api";
+
+export type SlackProbe = {
+  ok: boolean;
+  status?: number | null;
+  error?: string | null;
+  elapsedMs?: number | null;
+  bot?: { id?: string; name?: string };
+  team?: { id?: string; name?: string };
+};
+
+function withTimeout<T>(promise: Promise<T>, timeoutMs: number): Promise<T> {
+  if (!timeoutMs || timeoutMs <= 0) return promise;
+  let timer: NodeJS.Timeout | null = null;
+  const timeout = new Promise<T>((_, reject) => {
+    timer = setTimeout(() => reject(new Error("timeout")), timeoutMs);
+  });
+  return Promise.race([promise, timeout]).finally(() => {
+    if (timer) clearTimeout(timer);
+  });
+}
+
+export async function probeSlack(
+  token: string,
+  timeoutMs = 2500,
+): Promise<SlackProbe> {
+  const client = new WebClient(token);
+  const start = Date.now();
+  try {
+    const result = await withTimeout(client.auth.test(), timeoutMs);
+    if (!result.ok) {
+      return {
+        ok: false,
+        status: 200,
+        error: result.error ?? "unknown",
+        elapsedMs: Date.now() - start,
+      };
+    }
+    return {
+      ok: true,
+      status: 200,
+      elapsedMs: Date.now() - start,
+      bot: { id: result.user_id ?? undefined, name: result.user ?? undefined },
+      team: { id: result.team_id ?? undefined, name: result.team ?? undefined },
+    };
+  } catch (err) {
+    const message = err instanceof Error ? err.message : String(err);
+    const status =
+      typeof (err as { status?: number }).status === "number"
+        ? (err as { status?: number }).status
+        : null;
+    return {
+      ok: false,
+      status,
+      error: message,
+      elapsedMs: Date.now() - start,
+    };
+  }
+}