refactor(playlist): G.70 — extract three lifecycle hooks (route + bulk-picker dismiss + DnD reorder) (#637)

Three-cut cluster pulling the last cluster of useEffect bodies + the
DnD-reorder visual feedback out of PlaylistDetail.tsx. 452 → 423 LOC
(−29).

usePlaylistRouteEffects — bundles two route-driven effects:
contextMenu reset (clears contextMenuSongId whenever playerStore's
context menu closes) and openEditMeta-from-route (consumes the
`openEditMeta` location.state flag, opens the meta modal, and
clears the flag with a navigate-replace so back-nav doesn't
re-trigger). Subscribes to playerStore directly.

useBulkPlPickerOutsideClick — the global mousedown listener that
closes the bulk-add-to-playlist picker when clicking outside the
picker wrapper. No-op when closed.

usePlaylistDnDReorder — owns dropTargetIdx state, the
container.addEventListener('psy-drop', …) wiring that calls
runPlaylistReorderDrop, and the handleRowMouseEnter
drag-over-visual helper. Subscribes to DragDropContext directly.

PlaylistDetail drops the direct runPlaylistReorderDrop import and
the contextMenuOpen store subscription — both now live in the hooks
that need them. Pure code move otherwise.

src/hooks/useBulkPlPickerOutsideClick.ts

@@ -0,0 +1,15 @@
+import React, { useEffect } from 'react';
+
+export function useBulkPlPickerOutsideClick(
+  showBulkPlPicker: boolean,
+  setShowBulkPlPicker: React.Dispatch<React.SetStateAction<boolean>>,
+): void {
+  useEffect(() => {
+    if (!showBulkPlPicker) return;
+    const handler = (e: MouseEvent) => {
+      if (!(e.target as HTMLElement).closest('.bulk-pl-picker-wrap')) setShowBulkPlPicker(false);
+    };
+    document.addEventListener('mousedown', handler);
+    return () => document.removeEventListener('mousedown', handler);
+  }, [showBulkPlPicker, setShowBulkPlPicker]);
+}

src/hooks/usePlaylistDnDReorder.ts

@@ -0,0 +1,44 @@
+import React, { useEffect, useState } from 'react';
+import type { SubsonicSong } from '../api/subsonicTypes';
+import { useDragDrop } from '../contexts/DragDropContext';
+import { runPlaylistReorderDrop } from '../utils/runPlaylistReorderDrop';
+
+export interface PlaylistDnDReorderDeps {
+  tracklistRef: React.RefObject<HTMLDivElement | null>;
+  songs: SubsonicSong[];
+  savePlaylist: (updatedSongs: SubsonicSong[], prevCount?: number) => Promise<void>;
+  setSongs: React.Dispatch<React.SetStateAction<SubsonicSong[]>>;
+}
+
+export interface PlaylistDnDReorderResult {
+  dropTargetIdx: { idx: number; before: boolean } | null;
+  setDropTargetIdx: React.Dispatch<React.SetStateAction<{ idx: number; before: boolean } | null>>;
+  handleRowMouseEnter: (idx: number, e: React.MouseEvent) => void;
+}
+
+export function usePlaylistDnDReorder(deps: PlaylistDnDReorderDeps): PlaylistDnDReorderResult {
+  const { tracklistRef, songs, savePlaylist, setSongs } = deps;
+  const { isDragging } = useDragDrop();
+  const [dropTargetIdx, setDropTargetIdx] = useState<{ idx: number; before: boolean } | null>(null);
+
+  useEffect(() => {
+    const container = tracklistRef.current;
+    if (!container) return;
+
+    const onPsyDrop = (e: Event) => {
+      runPlaylistReorderDrop({ e, songs, savePlaylist, setDropTargetIdx, setSongs });
+    };
+
+    container.addEventListener('psy-drop', onPsyDrop);
+    return () => container.removeEventListener('psy-drop', onPsyDrop);
+  }, [songs, savePlaylist, tracklistRef, setSongs]);
+
+  const handleRowMouseEnter = (idx: number, e: React.MouseEvent) => {
+    if (!isDragging) return;
+    const rect = (e.currentTarget as HTMLElement).getBoundingClientRect();
+    const before = e.clientY < rect.top + rect.height / 2;
+    setDropTargetIdx({ idx, before });
+  };
+
+  return { dropTargetIdx, setDropTargetIdx, handleRowMouseEnter };
+}

src/hooks/usePlaylistRouteEffects.ts

@@ -0,0 +1,27 @@
+import React, { useEffect } from 'react';
+import type { Location, NavigateFunction } from 'react-router-dom';
+import { usePlayerStore } from '../store/playerStore';
+
+export interface PlaylistRouteEffectsDeps {
+  setContextMenuSongId: React.Dispatch<React.SetStateAction<string | null>>;
+  setEditingMeta: React.Dispatch<React.SetStateAction<boolean>>;
+  location: Location;
+  navigate: NavigateFunction;
+}
+
+export function usePlaylistRouteEffects(deps: PlaylistRouteEffectsDeps): void {
+  const { setContextMenuSongId, setEditingMeta, location, navigate } = deps;
+  const contextMenuOpen = usePlayerStore(s => s.contextMenu.isOpen);
+
+  useEffect(() => {
+    if (!contextMenuOpen) setContextMenuSongId(null);
+  }, [contextMenuOpen, setContextMenuSongId]);
+
+  useEffect(() => {
+    const state = (location.state as { openEditMeta?: boolean } | null) ?? null;
+    if (state?.openEditMeta) {
+      setEditingMeta(true);
+      navigate(location.pathname, { replace: true, state: null });
+    }
+  }, [location.state, location.pathname, navigate, setEditingMeta]);
+}

src/pages/PlaylistDetail.tsx

@@ -41,7 +41,6 @@ import { runPlaylistZipDownload } from '../utils/runPlaylistZipDownload';
 import { runPlaylistSaveMeta } from '../utils/runPlaylistSaveMeta';
 import { runPlaylistLoad } from '../utils/runPlaylistLoad';
 import { startPlaylistRowDrag } from '../utils/startPlaylistRowDrag';
-import { runPlaylistReorderDrop } from '../utils/runPlaylistReorderDrop';
 import { usePlaylistCovers } from '../hooks/usePlaylistCovers';
 import { usePlaylistSelection } from '../hooks/usePlaylistSelection';
 import { usePlaylistSuggestions } from '../hooks/usePlaylistSuggestions';
@@ -51,6 +50,9 @@ import { usePlaylistStarRating } from '../hooks/usePlaylistStarRating';
 import { usePlaylistPreview } from '../hooks/usePlaylistPreview';
 import { usePlaylistBulkPlayCallbacks } from '../hooks/usePlaylistBulkPlayCallbacks';
 import { usePlaylistDerived } from '../hooks/usePlaylistDerived';
+import { usePlaylistRouteEffects } from '../hooks/usePlaylistRouteEffects';
+import { useBulkPlPickerOutsideClick } from '../hooks/useBulkPlPickerOutsideClick';
+import { usePlaylistDnDReorder } from '../hooks/usePlaylistDnDReorder';
 
 // ── Column configuration ──────────────────────────────────────────────────────
 const PL_COLUMNS: readonly ColDef[] = [
@@ -126,7 +128,6 @@ export default function PlaylistDetail() {
   const previewingId = usePreviewStore(s => s.previewingId);
   const previewAudioStarted = usePreviewStore(s => s.audioStarted);
   const [contextMenuSongId, setContextMenuSongId] = useState<string | null>(null);
-  const contextMenuOpen = usePlayerStore(s => s.contextMenu.isOpen);
   const zipDownloads = useZipDownloadStore(s => s.downloads);
   const [zipDownloadId, setZipDownloadId] = useState<string | null>(null);
   const activeZip = zipDownloadId ? zipDownloads.find(d => d.id === zipDownloadId) : undefined;
@@ -157,15 +158,7 @@ export default function PlaylistDetail() {
   const [showBulkPlPicker, setShowBulkPlPicker] = useState(false);
   const { selectedIds, setSelectedIds, allSelected, toggleAll, toggleSelect, bulkRemove } =
     usePlaylistSelection(songs, setSongs, savePlaylist);
-
-  useEffect(() => {
-    if (!showBulkPlPicker) return;
-    const handler = (e: MouseEvent) => {
-      if (!(e.target as HTMLElement).closest('.bulk-pl-picker-wrap')) setShowBulkPlPicker(false);
-    };
-    document.addEventListener('mousedown', handler);
-    return () => document.removeEventListener('mousedown', handler);
-  }, [showBulkPlPicker]);
+  useBulkPlPickerOutsideClick(showBulkPlPicker, setShowBulkPlPicker);
 
   // ── 2×2 cover quad (first 4 unique album covers) ─────────────
   const { coverQuadUrls, customCoverFetchUrl, customCoverCacheKey, resolvedBgUrl } =
@@ -190,20 +183,7 @@ export default function PlaylistDetail() {
     pickerOpen, setPickerOpen, pickerRef, tracklistRef,
   } = useTracklistColumns(PL_COLUMNS, 'psysonic_playlist_columns');
 
-  // DnD
-  const [dropTargetIdx, setDropTargetIdx] = useState<{ idx: number; before: boolean } | null>(null);
-
-  useEffect(() => {
-    if (!contextMenuOpen) setContextMenuSongId(null);
-  }, [contextMenuOpen]);
-
-  useEffect(() => {
-    const state = (location.state as { openEditMeta?: boolean } | null) ?? null;
-    if (state?.openEditMeta) {
-      setEditingMeta(true);
-      navigate(location.pathname, { replace: true, state: null });
-    }
-  }, [location.state, location.pathname, navigate]);
+  usePlaylistRouteEffects({ setContextMenuSongId, setEditingMeta, location, navigate });
 
   // ── Load ─────────────────────────────────────────────────────
   const lastModified = usePlaylistStore(s => (id ? s.lastModified[id] : undefined));
@@ -257,18 +237,10 @@ export default function PlaylistDetail() {
     ratings, setRatings, starredSongs, setStarredSongs,
   });
 
-  // ── psy-drop DnD reordering ───────────────────────────────────
-  useEffect(() => {
-    const container = tracklistRef.current;
-    if (!container) return;
-
-    const onPsyDrop = (e: Event) => {
-      runPlaylistReorderDrop({ e, songs, savePlaylist, setDropTargetIdx, setSongs });
-    };
-
-    container.addEventListener('psy-drop', onPsyDrop);
-    return () => container.removeEventListener('psy-drop', onPsyDrop);
-  }, [songs, savePlaylist, tracklistRef]);
+  // ── DnD reorder listener + drag-over visual feedback ──────────
+  const { dropTargetIdx, handleRowMouseEnter } = usePlaylistDnDReorder({
+    tracklistRef, songs, savePlaylist, setSongs,
+  });
 
   // ── Row mousedown: threshold drag for reorder (from anywhere on the row) ──
   const handleRowMouseDown = (e: React.MouseEvent, idx: number) => {
@@ -280,14 +252,6 @@ export default function PlaylistDetail() {
     filterText, sortKey, sortDir, ratings, starredSongs,
   });
 
-  // ── Drag-over visual feedback ─────────────────────────────────
-  const handleRowMouseEnter = (idx: number, e: React.MouseEvent) => {
-    if (!isDragging) return;
-    const rect = (e.currentTarget as HTMLElement).getBoundingClientRect();
-    const before = e.clientY < rect.top + rect.height / 2;
-    setDropTargetIdx({ idx, before });
-  };
-
   // ── Playback actions (encapsulated like AlbumHeader) ─────────
   const { handlePlayAll, handleShuffleAll, handleEnqueueAll } = usePlaylistBulkPlayCallbacks({
     songsLength: songs.length, id, tracks, touchPlaylist, playTrack, enqueue,