From 28c0ab87b8c3452ade759ec23adfd00ffff72471 Mon Sep 17 00:00:00 2001
From: Marten Klitzke <marten@klitzke.xyz>
Date: Thu, 28 May 2026 09:48:49 +0200
Subject: [PATCH] feat(scheduler): cron-scheduled sweep on top of on-startup
 sweep
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Extracts the verifications loop into sweepAll() and adds scheduleSweep()
that wires node-cron to the configured `sweep.cron` expression. The READY
handler runs the startup sweep (when enabled) and then registers the
cron — so the scheduler only starts ticking after the gateway is up.

- src/scheduler.ts: sweepAll + scheduleSweep
- src/events/ready.ts: uses sweepAll for the startup pass, calls
  scheduleSweep at the end
- test/scheduler.test.ts: 3 unit tests covering iteration, error
  isolation between verifications, and empty-array safety

Verified live with cron "* * * * *": fired at the next minute boundary
~15s after start.

Co-Authored-By: Claude Opus 4.7 (1M context) <noreply@anthropic.com>
---
 src/events/ready.ts    | 17 +++++------
 src/scheduler.ts       | 22 ++++++++++++++
 test/scheduler.test.ts | 69 ++++++++++++++++++++++++++++++++++++++++++
 3 files changed, 98 insertions(+), 10 deletions(-)
 create mode 100644 src/scheduler.ts
 create mode 100644 test/scheduler.test.ts

diff --git a/src/events/ready.ts b/src/events/ready.ts
index f25fa78..01c719b 100644
--- a/src/events/ready.ts
+++ b/src/events/ready.ts
@@ -1,7 +1,8 @@
 import { type Client, Events } from "discord.js";
 import type { Config } from "../config.js";
 import { logger } from "../logger.js";
-import { type DiscordRestLike, runSweep } from "../sweep.js";
+import { scheduleSweep, sweepAll } from "../scheduler.js";
+import type { DiscordRestLike } from "../sweep.js";
 
 export function registerReady(client: Client, cfg: Config, rest: DiscordRestLike): void {
   client.once(Events.ClientReady, async (readyClient) => {
@@ -16,15 +17,11 @@ export function registerReady(client: Client, cfg: Config, rest: DiscordRestLike
       "ready",
     );
 
-    if (!cfg.sweep.on_startup) return;
-
-    for (const v of cfg.verifications) {
-      try {
-        const result = await runSweep(rest, v);
-        logger.info({ verification: v.name, ...result }, "sweep complete");
-      } catch (err) {
-        logger.error({ err, verification: v.name }, "sweep failed");
-      }
+    if (cfg.sweep.on_startup) {
+      await sweepAll(cfg, rest);
     }
+
+    scheduleSweep(cfg, rest);
+    logger.info({ cron: cfg.sweep.cron }, "cron sweep scheduled");
   });
 }
diff --git a/src/scheduler.ts b/src/scheduler.ts
new file mode 100644
index 0000000..2709713
--- /dev/null
+++ b/src/scheduler.ts
@@ -0,0 +1,22 @@
+import cron, { type ScheduledTask } from "node-cron";
+import type { Config } from "./config.js";
+import { logger } from "./logger.js";
+import { type DiscordRestLike, runSweep } from "./sweep.js";
+
+export async function sweepAll(cfg: Config, rest: DiscordRestLike): Promise<void> {
+  for (const v of cfg.verifications) {
+    try {
+      const result = await runSweep(rest, v);
+      logger.info({ verification: v.name, ...result }, "sweep complete");
+    } catch (err) {
+      logger.error({ err, verification: v.name }, "sweep failed");
+    }
+  }
+}
+
+export function scheduleSweep(cfg: Config, rest: DiscordRestLike): ScheduledTask {
+  return cron.schedule(cfg.sweep.cron, async () => {
+    logger.info({ cron: cfg.sweep.cron }, "scheduled sweep starting");
+    await sweepAll(cfg, rest);
+  });
+}
diff --git a/test/scheduler.test.ts b/test/scheduler.test.ts
new file mode 100644
index 0000000..0557261
--- /dev/null
+++ b/test/scheduler.test.ts
@@ -0,0 +1,69 @@
+import { describe, expect, it, vi } from "vitest";
+import type { Config, Verification } from "../src/config.js";
+import { sweepAll } from "../src/scheduler.js";
+import type { DiscordRestLike } from "../src/sweep.js";
+
+function verification(name: string, message_id: string): Verification {
+  return {
+    name,
+    guild_id: "1000000000000000001",
+    channel_id: "1000000000000000002",
+    message_id,
+    emoji: "✅",
+    role_id: "1000000000000000004",
+    on_remove: "keep",
+  };
+}
+
+function mockRest(overrides: Partial<DiscordRestLike> = {}): DiscordRestLike {
+  return {
+    listReactors: vi.fn().mockResolvedValue([]),
+    getMember: vi.fn().mockResolvedValue(null),
+    addMemberRole: vi.fn().mockResolvedValue(undefined),
+    removeMemberRole: vi.fn().mockResolvedValue(undefined),
+    ...overrides,
+  };
+}
+
+function configWith(verifications: Verification[]): Config {
+  return {
+    verifications,
+    sweep: { on_startup: false, cron: "0 */6 * * *" },
+  };
+}
+
+describe("sweepAll", () => {
+  it("runs sweep for each verification", async () => {
+    const cfg = configWith([
+      verification("a", "1000000000000000003"),
+      verification("b", "1000000000000000005"),
+    ]);
+    const rest = mockRest();
+    await sweepAll(cfg, rest);
+    expect(rest.listReactors).toHaveBeenCalledTimes(2);
+  });
+
+  it("continues to next verification when one throws", async () => {
+    const cfg = configWith([
+      verification("a", "1000000000000000003"),
+      verification("b", "1000000000000000005"),
+    ]);
+    const rest = mockRest({
+      listReactors: vi.fn().mockRejectedValueOnce(new Error("boom")).mockResolvedValue([]),
+    });
+    await sweepAll(cfg, rest);
+    expect(rest.listReactors).toHaveBeenCalledTimes(2);
+  });
+
+  it("no-ops on an empty-verification config (shouldn't happen, but doesn't crash)", async () => {
+    // The zod schema rejects empty arrays at parse time, so this only matters
+    // if a future caller constructs Config in-memory; just confirm no throw.
+    const cfg: Config = {
+      verifications: [],
+      sweep: { on_startup: false, cron: "0 */6 * * *" },
+    };
+    const rest = mockRest();
+    await expect(sweepAll(cfg, rest)).resolves.toBeUndefined();
+    expect(rest.listReactors).not.toHaveBeenCalled();
+  });
+});