// bookshelf's events. The tool runtime imports this once the broker is bound. It watches the
// download queue and turns its comings and goings into mesh events — the same mechanism radarr uses,
// applied to a Servarr book manager.
//
// Emits (novox/hq ADR 0041/0042):
//   module.bookshelf.book.grabbed        — a release entered the queue (Bookshelf grabbed it)
//   module.bookshelf.download.completed  — a release left the queue, imported. This routing key is
//                                          what the plex module consumes (module.*.download.completed)
//                                          to rescan, so a new audiobook becomes a visible item.
// Consumes: none.
//
// NOTE: the hal bookshelf module emitted no events (its hooks only did install-time provisioning).
// This queue watcher is new in nox, modelled exactly on radarr's — bookshelf is a Servarr app with
// the same queue semantics, so the diff-and-emit pattern carries over unchanged.
//
// The queue is polled and diffed, primed silently on the first look (like plex's index.ts) so a
// restart mid-download does not re-announce everything already in flight as freshly grabbed.

import { emit } from "@novox/mesh-sdk/events";
import { BookshelfClient, type BookshelfQueueItem } from "./client.js";

// Building the client throws when Bookshelf has no URL/key yet. Like the tools (see tools/index.ts),
// the events entrypoint must not crash the runtime for that — it stays idle until configured.
function buildClient(): BookshelfClient | null {
  try {
    return BookshelfClient.fromEnv();
  } catch {
    return null;
  }
}

const bookshelf = buildClient();

// Bookshelf removes an item from the queue once it has been imported; a "warning"/"failed" status is
// how a stuck or broken grab shows itself, so we do not call those a completion when they vanish.
const FAILED_STATUSES = new Set(["failed", "warning"]);

const inQueue = new Map<number, BookshelfQueueItem>();
let primed = false;

async function pollQueue(bookshelf: BookshelfClient): Promise<void> {
  const { items } = await bookshelf.getQueue();
  const now = new Map(items.map((i) => [i.id, i]));

  if (primed) {
    // Entered the queue since last look — Bookshelf grabbed a release.
    for (const [id, item] of now) {
      if (!inQueue.has(id)) await emit("module.bookshelf.book.grabbed", { title: item.title, status: item.status });
    }
    // Left the queue — imported and done, unless it was last seen failing.
    for (const [id, item] of inQueue) {
      if (!now.has(id) && !FAILED_STATUSES.has(item.status)) {
        await emit("module.bookshelf.download.completed", { title: item.title });
      }
    }
  }

  inQueue.clear();
  for (const [id, item] of now) inQueue.set(id, item);
  primed = true;
}

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

if (bookshelf) {
  tick(() => pollQueue(bookshelf), 30_000);
  console.log("[bookshelf] watching the download queue, emitting grabs and completions");
} else {
  console.log("[bookshelf] not configured — events idle until an API key is available");
}