Merge branch 'develop' into feature/18-json-validation

# Conflicts:
#	pubspec.yaml

lib/services/local_storage_service.dart

@@ -0,0 +1,164 @@
+import 'dart:convert';
+import 'dart:io';
+
+import 'package:cabo_counter/data/game_session.dart';
+import 'package:cabo_counter/utility/globals.dart';
+import 'package:file_picker/file_picker.dart';
+import 'package:file_saver/file_saver.dart';
+import 'package:flutter/services.dart';
+import 'package:json_schema/json_schema.dart';
+import 'package:path_provider/path_provider.dart';
+
+class LocalStorageService {
+  static const String _fileName = 'game_data.json';
+
+  /// Writes the game session list to a  JSON file and returns it as string.
+  static String getJsonFile() {
+    final jsonFile =
+        Globals.gameList.map((session) => session.toJson()).toList();
+    return json.encode(jsonFile);
+  }
+
+  /// Returns the path to the local JSON file.
+  static Future<File> _getFilePath() async {
+    final directory = await getApplicationDocumentsDirectory();
+    final path = '${directory.path}/$_fileName';
+    return File(path);
+  }
+
+  /// Saves the game sessions to a local JSON file.
+  static Future<void> saveGameSessions() async {
+    try {
+      final file = await _getFilePath();
+      final jsonFile = getJsonFile();
+      await file.writeAsString(jsonFile);
+      print('Daten gespeichert');
+    } catch (e) {
+      print('Fehler beim Speichern: $e');
+    }
+  }
+
+  /// Loads the game data from a local JSON file.
+  static Future<bool> loadGameSessions() async {
+    print('Versuche, Daten zu laden...');
+    try {
+      final file = await _getFilePath();
+
+      if (!await file.exists()) {
+        print('Es existiert noch keine Datei mit Spieldaten');
+        return false;
+      }
+
+      print('Es existiert bereits eine Datei mit Spieldaten');
+      final jsonString = await file.readAsString();
+
+      if (jsonString.isEmpty) {
+        print('Die gefundene Datei ist leer');
+        return false;
+      }
+
+      if (!await validateJsonSchema(jsonString)) {
+        print('Die Datei konnte nicht validiert werden');
+        Globals.gameList = [];
+        return false;
+      }
+
+      print('Die gefundene Datei ist nicht leer und validiert');
+      final jsonList = json.decode(jsonString) as List<dynamic>;
+
+      Globals.gameList = jsonList
+          .map((jsonItem) =>
+              GameSession.fromJson(jsonItem as Map<String, dynamic>))
+          .toList();
+
+      print('Die Daten wurden erfolgreich geladen und verarbeitet');
+      return true;
+    } catch (e) {
+      print('Fehler beim Laden der Spieldaten:\n$e');
+      Globals.gameList = [];
+      return false;
+    }
+  }
+
+  /// Opens the file picker to save a JSON file with the current game data.
+  static Future<bool> exportJsonFile() async {
+    final jsonString = getJsonFile();
+    try {
+      final bytes = Uint8List.fromList(utf8.encode(jsonString));
+      final result = await FileSaver.instance.saveAs(
+        name: 'cabo_counter_data',
+        bytes: bytes,
+        ext: 'json',
+        mimeType: MimeType.json,
+      );
+      print('Datei gespeichert: $result');
+      return true;
+    } catch (e) {
+      print('Fehler beim Speichern: $e');
+      return false;
+    }
+  }
+
+  /// Opens the file picker to import a JSON file and loads the game data from it.
+  static Future<bool> importJsonFile() async {
+    final result = await FilePicker.platform.pickFiles(
+      dialogTitle: 'Wähle eine Datei mit Spieldaten aus',
+      type: FileType.custom,
+      allowedExtensions: ['json'],
+    );
+
+    if (result == null) {
+      print('Der Dialog wurde abgebrochen');
+      return false;
+    }
+
+    try {
+      final jsonString = await _readFileContent(result.files.single);
+
+      if (!await validateJsonSchema(jsonString)) {
+        return false;
+      }
+      final jsonData = json.decode(jsonString) as List<dynamic>;
+      print('JSON Inhalt: $jsonData');
+      Globals.gameList = jsonData
+          .map((jsonItem) =>
+              GameSession.fromJson(jsonItem as Map<String, dynamic>))
+          .toList();
+      return true;
+    } on FormatException catch (e) {
+      print('Ungültiges JSON-Format: $e');
+      return false;
+    } on Exception catch (e) {
+      print('Fehler beim Dateizugriff: $e');
+      return false;
+    }
+  }
+
+  /// Helper method to read file content from either bytes or path
+  static Future<String> _readFileContent(PlatformFile file) async {
+    if (file.bytes != null) return utf8.decode(file.bytes!);
+    if (file.path != null) return await File(file.path!).readAsString();
+
+    throw Exception('Die Datei hat keinen lesbaren Inhalt');
+  }
+
+  /// Validates the JSON data against the schema.
+  static Future<bool> validateJsonSchema(String jsonString) async {
+    try {
+      final schemaString = await rootBundle.loadString('assets/schema.json');
+      final schema = JsonSchema.create(json.decode(schemaString));
+      final jsonData = json.decode(jsonString);
+      final result = schema.validate(jsonData);
+
+      if (result.isValid) {
+        print('JSON ist erfolgreich validiert.');
+        return true;
+      }
+      print('JSON ist nicht gültig: ${result.errors}');
+      return false;
+    } catch (e) {
+      print('Fehler beim Validieren des JSON-Schemas: $e');
+      return false;
+    }
+  }
+}