From 81f34aec92ffebec506bae0542ddc718f42cdf9b Mon Sep 17 00:00:00 2001
From: fallenbagel <98979876+Fallenbagel@users.noreply.github.com>
Date: Fri, 10 Apr 2026 07:18:44 +0800
Subject: [PATCH] fix(availability-sync): add caching for expisode exist checks
 for plex/jellyfin

---
 server/lib/availabilitySync.ts | 71 ++++++++++++++++++++++------------
 1 file changed, 46 insertions(+), 25 deletions(-)

diff --git a/server/lib/availabilitySync.ts b/server/lib/availabilitySync.ts
index 471f8497d..cdbe80b54 100644
--- a/server/lib/availabilitySync.ts
+++ b/server/lib/availabilitySync.ts
@@ -21,9 +21,11 @@ class AvailabilitySync {
   public running = false;
   private plexClient: PlexAPI;
   private plexSeasonsCache: Record<string, PlexMetadata[]>;
+  private plexEpisodeExistsCache: Record<string, boolean>;
 
   private jellyfinClient: JellyfinAPI;
   private jellyfinSeasonsCache: Record<string, JellyfinLibraryItem[]>;
+  private jellyfinEpisodeExistsCache: Record<string, boolean>;
 
   private sonarrSeasonsCache: Record<string, SonarrSeason[]>;
   private radarrServers: RadarrSettings[];
@@ -34,7 +36,9 @@ class AvailabilitySync {
     const mediaServerType = getSettings().main.mediaServerType;
     this.running = true;
     this.plexSeasonsCache = {};
+    this.plexEpisodeExistsCache = {};
     this.jellyfinSeasonsCache = {};
+    this.jellyfinEpisodeExistsCache = {};
     this.sonarrSeasonsCache = {};
     this.radarrServers = settings.radarr.filter((server) => server.syncEnabled);
     this.sonarrServers = settings.sonarr.filter((server) => server.syncEnabled);
@@ -939,7 +943,6 @@ class AvailabilitySync {
     const ratingKey4k = media.ratingKey4k;
     let seasonExistsInPlex = false;
 
-    // Check each plex instance to see if the season exists
     let plexSeasons: PlexMetadata[] | undefined;
 
     if (ratingKey && !is4k) {
@@ -955,18 +958,27 @@ class AvailabilitySync {
     );
 
     if (seasonMeta) {
-      // Season metadata exists, but verify it has actual episode files.
-      // This is to ensure we don't keep seasons marked as available
-      // when all episode files have been removed in Plex.
-      try {
-        const episodes = await this.plexClient?.getChildrenMetadata(
-          seasonMeta.ratingKey
-        );
+      const cacheKey = seasonMeta.ratingKey;
 
-        seasonExistsInPlex = episodes?.length > 0;
-      } catch {
-        // If we can't fetch episodes, assume the season exists to avoid false removal
-        seasonExistsInPlex = true;
+      if (cacheKey in this.plexEpisodeExistsCache) {
+        seasonExistsInPlex = this.plexEpisodeExistsCache[cacheKey];
+      } else {
+        try {
+          // Season metadata exists, but we need to verify it has actual
+          // episode files. Plex can keep empty season entries.
+          const episodes = await this.plexClient?.getChildrenMetadata(
+            seasonMeta.ratingKey
+          );
+
+          seasonExistsInPlex =
+            episodes?.some((episode) => episode.Media?.length > 0) ?? false;
+        } catch {
+          // If we can't fetch episodes, assume the season exists
+          // to avoid false removal
+          seasonExistsInPlex = true;
+        }
+
+        this.plexEpisodeExistsCache[cacheKey] = seasonExistsInPlex;
       }
     }
 
@@ -1068,7 +1080,6 @@ class AvailabilitySync {
     const ratingKey4k = media.jellyfinMediaId4k;
     let seasonExistsInJellyfin = false;
 
-    // Check each jellyfin instance to see if the season exists
     let jellyfinSeasons: JellyfinLibraryItem[] | undefined;
 
     if (ratingKey && !is4k) {
@@ -1084,22 +1095,32 @@ class AvailabilitySync {
     );
 
     if (seasonMeta) {
-      // Season metadata exists, but we need to verify it has actual episode files.
-      // Sometimes Jellyfin keeps season entries even after all episodes are deleted.
-      // getEpisodes already filters out virtual episodes.
       const seriesId = is4k ? ratingKey4k : ratingKey;
 
       if (seriesId) {
-        try {
-          const episodes = await this.jellyfinClient.getEpisodes(
-            seriesId,
-            seasonMeta.Id
-          );
+        const cacheKey = `${seriesId}-${seasonMeta.Id}`;
 
-          seasonExistsInJellyfin = episodes.length > 0;
-        } catch {
-          // If we can't fetch episodes, assume the season exists to avoid false removal
-          seasonExistsInJellyfin = true;
+        if (cacheKey in this.jellyfinEpisodeExistsCache) {
+          seasonExistsInJellyfin = this.jellyfinEpisodeExistsCache[cacheKey];
+        } else {
+          try {
+            // Season metadata exists, but we need to verify it has actual
+            // episode files. Jellyfin keeps season entries even after all
+            // episodes are deleted. getEpisodes already filters out
+            // virtual episodes.
+            const episodes = await this.jellyfinClient.getEpisodes(
+              seriesId,
+              seasonMeta.Id
+            );
+
+            seasonExistsInJellyfin = episodes.length > 0;
+          } catch {
+            // If we can't fetch episodes, assume the season exists
+            // to avoid false removal
+            seasonExistsInJellyfin = true;
+          }
+
+          this.jellyfinEpisodeExistsCache[cacheKey] = seasonExistsInJellyfin;
         }
       }
     }