fix(queue): extract shared arr cache helper, annotate season packs, null-guard flatMap (closes #61)

server/utils/arrQueueHelpers.js

@@ -0,0 +1,97 @@
+// Copyright (c) 2026 Gordon Bolton. MIT License.
+//
+// Shared helpers for assembling the cached *arr queue payload.
+//
+// Both the background poller (`server/utils/poller.js`) and the webhook
+// processor (`server/routes/webhook.js`) build the `poll:sonarr-queue` and
+// `poll:radarr-queue` cache entries from an array of per-instance queue
+// responses. Historically the same `flatMap` block was duplicated across all
+// four call sites (Sonarr + Radarr × poller + webhook) and had begun to drift.
+//
+// This module centralises that logic, adds defensive null-guards, and — for
+// Sonarr only — annotates season-pack records (queue entries sharing a
+// `downloadId`) with `isSeasonPack` and `episodeCount`. See Issue #61.
+//
+const { logToFile } = require('./logger');
+
+/**
+ * Build the flattened, instance-tagged `records` array for the
+ * `poll:sonarr-queue` / `poll:radarr-queue` cache entry.
+ *
+ * @param {Array<{ instance: string, data: { records?: Array<object> } }>} queues
+ *   Per-instance queue responses as returned by
+ *   `arrRetrieverRegistry.getQueuesByType()` (or the equivalent batched
+ *   retrieval in the poller).
+ * @param {Array<{ id: string, url: string, apiKey: string, name?: string }>} instances
+ *   Configured instances; used to resolve `_instanceUrl` / `_instanceKey`.
+ * @param {'series'|'movie'} mediaKey
+ *   Sonarr records embed a `series` object; Radarr records embed a `movie`
+ *   object. The embedded object is annotated with `_instanceUrl` so that
+ *   downstream link builders work.
+ * @returns {Array<object>} The flattened, annotated records array.
+ */
+function buildArrQueueCache(queues, instances, mediaKey) {
+  if (!Array.isArray(queues) || queues.length === 0) return [];
+  if (mediaKey !== 'series' && mediaKey !== 'movie') {
+    logToFile(`[arrQueueHelpers] Invalid mediaKey "${mediaKey}"; expected 'series' or 'movie'`);
+    return [];
+  }
+  const safeInstances = Array.isArray(instances) ? instances : [];
+
+  const out = [];
+  for (const q of queues) {
+    try {
+      if (!q || !q.data) continue;
+      const inst = safeInstances.find(i => i.id === q.instance);
+      const url = inst ? inst.url : null;
+      const key = inst ? inst.apiKey : null;
+      const records = Array.isArray(q.data.records) ? q.data.records : [];
+      for (const r of records) {
+        try {
+          if (!r) continue;
+          if (r[mediaKey]) {
+            r[mediaKey]._instanceUrl = url;
+          }
+          r._instanceUrl = url;
+          r._instanceKey = key;
+          out.push(r);
+        } catch (perRecordErr) {
+          logToFile(`[arrQueueHelpers] Skipping malformed ${mediaKey} record: ${perRecordErr.message}`);
+        }
+      }
+    } catch (perInstanceErr) {
+      logToFile(`[arrQueueHelpers] Skipping malformed ${mediaKey} queue payload: ${perInstanceErr.message}`);
+    }
+  }
+
+  // Sonarr-only: season pack annotation. Group by downloadId; entries that
+  // share a downloadId are episodes belonging to the same release (a season
+  // pack). Movies (mediaKey === 'movie') are single-record by nature.
+  if (mediaKey === 'series') {
+    try {
+      const groups = new Map();
+      for (const r of out) {
+        const dlId = r && r.downloadId;
+        if (!dlId) continue;
+        if (!groups.has(dlId)) groups.set(dlId, []);
+        groups.get(dlId).push(r);
+      }
+      for (const group of groups.values()) {
+        if (group.length > 1) {
+          for (const r of group) {
+            r.isSeasonPack = true;
+            r.episodeCount = group.length;
+          }
+        }
+      }
+    } catch (annotateErr) {
+      logToFile(`[arrQueueHelpers] Season-pack annotation failed: ${annotateErr.message}`);
+    }
+  }
+
+  return out;
+}
+
+module.exports = {
+  buildArrQueueCache
+};