feat(services): youtubeMetaService with 7d localStorage cache and ID extraction

src/services/youtubeMetaService.ts

@@ -0,0 +1,77 @@
+export type Caption = { start: number; dur: number; text: string }
+export type YouTubeMeta = {
+  title: string
+  description?: string
+  captions: Caption[]
+  transcript?: string
+  lang: string
+  isAuto?: boolean
+  source: 'youtube'
+}
+
+type CachedMeta = {
+  data: YouTubeMeta
+  timestamp: number
+}
+
+const TTL_MS = 7 * 24 * 60 * 60 * 1000 // 7 days
+
+function cacheKey(videoId: string, lang: string) {
+  return `yt_meta_${videoId}_${lang}`
+}
+
+function load(videoId: string, lang: string): YouTubeMeta | null {
+  try {
+    const raw = localStorage.getItem(cacheKey(videoId, lang))
+    if (!raw) return null
+    const { data, timestamp } = JSON.parse(raw) as CachedMeta
+    if (Date.now() - timestamp > TTL_MS) {
+      localStorage.removeItem(cacheKey(videoId, lang))
+      return null
+    }
+    return data
+  } catch {
+    return null
+  }
+}
+
+function save(videoId: string, lang: string, data: YouTubeMeta) {
+  try {
+    const value: CachedMeta = { data, timestamp: Date.now() }
+    localStorage.setItem(cacheKey(videoId, lang), JSON.stringify(value))
+  } catch {
+    // ignore
+  }
+}
+
+export function extractYouTubeId(url: string): string | null {
+  try {
+    const u = new URL(url)
+    if (u.hostname === 'youtu.be') {
+      return u.pathname.slice(1)
+    }
+    if (u.searchParams.get('v')) return u.searchParams.get('v')
+    const parts = u.pathname.split('/').filter(Boolean)
+    // /shorts/:id or /embed/:id
+    if ((parts[0] === 'shorts' || parts[0] === 'embed') && parts[1]) return parts[1]
+    return null
+  } catch {
+    return null
+  }
+}
+
+export async function getYouTubeMeta(videoId: string, lang = 'en'): Promise<YouTubeMeta | null> {
+  const cached = load(videoId, lang)
+  if (cached) return cached
+  const res = await fetch(`/api/youtube-meta?videoId=${encodeURIComponent(videoId)}&lang=${encodeURIComponent(lang)}`, {
+    headers: {
+      'x-ui-locale': lang
+    }
+  })
+  if (!res.ok) return null
+  const data = (await res.json()) as YouTubeMeta
+  save(videoId, lang, data)
+  return data
+}
+
+