1 files changed, 83 insertions, 0 deletions
diff --git a/src/frontend/app/utils/idb.ts b/src/frontend/app/utils/idb.ts
new file mode 100644
index 0000000..4d0aba7
--- /dev/null
+++ b/src/frontend/app/utils/idb.ts
@@ -0,0 +1,83 @@
+/**
+ * IndexedDB helpers for sharing data with the service worker.
+ *
+ * The service worker is a classic script and cannot import ES modules, so it
+ * contains its own equivalent implementation. Keep the schema (DB name, version,
+ * store names, and key shapes) in sync with the inline IDB code in pwa-worker.js.
+ *
+ * DB: "enmarcha-sw", version 1
+ *   Store "favorites"   — { key: string, ids: string[] }
+ *   Store "alertState"  — { alertId: string, silenced: boolean, lastVersion: number }
+ */
+
+const DB_NAME = "enmarcha-sw";
+const DB_VERSION = 1;
+
+function openDb(): Promise<IDBDatabase> {
+  return new Promise((resolve, reject) => {
+    const req = indexedDB.open(DB_NAME, DB_VERSION);
+
+    req.onupgradeneeded = () => {
+      const db = req.result;
+      if (!db.objectStoreNames.contains("favorites")) {
+        db.createObjectStore("favorites", { keyPath: "key" });
+      }
+      if (!db.objectStoreNames.contains("alertState")) {
+        db.createObjectStore("alertState", { keyPath: "alertId" });
+      }
+    };
+
+    req.onsuccess = () => resolve(req.result);
+    req.onerror = () => reject(req.error);
+  });
+}
+
+/** Persist a favourites list to IndexedDB so the service worker can read it. */
+export async function writeFavorites(
+  key: string,
+  ids: string[]
+): Promise<void> {
+  const db = await openDb();
+  return new Promise((resolve, reject) => {
+    const tx = db.transaction("favorites", "readwrite");
+    tx.objectStore("favorites").put({ key, ids });
+    tx.oncomplete = () => {
+      db.close();
+      resolve();
+    };
+    tx.onerror = () => reject(tx.error);
+  });
+}
+
+/** Read a favourites list from IndexedDB. */
+export async function readFavorites(key: string): Promise<string[]> {
+  const db = await openDb();
+  return new Promise((resolve, reject) => {
+    const tx = db.transaction("favorites", "readonly");
+    const req = tx.objectStore("favorites").get(key);
+    req.onsuccess = () => {
+      db.close();
+      resolve(
+        (req.result as { key: string; ids: string[] } | undefined)?.ids ?? []
+      );
+    };
+    req.onerror = () => reject(req.error);
+  });
+}
+
+/** Persist per-alert notification state (silenced flag and last notified version). */
+export async function writeAlertState(
+  alertId: string,
+  state: { silenced: boolean; lastVersion: number }
+): Promise<void> {
+  const db = await openDb();
+  return new Promise((resolve, reject) => {
+    const tx = db.transaction("alertState", "readwrite");
+    tx.objectStore("alertState").put({ alertId, ...state });
+    tx.oncomplete = () => {
+      db.close();
+      resolve();
+    };
+    tx.onerror = () => reject(tx.error);
+  });
+}