feat: Implement updated receive share logic

lib/features/sharing/cubit/receive_share_cubit.dart

@@ -0,0 +1,72 @@
+import 'dart:io';
+
+import 'package:bloc/bloc.dart';
+import 'package:flutter/foundation.dart';
+import 'package:paperless_mobile/core/service/file_service.dart';
+import 'package:path/path.dart' as p;
+import 'package:provider/provider.dart';
+
+part 'receive_share_state.dart';
+
+class ConsumptionChangeNotifier extends ChangeNotifier {
+  List<File> pendingFiles = [];
+
+  ConsumptionChangeNotifier();
+
+  Future<void> loadFromConsumptionDirectory({required String userId}) async {
+    pendingFiles = await _getCurrentFiles(userId);
+    notifyListeners();
+  }
+
+  /// Creates a local copy of all shared files and reloads all files
+  /// from the user's consumption directory.
+  Future<void> addFiles({
+    required List<File> files,
+    required String userId,
+  }) async {
+    if (files.isEmpty) {
+      return;
+    }
+    final consumptionDirectory =
+        await FileService.getConsumptionDirectory(userId: userId);
+    for (final file in files) {
+      File localFile;
+      if (file.path.startsWith(consumptionDirectory.path)) {
+        localFile = file;
+      } else {
+        final fileName = p.basename(file.path);
+        localFile = File(p.join(consumptionDirectory.path, fileName));
+        await file.copy(localFile.path);
+      }
+    }
+    return loadFromConsumptionDirectory(userId: userId);
+  }
+
+  /// Marks a file as processed by removing it from the queue and deleting the local copy of the file.
+  Future<void> discardFile(
+    File file, {
+    required String userId,
+  }) async {
+    final consumptionDirectory =
+        await FileService.getConsumptionDirectory(userId: userId);
+    if (file.path.startsWith(consumptionDirectory.path)) {
+      await file.delete();
+    }
+    return loadFromConsumptionDirectory(userId: userId);
+  }
+
+  /// Returns the next file to process of null if no file exists.
+  Future<File?> getNextFile({required String userId}) async {
+    final files = await _getCurrentFiles(userId);
+    if (files.isEmpty) {
+      return null;
+    }
+    return files.first;
+  }
+
+  Future<List<File>> _getCurrentFiles(String userId) async {
+    final directory = await FileService.getConsumptionDirectory(userId: userId);
+    final files = await FileService.getAllFiles(directory);
+    return files;
+  }
+}