Refactored DI, serialization, added feedback to document download

lib/features/document_details/view/widgets/document_download_button.dart

@@ -0,0 +1,61 @@
+import 'dart:developer';
+import 'dart:io';
+
+import 'package:flutter/material.dart';
+import 'package:paperless_api/paperless_api.dart';
+import 'package:paperless_mobile/core/service/file_service.dart';
+import 'package:paperless_mobile/di_initializer.dart';
+import 'package:paperless_mobile/extensions/flutter_extensions.dart';
+import 'package:paperless_mobile/generated/l10n.dart';
+import 'package:paperless_mobile/util.dart';
+
+class DocumentDownloadButton extends StatefulWidget {
+  final DocumentModel? document;
+  const DocumentDownloadButton({super.key, required this.document});
+
+  @override
+  State<DocumentDownloadButton> createState() => _DocumentDownloadButtonState();
+}
+
+class _DocumentDownloadButtonState extends State<DocumentDownloadButton> {
+  bool _isDownloadPending = false;
+
+  @override
+  Widget build(BuildContext context) {
+    return IconButton(
+      icon: _isDownloadPending
+          ? const SizedBox(
+              child: CircularProgressIndicator(),
+              height: 16,
+              width: 16,
+            )
+          : const Icon(Icons.download),
+      onPressed: Platform.isAndroid && widget.document != null
+          ? () => _onDownload(widget.document!)
+          : null,
+    ).padded(const EdgeInsets.only(right: 4));
+  }
+
+  Future<void> _onDownload(DocumentModel document) async {
+    if (!Platform.isAndroid) {
+      showSnackBar(
+          context, "This feature is currently only supported on Android!");
+      return;
+    }
+    setState(() => _isDownloadPending = true);
+    try {
+      final bytes = await getIt<PaperlessDocumentsApi>().download(document);
+      final Directory dir = await FileService.downloadsDirectory;
+      String filePath = "${dir.path}/${document.originalFileName}";
+      //TODO: Add replacement mechanism here (ask user if file should be replaced if exists)
+      await File(filePath).writeAsBytes(bytes);
+      showSnackBar(context, S.of(context).documentDownloadSuccessMessage);
+    } on PaperlessServerException catch (error, stackTrace) {
+      showErrorMessage(context, error, stackTrace);
+    } catch (error) {
+      showGenericError(context, error);
+    } finally {
+      setState(() => _isDownloadPending = false);
+    }
+  }
+}