// nzbget's events. The tool runtime imports this once the broker is bound. It watches the download
// queue and the history and turns their comings and goings into mesh events.
//
// Emits (novox/hq ADR 0041/0042):
//   module.nzbget.download.added       — an NZB entered the queue
//   module.nzbget.download.completed   — an NZB finished successfully (left the queue, landed in
//                                        history as SUCCESS). This exact routing key is what the
//                                        plex module consumes (module.*.download.completed) to
//                                        rescan, so the new file becomes a visible item.
// Consumes: none.
//
// Two diffs, each primed silently on the first look (like plex's and sonarr's index.ts) so a
// restart mid-download does not re-announce everything already in flight or already finished. The
// queue tells us what was grabbed; history — not the queue's disappearance — tells us what actually
// succeeded, since a failed or deleted download also leaves the queue.

import { emit } from "@novox/mesh-sdk/events";
import { NzbgetClient } from "./client.js";

const nzbget = NzbgetClient.fromEnv();

const inQueue = new Set<number>();
let queuePrimed = false;
async function pollQueue(): Promise<void> {
  const items = await nzbget.getQueue();
  const now = new Set(items.map((i) => i.id));
  if (queuePrimed) {
    for (const item of items) {
      if (!inQueue.has(item.id)) {
        await emit("module.nzbget.download.added", { name: item.name, category: item.category, sizeMB: item.sizeMB });
      }
    }
  }
  inQueue.clear();
  for (const id of now) inQueue.add(id);
  queuePrimed = true;
}

const seenHistory = new Set<number>();
let historyPrimed = false;
async function pollHistory(): Promise<void> {
  const items = await nzbget.getHistory(50);
  for (const item of items) {
    if (!seenHistory.has(item.id)) {
      // A newly-appeared history entry is a completion only if it actually succeeded; a failure or
      // a manual delete lands in history too, and neither is a "download.completed".
      if (historyPrimed && item.success) {
        await emit("module.nzbget.download.completed", { name: item.name, category: item.category, sizeMB: item.sizeMB });
      }
      seenHistory.add(item.id);
    }
  }
  historyPrimed = true;
}

const tick = (fn: () => Promise<void>, everyMs: number): void => {
  const run = (): void => void fn().catch((err) => console.error(`[nzbget] ${err}`));
  setInterval(run, everyMs);
  run();
};
tick(pollQueue, 20_000);
tick(pollHistory, 30_000);

console.log("[nzbget] watching the queue and history, emitting adds and completions");