add DB logging for service-worker events

sw_scripts/safari-notifications.js

@@ -404,6 +404,27 @@ async function setMostRecentNotified(id) {
   }
 }
 
+async function logMessage(message) {
+  try {
+    const db = await openIndexedDB("TimeSafari");
+    const transaction = db.transaction("worker_log", "readwrite");
+    const store = transaction.objectStore("worker_log");
+    // will only keep one day's worth of logs
+    let data = await getRecord(store, new Date().toDateString());
+    if (!data) {
+      await store.clear(); // clear out anything older than today
+    }
+    data = data || "";
+    data += `\n${message}`;
+    await updateRecord(store, data);
+    transaction.oncomplete = () => db.close();
+    return true;
+  } catch (error) {
+    console.error("IndexedDB logMessage error:", error);
+    return false;
+  }
+}
+
 function openIndexedDB(dbName) {
   return new Promise((resolve, reject) => {
     const request = indexedDB.open(dbName);
@@ -420,6 +441,7 @@ function getRecord(store, key) {
   });
 }
 
+// Note that this assumes there is only one record in the store.
 function updateRecord(store, data) {
   return new Promise((resolve, reject) => {
     const request = store.put(data);
@@ -437,6 +459,9 @@ async function fetchAllAccounts() {
       if (!db.objectStoreNames.contains("accounts")) {
         db.createObjectStore("accounts", { keyPath: "id" });
       }
+      if (!db.objectStoreNames.contains("worker_log")) {
+        db.createObjectStore("worker_log");
+      }
     };
 
     openRequest.onsuccess = function (event) {