downloads and offline playback

lib/features/downloads/view/downloads_page.dart

@@ -0,0 +1,51 @@
+import 'package:flutter/material.dart';
+import 'package:hooks_riverpod/hooks_riverpod.dart';
+import 'package:whispering_pages/features/downloads/providers/download_manager.dart';
+
+class DownloadsPage extends HookConsumerWidget {
+  const DownloadsPage({super.key});
+
+  @override
+  Widget build(BuildContext context, WidgetRef ref) {
+    final manager = ref.read(simpleDownloadManagerProvider);
+    final downloadHistory = ref.watch(downloadHistoryProvider());
+
+    return Scaffold(
+      appBar: AppBar(
+        title: const Text('Downloads'),
+        backgroundColor: Colors.transparent,
+      ),
+      body: Center(
+        // history of downloads
+        child: downloadHistory.when(
+          data: (records) {
+            // each group is one list tile, which contains the files downloaded
+            final uniqueGroups = records.map((e) => e.group).toSet();
+            return ListView.builder(
+              itemCount: uniqueGroups.length,
+              itemBuilder: (context, index) {
+                final group = uniqueGroups.elementAt(index);
+                final groupRecords = records.where((e) => e.group == group);
+                return ExpansionTile(
+                  title: Text(group ?? 'No Group'),
+                  children: groupRecords
+                      .map(
+                        (e) => ListTile(
+                          title: Text('${e.task.directory}/${e.task.filename}'),
+                          subtitle: Text(e.task.creationTime.toString()),
+                        ),
+                      )
+                      .toList(),
+                );
+              },
+            );
+          },
+          loading: () => const CircularProgressIndicator(),
+          error: (error, stackTrace) {
+            return Text('Error: $error');
+          },
+        ),
+      ),
+    );
+  }
+}