fix(search): harden global search pagination

apps/electron-backend/src/app/database/operations/content.operations.spec.ts

@@ -574,7 +574,30 @@ describe('content.operations', () => {
         expect(matchSqlCall?.[1]).toBe('"and"');
     });
 
-    it('limits M3U playlist payload candidates before parsing large JSON payloads', async () => {
+    it('uses a stable max candidate limit for M3U playlist payload searches', async () => {
+        const limit = jest.fn().mockResolvedValue([]);
+        const orderedQuery = {
+            limit,
+            then: (resolve: (value: unknown[]) => void) => resolve([]),
+        };
+        const orderBy = jest.fn().mockReturnValue(orderedQuery);
+        const where = jest.fn().mockReturnValue({ orderBy });
+        const from = jest.fn().mockReturnValue({ where });
+        const select = jest.fn().mockReturnValue({ from });
+        const db = {
+            select,
+        } as unknown as AppDatabase;
+
+        await globalSearch(db, 'news', ['live'], false, ['m3u'], {
+            limit: 10,
+            offset: 100,
+        });
+
+        expect(orderBy).toHaveBeenCalledWith(schema.playlists.name);
+        expect(limit).toHaveBeenCalledWith(5000);
+    });
+
+    it('prefilters M3U payloads by searchable text fields instead of raw payload contains', async () => {
         const limit = jest.fn().mockResolvedValue([]);
         const orderedQuery = {
             limit,
@@ -592,7 +615,21 @@ describe('content.operations', () => {
             limit: 10,
         });
 
-        expect(orderBy).toHaveBeenCalledWith(schema.playlists.name);
-        expect(limit).toHaveBeenCalledWith(500);
+        const searchPatterns = sqlMock.mock.calls
+            .flatMap(([, ...values]) => values)
+            .filter(
+                (value): value is string =>
+                    typeof value === 'string' &&
+                    value.toLocaleLowerCase().includes('news')
+            );
+
+        expect(searchPatterns.length).toBeGreaterThan(0);
+        expect(searchPatterns).not.toContain('%news%');
+        expect(
+            searchPatterns.every(
+                (pattern) =>
+                    pattern.includes('"name"') || pattern.includes('"title"')
+            )
+        ).toBe(true);
     });
 });

apps/electron-backend/src/app/database/operations/content.operations.ts

@@ -74,7 +74,6 @@ function buildLikePatterns(
 
 const DEFAULT_GLOBAL_SEARCH_LIMIT = 50;
 const MAX_GLOBAL_SEARCH_LIMIT = 500;
-const MIN_GLOBAL_SEARCH_CANDIDATE_LIMIT = 500;
 const MAX_GLOBAL_SEARCH_CANDIDATE_LIMIT = 5000;
 const M3U_PLAYLIST_TYPES = ['m3u-file', 'm3u-text', 'm3u-url'] as const;
 
@@ -245,16 +244,8 @@ function paginateScoredResults<T extends GlobalSearchResult>(
         .map((item) => item.result);
 }
 
-function getGlobalSearchCandidateLimit(
-    pagination: NormalizedGlobalSearchPagination
-): number {
-    return Math.min(
-        Math.max(
-            (pagination.offset + pagination.limit) * 4,
-            MIN_GLOBAL_SEARCH_CANDIDATE_LIMIT
-        ),
-        MAX_GLOBAL_SEARCH_CANDIDATE_LIMIT
-    );
+function getGlobalSearchCandidateLimit(): number {
+    return MAX_GLOBAL_SEARCH_CANDIDATE_LIMIT;
 }
 
 function buildContentTitleSearchConditions(searchTerm: string) {
@@ -453,12 +444,15 @@ async function selectXtreamGlobalSearchCandidatesWithContentScan(
         .limit(candidateLimit);
 }
 
-function buildM3uPayloadPrefixPatterns(token: string): string[] {
-    return buildLikePatterns(token, 'prefix').flatMap((pattern) => [
-        `%"name":"${pattern}`,
-        `%"name": "${pattern}`,
-        `%"title":"${pattern}`,
-        `%"title": "${pattern}`,
+function buildM3uPayloadTextFieldPatterns(
+    token: string,
+    mode: 'contains' | 'prefix'
+): string[] {
+    return buildLikePatterns(token, mode).flatMap((pattern) => [
+        `%"name":"${pattern}"%`,
+        `%"name": "${pattern}"%`,
+        `%"title":"${pattern}"%`,
+        `%"title": "${pattern}"%`,
     ]);
 }
 
@@ -472,8 +466,8 @@ function buildM3uPayloadSearchConditions(searchTerm: string) {
         .map((token, index) => {
             const patterns =
                 index === 0 && token.length <= 2
-                    ? buildM3uPayloadPrefixPatterns(token)
-                    : buildLikePatterns(token);
+                    ? buildM3uPayloadTextFieldPatterns(token, 'prefix')
+                    : buildM3uPayloadTextFieldPatterns(token, 'contains');
             const likeConditions = patterns.map(
                 (pattern) =>
                     sql`${schema.playlists.payload} LIKE ${pattern} ESCAPE '\\'`
@@ -1099,7 +1093,7 @@ export async function globalSearch(
     }
 
     const pagination = normalizeGlobalSearchPagination(options);
-    const candidateLimit = getGlobalSearchCandidateLimit(pagination);
+    const candidateLimit = getGlobalSearchCandidateLimit();
     const results: ScoredGlobalSearchResult[] = [];
 
     if (hasGlobalSearchSource(sources, GLOBAL_SEARCH_RESULT_SOURCES.Xtream)) {

docs/architecture/sqlite-db-worker.md

@@ -217,18 +217,21 @@ Xtream-only row shape:
    fresh inserts, deletes, and title updates stay synchronized through SQLite
    triggers.
 2. `source_type = "m3u"` rows come from M3U playlist payloads stored in
-   `playlists.payload`. The worker uses SQL `payload LIKE` only as a coarse
-   candidate prefilter, then parses candidate JSON payloads and matches channel
-   name, TVG name, and group title case-insensitively in the worker. The SQL
-   candidate query is capped by the same candidate limit used for Xtream search,
-   so large matching M3U payloads are not loaded without an upper bound.
+   `playlists.payload`. The worker uses SQL `payload LIKE` against channel
+   `name`/`title` JSON fields only as a coarse candidate prefilter, then parses
+   candidate JSON payloads and matches channel name, TVG name, and group title
+   case-insensitively in the worker. The SQL candidate query is capped by the
+   same stable 5000-row candidate limit used for Xtream search, so large
+   matching M3U payloads are not loaded without an upper bound.
 3. The optional `sources` argument can restrict search to `xtream` or `m3u`,
    but omitted callers keep the backward-compatible behavior of searching all
    supported global-search sources.
 4. The optional pagination argument accepts `{ limit, offset }`. The worker
    keeps the legacy default of 50 results when the argument is omitted, but the
    routed global-search view requests one extra row per page to implement
-   lazy loading without requiring a separate count query.
+   lazy loading without requiring a separate count query. Candidate selection
+   uses a stable max-size pool for every page so score-based in-memory ranking
+   cannot shift already-rendered items into later pages.
 5. Candidate rows are ranked in the worker after the coarse SQL prefilter.
    Exact and prefix matches sort ahead of word-prefix and substring matches;
    short first tokens such as `tv` stay anchored to the start of the title, so

libs/portal/shared/ui/src/lib/components/search-layout/search-layout.component.spec.ts

@@ -27,33 +27,70 @@ describe('SearchLayoutComponent', () => {
         fixture = TestBed.createComponent(SearchLayoutComponent);
     });
 
-    it('emits nearEnd when the results container is scrolled near the bottom', () => {
-        const nearEndSpy = jest.fn();
+    function renderResultsContainer(): HTMLElement {
         fixture.componentRef.setInput('searchTerm', 'matrix');
         fixture.componentRef.setInput('resultsCount', 1);
-        fixture.componentInstance.nearEnd.subscribe(nearEndSpy);
         fixture.detectChanges();
 
-        const resultsContainer = fixture.debugElement.query(
-            By.css('.results-container')
-        ).nativeElement as HTMLElement;
-        Object.defineProperties(resultsContainer, {
+        return fixture.debugElement.query(By.css('.results-container'))
+            .nativeElement as HTMLElement;
+    }
+
+    function setScrollMetrics(
+        element: HTMLElement,
+        scrollTop: number,
+        scrollHeight = 1000,
+        clientHeight = 120
+    ): void {
+        Object.defineProperties(element, {
             scrollHeight: {
                 configurable: true,
-                value: 1000,
+                value: scrollHeight,
             },
             scrollTop: {
                 configurable: true,
-                value: 700,
+                value: scrollTop,
             },
             clientHeight: {
                 configurable: true,
-                value: 120,
+                value: clientHeight,
             },
         });
+    }
+
+    it('emits nearEnd when the results container is scrolled near the bottom', () => {
+        const nearEndSpy = jest.fn();
+        fixture.componentInstance.nearEnd.subscribe(nearEndSpy);
+        const resultsContainer = renderResultsContainer();
+
+        setScrollMetrics(resultsContainer, 700);
 
         resultsContainer.dispatchEvent(new Event('scroll'));
 
         expect(nearEndSpy).toHaveBeenCalledTimes(1);
     });
+
+    it('emits nearEnd only when crossing into the bottom threshold', () => {
+        const nearEndSpy = jest.fn();
+        fixture.componentInstance.nearEnd.subscribe(nearEndSpy);
+        const resultsContainer = renderResultsContainer();
+
+        setScrollMetrics(resultsContainer, 500);
+        resultsContainer.dispatchEvent(new Event('scroll'));
+        expect(nearEndSpy).not.toHaveBeenCalled();
+
+        setScrollMetrics(resultsContainer, 700);
+        resultsContainer.dispatchEvent(new Event('scroll'));
+        expect(nearEndSpy).toHaveBeenCalledTimes(1);
+
+        setScrollMetrics(resultsContainer, 710);
+        resultsContainer.dispatchEvent(new Event('scroll'));
+        expect(nearEndSpy).toHaveBeenCalledTimes(1);
+
+        setScrollMetrics(resultsContainer, 500);
+        resultsContainer.dispatchEvent(new Event('scroll'));
+        setScrollMetrics(resultsContainer, 760);
+        resultsContainer.dispatchEvent(new Event('scroll'));
+        expect(nearEndSpy).toHaveBeenCalledTimes(2);
+    });
 });

libs/portal/shared/ui/src/lib/components/search-layout/search-layout.component.ts

@@ -28,6 +28,7 @@ import { SearchFormComponent } from '../search-form/search-form.component';
 export class SearchLayoutComponent {
     private readonly searchFormComponent = viewChild(SearchFormComponent);
     private readonly nearEndThresholdPx = 240;
+    private isWithinNearEndThreshold = false;
 
     /** Page title translation key */
     readonly title = input<string>('PORTALS.SIDEBAR.SEARCH');
@@ -91,9 +92,13 @@ export class SearchLayoutComponent {
 
         const distanceToBottom =
             target.scrollHeight - target.scrollTop - target.clientHeight;
-        if (distanceToBottom <= this.nearEndThresholdPx) {
+        const isNearEnd = distanceToBottom <= this.nearEndThresholdPx;
+
+        if (isNearEnd && !this.isWithinNearEndThreshold) {
             this.nearEnd.emit();
         }
+
+        this.isWithinNearEndThreshold = isNearEnd;
     }
 
     /** Check if we should show the "no results" state */