feat(app): loadTranslations liefert sprach-varianten eines posts

app/src/lib/nostr/loaders.loadTranslations.test.ts

@@ -0,0 +1,74 @@
+import { describe, it, expect } from 'vitest';
+import { resolveTranslationsFromRefs } from './loaders';
+import type { NostrEvent } from './loaders';
+import type { TranslationRef } from './translations';
+
+function ev(tags: string[][]): NostrEvent {
+  return {
+    id: 'x',
+    pubkey: 'p',
+    created_at: 0,
+    kind: 30023,
+    tags,
+    content: '',
+    sig: 's'
+  } as unknown as NostrEvent;
+}
+
+describe('resolveTranslationsFromRefs', () => {
+  it('liefert lang/slug/title für jeden aufgelösten ref', async () => {
+    const refs: TranslationRef[] = [
+      { kind: 30023, pubkey: 'p1', dtag: 'hello' }
+    ];
+    const fetcher = async () => [
+      ev([
+        ['d', 'hello'],
+        ['title', 'Hello World'],
+        ['L', 'ISO-639-1'],
+        ['l', 'en', 'ISO-639-1']
+      ])
+    ];
+    const result = await resolveTranslationsFromRefs(refs, fetcher);
+    expect(result).toEqual([
+      { lang: 'en', slug: 'hello', title: 'Hello World' }
+    ]);
+  });
+
+  it('ignoriert refs, zu denen kein event gefunden wird', async () => {
+    const refs: TranslationRef[] = [
+      { kind: 30023, pubkey: 'p1', dtag: 'hello' },
+      { kind: 30023, pubkey: 'p1', dtag: 'missing' }
+    ];
+    const fetcher = async (r: TranslationRef) =>
+      r.dtag === 'hello'
+        ? [ev([
+            ['d', 'hello'],
+            ['title', 'Hi'],
+            ['l', 'en', 'ISO-639-1']
+          ])]
+        : [];
+    const result = await resolveTranslationsFromRefs(refs, fetcher);
+    expect(result).toEqual([{ lang: 'en', slug: 'hello', title: 'Hi' }]);
+  });
+
+  it('ignoriert events ohne l-tag (sprache unklar)', async () => {
+    const refs: TranslationRef[] = [
+      { kind: 30023, pubkey: 'p', dtag: 'x' }
+    ];
+    const fetcher = async () => [
+      ev([
+        ['d', 'x'],
+        ['title', 'kein lang-tag']
+      ])
+    ];
+    const result = await resolveTranslationsFromRefs(refs, fetcher);
+    expect(result).toEqual([]);
+  });
+
+  it('leere ref-liste → leere ergebnis-liste', async () => {
+    const fetcher = async () => {
+      throw new Error('should not be called');
+    };
+    expect(await resolveTranslationsFromRefs([], fetcher)).toEqual([]);
+  });
+});

app/src/lib/nostr/loaders.ts

@@ -6,6 +6,7 @@ import type { Filter as ApplesauceFilter } from 'applesauce-core/helpers/filter'
 import { pool } from './pool';
 import { readRelays } from '$lib/stores/readRelays';
 import { AUTHOR_PUBKEY_HEX, RELAY_HARD_TIMEOUT_MS } from './config';
+import type { TranslationRef } from './translations';
 
 /** Re-export als sprechenden Alias */
 export type { NostrEvent };
@@ -189,3 +190,55 @@ export async function loadReactions(dtag: string): Promise<ReactionSummary[]> {
     .map(([content, count]) => ({ content, count }))
     .sort((a, b) => b.count - a.count);
 }
+
+export interface TranslationInfo {
+  lang: string;
+  slug: string;
+  title: string;
+}
+
+/**
+ * Pure Variante für Tests — erhält die Events via Fetcher statt Relays.
+ */
+export async function resolveTranslationsFromRefs(
+  refs: TranslationRef[],
+  fetcher: (ref: TranslationRef) => Promise<NostrEvent[]>
+): Promise<TranslationInfo[]> {
+  if (refs.length === 0) return [];
+  const results = await Promise.all(refs.map(fetcher));
+  const infos: TranslationInfo[] = [];
+  for (let i = 0; i < refs.length; i++) {
+    const evs = results[i];
+    if (evs.length === 0) continue;
+    const latest = evs.reduce((best, cur) =>
+      cur.created_at > best.created_at ? cur : best
+    );
+    const lang = latest.tags.find((t) => t[0] === 'l')?.[1];
+    if (!lang) continue;
+    const slug = latest.tags.find((t) => t[0] === 'd')?.[1] ?? refs[i].dtag;
+    const title = latest.tags.find((t) => t[0] === 'title')?.[1] ?? '';
+    infos.push({ lang, slug, title });
+  }
+  return infos;
+}
+
+/**
+ * Loader: findet die anderssprachigen Varianten eines Posts.
+ * Liefert leere Liste, wenn keine a-Tags mit marker "translation" vorhanden.
+ */
+export async function loadTranslations(
+  event: NostrEvent
+): Promise<TranslationInfo[]> {
+  const { parseTranslationRefs } = await import('./translations');
+  const refs = parseTranslationRefs(event);
+  if (refs.length === 0) return [];
+  const relays = get(readRelays);
+  return resolveTranslationsFromRefs(refs, (ref) =>
+    collectEvents(relays, {
+      kinds: [ref.kind],
+      authors: [ref.pubkey],
+      '#d': [ref.dtag],
+      limit: 1
+    })
+  );
+}