feat(tv): persist downloaded opensubtitles across app restarts

utils/atoms/downloadedSubtitles.ts

@@ -0,0 +1,162 @@
+/**
+ * Downloaded Subtitles Storage
+ *
+ * Persists metadata about client-side downloaded subtitles (from OpenSubtitles).
+ * Subtitle files are stored in Paths.cache/streamyfin-subtitles/ directory.
+ * Filenames are prefixed with itemId for organization: {itemId}_{filename}
+ *
+ * While files are in cache, metadata is persisted in MMKV so subtitles survive
+ * app restarts (unless cache is manually cleared by the user).
+ *
+ * TV platform only.
+ */
+
+import { storage } from "../mmkv";
+
+// MMKV storage key
+const DOWNLOADED_SUBTITLES_KEY = "downloadedSubtitles.json";
+
+/**
+ * Metadata for a downloaded subtitle file
+ */
+export interface DownloadedSubtitle {
+  /** Unique identifier (uuid) */
+  id: string;
+  /** Jellyfin item ID */
+  itemId: string;
+  /** Local file path in documents directory */
+  filePath: string;
+  /** Display name */
+  name: string;
+  /** 3-letter language code */
+  language: string;
+  /** File format (srt, ass, etc.) */
+  format: string;
+  /** Source provider */
+  source: "opensubtitles";
+  /** Unix timestamp when downloaded */
+  downloadedAt: number;
+}
+
+/**
+ * Storage structure for downloaded subtitles
+ */
+interface DownloadedSubtitlesStorage {
+  /** Map of itemId to array of downloaded subtitles */
+  byItemId: Record<string, DownloadedSubtitle[]>;
+}
+
+/**
+ * Load the storage from MMKV
+ */
+function loadStorage(): DownloadedSubtitlesStorage {
+  try {
+    const data = storage.getString(DOWNLOADED_SUBTITLES_KEY);
+    if (data) {
+      return JSON.parse(data) as DownloadedSubtitlesStorage;
+    }
+  } catch {
+    // Ignore parse errors, return empty storage
+  }
+  return { byItemId: {} };
+}
+
+/**
+ * Save the storage to MMKV
+ */
+function saveStorage(data: DownloadedSubtitlesStorage): void {
+  try {
+    storage.set(DOWNLOADED_SUBTITLES_KEY, JSON.stringify(data));
+  } catch (error) {
+    console.error("Failed to save downloaded subtitles:", error);
+  }
+}
+
+/**
+ * Get all downloaded subtitles for a specific Jellyfin item
+ */
+export function getSubtitlesForItem(itemId: string): DownloadedSubtitle[] {
+  const data = loadStorage();
+  return data.byItemId[itemId] ?? [];
+}
+
+/**
+ * Add a downloaded subtitle to storage
+ */
+export function addDownloadedSubtitle(subtitle: DownloadedSubtitle): void {
+  const data = loadStorage();
+
+  // Initialize array for item if it doesn't exist
+  if (!data.byItemId[subtitle.itemId]) {
+    data.byItemId[subtitle.itemId] = [];
+  }
+
+  // Check if subtitle with same id already exists and update it
+  const existingIndex = data.byItemId[subtitle.itemId].findIndex(
+    (s) => s.id === subtitle.id,
+  );
+
+  if (existingIndex !== -1) {
+    // Update existing entry
+    data.byItemId[subtitle.itemId][existingIndex] = subtitle;
+  } else {
+    // Add new entry
+    data.byItemId[subtitle.itemId].push(subtitle);
+  }
+
+  saveStorage(data);
+}
+
+/**
+ * Remove a downloaded subtitle from storage
+ */
+export function removeDownloadedSubtitle(
+  itemId: string,
+  subtitleId: string,
+): void {
+  const data = loadStorage();
+
+  if (data.byItemId[itemId]) {
+    data.byItemId[itemId] = data.byItemId[itemId].filter(
+      (s) => s.id !== subtitleId,
+    );
+
+    // Clean up empty arrays
+    if (data.byItemId[itemId].length === 0) {
+      delete data.byItemId[itemId];
+    }
+
+    saveStorage(data);
+  }
+}
+
+/**
+ * Remove all downloaded subtitles for a specific item
+ */
+export function removeAllSubtitlesForItem(itemId: string): void {
+  const data = loadStorage();
+
+  if (data.byItemId[itemId]) {
+    delete data.byItemId[itemId];
+    saveStorage(data);
+  }
+}
+
+/**
+ * Check if a subtitle file already exists for an item by language
+ */
+export function hasSubtitleForLanguage(
+  itemId: string,
+  language: string,
+): boolean {
+  const subtitles = getSubtitlesForItem(itemId);
+  return subtitles.some((s) => s.language === language);
+}
+
+/**
+ * Get all downloaded subtitles across all items
+ */
+export function getAllDownloadedSubtitles(): DownloadedSubtitle[] {
+  const data = loadStorage();
+  return Object.values(data.byItemId).flat();
+}