feat: extract snippets into widgets, code cleanup document details

lib/features/paged_document_view/view/document_paging_view_mixin.dart

@@ -0,0 +1,43 @@
+import 'package:flutter/widgets.dart';
+import 'package:flutter_bloc/flutter_bloc.dart';
+import 'package:paperless_api/paperless_api.dart';
+import 'package:paperless_mobile/features/paged_document_view/cubit/document_paging_bloc_mixin.dart';
+import 'package:paperless_mobile/helpers/message_helpers.dart';
+import 'package:paperless_mobile/features/inbox/cubit/inbox_cubit.dart';
+
+mixin DocumentPagingViewMixin<T extends StatefulWidget> on State<T> {
+  ScrollController get pagingScrollController;
+
+  @override
+  void initState() {
+    super.initState();
+    pagingScrollController.addListener(shouldLoadMoreDocumentsListener);
+  }
+
+  @override
+  void dispose() {
+    pagingScrollController.removeListener(shouldLoadMoreDocumentsListener);
+    super.dispose();
+  }
+
+  DocumentPagingBlocMixin get _bloc => context.read<DocumentPagingBlocMixin>();
+
+  void shouldLoadMoreDocumentsListener() async {
+    if (shouldLoadMoreDocuments) {
+      try {
+        await _bloc.loadMore();
+      } on PaperlessServerException catch (error, stackTrace) {
+        showErrorMessage(context, error, stackTrace);
+      }
+    }
+  }
+
+  bool get shouldLoadMoreDocuments {
+    final currState = _bloc.state;
+    return pagingScrollController.position.maxScrollExtent != 0 &&
+        !currState.isLoading &&
+        !currState.isLastPageLoaded &&
+        pagingScrollController.offset >=
+            pagingScrollController.position.maxScrollExtent * 0.75;
+  }
+}