fix(stats): keep Overview usable when refresh fails

changes/stats-mining-and-delete-accuracy.md

@@ -4,4 +4,4 @@ area: stats
 - Fixed sentence mining (single and multi-line) counting each created card twice in session and lifetime stats.
 - Fixed deleting a session leaving word and kanji "last seen" dates pointing at the deleted session; affected rows are repaired once in the background on next launch.
 - Fixed re-seen words that the vocabulary filter hides still being counted in the new-words charts, so charts and the vocabulary summary now agree. Existing mismatches are repaired by the same background pass.
-- Fixed Overview totals, charts, activity calendar, and vocabulary summary staying stale after deleting sessions.
+- Fixed Overview totals, charts, activity calendar, and vocabulary summary staying stale after deleting sessions. Failed refreshes keep the dashboard visible and offer a retry.

changes/stats-overview-refresh-docs.md

@@ -1,4 +1,4 @@
 type: docs
 area: stats
 
-- Documented the automatic Overview refresh after deleting sessions or session groups.
+- Documented the automatic Overview refresh after deleting sessions or session groups and retrying failed refreshes.

docs-site/immersion-tracking.md

@@ -42,7 +42,7 @@ To share stats and watch history between machines, use [`subminer sync <host>`](
 
 Recent sessions, a streak calendar, watch-time history, and totals for completed episodes and shows.
 
-Deleting a session or session group refreshes the Overview totals, charts, calendar, and vocabulary summary automatically.
+Deleting a session or session group refreshes the Overview totals, charts, calendar, and vocabulary summary automatically. If a refresh fails, Overview keeps the previous totals visible and offers **Retry**.
 
 ![Stats Overview](/screenshots/stats-overview.png)
 

stats/src/components/overview/OverviewTab.test.tsx

@@ -195,3 +195,72 @@ for (const mode of ['session', 'day', 'anime', 'failed'] as const) {
     }
   });
 }
+
+for (const failedRead of ['overview', 'sessions'] as const) {
+  test(`Overview stays available during a failed ${failedRead} refresh and can retry`, async () => {
+    const uninstallDom = installDom();
+    const original = { ...apiClient };
+    const restoreConfirm = setDeleteConfirmPresenter(() => true);
+    let sessions = [session(1)];
+    let refreshing = false;
+    let failRefresh = true;
+    let rejectRefresh = (_error: Error) => {};
+    const pendingRefresh = new Promise<never>((_resolve, reject) => {
+      rejectRefresh = reject;
+    });
+    apiClient.getOverview = async () => {
+      if (refreshing && failRefresh && failedRead === 'overview') return pendingRefresh;
+      return overview(sessions);
+    };
+    apiClient.getSessions = async () => {
+      if (refreshing && failRefresh && failedRead === 'sessions') return pendingRefresh;
+      return sessions;
+    };
+    apiClient.getStreakCalendar = async () => [];
+    apiClient.getKnownWordsSummary = async () => ({
+      totalUniqueWords: 0,
+      knownWordCount: 0,
+    });
+    apiClient.deleteSession = async () => {
+      sessions = [];
+      refreshing = true;
+    };
+    const container = document.createElement('div');
+    document.body.append(container);
+    const root = createRoot(container);
+    try {
+      await act(async () =>
+        root.render(
+          <OverviewTab onNavigateToMediaDetail={() => {}} onNavigateToSession={() => {}} />,
+        ),
+      );
+      const deleteButton = [...container.querySelectorAll('button')].find((button) =>
+        button.getAttribute('aria-label')?.startsWith('Delete session '),
+      );
+      assert.ok(deleteButton);
+      await act(async () => deleteButton.click());
+      assert.match(container.textContent ?? '', /Tracking Snapshot/);
+      assert.equal(metric(container, 'Cards Mined Today'), '2');
+      assert.match(container.textContent ?? '', /No sessions yet/);
+
+      await act(async () => rejectRefresh(new Error(`${failedRead} unavailable`)));
+      assert.match(container.textContent ?? '', /Tracking Snapshot/);
+      assert.equal(metric(container, 'Cards Mined Today'), '2');
+      assert.match(container.querySelector('[role="alert"]')?.textContent ?? '', /unavailable/);
+
+      const retryButton = [...container.querySelectorAll('button')].find(
+        (button) => button.textContent === 'Retry',
+      );
+      assert.ok(retryButton, 'failed refresh should offer a retry');
+      failRefresh = false;
+      await act(async () => retryButton.click());
+      assert.equal(metric(container, 'Cards Mined Today'), '0');
+      assert.equal(container.querySelector('[role="alert"]'), null);
+    } finally {
+      await act(async () => root.unmount());
+      restoreConfirm();
+      Object.assign(apiClient, original);
+      uninstallDom();
+    }
+  });
+}

stats/src/components/overview/OverviewTab.tsx

@@ -123,9 +123,29 @@ export function OverviewTab({
     }
   };
 
-  if (loading) return <div className="text-ctp-overlay2 p-4">Loading...</div>;
-  if (error) return <div className="text-ctp-red p-4">Error: {error}</div>;
-  if (!data) return null;
+  const errorNotice = error ? (
+    <div
+      role="alert"
+      className="flex items-center justify-between gap-3 rounded-lg border border-ctp-red/30 bg-ctp-red/10 p-3 text-sm text-ctp-red"
+    >
+      <span>
+        {data
+          ? 'Could not refresh Overview. Displayed totals may be out of date.'
+          : 'Could not load Overview.'}{' '}
+        {error}
+      </span>
+      <button
+        type="button"
+        onClick={() => setRefreshKey((prev) => prev + 1)}
+        className="shrink-0 rounded border border-ctp-red/30 px-3 py-1 hover:bg-ctp-red/10"
+      >
+        Retry
+      </button>
+    </div>
+  ) : null;
+
+  if (loading && !data) return <div className="text-ctp-overlay2 p-4">Loading...</div>;
+  if (!data) return errorNotice;
 
   const summary = buildOverviewSummary(data);
   const streakData = buildStreakCalendar(calendar);
@@ -133,6 +153,7 @@ export function OverviewTab({
 
   return (
     <div className="space-y-4">
+      {errorNotice}
       <HeroStats summary={summary} sessions={sessions} />
 
       <div className="grid grid-cols-1 md:grid-cols-2 gap-4">