Add resumable downloads, download paths, queue controls and history

web/static/js/notify.js

@@ -0,0 +1,68 @@
+const storageKey = "ddc-notifications";
+const finishedTitles = {
+  ready: "Download ready",
+  completed: "Download moved",
+  failed: "Download failed",
+};
+const previousStatuses = new Map();
+
+function notificationsSupported() {
+  return "Notification" in window;
+}
+
+function readPreference() {
+  try {
+    return localStorage.getItem(storageKey) === "on";
+  } catch {
+    return false;
+  }
+}
+
+function storePreference(enabled) {
+  try {
+    localStorage.setItem(storageKey, enabled ? "on" : "off");
+  } catch {
+    return;
+  }
+}
+
+export function notificationsEnabled() {
+  return notificationsSupported() && Notification.permission === "granted" && readPreference();
+}
+
+export async function setNotificationsEnabled(enabled) {
+  if (!enabled) {
+    storePreference(false);
+    return;
+  }
+  if (!notificationsSupported()) throw new Error("This browser does not support notifications.");
+  const permission = await Notification.requestPermission();
+  if (permission !== "granted") throw new Error("Notifications are blocked for this site in the browser settings.");
+  storePreference(true);
+}
+
+export function collectTransitions(jobs) {
+  const transitions = [];
+  const seenIds = new Set();
+  for (const job of jobs) {
+    seenIds.add(job.id);
+    const previous = previousStatuses.get(job.id);
+    if (previous && previous !== job.status) transitions.push({ job, previous });
+    previousStatuses.set(job.id, job.status);
+  }
+  for (const id of previousStatuses.keys()) {
+    if (!seenIds.has(id)) previousStatuses.delete(id);
+  }
+  return transitions;
+}
+
+export function notifyTransitions(transitions) {
+  if (!notificationsEnabled()) return;
+  for (const { job, previous } of transitions) {
+    const title = finishedTitles[job.status];
+    const wasWorking = previous === "queued" || previous === "downloading" || previous === "extracting" || previous === "moving";
+    if (!title || !wasWorking) continue;
+    if (job.status === "ready" && previous === "moving") continue;
+    new Notification(title, { body: job.fileName || job.sourceUrl, tag: `ddc-${job.id}` });
+  }
+}