Changed file directories, added clear storage setting, updated readme w/ Google Play reference

lib/core/service/file_service.dart

@@ -0,0 +1,95 @@
+import 'dart:io';
+
+import 'package:flutter/foundation.dart';
+import 'package:paperless_mobile/core/model/error_message.dart';
+import 'package:path_provider/path_provider.dart';
+import 'package:uuid/uuid.dart';
+
+class FileService {
+  static Future<File> saveToFile(
+    Uint8List bytes,
+    String filename,
+  ) async {
+    final dir = await documentsDirectory;
+    if (dir == null) {
+      throw ErrorMessage.unknown(); //TODO: better handling
+    }
+    File file = File("${dir.path}/$filename");
+    return file..writeAsBytes(bytes);
+  }
+
+  static Future<Directory?> getDirectory(PaperlessDirectoryType type) {
+    switch (type) {
+      case PaperlessDirectoryType.documents:
+        return documentsDirectory;
+      case PaperlessDirectoryType.temporary:
+        return temporaryDirectory;
+      case PaperlessDirectoryType.scans:
+        return scanDirectory;
+      case PaperlessDirectoryType.download:
+        return downloadsDirectory;
+    }
+  }
+
+  static Future<File> allocateTemporaryFile(
+    PaperlessDirectoryType type, {
+    required String extension,
+    String? fileName,
+  }) async {
+    final dir = await getDirectory(type);
+    final _fileName = (fileName ?? const Uuid().v1()) + '.$extension';
+    return File('${dir?.path}/$_fileName');
+  }
+
+  static Future<Directory> get temporaryDirectory => getTemporaryDirectory();
+
+  static Future<Directory?> get documentsDirectory async {
+    if (Platform.isAndroid) {
+      return (await getExternalStorageDirectories(
+        type: StorageDirectory.documents,
+      ))!
+          .first;
+    } else if (Platform.isIOS) {
+      return getApplicationDocumentsDirectory();
+    } else {
+      throw UnsupportedError("Platform not supported.");
+    }
+  }
+
+  static Future<Directory?> get downloadsDirectory async {
+    if (Platform.isAndroid) {
+      return (await getExternalStorageDirectories(
+              type: StorageDirectory.downloads))!
+          .first;
+    } else if (Platform.isIOS) {
+      return getApplicationDocumentsDirectory();
+    } else {
+      throw UnsupportedError("Platform not supported.");
+    }
+  }
+
+  static Future<Directory?> get scanDirectory async {
+    if (Platform.isAndroid) {
+      return (await getExternalStorageDirectories(type: StorageDirectory.dcim))!
+          .first;
+    } else if (Platform.isIOS) {
+      return getApplicationDocumentsDirectory();
+    } else {
+      throw UnsupportedError("Platform not supported.");
+    }
+  }
+
+  static Future<void> clearUserData() async {
+    final scanDir = await scanDirectory;
+    final tempDir = await temporaryDirectory;
+    scanDir?.delete(recursive: true);
+    tempDir.delete(recursive: true);
+  }
+}
+
+enum PaperlessDirectoryType {
+  documents,
+  temporary,
+  scans,
+  download;
+}