add "downloads" button (UNTRANSLATED), implement that thing (UNTESTED)

lib/pages/chat/events/message_download_content.dart

@@ -42,7 +42,12 @@ class MessageDownloadContent extends StatelessWidget {
           color: Colors.transparent,
           child: InkWell(
             borderRadius: BorderRadius.circular(AppConfig.borderRadius / 2),
-            onTap: () => event.saveFile(context),
+            onTap: () => {
+              if (event.canDownloadInBackground)
+                event.downloadInBackground(context)
+              else
+                event.saveFile(context)
+            },
             child: Container(
               width: 400,
               padding: const EdgeInsets.all(16.0),

lib/pages/chat_list/client_chooser_button.dart

@@ -1,3 +1,4 @@
+import 'package:extera_next/pages/download_manager/download_manager_view.dart';
 import 'package:flutter/material.dart';
 
 import 'package:extera_next/generated/l10n/l10n.dart';
@@ -56,6 +57,16 @@ class ClientChooserButton extends StatelessWidget {
           ],
         ),
       ),
+      PopupMenuItem(
+        value: SettingsAction.downloads,
+        child: Row(
+          children: [
+            Icon(Icons.download_outlined),
+            const SizedBox(width: 18),
+            Text("Downloads"),
+          ],
+        ),
+      ),
       PopupMenuItem(
         value: SettingsAction.archive,
         child: Row(
@@ -220,6 +231,9 @@ class ClientChooserButton extends StatelessWidget {
         case SettingsAction.setStatus:
           controller.setStatus();
           break;
+        case SettingsAction.downloads:
+          DownloadManagerView.showDownloads(context);
+          break;
       }
     }
   }
@@ -229,6 +243,7 @@ enum SettingsAction {
   addAccount,
   newGroup,
   setStatus,
+  downloads,
   invite,
   settings,
   archive,

lib/pages/download_manager/download_manager_view.dart

@@ -1,14 +1,25 @@
 import 'package:extera_next/pages/download_manager/download_manager.dart';
 import 'package:flutter/material.dart';
+import 'package:provider/provider.dart';
 
 class DownloadManagerView extends StatelessWidget {
   final DownloadManagerController controller;
   const DownloadManagerView(this.controller, {super.key});
 
+  static void showDownloads(BuildContext context) {
+    showAdaptiveDialog(
+      context: context,
+      builder: (context) => DownloadManagerView(Provider.of<DownloadManagerController>(context)),
+      barrierDismissible: true
+    );
+  }
+
   @override
   Widget build(BuildContext context) {
-    return Scaffold(
-      body: ListView.builder(
+    return AlertDialog.adaptive(
+      content: ConstrainedBox(
+        constraints: const BoxConstraints(maxHeight: 256, maxWidth: 256),
+        child: ListView.builder(
           itemCount: controller.downloads.length,
           itemBuilder: (context, index) {
             final download = controller.downloads[index];
@@ -28,6 +39,11 @@ class DownloadManagerView extends StatelessWidget {
             );
           },
         ),
+      ),
+      title: ConstrainedBox(
+        constraints: const BoxConstraints(maxWidth: 256),
+        child: const Center(child: Text("Downloads", textAlign: TextAlign.center)),
+      ),
     );
   }
 }

lib/utils/matrix_sdk_extensions/event_extension.dart

@@ -27,10 +27,12 @@ extension LocalizedBody on Event {
   }
 
   void downloadInBackground(BuildContext context) async {
-    if (this.hasAttachment && this.status.isSent && !room.encrypted) {
+    if (!canDownloadInBackground) {
       final dmc = Provider.of<DownloadManagerController>(context);
       final filename = content.tryGet<String>('filename') ?? body;
       dmc.download(context, "$filename.${roomId!.substring(0, 4)}.${eventId.substring(0, 4)}.${extensionFromMime(attachmentMimetype)}", attachmentMxcUrl.toString());
+    } else {
+        throw Exception("Cannot download in background");
     }
   }
 
@@ -41,6 +43,11 @@ extension LocalizedBody on Event {
     matrixFile.result?.share(context);
   }
 
+  bool get canDownloadInBackground =>
+      hasAttachment &&
+      status.isSent &&
+      !room.encrypted;
+
   bool get isAttachmentSmallEnough =>
       infoMap['size'] is int &&
       infoMap['size'] < room.client.database!.maxFileSize;