fix(search): locale-invariant Turkish case folding in every search path (#1640)

Turkish upper and lower case queries now return the same results everywhere a
title can be searched. Lower-casing the dotted capital "İ" (U+0130) leaves a
combining dot behind, so "İnş" and "inş" reached different search arms and
different results.

- Case folding is locale-invariant: `toLowerCase()`, never `toLocaleLowerCase()`,
  which under a Turkish or Azeri OS locale maps ASCII "I" to the dotless "ı".
- The Electron content search composes to NFC and drops the leftover combining
  marks before tokenizing, and its LIKE/GLOB pattern builders additionally spell
  the `'tr'`-locale İ forms, since SQLite LIKE folds only ASCII.
- A shared `foldSearchText` covers every in-memory filter: channel lists, the
  Xtream and Stalker catalogs, category filters, collections, the EPG guide, the
  command palette, sources, the playlist switcher and the download lists.
- Composing before the strip keeps canonically equivalent spellings equal while
  the fold stays accent-sensitive; the Turkish I/ı pair is deliberately left
  alone, as the FTS index does not fold it either.

Covered by a SQLite-backed spec over the real trigram index plus regression
cases in the affected renderer specs.

Closes #609.

Co-Authored-By: Justin Willhite <5132924+thejdubb02@users.noreply.github.com>
Co-Authored-By: Claude Opus 5 <noreply@anthropic.com>

libs/playlist/shared/ui/src/lib/playlist-switcher/playlist-switcher.component.ts

@@ -1,7 +1,7 @@
 import { Injector } from '@angular/core';
 import { RuntimeCapabilitiesService } from '@iptvnator/services';
 import { SourceHealthService } from '@iptvnator/portal/shared/data-access';
-import { sourceHealthType } from '@iptvnator/shared/interfaces';
+import { foldSearchText, sourceHealthType } from '@iptvnator/shared/interfaces';
 import { SourceHealthIndicatorComponent } from '../source-health/source-health-indicator.component';
 import { DatePipe, DOCUMENT } from '@angular/common';
 import {
@@ -138,7 +138,7 @@ export class PlaylistSwitcherComponent {
     readonly activePlaylistId = this.playlistContext.resolvedPlaylistId;
     readonly activePlaylist = this.playlistContext.activePlaylist;
     readonly filteredPlaylists = computed(() => {
-        const query = this.searchQuery().toLowerCase().trim();
+        const query = foldSearchText(this.searchQuery()).trim();
         const filters = this.playlistTypeFilters();
         const allPlaylists = this.playlists();
         const filteredByType = allPlaylists.filter((playlist) => {
@@ -148,8 +148,8 @@ export class PlaylistSwitcherComponent {
         const filtered = query
             ? filteredByType.filter(
                   (playlist) =>
-                      playlist.title?.toLowerCase().includes(query) ||
-                      playlist.filename?.toLowerCase().includes(query)
+                      foldSearchText(playlist.title ?? '').includes(query) ||
+                      foldSearchText(playlist.filename ?? '').includes(query)
               )
             : filteredByType;
 

libs/playlist/shared/ui/src/lib/recent-playlists/recent-playlists.component.ts

@@ -40,6 +40,7 @@ import {
     SortService,
 } from '@iptvnator/services';
 import {
+    foldSearchText,
     PLAYLIST_UPDATE,
     PlaylistMeta,
     PlaylistRefreshEvent,
@@ -169,9 +170,9 @@ export class RecentPlaylistsComponent {
                     );
                 })
                 .filter((item) =>
-                    (item.title || '')
-                        .toLowerCase()
-                        .includes(searchQuery.toLowerCase())
+                    foldSearchText(item.title || '').includes(
+                        foldSearchText(searchQuery)
+                    )
                 );
 
             // Apply sorting using the SortService

libs/portal/downloads/feature/src/lib/download-manager.viewmodel.ts

@@ -9,6 +9,7 @@ import {
     type DownloadLibraryEntity,
     type DownloadLibraryRow,
 } from './download-library.viewmodel';
+import { foldSearchText } from '@iptvnator/shared/interfaces';
 
 export type {
     DownloadCatchupCardViewModel,
@@ -124,7 +125,7 @@ function matchesSearch(
     row: DownloadListItemViewModel,
     searchTerm: string
 ): boolean {
-    const query = searchTerm.trim().toLowerCase();
+    const query = foldSearchText(searchTerm.trim());
     return (
         query.length === 0 ||
         [
@@ -133,7 +134,7 @@ function matchesSearch(
             row.sourceName,
             row.episodeLabel,
             row.item.errorMessage ?? '',
-        ].some((value) => value.toLowerCase().includes(query))
+        ].some((value) => foldSearchText(value).includes(query))
     );
 }
 

libs/portal/downloads/feature/src/lib/recording-manager.viewmodel.ts

@@ -1,5 +1,6 @@
 import type { RecordingItem } from '@iptvnator/services';
 import { normalizeDownloadFilter } from './download-manager.viewmodel';
+import { foldSearchText } from '@iptvnator/shared/interfaces';
 
 export type RecordingAttentionReason = 'file-missing' | 'failed';
 
@@ -96,7 +97,7 @@ function toRow(item: RecordingItem): RecordingRowViewModel {
 }
 
 function matchesSearch(row: RecordingRowViewModel, searchTerm: string): boolean {
-    const query = searchTerm.trim().toLowerCase();
+    const query = foldSearchText(searchTerm.trim());
     return (
         query.length === 0 ||
         [
@@ -104,7 +105,7 @@ function matchesSearch(row: RecordingRowViewModel, searchTerm: string): boolean
             row.channelName,
             row.item.playlistName ?? '',
             row.item.errorMessage ?? '',
-        ].some((value) => value.toLowerCase().includes(query))
+        ].some((value) => foldSearchText(value).includes(query))
     );
 }
 

libs/portal/shared/ui/src/lib/components/unified-collection/unified-grid-tab.component.ts

@@ -12,6 +12,7 @@ import {
     UnifiedCollectionItem,
 } from '@iptvnator/portal/shared/util';
 import { ContentCardComponent } from '../content-card/content-card.component';
+import { foldSearchText } from '@iptvnator/shared/interfaces';
 
 @Component({
     selector: 'app-unified-grid-tab',
@@ -30,7 +31,7 @@ export class UnifiedGridTabComponent {
     readonly itemSelected = output<UnifiedCollectionItem>();
 
     private readonly normalizedSearchTerm = computed(() =>
-        this.searchTerm().trim().toLowerCase()
+        foldSearchText(this.searchTerm().trim())
     );
     /**
      * Search results are identified by the name the user typed, so a
@@ -44,7 +45,7 @@ export class UnifiedGridTabComponent {
         const term = this.normalizedSearchTerm();
         const all = this.items();
         return term
-            ? all.filter((i) => i.name.toLowerCase().includes(term))
+            ? all.filter((i) => foldSearchText(i.name).includes(term))
             : all;
     });
 

libs/portal/shared/util/src/lib/favorites-channel-sort.ts

@@ -1,3 +1,5 @@
+import { foldSearchText } from '@iptvnator/shared/interfaces';
+
 const FAVORITES_SORT_COLLATOR = new Intl.Collator(undefined, {
     numeric: true,
     sensitivity: 'base',
@@ -72,10 +74,10 @@ export function deriveVisibleFavoriteChannels<T>(
         getAddedAt?: (item: T) => string | null | undefined;
     }
 ): readonly T[] {
-    const term = options.searchTerm.trim().toLowerCase();
+    const term = foldSearchText(options.searchTerm.trim());
     const filtered = term
         ? channels.filter((channel) =>
-              (options.getName(channel) ?? '').toLowerCase().includes(term)
+              foldSearchText(options.getName(channel) ?? '').includes(term)
           )
         : channels;
 

libs/portal/shared/util/src/lib/portal-collection-items.spec.ts

@@ -135,4 +135,25 @@ describe('portal-collection-items', () => {
 
         expect(filtered).toEqual([items[1]]);
     });
+
+    it('folds the Turkish dotted capital İ so upper and lower case terms agree (issue #609)', () => {
+        const items = [
+            { name: 'İnşaat Kanalı', o_name: '' },
+            { name: 'Matrix', o_name: 'Neo' },
+        ];
+        const filter = (searchTerm: string) =>
+            filterCollectionBucket({
+                selectedCategoryId: 'all',
+                allItems: items,
+                buckets: {
+                    movie: items,
+                },
+                searchTerm,
+                textOf: (item) => `${item.name} ${item.o_name}`,
+            });
+
+        expect(filter('inş')).toEqual([items[0]]);
+        expect(filter('İnş')).toEqual([items[0]]);
+        expect(filter('İNŞ')).toEqual([items[0]]);
+    });
 });

libs/portal/shared/util/src/lib/portal-collection-items.ts

@@ -1,4 +1,4 @@
-import { XtreamCategory } from '@iptvnator/shared/interfaces';
+import { foldSearchText, XtreamCategory } from '@iptvnator/shared/interfaces';
 
 type StandardCollectionBucket = 'all' | 'movie' | 'live' | 'series';
 
@@ -84,13 +84,13 @@ export function filterCollectionBucket<T>(
               : selectedCategoryId === 'series'
                 ? buckets.series ?? []
                 : allItems ?? [];
-    const normalizedTerm = (searchTerm ?? '').trim().toLowerCase();
+    const normalizedTerm = foldSearchText((searchTerm ?? '').trim());
 
     if (!normalizedTerm) {
         return [...baseItems];
     }
 
     return baseItems.filter((item) =>
-        String(textOf(item)).toLowerCase().includes(normalizedTerm)
+        foldSearchText(String(textOf(item))).includes(normalizedTerm)
     );
 }

libs/portal/stalker/feature/src/lib/stalker-live-stream-layout/stalker-itv-all-items.component.ts

@@ -16,6 +16,7 @@ import {
     StalkerItvChannel,
     StalkerItvLoadProgress,
 } from '@iptvnator/portal/stalker/data-access';
+import { foldSearchText } from '@iptvnator/shared/interfaces';
 
 /** Initial render window and per-`loadMore` growth over the cached list. */
 const RENDER_CHUNK = 50;
@@ -101,16 +102,16 @@ export class StalkerItvAllItemsComponent {
     });
 
     readonly filteredChannels = computed(() => {
-        const term = this.searchTerm().trim().toLowerCase();
+        const term = foldSearchText(this.searchTerm().trim());
         const channels = this.channels();
         if (!term) {
             return channels;
         }
 
         return channels.filter((channel) =>
-            `${channel.o_name ?? ''} ${channel.name ?? ''}`
-                .toLowerCase()
-                .includes(term)
+            foldSearchText(
+                `${channel.o_name ?? ''} ${channel.name ?? ''}`
+            ).includes(term)
         );
     });
 

libs/portal/stalker/feature/src/lib/stalker-live-stream-layout/stalker-live-stream-layout.component.ts

@@ -42,6 +42,7 @@ import {
     SettingsStore,
 } from '@iptvnator/services';
 import {
+    foldSearchText,
     buildStalkerEpgMappingKey,
     Channel,
     EpgItem,
@@ -132,9 +133,9 @@ function matchesStalkerChannelTerm(
     item: StalkerItvChannel,
     term: string
 ): boolean {
-    return `${item.o_name ?? ''} ${item.name ?? ''}`
-        .toLowerCase()
-        .includes(term);
+    return foldSearchText(`${item.o_name ?? ''} ${item.name ?? ''}`).includes(
+        term
+    );
 }
 
 import { StalkerLiveNavigation } from './stalker-live-navigation';
@@ -203,7 +204,7 @@ export class StalkerLiveStreamLayoutComponent
         this.isRadioMode() ? this.radioChannels() : this.itvChannels()
     );
     readonly searchTerm = computed(() =>
-        this.stalkerStore.searchPhrase().trim().toLowerCase()
+        foldSearchText(this.stalkerStore.searchPhrase().trim())
     );
     /** Full-list mode: the complete channel list is cached, so search covers everything. */
     readonly isFullListMode = computed(
@@ -1099,7 +1100,7 @@ export class StalkerLiveStreamLayoutComponent
      * instance shows the sidebar's windowed rows.
      */
     channelsForList(panelSearchTerm?: Signal<string>): StalkerItvChannel[] {
-        const term = panelSearchTerm?.().trim().toLowerCase() ?? '';
+        const term = foldSearchText(panelSearchTerm?.().trim() ?? '');
         if (!term) {
             if (!panelSearchTerm) {
                 return this.visibleChannels();
@@ -1776,7 +1777,7 @@ export class StalkerLiveStreamLayoutComponent
                       matchesStalkerChannelTerm(item, this.searchTerm())
                   )
                 : this.filteredChannels();
-        const query = term().trim().toLowerCase();
+        const query = foldSearchText(term().trim());
         return query
             ? this.searchableChannels().filter((item) =>
                   matchesStalkerChannelTerm(item, query)

libs/portal/xtream/data-access/src/lib/data-sources/pwa-xtream-data-source.ts

@@ -1,5 +1,6 @@
 import { inject, Injectable, Injector } from '@angular/core';
 import {
+    foldSearchText,
     ContentMetadataPatch,
     Playlist,
     PlaybackPositionData,
@@ -548,7 +549,7 @@ export class PwaXtreamDataSource implements IXtreamDataSource {
     ): Promise<XtreamContentItem[]> {
         void excludeHidden;
         const results: XtreamCachedContentItem[] = [];
-        const searchLower = searchTerm.toLowerCase();
+        const searchLower = foldSearchText(searchTerm);
 
         for (const type of types) {
             const cacheKey = `${playlistId}-${type}-content`;
@@ -557,7 +558,7 @@ export class PwaXtreamDataSource implements IXtreamDataSource {
             const filtered = content.filter((item) => {
                 const title =
                     item.name || item.title || item.stream_display_name || '';
-                return title.toLowerCase().includes(searchLower);
+                return foldSearchText(title).includes(searchLower);
             });
 
             results.push(...filtered);

libs/portal/xtream/data-access/src/lib/stores/features/with-selection.feature.spec.ts

@@ -110,6 +110,12 @@ const TestSelectionStore = signalStore(
                 title: 'Cosmos',
                 added: '6',
             },
+            {
+                xtream_id: 7,
+                category_id: '20',
+                title: 'İnşaat Belgeseli',
+                added: '7',
+            },
             ...bulkVodStreams,
         ],
         serialCategories: [
@@ -191,6 +197,21 @@ describe('withSelection', () => {
         expect(store.visibleCount()).toBe(coveredCount);
     });
 
+    it('matches the Turkish dotted capital İ from a lower-case search term (issue #609)', () => {
+        store.setSelectedContentType('vod');
+        store.setSelectedCategory(20);
+
+        store.setCategorySearchTerm('inş');
+        expect(store.getPaginatedContent().map((item) => item.title)).toEqual([
+            'İnşaat Belgeseli',
+        ]);
+
+        store.setCategorySearchTerm('İNŞ');
+        expect(store.getPaginatedContent().map((item) => item.title)).toEqual([
+            'İnşaat Belgeseli',
+        ]);
+    });
+
     it('keeps the render window when the category search term is unchanged', () => {
         store.setSelectedContentType('vod');
         store.setSelectedCategory(90);

libs/portal/xtream/data-access/src/lib/stores/features/with-selection.feature.ts

@@ -7,6 +7,7 @@ import {
     withState,
 } from '@ngrx/signals';
 import { ContentType, XtreamContentLoadState } from '../../xtream-state';
+import { foldSearchText } from '@iptvnator/shared/interfaces';
 
 /**
  * Module-level collator — allocating Intl.Collator is expensive;
@@ -295,14 +296,14 @@ export function withSelection() {
                 items: XtreamSelectionItem[],
                 searchTerm: string
             ): XtreamSelectionItem[] => {
-                const normalized = searchTerm.trim().toLocaleLowerCase();
+                const normalized = foldSearchText(searchTerm.trim());
                 if (!normalized) {
                     return items;
                 }
 
                 return items.filter((item) => {
                     const title = (item.title ?? item.name ?? '').toString();
-                    return title.toLocaleLowerCase().includes(normalized);
+                    return foldSearchText(title).includes(normalized);
                 });
             };
 

libs/portal/xtream/feature/src/lib/category-management-dialog/category-management-dialog.component.ts

@@ -19,6 +19,7 @@ import { MatSnackBar } from '@angular/material/snack-bar';
 import { TranslatePipe } from '@ngx-translate/core';
 import { DatabaseService, XCategoryFromDb } from '@iptvnator/services';
 import { createLogger } from '@iptvnator/portal/shared/util';
+import { foldSearchText } from '@iptvnator/shared/interfaces';
 
 export interface CategoryManagementDialogData {
     playlistId: string;
@@ -58,10 +59,10 @@ export class CategoryManagementDialogComponent implements OnInit {
     readonly searchTerm = signal('');
 
     readonly filteredCategories = computed(() => {
-        const term = this.searchTerm().toLowerCase();
+        const term = foldSearchText(this.searchTerm());
         if (!term) return this.categories();
         return this.categories().filter((c) =>
-            c.name.toLowerCase().includes(term)
+            foldSearchText(c.name).includes(term)
         );
     });
 

libs/portal/xtream/feature/src/lib/live-stream-layout/xtream-live-channel-navigation.service.spec.ts

@@ -15,6 +15,7 @@ import {
 } from '@angular/router';
 import { RouterTestingHarness } from '@angular/router/testing';
 import { LiveLayoutSidebarStateService } from '@iptvnator/portal/shared/util';
+import { foldSearchText } from '@iptvnator/shared/interfaces';
 import { XtreamStore } from '@iptvnator/portal/xtream/data-access';
 import { BehaviorSubject, Subject } from 'rxjs';
 import { XtreamLiveChannelNavigationService } from './xtream-live-channel-navigation.service';
@@ -22,6 +23,7 @@ import { XtreamLiveChannelNavigationService } from './xtream-live-channel-naviga
 const first = { xtream_id: 1, category_id: '10', title: 'Zulu' };
 const second = { xtream_id: 2, category_id: '10', title: 'Alpha' };
 const other = { xtream_id: 3, category_id: '20', title: 'Other' };
+const turkish = { xtream_id: 4, category_id: '10', title: 'İnşaat TV' };
 
 @Component({
     template: '',
@@ -47,9 +49,11 @@ describe('XtreamLiveChannelNavigationService', () => {
             (item) =>
                 (!selectedCategoryId() ||
                     Number(item.category_id) === selectedCategoryId()) &&
-                item.title
-                    .toLowerCase()
-                    .includes(categorySearchTerm().toLowerCase())
+                // Mirrors the real store's withSelection filter, which
+                // folds the term (issue #609).
+                foldSearchText(item.title).includes(
+                    foldSearchText(categorySearchTerm())
+                )
         )
     );
     const store = {
@@ -118,6 +122,19 @@ describe('XtreamLiveChannelNavigationService', () => {
         TestBed.flushEffects();
     });
 
+    it('lists the dotted capital İ for a lower-case route query, like the sidebar (issue #609)', () => {
+        // The rendered sidebar and this playback-order source must agree on
+        // what the query matches, or capture() records a queue that does not
+        // contain the row the user just clicked.
+        liveStreams.set([first, second, other, turkish]);
+
+        query.next(convertToParamMap({ q: 'inş' }));
+        expect(service.displayedChannels()).toEqual([turkish]);
+
+        query.next(convertToParamMap({ q: 'İNŞ' }));
+        expect(service.displayedChannels()).toEqual([turkish]);
+    });
+
     it('captures the displayed sort and keeps it after category, search, and sort changes', () => {
         service.sortMode.set('name-asc');
         service.capture(first);

libs/portal/xtream/feature/src/lib/live-stream-layout/xtream-live-channel-navigation.service.ts

@@ -17,6 +17,7 @@ import {
     sortPortalChannelItems,
 } from '@iptvnator/portal/shared/util';
 import { XtreamStore } from '@iptvnator/portal/xtream/data-access';
+import { foldSearchText } from '@iptvnator/shared/interfaces';
 
 export interface XtreamLiveChannelItem {
     readonly added?: string;
@@ -59,7 +60,7 @@ export class XtreamLiveChannelNavigationService {
         return playing?.owner === this.owner() ? playing.item : null;
     });
     readonly displayedChannels = computed(() => {
-        const term = this.query().trim().toLowerCase();
+        const term = foldSearchText(this.query().trim());
         const channels = sortPortalChannelItems(
             this.store.selectItemsFromSelectedCategory() as XtreamLiveChannelItem[],
             this.sortMode(),
@@ -67,9 +68,9 @@ export class XtreamLiveChannelNavigationService {
         );
         return term
             ? channels.filter((item) =>
-                  `${item.title ?? ''} ${item.name ?? ''}`
-                      .toLowerCase()
-                      .includes(term)
+                  foldSearchText(
+                      `${item.title ?? ''} ${item.name ?? ''}`
+                  ).includes(term)
               )
             : channels;
     });

libs/portal/xtream/feature/src/lib/portal-channels-list/portal-channels-list.component.ts

@@ -28,6 +28,7 @@ import { TranslatePipe } from '@ngx-translate/core';
 import { Subscription } from 'rxjs';
 import { debounceTime } from 'rxjs/operators';
 import {
+    foldSearchText,
     buildXtreamEpgMappingKey,
     EpgItem,
     EpgProgram,
@@ -146,7 +147,7 @@ export class PortalChannelsListComponent implements AfterViewInit, OnDestroy {
         );
     });
     readonly filteredChannels = computed(() => {
-        const term = this.searchTermInput().trim().toLowerCase();
+        const term = foldSearchText(this.searchTermInput().trim());
         const channels = this.sortedChannels();
 
         if (!term) {
@@ -154,9 +155,9 @@ export class PortalChannelsListComponent implements AfterViewInit, OnDestroy {
         }
 
         return channels.filter((item) =>
-            `${item.title ?? ''} ${item.name ?? ''}`
-                .toLowerCase()
-                .includes(term)
+            foldSearchText(`${item.title ?? ''} ${item.name ?? ''}`).includes(
+                term
+            )
         );
     });
 

libs/shared/interfaces/src/index.ts

@@ -60,6 +60,7 @@ export * from './lib/stream-format.enum';
 export * from './lib/catalog-title-match.interface';
 export * from './lib/theme.enum';
 export * from './lib/season-marker.util';
+export * from './lib/search-text-fold.util';
 export * from './lib/stalker-account-info-dialog-data.interface';
 export * from './lib/title-normalization.util';
 export * from './lib/tmdb.interface';

libs/shared/interfaces/src/lib/search-text-fold.util.spec.ts

@@ -0,0 +1,58 @@
+import { foldSearchText } from './search-text-fold.util';
+
+describe('foldSearchText', () => {
+    it('folds the Turkish dotted capital I onto a plain lower-case i (issue #609)', () => {
+        expect(foldSearchText('İnşaat Kanalı')).toBe('inşaat kanalı');
+        expect(
+            foldSearchText('İnşaat Kanalı').includes(foldSearchText('inş'))
+        ).toBe(true);
+        expect(foldSearchText('İnş')).toBe(foldSearchText('inş'));
+    });
+
+    it.each([
+        ['Ünlü Şef', 'ünlü şef'],
+        ['ÇANAKKALE', 'çanakkale'],
+        ['Первый канал HD', 'первый канал hd'],
+        ['Ёлки', 'ёлки'],
+        ['Йога для всех', 'йога для всех'],
+        ['Ελλάδα Σήμερα', 'ελλάδα σήμερα'],
+        ['Amélie', 'amélie'],
+        ['Straße', 'straße'],
+    ])(
+        'keeps precomposed letters of other scripts intact: %s',
+        (input, expected) => {
+            expect(foldSearchText(input)).toBe(expected);
+        }
+    );
+
+    it.each([
+        ['Amélie', 'Amélie'],
+        ['İnşaat', 'İnşaat'],
+        ['Ёлки', 'Ёлки'],
+        ['Йога', 'Йога'],
+        ['Ünlü', 'Ünlü'],
+        ['Ά', 'Ά'],
+    ])(
+        'folds canonically equivalent spellings of %s to one string',
+        (precomposed, decomposed) => {
+            expect(foldSearchText(decomposed)).toBe(
+                foldSearchText(precomposed)
+            );
+        }
+    );
+
+    it('stays accent-sensitive, unlike the diacritic-folding SQL index', () => {
+        // The renderer filters were accent-sensitive before this helper and
+        // stay so: only marks that cannot compose are dropped. Accent-blind
+        // matching is the FTS index's own behaviour, not this fold's.
+        expect(foldSearchText('Amélie')).not.toBe(foldSearchText('Amelie'));
+    });
+
+    it('does not fold the dotless ı onto i', () => {
+        // The Turkish I/ı pair is a separate letter, not a case form of i;
+        // it is deliberately left alone (see the FTS index, which does not
+        // fold it either).
+        expect(foldSearchText('Işık')).toBe('işık');
+        expect(foldSearchText('ışık')).toBe('ışık');
+    });
+});

libs/shared/interfaces/src/lib/search-text-fold.util.ts

@@ -0,0 +1,35 @@
+/**
+ * Locale-invariant case fold for in-memory search filters (channel lists,
+ * catalog and category filters, source and download lists). Pure function,
+ * no Angular/Node dependencies.
+ *
+ * `toLowerCase()` alone is not enough for one visible input: the Turkish
+ * dotted capital "İ" (U+0130) lower-cases to "i" plus a combining dot above
+ * (U+0307), so `"İnşaat".toLowerCase().includes("inş")` is `false` even
+ * though the two spellings are the same word (issue #609).
+ *
+ * The fold therefore runs `toLowerCase()`, re-composes the result to NFC and
+ * drops whatever combining marks are left. Composing first is what makes the
+ * fold agree on canonically equivalent text: a provider title stored
+ * decomposed ("e" + U+0301) and a query typed precomposed ("é") reach the
+ * same string, and a Greek "Ά" lower-cases to a form NFC maps onto the same
+ * "ά" the user types. Only marks that cannot compose survive to be stripped —
+ * the dotted I's leftover dot among them — so precomposed letters (ç, ş, ü,
+ * é, ё, й) are preserved and the fold stays accent-sensitive, exactly as the
+ * filters were before. A lower-cased string of printable ASCII is already NFC
+ * and carries no marks, which is the fast path taken by most titles.
+ *
+ * `toLocaleLowerCase()` is deliberately not used: under a Turkish or Azeri
+ * OS locale it maps ASCII "I" to the dotless "ı", so the same list would
+ * filter differently per machine.
+ */
+const COMBINING_MARKS_REGEXP = /[̀-ͯ]/g;
+const NON_PRINTABLE_ASCII_REGEXP = /[^ -~]/;
+
+export function foldSearchText(value: string): string {
+    const lowered = value.toLowerCase();
+
+    return NON_PRINTABLE_ASCII_REGEXP.test(lowered)
+        ? lowered.normalize('NFC').replace(COMBINING_MARKS_REGEXP, '')
+        : lowered;
+}

libs/ui/components/src/lib/channel-list-container/all-channels-view/all-channels-view.component.spec.ts

@@ -91,6 +91,30 @@ describe('AllChannelsViewComponent', () => {
         localStorage.removeItem(ALL_CHANNELS_SORT_STORAGE_KEY);
     });
 
+    it('filters the Turkish dotted capital İ case-insensitively (issue #609)', () => {
+        const turkishChannel = createChannel(
+            'channel-2',
+            'İnşaat Kanalı',
+            'https://example.com/insaat.m3u8'
+        );
+        fixture.componentRef.setInput('channels', [
+            primaryChannel,
+            turkishChannel,
+        ]);
+
+        fixture.componentRef.setInput('searchTerm', 'inş');
+        fixture.detectChanges();
+        expect(component.filteredChannels()).toEqual([turkishChannel]);
+
+        fixture.componentRef.setInput('searchTerm', 'İNŞ');
+        fixture.detectChanges();
+        expect(component.filteredChannels()).toEqual([turkishChannel]);
+
+        fixture.componentRef.setInput('searchTerm', 'news');
+        fixture.detectChanges();
+        expect(component.filteredChannels()).toEqual([primaryChannel]);
+    });
+
     it('defaults to playlist order when no saved sort mode exists', () => {
         expect(component.allChannelsSortMode()).toBe('server');
         expect(component.allChannelsSortLabel()).toBe('Playlist Order');

libs/ui/components/src/lib/channel-list-container/all-channels-view/all-channels-view.component.ts

@@ -21,6 +21,7 @@ import { EpgRuntimeBridgeService } from '@iptvnator/epg/data-access';
 import { SettingsStore } from '@iptvnator/services';
 import { resolveChannelEpgLookupKey } from '@iptvnator/m3u-state';
 import {
+    foldSearchText,
     Channel,
     EpgProgram,
     epgProviderClockMs,
@@ -127,10 +128,12 @@ export class AllChannelsViewComponent {
      * reference when there is no search term, so large lists avoid cloning.
      */
     readonly filteredChannels = computed(() => {
-        const term = this.searchTerm().trim().toLowerCase();
+        const term = foldSearchText(this.searchTerm().trim());
         const channels = this.channels();
         const filteredChannels = term
-            ? channels.filter((ch) => ch.name?.toLowerCase().includes(term))
+            ? channels.filter((ch) =>
+                  foldSearchText(ch.name ?? '').includes(term)
+              )
             : channels;
 
         return sortPlaylistChannelItems(

libs/ui/components/src/lib/channel-list-container/channel-list-container.component.ts

@@ -50,6 +50,7 @@ import {
     SettingsStore,
 } from '@iptvnator/services';
 import {
+    foldSearchText,
     Channel,
     EpgProgram,
     isM3uRecentlyViewedItem,
@@ -217,12 +218,12 @@ export class ChannelListContainerComponent implements OnInit, OnDestroy {
     private readonly routeSearchTerm = queryParamSignal(
         this.route,
         'q',
-        (value) => (value ?? '').trim().toLowerCase()
+        (value) => foldSearchText((value ?? '').trim())
     );
     readonly workspaceSearchTerm = computed(() => {
         const hostTerm = this.searchTerm();
         if (hostTerm !== null) {
-            return hostTerm.trim().toLowerCase();
+            return foldSearchText(hostTerm.trim());
         }
         return this.isWorkspaceLayout ? this.routeSearchTerm() : '';
     });

libs/ui/components/src/lib/channel-list-container/favorites-view/favorites-view.component.ts

@@ -22,6 +22,7 @@ import { EpgRuntimeBridgeService } from '@iptvnator/epg/data-access';
 import { SettingsStore } from '@iptvnator/services';
 import { resolveChannelEpgLookupKey } from '@iptvnator/m3u-state';
 import {
+    foldSearchText,
     Channel,
     EpgProgram,
     epgProviderClockMs,
@@ -97,16 +98,16 @@ export class FavoritesViewComponent {
     );
     readonly filteredFavorites = computed(() => {
         const favorites = this.favorites();
-        const term = this.searchTerm().trim().toLowerCase();
+        const term = foldSearchText(this.searchTerm().trim());
 
         if (!term) {
             return favorites;
         }
 
         return favorites.filter((channel) =>
-            `${channel.name ?? ''} ${channel.group?.title ?? ''}`
-                .toLowerCase()
-                .includes(term)
+            foldSearchText(
+                `${channel.name ?? ''} ${channel.group?.title ?? ''}`
+            ).includes(term)
         );
     });
 

libs/ui/components/src/lib/channel-list-container/groups-view/group-management-dialog/group-management-dialog.component.ts

@@ -15,6 +15,7 @@ import {
 } from '@angular/material/dialog';
 import { MatIconModule } from '@angular/material/icon';
 import { TranslatePipe } from '@ngx-translate/core';
+import { foldSearchText } from '@iptvnator/shared/interfaces';
 
 export interface GroupManagementDialogGroup {
     readonly count: number;
@@ -59,14 +60,14 @@ export class GroupManagementDialogComponent {
     );
 
     readonly filteredGroups = computed(() => {
-        const term = this.searchTerm().trim().toLowerCase();
+        const term = foldSearchText(this.searchTerm().trim());
 
         if (!term) {
             return this.groups();
         }
 
         return this.groups().filter((group) =>
-            group.key.toLowerCase().includes(term)
+            foldSearchText(group.key).includes(term)
         );
     });
 

libs/ui/components/src/lib/channel-list-container/groups-view/groups-view.component.ts

@@ -24,6 +24,7 @@ import { EpgRuntimeBridgeService } from '@iptvnator/epg/data-access';
 import { resolveChannelEpgLookupKey } from '@iptvnator/m3u-state';
 import { SettingsStore } from '@iptvnator/services';
 import {
+    foldSearchText,
     Channel,
     EpgProgram,
     epgProviderClockMs,
@@ -320,7 +321,7 @@ export class GroupsViewComponent {
     });
 
     readonly workspaceFilteredGroups = computed<FilteredGroupView[]>(() => {
-        const term = this.searchTerm().trim().toLowerCase();
+        const term = foldSearchText(this.searchTerm().trim());
         const groups = this.visibleGroups();
 
         if (!term) {
@@ -333,11 +334,11 @@ export class GroupsViewComponent {
         }
 
         return groups.reduce<FilteredGroupView[]>((acc, group) => {
-            const titleMatches = group.key.toLowerCase().includes(term);
+            const titleMatches = foldSearchText(group.key).includes(term);
             const channels = titleMatches
                 ? group.channels
                 : group.channels.filter((channel) =>
-                      `${channel.name ?? ''}`.toLowerCase().includes(term)
+                      foldSearchText(`${channel.name ?? ''}`).includes(term)
                   );
 
             if (channels.length === 0) {
@@ -355,14 +356,16 @@ export class GroupsViewComponent {
     });
 
     readonly filteredGroups = computed<FilteredGroupView[]>(() => {
-        const term = this.localGroupSearchTerm().trim().toLowerCase();
+        const term = foldSearchText(this.localGroupSearchTerm().trim());
         const groups = this.workspaceFilteredGroups();
 
         if (!term) {
             return groups;
         }
 
-        return groups.filter((group) => group.key.toLowerCase().includes(term));
+        return groups.filter((group) =>
+            foldSearchText(group.key).includes(term)
+        );
     });
 
     readonly hasAnyGroups = computed(() => this.allGroups().length > 0);

libs/ui/components/src/lib/channel-list-container/recent-view/recent-view.component.ts

@@ -17,6 +17,7 @@ import { EpgRuntimeBridgeService } from '@iptvnator/epg/data-access';
 import { resolveChannelEpgLookupKey } from '@iptvnator/m3u-state';
 import { SettingsStore } from '@iptvnator/services';
 import {
+    foldSearchText,
     Channel,
     EpgProgram,
     epgProviderClockMs,
@@ -78,16 +79,16 @@ export class RecentViewComponent {
 
     readonly filteredRecentItems = computed(() => {
         const recentItems = this.recentItems();
-        const term = this.searchTerm().trim().toLowerCase();
+        const term = foldSearchText(this.searchTerm().trim());
 
         if (!term) {
             return recentItems;
         }
 
         return recentItems.filter(({ channel }) =>
-            `${channel.name ?? ''} ${channel.group?.title ?? ''}`
-                .toLowerCase()
-                .includes(term)
+            foldSearchText(
+                `${channel.name ?? ''} ${channel.group?.title ?? ''}`
+            ).includes(term)
         );
     });
 

libs/ui/components/src/lib/vod-sources/vod-sources-menu.component.ts

@@ -14,6 +14,7 @@ import {
 } from '@angular/material/slide-toggle';
 import { TranslatePipe } from '@ngx-translate/core';
 import {
+    foldSearchText,
     playlistDisplayLabel,
     VodSourceDescriptor,
     VodSourceMatchKind,
@@ -111,16 +112,16 @@ export class VodSourcesMenuComponent {
 
     /** Sources surviving the search box; what "check all" acts on. */
     private readonly searchedSources = computed(() => {
-        const query = this.filter().trim().toLowerCase();
+        const query = foldSearchText(this.filter().trim());
         const sources = this.sources();
         if (!query || !this.showFilter()) {
             return sources;
         }
 
         return sources.filter((source) =>
-            playlistDisplayLabel(source.playlistName, source.playlistId)
-                .toLowerCase()
-                .includes(query)
+            foldSearchText(
+                playlistDisplayLabel(source.playlistName, source.playlistId)
+            ).includes(query)
         );
     });
 

libs/ui/epg/src/lib/epg-guide/epg-guide-view-state.ts

@@ -1,5 +1,5 @@
 import { computed, effect, signal } from '@angular/core';
-import { EpgProgram } from '@iptvnator/shared/interfaces';
+import { foldSearchText, EpgProgram } from '@iptvnator/shared/interfaces';
 import {
     EpgDateNavigationDirection,
     getTodayEpgDateKey,
@@ -101,11 +101,11 @@ export class EpgGuideViewState {
         channels: readonly EpgGuideChannel[],
         isCovered: (channelId: string) => boolean
     ): EpgGuideChannel[] {
-        const needle = this.filter().trim().toLowerCase();
+        const needle = foldSearchText(this.filter().trim());
         const onlyWithEpg = this.onlyWithEpg();
         return channels.filter(
             (channel) =>
-                (!needle || channel.name.toLowerCase().includes(needle)) &&
+                (!needle || foldSearchText(channel.name).includes(needle)) &&
                 (!onlyWithEpg || isCovered(channel.id))
         );
     }

libs/workspace/shell/feature/src/lib/workspace-command-palette/workspace-command-palette.component.spec.ts

@@ -164,6 +164,78 @@ describe('WorkspaceCommandPaletteComponent', () => {
     });
 });
 
+describe('WorkspaceCommandPaletteComponent - Turkish case folding', () => {
+    const turkishCommands: WorkspaceResolvedCommandItem[] = [
+        {
+            id: 'open-downloads',
+            label: 'İndirilenleri aç',
+            description: '',
+            group: 'global',
+            icon: 'download',
+            keywords: [],
+            priority: 50,
+            visible: true,
+            enabled: true,
+            run: () => undefined,
+        },
+        {
+            id: 'open-settings',
+            label: 'Ayarlar',
+            description: '',
+            group: 'global',
+            icon: 'settings',
+            keywords: [],
+            priority: 40,
+            visible: true,
+            enabled: true,
+            run: () => undefined,
+        },
+    ];
+
+    function setup(query: string): WorkspaceCommandPaletteComponent {
+        TestBed.resetTestingModule();
+        TestBed.configureTestingModule({
+            imports: [WorkspaceCommandPaletteComponent],
+            providers: [
+                { provide: MatDialogRef, useValue: { close: jest.fn() } },
+                {
+                    provide: MAT_DIALOG_DATA,
+                    useValue: { query, commands: turkishCommands },
+                },
+                {
+                    provide: TranslateService,
+                    useValue: {
+                        instant: (key: string) => key,
+                        get: (key: string) => of(key),
+                        stream: (key: string) => of(key),
+                        onLangChange: of(null),
+                        onTranslationChange: of(null),
+                        onDefaultLangChange: of(null),
+                        currentLang: 'en',
+                        defaultLang: 'en',
+                    },
+                },
+            ],
+        });
+        const fixture = TestBed.createComponent(
+            WorkspaceCommandPaletteComponent
+        );
+        fixture.detectChanges();
+        return fixture.componentInstance;
+    }
+
+    it.each(['indir', 'İndir', 'İNDİR'])(
+        'finds a command whose label carries the dotted capital İ for the query %s (issue #609)',
+        (query) => {
+            expect(
+                setup(query)
+                    .flatCommands()
+                    .map((command) => command.id)
+            ).toEqual(['open-downloads']);
+        }
+    );
+});
+
 describe('WorkspaceCommandPaletteComponent - recent section', () => {
     function setupComponent(options: {
         query: string;

libs/workspace/shell/feature/src/lib/workspace-command-palette/workspace-command-palette.component.ts

@@ -21,6 +21,7 @@ import {
     WorkspaceCommandSelection,
     WorkspaceResolvedCommandItem,
 } from '@iptvnator/portal/shared/util';
+import { foldSearchText } from '@iptvnator/shared/interfaces';
 
 interface WorkspaceCommandPaletteData {
     commands: WorkspaceResolvedCommandItem[];
@@ -63,7 +64,7 @@ export class WorkspaceCommandPaletteComponent implements AfterViewInit {
     );
 
     readonly filteredCommands = computed(() => {
-        const term = this.query().trim().toLowerCase();
+        const term = foldSearchText(this.query().trim());
         const commands = this.visibleCommands();
 
         if (!term) {
@@ -75,11 +76,9 @@ export class WorkspaceCommandPaletteComponent implements AfterViewInit {
                 command.label,
                 command.description,
                 ...(command.keywords ?? []),
-            ]
-                .join(' ')
-                .toLowerCase();
+            ].join(' ');
 
-            return haystack.includes(term);
+            return foldSearchText(haystack).includes(term);
         });
     });
 

libs/workspace/shell/feature/src/lib/workspace-context-panel/workspace-context-panel.component.ts

@@ -34,6 +34,7 @@ import { WorkspaceContextCategoryViewComponent } from './components/workspace-co
 import { WorkspaceContextErrorViewComponent } from './components/workspace-context-error-view.component';
 import { hasActiveLiveCategoryRoute } from './workspace-context-panel-route.utils';
 import { WorkspaceShellContextDrawerService } from '@iptvnator/workspace/shell/util';
+import { foldSearchText } from '@iptvnator/shared/interfaces';
 
 type WorkspaceProvider = 'xtreams' | 'stalker' | 'playlists';
 
@@ -297,10 +298,10 @@ export class WorkspaceContextPanelComponent {
 
     readonly filteredXtreamCategories = computed(() => {
         const cats = this.xtreamCategories();
-        const term = this.categorySearchTerm().trim().toLowerCase();
+        const term = foldSearchText(this.categorySearchTerm().trim());
         const filtered = term
             ? cats.filter((category) =>
-                  this.getCategoryLabel(category).toLowerCase().includes(term)
+                  foldSearchText(this.getCategoryLabel(category)).includes(term)
               )
             : cats;
 
@@ -314,10 +315,10 @@ export class WorkspaceContextPanelComponent {
 
     readonly filteredStalkerCategories = computed(() => {
         const cats = this.stalkerCategories();
-        const term = this.categorySearchTerm().trim().toLowerCase();
+        const term = foldSearchText(this.categorySearchTerm().trim());
         const filtered = term
             ? cats.filter((category) =>
-                  this.getCategoryLabel(category).toLowerCase().includes(term)
+                  foldSearchText(this.getCategoryLabel(category)).includes(term)
               )
             : cats;
 

libs/workspace/shell/feature/src/lib/workspace-sources/workspace-sources.component.ts

@@ -15,6 +15,7 @@ import {
 } from '@iptvnator/portal/shared/util';
 import { PlaylistActions } from '@iptvnator/m3u-state';
 import {
+    foldSearchText,
     sourceHealthType,
     PlaylistUpdateState,
 } from '@iptvnator/shared/interfaces';
@@ -195,7 +196,7 @@ export class WorkspaceSourcesComponent {
     });
 
     readonly visibleSourcesCount = computed(() => {
-        const query = this.searchQuery().trim().toLowerCase();
+        const query = foldSearchText(this.searchQuery().trim());
         const filters = this.activeTypeFilters();
         const allPlaylists = this.playlists();
 
@@ -217,7 +218,7 @@ export class WorkspaceSourcesComponent {
 
                 return isStalkerFilter || isXtreamFilter || isM3uFilter;
             })
-            .filter((item) => (item.title || '').toLowerCase().includes(query))
+            .filter((item) => foldSearchText(item.title || '').includes(query))
             .length;
     });