refactor: consolidate format utils, extract route helpers, remove dead code

- Consolidate 5 duplicate format functions (formatDuration, formatRelativeTime,
  formatFileSize, formatSubscriberCount) into shared utils/format.ts
- Extract parseIdParam() route helper, replacing 22 copy-paste blocks across 9 route files
- Remove dead exports: useScanStatus, useChannelContent (non-paginated),
  getContentItemsByStatus, deleteQueueItem, deletePlaylistsByChannelId
- Fix as-any type assertion in system.ts (queueService already typed on FastifyInstance)
- Net: -411 lines, 23 files touched

src/__tests__/format-profile.test.ts

@@ -21,7 +21,6 @@ import {
   createContentItem,
   getContentItemById,
   updateContentItem,
-  getContentItemsByStatus,
 } from '../db/repositories/content-repository';
 import type { Platform } from '../types/index';
 
@@ -440,95 +439,6 @@ describe('Content Item Update & Query Functions', () => {
     const result = await updateContentItem(db, 999, { status: 'failed' });
     expect(result).toBeNull();
   });
-
-  it('gets content items by status', async () => {
-    const dbPath = freshDbPath();
-    const db = await initDatabaseAsync(dbPath);
-    await runMigrations(dbPath);
-
-    const channel = await createChannel(db, {
-      name: 'Multi Channel',
-      platform: 'youtube' as Platform,
-      platformId: 'UC_MULTI',
-      url: 'https://www.youtube.com/@Multi',
-      monitoringEnabled: true,
-      checkInterval: 360,
-      imageUrl: null,
-      metadata: null,
-      formatProfileId: null,
-    });
-
-    // Create items with different statuses
-    await createContentItem(db, {
-      channelId: channel.id,
-      title: 'Item 1',
-      platformContentId: 'v1',
-      url: 'https://youtube.com/watch?v=v1',
-      contentType: 'video' as const,
-      duration: null,
-      status: 'monitored',
-    });
-
-    const item2 = await createContentItem(db, {
-      channelId: channel.id,
-      title: 'Item 2',
-      platformContentId: 'v2',
-      url: 'https://youtube.com/watch?v=v2',
-      contentType: 'video' as const,
-      duration: null,
-      status: 'monitored',
-    });
-
-    await createContentItem(db, {
-      channelId: channel.id,
-      title: 'Item 3',
-      platformContentId: 'v3',
-      url: 'https://youtube.com/watch?v=v3',
-      contentType: 'audio' as const,
-      duration: null,
-      status: 'downloaded',
-    });
-
-    const monitored = await getContentItemsByStatus(db, 'monitored');
-    expect(monitored).toHaveLength(2);
-
-    const downloaded = await getContentItemsByStatus(db, 'downloaded');
-    expect(downloaded).toHaveLength(1);
-    expect(downloaded[0].title).toBe('Item 3');
-  });
-
-  it('respects limit parameter on getContentItemsByStatus', async () => {
-    const dbPath = freshDbPath();
-    const db = await initDatabaseAsync(dbPath);
-    await runMigrations(dbPath);
-
-    const channel = await createChannel(db, {
-      name: 'Limit Channel',
-      platform: 'youtube' as Platform,
-      platformId: 'UC_LIMIT',
-      url: 'https://www.youtube.com/@Limit',
-      monitoringEnabled: true,
-      checkInterval: 360,
-      imageUrl: null,
-      metadata: null,
-      formatProfileId: null,
-    });
-
-    for (let i = 0; i < 5; i++) {
-      await createContentItem(db, {
-        channelId: channel.id,
-        title: `Item ${i}`,
-        platformContentId: `vid_${i}`,
-        url: `https://youtube.com/watch?v=vid_${i}`,
-        contentType: 'video' as const,
-        duration: null,
-        status: 'monitored',
-      });
-    }
-
-    const limited = await getContentItemsByStatus(db, 'monitored', 2);
-    expect(limited).toHaveLength(2);
-  });
 });
 
 // ── Config ──

src/__tests__/queue-repository.test.ts

@@ -14,7 +14,6 @@ import {
   getPendingQueueItems,
   updateQueueItemStatus,
   countQueueItemsByStatus,
-  deleteQueueItem,
   getQueueItemByContentItemId,
 } from '../db/repositories/queue-repository';
 import type { Channel, ContentItem } from '../types/index';
@@ -344,25 +343,6 @@ describe('Queue Repository', () => {
     });
   });
 
-  describe('deleteQueueItem', () => {
-    it('deletes an existing item and returns true', async () => {
-      const item = await createQueueItem(db, {
-        contentItemId: testContentItem.id,
-      });
-
-      const deleted = await deleteQueueItem(db, item.id);
-      expect(deleted).toBe(true);
-
-      const found = await getQueueItemById(db, item.id);
-      expect(found).toBeNull();
-    });
-
-    it('returns false for non-existent ID', async () => {
-      const deleted = await deleteQueueItem(db, 99999);
-      expect(deleted).toBe(false);
-    });
-  });
-
   describe('getQueueItemByContentItemId', () => {
     it('returns queue item for a given content item ID', async () => {
       const item = await createQueueItem(db, {

src/db/repositories/content-repository.ts

@@ -288,24 +288,6 @@ export async function bulkSetMonitored(
 }
 
 /** Get content items by status, ordered by creation date (oldest first). */
-export async function getContentItemsByStatus(
-  db: Db,
-  status: ContentStatus,
-  limit?: number
-): Promise<ContentItem[]> {
-  let query = db
-    .select()
-    .from(contentItems)
-    .where(eq(contentItems.status, status))
-    .orderBy(contentItems.createdAt);
-
-  if (limit !== undefined) {
-    query = query.limit(limit) as typeof query;
-  }
-
-  const rows = await query;
-  return rows.map(mapRow);
-}
 
 // ── Paginated Listing ──
 

src/db/repositories/playlist-repository.ts

@@ -150,12 +150,6 @@ export async function getContentPlaylistMappings(
 }
 
 /** Delete all playlists for a channel. Cascade handles junction rows. */
-export async function deletePlaylistsByChannelId(
-  db: Db,
-  channelId: number
-): Promise<void> {
-  await db.delete(playlists).where(eq(playlists.channelId, channelId));
-}
 
 // ── Row Mapping ──
 

src/db/repositories/queue-repository.ts

@@ -202,17 +202,6 @@ export async function countQueueItemsByStatus(
 }
 
 /** Delete a queue item by ID. Returns true if a row was deleted. */
-export async function deleteQueueItem(
-  db: Db,
-  id: number
-): Promise<boolean> {
-  const result = await db
-    .delete(queueItems)
-    .where(eq(queueItems.id, id))
-    .returning({ id: queueItems.id });
-
-  return result.length > 0;
-}
 
 /**
  * Get a queue item by content item ID (for dedup checking before enqueue).

src/frontend/src/api/hooks/useChannels.ts

@@ -130,46 +130,6 @@ export function useScanAllChannels() {
   });
 }
 
-// ── Scan Status Polling ──
-
-interface ScanStatusResponse {
-  scanning: boolean;
-}
-
-/**
- * Poll the scan-status endpoint while `enabled` is true.
- * When the scan completes (scanning flips false), calls `onComplete`.
- * Polls every 2s.
- */
-export function useScanStatus(
-  channelId: number,
-  enabled: boolean,
-  onComplete?: () => void,
-) {
-  const queryClient = useQueryClient();
-  const onCompleteRef = { current: onComplete };
-  onCompleteRef.current = onComplete;
-
-  return useQuery({
-    queryKey: ['scan-status', channelId] as const,
-    queryFn: async () => {
-      const result = await apiClient.get<ScanStatusResponse>(
-        `/api/v1/channel/${channelId}/scan-status`,
-      );
-      // When scan just finished, refetch content and notify caller
-      if (!result.scanning) {
-        queryClient.invalidateQueries({ queryKey: channelKeys.all });
-        queryClient.invalidateQueries({ queryKey: channelKeys.detail(channelId) });
-        queryClient.invalidateQueries({ queryKey: contentKeys.byChannel(channelId) });
-        onCompleteRef.current?.();
-      }
-      return result;
-    },
-    enabled: enabled && channelId > 0,
-    refetchInterval: enabled ? 2000 : false,
-  });
-}
-
 /** Set the monitoring mode for a channel (cascades to content items). */
 export function useSetMonitoringMode(channelId: number) {
   const queryClient = useQueryClient();

src/frontend/src/api/hooks/useContent.ts

@@ -35,20 +35,6 @@ export const contentKeys = {
 
 // ── Queries ──
 
-/** Fetch content items for a specific channel (legacy — all items). */
-export function useChannelContent(channelId: number) {
-  return useQuery({
-    queryKey: contentKeys.byChannel(channelId),
-    queryFn: async () => {
-      const response = await apiClient.get<ApiResponse<ContentItem[]>>(
-        `/api/v1/channel/${channelId}/content`,
-      );
-      return response.data;
-    },
-    enabled: channelId > 0,
-  });
-}
-
 /** Fetch paginated content items for a channel with search/filter/sort. */
 export function useChannelContentPaginated(channelId: number, filters: ChannelContentFilters) {
   return useQuery({

src/frontend/src/components/ContentCard.tsx

@@ -2,36 +2,9 @@ import { Bookmark, BookmarkPlus, Download, ExternalLink, Film, Music } from 'luc
 import { StatusBadge } from './StatusBadge';
 import { DownloadProgressBar } from './DownloadProgressBar';
 import { useDownloadProgress } from '../contexts/DownloadProgressContext';
+import { formatDuration, formatRelativeTime } from '../utils/format';
 import type { ContentItem } from '@shared/types/index';
 
-// ── Helpers ──
-
-function formatDuration(seconds: number | null): string {
-  if (seconds == null) return '';
-  const h = Math.floor(seconds / 3600);
-  const m = Math.floor((seconds % 3600) / 60);
-  const s = seconds % 60;
-  if (h > 0) return `${h}:${String(m).padStart(2, '0')}:${String(s).padStart(2, '0')}`;
-  return `${m}:${String(s).padStart(2, '0')}`;
-}
-
-function formatRelativeTime(isoString: string | null): string {
-  if (!isoString) return '';
-  const delta = Date.now() - Date.parse(isoString);
-  if (delta < 0) return 'just now';
-  const seconds = Math.floor(delta / 1000);
-  if (seconds < 60) return 'just now';
-  const minutes = Math.floor(seconds / 60);
-  if (minutes < 60) return `${minutes}m ago`;
-  const hours = Math.floor(minutes / 60);
-  if (hours < 24) return `${hours}h ago`;
-  const days = Math.floor(hours / 24);
-  if (days < 30) return `${days}d ago`;
-  const months = Math.floor(days / 30);
-  if (months < 12) return `${months}mo ago`;
-  return `${Math.floor(months / 12)}y ago`;
-}
-
 // ── Component ──
 
 interface ContentCardProps {

src/frontend/src/components/ContentListItem.tsx

@@ -2,36 +2,9 @@ import { Bookmark, BookmarkPlus, Download, ExternalLink, Film, Music } from 'luc
 import { StatusBadge } from './StatusBadge';
 import { DownloadProgressBar } from './DownloadProgressBar';
 import { useDownloadProgress } from '../contexts/DownloadProgressContext';
+import { formatDuration, formatRelativeTime } from '../utils/format';
 import type { ContentItem } from '@shared/types/index';
 
-// ── Helpers (shared pattern with ContentCard) ──
-
-function formatDuration(seconds: number | null): string {
-  if (seconds == null) return '';
-  const h = Math.floor(seconds / 3600);
-  const m = Math.floor((seconds % 3600) / 60);
-  const s = seconds % 60;
-  if (h > 0) return `${h}:${String(m).padStart(2, '0')}:${String(s).padStart(2, '0')}`;
-  return `${m}:${String(s).padStart(2, '0')}`;
-}
-
-function formatRelativeTime(isoString: string | null): string {
-  if (!isoString) return '';
-  const delta = Date.now() - Date.parse(isoString);
-  if (delta < 0) return 'just now';
-  const seconds = Math.floor(delta / 1000);
-  if (seconds < 60) return 'just now';
-  const minutes = Math.floor(seconds / 60);
-  if (minutes < 60) return `${minutes}m ago`;
-  const hours = Math.floor(minutes / 60);
-  if (hours < 24) return `${hours}h ago`;
-  const days = Math.floor(hours / 24);
-  if (days < 30) return `${days}d ago`;
-  const months = Math.floor(days / 30);
-  if (months < 12) return `${months}mo ago`;
-  return `${Math.floor(months / 12)}y ago`;
-}
-
 // ── Component ──
 
 interface ContentListItemProps {

src/frontend/src/pages/Activity.tsx

@@ -6,6 +6,7 @@ import { Pagination } from '../components/Pagination';
 import { FilterBar, type FilterDefinition } from '../components/FilterBar';
 import { SkeletonActivityList } from '../components/Skeleton';
 import { useHistory, useActivity, type HistoryFilters } from '../api/hooks/useActivity';
+import { formatRelativeTime } from '../utils/format';
 import type { DownloadHistoryRecord } from '@shared/types/index';
 
 // ── Helpers ──
@@ -21,18 +22,6 @@ function formatTimestamp(iso: string): string {
   });
 }
 
-function formatRelativeTime(iso: string): string {
-  const d = new Date(iso);
-  const now = new Date();
-  const diffMs = now.getTime() - d.getTime();
-
-  if (diffMs < 60_000) return 'just now';
-  if (diffMs < 3600_000) return `${Math.floor(diffMs / 60_000)}m ago`;
-  if (diffMs < 86400_000) return `${Math.floor(diffMs / 3600_000)}h ago`;
-  if (diffMs < 604800_000) return `${Math.floor(diffMs / 86400_000)}d ago`;
-  return d.toLocaleDateString(undefined, { month: 'short', day: 'numeric' });
-}
-
 function formatEventType(type: string): string {
   return type
     .split('_')

src/frontend/src/pages/ChannelDetail.tsx

@@ -40,6 +40,7 @@ import { SortGroupBar, type GroupByKey } from '../components/SortGroupBar';
 import { Modal } from '../components/Modal';
 import { useToast } from '../components/Toast';
 import { useDownloadProgress, useScanProgress } from '../contexts/DownloadProgressContext';
+import { formatDuration, formatFileSize, formatRelativeTime, formatSubscriberCount } from '../utils/format';
 import type { ContentItem, MonitoringMode } from '@shared/types/index';
 
 // ── Helpers ──
@@ -55,49 +56,6 @@ function ContentStatusCell({ item }: { item: ContentItem }) {
   return <StatusBadge status={item.status} />;
 }
 
-function formatDuration(seconds: number | null): string {
-  if (seconds == null) return '—';
-  const h = Math.floor(seconds / 3600);
-  const m = Math.floor((seconds % 3600) / 60);
-  const s = seconds % 60;
-  if (h > 0) return `${h}:${String(m).padStart(2, '0')}:${String(s).padStart(2, '0')}`;
-  return `${m}:${String(s).padStart(2, '0')}`;
-}
-
-function formatFileSize(bytes: number | null): string {
-  if (bytes == null) return '—';
-  if (bytes < 1024) return `${bytes} B`;
-  if (bytes < 1024 * 1024) return `${(bytes / 1024).toFixed(1)} KB`;
-  if (bytes < 1024 * 1024 * 1024) return `${(bytes / (1024 * 1024)).toFixed(1)} MB`;
-  return `${(bytes / (1024 * 1024 * 1024)).toFixed(2)} GB`;
-}
-
-function formatRelativeTime(isoString: string | null): string {
-  if (!isoString) return '—';
-  const delta = Date.now() - Date.parse(isoString);
-  if (delta < 0) return 'just now';
-  const seconds = Math.floor(delta / 1000);
-  if (seconds < 60) return 'just now';
-  const minutes = Math.floor(seconds / 60);
-  if (minutes < 60) return `${minutes}m ago`;
-  const hours = Math.floor(minutes / 60);
-  if (hours < 24) return `${hours}h ago`;
-  const days = Math.floor(hours / 24);
-  if (days < 30) return `${days}d ago`;
-  const months = Math.floor(days / 30);
-  if (months < 12) return `${months}mo ago`;
-  const years = Math.floor(months / 12);
-  return `${years}y ago`;
-}
-
-function formatSubscriberCount(count: number | null): string | null {
-  if (count == null) return null;
-  if (count < 1000) return `${count}`;
-  if (count < 1_000_000) return `${(count / 1000).toFixed(1).replace(/\.0$/, '')}K`;
-  if (count < 1_000_000_000) return `${(count / 1_000_000).toFixed(1).replace(/\.0$/, '')}M`;
-  return `${(count / 1_000_000_000).toFixed(1).replace(/\.0$/, '')}B`;
-}
-
 const MONITORING_MODE_OPTIONS: { value: MonitoringMode; label: string }[] = [
   { value: 'all', label: 'All Content' },
   { value: 'future', label: 'Future Only' },

src/frontend/src/pages/Channels.tsx

@@ -10,23 +10,9 @@ import { ProgressBar } from '../components/ProgressBar';
 import { AddChannelModal } from '../components/AddChannelModal';
 import { SkeletonChannelsList } from '../components/Skeleton';
 import { useToast } from '../components/Toast';
+import { formatRelativeTime } from '../utils/format';
 import type { ChannelWithCounts } from '@shared/types/api';
 
-// ── Helpers ──
-
-function formatRelativeTime(dateStr: string | null): string {
-  if (!dateStr) return '—';
-  const diff = Date.now() - new Date(dateStr).getTime();
-  const seconds = Math.floor(diff / 1000);
-  if (seconds < 60) return 'just now';
-  const minutes = Math.floor(seconds / 60);
-  if (minutes < 60) return `${minutes}m ago`;
-  const hours = Math.floor(minutes / 60);
-  if (hours < 24) return `${hours}h ago`;
-  const days = Math.floor(hours / 24);
-  return `${days}d ago`;
-}
-
 // ── Component ──
 
 export function Channels() {

src/frontend/src/pages/Library.tsx

@@ -11,27 +11,9 @@ import { FilterBar, type FilterDefinition } from '../components/FilterBar';
 import { SkeletonLibrary } from '../components/Skeleton';
 import { useLibraryContent, type LibraryFilters } from '../api/hooks/useLibrary';
 import { useChannels } from '../api/hooks/useChannels';
+import { formatDuration, formatFileSize } from '../utils/format';
 import type { ContentItem, ContentStatus, ContentType } from '@shared/types/index';
 
-// ── Helpers ──
-
-function formatDuration(seconds: number | null): string {
-  if (seconds == null) return '—';
-  const h = Math.floor(seconds / 3600);
-  const m = Math.floor((seconds % 3600) / 60);
-  const s = seconds % 60;
-  if (h > 0) return `${h}:${String(m).padStart(2, '0')}:${String(s).padStart(2, '0')}`;
-  return `${m}:${String(s).padStart(2, '0')}`;
-}
-
-function formatFileSize(bytes: number | null): string {
-  if (bytes == null) return '—';
-  if (bytes < 1024) return `${bytes} B`;
-  if (bytes < 1024 * 1024) return `${(bytes / 1024).toFixed(1)} KB`;
-  if (bytes < 1024 * 1024 * 1024) return `${(bytes / (1024 * 1024)).toFixed(1)} MB`;
-  return `${(bytes / (1024 * 1024 * 1024)).toFixed(2)} GB`;
-}
-
 // ── Component ──
 
 export function Library() {

src/frontend/src/utils/format.ts

@@ -1,6 +1,11 @@
 /**
- * Format a byte count into a human-readable string (B, KB, MB, GB, TB).
+ * Shared formatting utilities for the Tubearr frontend.
+ *
+ * Consolidates format helpers that were previously duplicated across
+ * ChannelDetail, Library, ContentCard, ContentListItem, Channels, Activity.
  */
+
+/** Format a byte count into a human-readable string (B, KB, MB, GB, TB). */
 export function formatBytes(bytes: number): string {
   if (bytes < 1024) return `${bytes} B`;
   if (bytes < 1024 * 1024) return `${(bytes / 1024).toFixed(1)} KB`;
@@ -8,3 +13,50 @@ export function formatBytes(bytes: number): string {
   if (bytes < 1024 ** 4) return `${(bytes / 1024 ** 3).toFixed(1)} GB`;
   return `${(bytes / 1024 ** 4).toFixed(1)} TB`;
 }
+
+/** Format a file size in bytes to a human-readable string with appropriate precision. */
+export function formatFileSize(bytes: number | null): string {
+  if (bytes == null) return '—';
+  if (bytes < 1024) return `${bytes} B`;
+  if (bytes < 1024 * 1024) return `${(bytes / 1024).toFixed(1)} KB`;
+  if (bytes < 1024 * 1024 * 1024) return `${(bytes / (1024 * 1024)).toFixed(1)} MB`;
+  return `${(bytes / (1024 * 1024 * 1024)).toFixed(2)} GB`;
+}
+
+/** Format seconds into h:mm:ss or m:ss. */
+export function formatDuration(seconds: number | null): string {
+  if (seconds == null) return '—';
+  const h = Math.floor(seconds / 3600);
+  const m = Math.floor((seconds % 3600) / 60);
+  const s = seconds % 60;
+  if (h > 0) return `${h}:${String(m).padStart(2, '0')}:${String(s).padStart(2, '0')}`;
+  return `${m}:${String(s).padStart(2, '0')}`;
+}
+
+/** Format an ISO date string as a relative time (e.g. "2h ago", "3d ago"). */
+export function formatRelativeTime(isoString: string | null): string {
+  if (!isoString) return '—';
+  const delta = Date.now() - Date.parse(isoString);
+  if (delta < 0) return 'just now';
+  const seconds = Math.floor(delta / 1000);
+  if (seconds < 60) return 'just now';
+  const minutes = Math.floor(seconds / 60);
+  if (minutes < 60) return `${minutes}m ago`;
+  const hours = Math.floor(minutes / 60);
+  if (hours < 24) return `${hours}h ago`;
+  const days = Math.floor(hours / 24);
+  if (days < 30) return `${days}d ago`;
+  const months = Math.floor(days / 30);
+  if (months < 12) return `${months}mo ago`;
+  const years = Math.floor(months / 12);
+  return `${years}y ago`;
+}
+
+/** Format a subscriber/follower count to a compact string (e.g. "6.7M"). */
+export function formatSubscriberCount(count: number | null): string | null {
+  if (count == null) return null;
+  if (count < 1000) return `${count}`;
+  if (count < 1_000_000) return `${(count / 1000).toFixed(1).replace(/\.0$/, '')}K`;
+  if (count < 1_000_000_000) return `${(count / 1_000_000).toFixed(1).replace(/\.0$/, '')}M`;
+  return `${(count / 1_000_000_000).toFixed(1).replace(/\.0$/, '')}B`;
+}

src/server/routes/channel.ts

@@ -1,4 +1,5 @@
 import { type FastifyInstance } from 'fastify';
+import { parseIdParam } from './helpers';
 import { PlatformRegistry } from '../../sources/platform-source';
 import { YouTubeSource } from '../../sources/youtube';
 import { SoundCloudSource } from '../../sources/soundcloud';
@@ -230,14 +231,8 @@ export async function channelRoutes(fastify: FastifyInstance): Promise<void> {
   fastify.get<{ Params: { id: string } }>(
     '/api/v1/channel/:id',
     async (request, reply) => {
-      const id = parseInt(request.params.id, 10);
-      if (isNaN(id)) {
-        return reply.status(400).send({
-          statusCode: 400,
-          error: 'Bad Request',
-          message: 'Channel ID must be a number',
-        });
-      }
+      const id = parseIdParam(request.params.id, reply, 'Channel ID');
+      if (id === null) return;
 
       const channel = await getChannelById(fastify.db, id);
       if (!channel) {
@@ -263,14 +258,8 @@ export async function channelRoutes(fastify: FastifyInstance): Promise<void> {
       schema: { body: updateChannelBodySchema },
     },
     async (request, reply) => {
-      const id = parseInt(request.params.id, 10);
-      if (isNaN(id)) {
-        return reply.status(400).send({
-          statusCode: 400,
-          error: 'Bad Request',
-          message: 'Channel ID must be a number',
-        });
-      }
+      const id = parseIdParam(request.params.id, reply, 'Channel ID');
+      if (id === null) return;
 
       const updated = await updateChannel(fastify.db, id, request.body);
       if (!updated) {
@@ -297,14 +286,8 @@ export async function channelRoutes(fastify: FastifyInstance): Promise<void> {
     '/api/v1/channel/:id/monitoring-mode',
     { schema: { body: monitoringModeBodySchema } },
     async (request, reply) => {
-      const id = parseInt(request.params.id, 10);
-      if (isNaN(id)) {
-        return reply.status(400).send({
-          statusCode: 400,
-          error: 'Bad Request',
-          message: 'Channel ID must be a number',
-        });
-      }
+      const id = parseIdParam(request.params.id, reply, 'Channel ID');
+      if (id === null) return;
 
       try {
         const result = await setMonitoringMode(
@@ -341,14 +324,8 @@ export async function channelRoutes(fastify: FastifyInstance): Promise<void> {
   fastify.delete<{ Params: { id: string } }>(
     '/api/v1/channel/:id',
     async (request, reply) => {
-      const id = parseInt(request.params.id, 10);
-      if (isNaN(id)) {
-        return reply.status(400).send({
-          statusCode: 400,
-          error: 'Bad Request',
-          message: 'Channel ID must be a number',
-        });
-      }
+      const id = parseIdParam(request.params.id, reply, 'Channel ID');
+      if (id === null) return;
 
       // Verify channel exists before deleting
       const existing = await getChannelById(fastify.db, id);

src/server/routes/collect.ts

@@ -1,4 +1,5 @@
 import { type FastifyInstance } from 'fastify';
+import { parseIdParam } from './helpers';
 import { getCollectibleItems } from '../../db/repositories/content-repository';
 import { getChannelById } from '../../db/repositories/channel-repository';
 
@@ -57,14 +58,8 @@ export async function collectRoutes(fastify: FastifyInstance): Promise<void> {
   fastify.post<{ Params: { id: string } }>(
     '/api/v1/channel/:id/collect',
     async (request, reply) => {
-      const id = parseInt(request.params.id, 10);
-      if (isNaN(id)) {
-        return reply.status(400).send({
-          statusCode: 400,
-          error: 'Bad Request',
-          message: 'Channel ID must be a number',
-        });
-      }
+      const id = parseIdParam(request.params.id, reply, 'Channel ID');
+      if (id === null) return;
 
       const channel = await getChannelById(fastify.db, id);
       if (!channel) {

src/server/routes/content.ts

@@ -1,4 +1,5 @@
 import { type FastifyInstance } from 'fastify';
+import { parseIdParam } from './helpers';
 import {
   getAllContentItems,
   getContentByChannelId,
@@ -155,14 +156,8 @@ export async function contentRoutes(fastify: FastifyInstance): Promise<void> {
     '/api/v1/content/:id/monitored',
     { schema: { body: toggleMonitoredBodySchema } },
     async (request, reply) => {
-      const id = parseInt(request.params.id, 10);
-      if (isNaN(id)) {
-        return reply.status(400).send({
-          statusCode: 400,
-          error: 'Bad Request',
-          message: 'Content item ID must be a number',
-        });
-      }
+      const id = parseIdParam(request.params.id, reply, 'Content item ID');
+      if (id === null) return;
 
       try {
         const result = await setMonitored(
@@ -213,15 +208,8 @@ export async function contentRoutes(fastify: FastifyInstance): Promise<void> {
       sortDirection?: string;
     };
   }>('/api/v1/channel/:id/content', async (request, reply) => {
-    const channelId = parseInt(request.params.id, 10);
-
-    if (isNaN(channelId)) {
-      return reply.status(400).send({
-        statusCode: 400,
-        error: 'Bad Request',
-        message: 'Invalid channel ID',
-      });
-    }
+    const channelId = parseIdParam(request.params.id, reply, 'Channel ID');
+    if (channelId === null) return;
 
     const page = Math.max(1, parseInt(request.query.page ?? '1', 10) || 1);
     const pageSize = Math.min(

src/server/routes/format-profile.ts

@@ -1,4 +1,5 @@
 import { type FastifyInstance } from 'fastify';
+import { parseIdParam } from './helpers';
 import {
   createFormatProfile,
   getAllFormatProfiles,
@@ -88,14 +89,8 @@ export async function formatProfileRoutes(fastify: FastifyInstance): Promise<voi
   fastify.get<{ Params: { id: string } }>(
     '/api/v1/format-profile/:id',
     async (request, reply) => {
-      const id = parseInt(request.params.id, 10);
-      if (isNaN(id)) {
-        return reply.status(400).send({
-          statusCode: 400,
-          error: 'Bad Request',
-          message: 'Format profile ID must be a number',
-        });
-      }
+      const id = parseIdParam(request.params.id, reply, 'Format profile ID');
+      if (id === null) return;
 
       const profile = await getFormatProfileById(fastify.db, id);
       if (!profile) {
@@ -130,14 +125,8 @@ export async function formatProfileRoutes(fastify: FastifyInstance): Promise<voi
       schema: { body: updateFormatProfileBodySchema },
     },
     async (request, reply) => {
-      const id = parseInt(request.params.id, 10);
-      if (isNaN(id)) {
-        return reply.status(400).send({
-          statusCode: 400,
-          error: 'Bad Request',
-          message: 'Format profile ID must be a number',
-        });
-      }
+      const id = parseIdParam(request.params.id, reply, 'Format profile ID');
+      if (id === null) return;
 
       // Guard: prevent unsetting isDefault on the default profile
       const existing = await getFormatProfileById(fastify.db, id);
@@ -174,14 +163,8 @@ export async function formatProfileRoutes(fastify: FastifyInstance): Promise<voi
   fastify.delete<{ Params: { id: string } }>(
     '/api/v1/format-profile/:id',
     async (request, reply) => {
-      const id = parseInt(request.params.id, 10);
-      if (isNaN(id)) {
-        return reply.status(400).send({
-          statusCode: 400,
-          error: 'Bad Request',
-          message: 'Format profile ID must be a number',
-        });
-      }
+      const id = parseIdParam(request.params.id, reply, 'Format profile ID');
+      if (id === null) return;
 
       // Guard: prevent deleting the default profile
       const profile = await getFormatProfileById(fastify.db, id);

src/server/routes/helpers.ts

@@ -0,0 +1,26 @@
+import type { FastifyReply } from 'fastify';
+
+/**
+ * Parse a numeric ID from route params.
+ * Returns the parsed number, or sends a 400 response and returns null.
+ *
+ * Usage:
+ *   const id = parseIdParam(request.params.id, reply);
+ *   if (id === null) return;
+ */
+export function parseIdParam(
+  raw: string,
+  reply: FastifyReply,
+  label = 'ID',
+): number | null {
+  const id = parseInt(raw, 10);
+  if (isNaN(id)) {
+    reply.status(400).send({
+      statusCode: 400,
+      error: 'Bad Request',
+      message: `${label} must be a number`,
+    });
+    return null;
+  }
+  return id;
+}

src/server/routes/notification.ts

@@ -1,4 +1,5 @@
 import { type FastifyInstance } from 'fastify';
+import { parseIdParam } from './helpers';
 import {
   createNotificationSetting,
   getAllNotificationSettings,
@@ -122,14 +123,8 @@ export async function notificationRoutes(fastify: FastifyInstance): Promise<void
   fastify.get<{ Params: { id: string } }>(
     '/api/v1/notification/:id',
     async (request, reply) => {
-      const id = parseInt(request.params.id, 10);
-      if (isNaN(id)) {
-        return reply.status(400).send({
-          statusCode: 400,
-          error: 'Bad Request',
-          message: 'Notification setting ID must be a number',
-        });
-      }
+      const id = parseIdParam(request.params.id, reply, 'Notification setting ID');
+      if (id === null) return;
 
       const setting = await getNotificationSettingById(fastify.db, id);
       if (!setting) {
@@ -163,14 +158,8 @@ export async function notificationRoutes(fastify: FastifyInstance): Promise<void
       schema: { body: updateNotificationBodySchema },
     },
     async (request, reply) => {
-      const id = parseInt(request.params.id, 10);
-      if (isNaN(id)) {
-        return reply.status(400).send({
-          statusCode: 400,
-          error: 'Bad Request',
-          message: 'Notification setting ID must be a number',
-        });
-      }
+      const id = parseIdParam(request.params.id, reply, 'Notification setting ID');
+      if (id === null) return;
 
       const updated = await updateNotificationSetting(fastify.db, id, request.body);
       if (!updated) {
@@ -190,14 +179,8 @@ export async function notificationRoutes(fastify: FastifyInstance): Promise<void
   fastify.delete<{ Params: { id: string } }>(
     '/api/v1/notification/:id',
     async (request, reply) => {
-      const id = parseInt(request.params.id, 10);
-      if (isNaN(id)) {
-        return reply.status(400).send({
-          statusCode: 400,
-          error: 'Bad Request',
-          message: 'Notification setting ID must be a number',
-        });
-      }
+      const id = parseIdParam(request.params.id, reply, 'Notification setting ID');
+      if (id === null) return;
 
       const deleted = await deleteNotificationSetting(fastify.db, id);
       if (!deleted) {
@@ -217,14 +200,8 @@ export async function notificationRoutes(fastify: FastifyInstance): Promise<void
   fastify.post<{ Params: { id: string } }>(
     '/api/v1/notification/:id/test',
     async (request, reply) => {
-      const id = parseInt(request.params.id, 10);
-      if (isNaN(id)) {
-        return reply.status(400).send({
-          statusCode: 400,
-          error: 'Bad Request',
-          message: 'Notification setting ID must be a number',
-        });
-      }
+      const id = parseIdParam(request.params.id, reply, 'Notification setting ID');
+      if (id === null) return;
 
       const setting = await getNotificationSettingById(fastify.db, id);
       if (!setting) {

src/server/routes/playlist.ts

@@ -1,4 +1,5 @@
 import { type FastifyInstance } from 'fastify';
+import { parseIdParam } from './helpers';
 import { PlatformRegistry } from '../../sources/platform-source';
 import { YouTubeSource } from '../../sources/youtube';
 import { SoundCloudSource } from '../../sources/soundcloud';
@@ -36,14 +37,8 @@ export async function playlistRoutes(fastify: FastifyInstance): Promise<void> {
   fastify.get<{ Params: { id: string } }>(
     '/api/v1/channel/:id/playlists',
     async (request, reply) => {
-      const id = parseInt(request.params.id, 10);
-      if (isNaN(id)) {
-        return reply.status(400).send({
-          statusCode: 400,
-          error: 'Bad Request',
-          message: 'Channel ID must be a number',
-        });
-      }
+      const id = parseIdParam(request.params.id, reply, 'Channel ID');
+      if (id === null) return;
 
       const channel = await getChannelById(fastify.db, id);
       if (!channel) {
@@ -66,14 +61,8 @@ export async function playlistRoutes(fastify: FastifyInstance): Promise<void> {
   fastify.post<{ Params: { id: string } }>(
     '/api/v1/channel/:id/playlists/refresh',
     async (request, reply) => {
-      const id = parseInt(request.params.id, 10);
-      if (isNaN(id)) {
-        return reply.status(400).send({
-          statusCode: 400,
-          error: 'Bad Request',
-          message: 'Channel ID must be a number',
-        });
-      }
+      const id = parseIdParam(request.params.id, reply, 'Channel ID');
+      if (id === null) return;
 
       const channel = await getChannelById(fastify.db, id);
       if (!channel) {

src/server/routes/queue.ts

@@ -1,4 +1,5 @@
 import { type FastifyInstance } from 'fastify';
+import { parseIdParam } from './helpers';
 import {
   getQueueItemsByStatus,
   getQueueItemById,
@@ -57,14 +58,8 @@ export async function queueRoutes(fastify: FastifyInstance): Promise<void> {
   fastify.get<{ Params: { id: string } }>(
     '/api/v1/queue/:id',
     async (request, reply) => {
-      const id = parseInt(request.params.id, 10);
-      if (isNaN(id)) {
-        return reply.status(400).send({
-          statusCode: 400,
-          error: 'Bad Request',
-          message: 'Queue item ID must be a number',
-        });
-      }
+      const id = parseIdParam(request.params.id, reply, 'Queue item ID');
+      if (id === null) return;
 
       const item = await getQueueItemById(fastify.db, id);
       if (!item) {
@@ -141,14 +136,8 @@ export async function queueRoutes(fastify: FastifyInstance): Promise<void> {
   fastify.delete<{ Params: { id: string } }>(
     '/api/v1/queue/:id',
     async (request, reply) => {
-      const id = parseInt(request.params.id, 10);
-      if (isNaN(id)) {
-        return reply.status(400).send({
-          statusCode: 400,
-          error: 'Bad Request',
-          message: 'Queue item ID must be a number',
-        });
-      }
+      const id = parseIdParam(request.params.id, reply, 'Queue item ID');
+      if (id === null) return;
 
       if (!fastify.queueService) {
         return reply.status(503).send({
@@ -190,14 +179,8 @@ export async function queueRoutes(fastify: FastifyInstance): Promise<void> {
   fastify.post<{ Params: { id: string } }>(
     '/api/v1/queue/:id/retry',
     async (request, reply) => {
-      const id = parseInt(request.params.id, 10);
-      if (isNaN(id)) {
-        return reply.status(400).send({
-          statusCode: 400,
-          error: 'Bad Request',
-          message: 'Queue item ID must be a number',
-        });
-      }
+      const id = parseIdParam(request.params.id, reply, 'Queue item ID');
+      if (id === null) return;
 
       if (!fastify.queueService) {
         return reply.status(503).send({

src/server/routes/scan.ts

@@ -1,4 +1,5 @@
 import { type FastifyInstance } from 'fastify';
+import { parseIdParam } from './helpers';
 import type { CheckChannelResult } from '../../services/scheduler';
 import {
   getChannelById,
@@ -75,14 +76,8 @@ export async function scanRoutes(fastify: FastifyInstance): Promise<void> {
   fastify.post<{ Params: { id: string } }>(
     '/api/v1/channel/:id/scan',
     async (request, reply) => {
-      const id = parseInt(request.params.id, 10);
-      if (isNaN(id)) {
-        return reply.status(400).send({
-          statusCode: 400,
-          error: 'Bad Request',
-          message: 'Channel ID must be a number',
-        });
-      }
+      const id = parseIdParam(request.params.id, reply, 'Channel ID');
+      if (id === null) return;
 
       const channel = await getChannelById(fastify.db, id);
       if (!channel) {
@@ -137,14 +132,8 @@ export async function scanRoutes(fastify: FastifyInstance): Promise<void> {
   fastify.post<{ Params: { id: string } }>(
     '/api/v1/channel/:id/scan-cancel',
     async (request, reply) => {
-      const id = parseInt(request.params.id, 10);
-      if (isNaN(id)) {
-        return reply.status(400).send({
-          statusCode: 400,
-          error: 'Bad Request',
-          message: 'Channel ID must be a number',
-        });
-      }
+      const id = parseIdParam(request.params.id, reply, 'Channel ID');
+      if (id === null) return;
 
       if (!fastify.scheduler) {
         return reply.status(503).send({
@@ -164,14 +153,8 @@ export async function scanRoutes(fastify: FastifyInstance): Promise<void> {
   fastify.get<{ Params: { id: string } }>(
     '/api/v1/channel/:id/scan-status',
     async (request, reply) => {
-      const id = parseInt(request.params.id, 10);
-      if (isNaN(id)) {
-        return reply.status(400).send({
-          statusCode: 400,
-          error: 'Bad Request',
-          message: 'Channel ID must be a number',
-        });
-      }
+      const id = parseIdParam(request.params.id, reply, 'Channel ID');
+      if (id === null) return;
 
       const scanning = fastify.scheduler?.isScanning(id) ?? false;
       return { scanning };

src/server/routes/system.ts

@@ -168,8 +168,8 @@ export async function systemRoutes(fastify: FastifyInstance): Promise<void> {
       await setAppSetting(db, APP_CONCURRENT_DOWNLOADS, body.concurrentDownloads.toString());
 
       // Update queue concurrency at runtime
-      if ((fastify as any).queueService?.setConcurrency) {
-        (fastify as any).queueService.setConcurrency(body.concurrentDownloads);
+      if (fastify.queueService?.setConcurrency) {
+        fastify.queueService.setConcurrency(body.concurrentDownloads);
       }
     }