perf(explore): reduce tag cloud refresh pressure

Debounce Explore tag refreshes while AI tagging is active so the tag cloud catches up after worker activity settles instead of continuously re-querying.

Optimize the tag cloud aggregate query by fetching representative thumbnails in one pass and adding a supporting tag/image index.

CHANGELOG.md

@@ -63,6 +63,9 @@ aims to follow [Semantic Versioning](https://semver.org/spec/v2.0.0.html)
   so the info panel shows more at a glance with less scrolling.
 - **Faster Explore revisits** — returning to a folder's visual clusters should
   feel much faster now, even in big libraries.
+- **Calmer Tag Cloud during AI tagging** — Explore no longer keeps hammering the
+  tag list while a folder is actively being tagged, so tagging stays smoother and
+  the cloud catches up once the work settles.
 - **Faster first-time clustering** — large libraries build their first visual
   clusters much more quickly, while still keeping the groups nicely balanced.
 - **Better tag browsing** — the Tag manager now has live search, sorting

src-tauri/src/db.rs

@@ -303,6 +303,7 @@ pub fn migrate(conn: &Connection) -> Result<()> {
         CREATE INDEX IF NOT EXISTS idx_image_tags_image_id ON image_tags(image_id);
         CREATE INDEX IF NOT EXISTS idx_image_tags_source ON image_tags(source);
         CREATE INDEX IF NOT EXISTS idx_image_tags_tag ON image_tags(tag);
+        CREATE INDEX IF NOT EXISTS idx_image_tags_tag_image_id ON image_tags(tag, image_id);
 
         CREATE TABLE IF NOT EXISTS albums (
             id             INTEGER PRIMARY KEY AUTOINCREMENT,
@@ -2446,7 +2447,10 @@ pub fn get_explore_tags(
     limit: usize,
 ) -> Result<Vec<ExploreTagEntry>> {
     let mut stmt = conn.prepare(
-        "SELECT t.tag, COUNT(DISTINCT t.image_id) AS tag_count, MIN(t.image_id) AS representative_image_id,
+        "WITH tag_counts AS (
+             SELECT t.tag,
+                    COUNT(DISTINCT t.image_id) AS tag_count,
+                    MIN(t.image_id) AS representative_image_id,
                     MAX(CASE WHEN t.source = 'ai' THEN 1 ELSE 0 END) AS has_ai_source,
                     MAX(CASE WHEN t.source = 'user' THEN 1 ELSE 0 END) AS has_user_source
              FROM image_tags t
@@ -2455,23 +2459,30 @@ pub fn get_explore_tags(
              GROUP BY t.tag
              HAVING COUNT(DISTINCT t.image_id) >= 1
              ORDER BY tag_count DESC, t.tag ASC
-         LIMIT ?2",
+             LIMIT ?2
+         )
+         SELECT c.tag,
+                c.tag_count,
+                c.representative_image_id,
+                i.thumbnail_path,
+                c.has_ai_source,
+                c.has_user_source
+         FROM tag_counts c
+         JOIN images i ON i.id = c.representative_image_id
+         ORDER BY c.tag_count DESC, c.tag ASC",
     )?;
 
     let rows = stmt
         .query_map(params![folder_id, limit as i64], |row| {
             let representative_image_id = row.get::<_, i64>(2)?;
-            let thumbnail_path = get_image_by_id(conn, representative_image_id)
-                .ok()
-                .and_then(|image| image.thumbnail_path);
 
             Ok(ExploreTagEntry {
                 tag: row.get(0)?,
                 count: row.get(1)?,
                 representative_image_id,
-                thumbnail_path,
-                has_ai_source: row.get::<_, i64>(3)? != 0,
-                has_user_source: row.get::<_, i64>(4)? != 0,
+                thumbnail_path: row.get(3)?,
+                has_ai_source: row.get::<_, i64>(4)? != 0,
+                has_user_source: row.get::<_, i64>(5)? != 0,
             })
         })?
         .collect::<rusqlite::Result<Vec<_>>>()?;

src/store.ts

@@ -651,6 +651,34 @@ let galleryRequestToken = 0;
 let visualClusterRequestToken = 0;
 let exploreTagRequestToken = 0;
 let exploreTagRefreshTimer: ReturnType<typeof setTimeout> | null = null;
+const EXPLORE_TAG_REFRESH_IDLE_MS = 900;
+const EXPLORE_TAG_REFRESH_WHILE_TAGGING_MS = 4500;
+
+function scopeHasTaggingPending(
+  progressByFolder: Record<number, FolderJobProgress>,
+  folderId: number | null,
+): boolean {
+  if (folderId === null) {
+    return Object.values(progressByFolder).some((progress) => progress.tagging_pending > 0);
+  }
+  return (progressByFolder[folderId]?.tagging_pending ?? 0) > 0;
+}
+
+function taggingProgressAffectsScope(progressFolderId: number, scopeFolderId: number | null): boolean {
+  return scopeFolderId === null || scopeFolderId === progressFolderId;
+}
+
+function imagesAffectScope(images: ImageRecord[], scopeFolderId: number | null): boolean {
+  return scopeFolderId === null || images.some((image) => image.folder_id === scopeFolderId);
+}
+
+function scheduleExploreTagRefresh(load: () => void, delayMs: number) {
+  if (exploreTagRefreshTimer) clearTimeout(exploreTagRefreshTimer);
+  exploreTagRefreshTimer = setTimeout(() => {
+    exploreTagRefreshTimer = null;
+    load();
+  }, delayMs);
+}
 
 function initialAiCaptionsEnabled(): boolean {
   if (typeof window === "undefined") return false;
@@ -1498,6 +1526,9 @@ export const useGalleryStore = create<GalleryState>((set, get) => ({
   loadExploreTags: async (options) => {
     const { selectedFolderId, exploreTagsFolderId, exploreTagLoading } = get();
     const force = options?.force ?? false;
+    if (!force && exploreTagLoading) {
+      return;
+    }
     if (!force && !exploreTagLoading && exploreTagsFolderId !== undefined && exploreTagsFolderId === selectedFolderId) {
       return;
     }
@@ -2984,9 +3015,18 @@ export const useGalleryStore = create<GalleryState>((set, get) => ({
             notificationTimers.set(taggingKey, setTimeout(() => {
               notificationTimers.delete(taggingKey);
               void notifyTaskComplete("AI tagging complete", body);
-              // New tags landed — invalidate Explore tag cache.
-              set({ exploreTagsFolderId: undefined });
             }, NOTIFICATION_DEBOUNCE_MS));
+            const state = get();
+            if (taggingProgressAffectsScope(progress.folder_id, state.selectedFolderId)) {
+              // New tags landed — refresh the Explore tag cloud after the worker
+              // settles instead of waiting for the user to revisit Explore.
+              set({ exploreTagsFolderId: undefined });
+              if (state.activeView === "explore" && state.exploreMode === "tags") {
+                scheduleExploreTagRefresh(() => {
+                  void get().loadExploreTags({ force: true });
+                }, EXPLORE_TAG_REFRESH_IDLE_MS);
+              }
+            }
           } else if (previous.tagging_pending === 0 && progress.tagging_pending > 0) {
             clearTimeout(notificationTimers.get(taggingKey));
             notificationTimers.delete(taggingKey);
@@ -3067,15 +3107,16 @@ export const useGalleryStore = create<GalleryState>((set, get) => ({
     const unlistenThumbnails = await listen<ThumbnailBatch>("media-updated", (event) => {
       const batch = event.payload;
       const taggingUpdated = batch.images.some((image) => image.ai_tagged_at !== null || image.ai_tagger_error !== null);
-      if (taggingUpdated) {
+      const state = get();
+      if (taggingUpdated && imagesAffectScope(batch.images, state.selectedFolderId)) {
         set({ exploreTagsFolderId: undefined });
-        if (get().activeView === "explore") {
-          if (!exploreTagRefreshTimer) {
-            exploreTagRefreshTimer = setTimeout(() => {
-              exploreTagRefreshTimer = null;
+        if (state.activeView === "explore" && state.exploreMode === "tags") {
+          const delay = scopeHasTaggingPending(state.mediaJobProgress, state.selectedFolderId)
+            ? EXPLORE_TAG_REFRESH_WHILE_TAGGING_MS
+            : EXPLORE_TAG_REFRESH_IDLE_MS;
+          scheduleExploreTagRefresh(() => {
             void get().loadExploreTags({ force: true });
-            }, 700);
-          }
+          }, delay);
         }
       }
 
@@ -3179,6 +3220,10 @@ export const useGalleryStore = create<GalleryState>((set, get) => ({
     );
 
     return () => {
+      if (exploreTagRefreshTimer) {
+        clearTimeout(exploreTagRefreshTimer);
+        exploreTagRefreshTimer = null;
+      }
       unlistenProgress();
       unlistenMediaJobs();
       unlistenCaptionModelProgress();