feat(wip): Update entities and adopt a proper repository workflow for trip "obtention"

frontend/lib/data/repositories/preferences_repository_impl.dart

@@ -0,0 +1,50 @@
+import 'dart:convert';
+
+import 'package:shared_preferences/shared_preferences.dart';
+import 'package:anyway/domain/entities/preferences.dart';
+import 'package:anyway/domain/repositories/preferences_repository.dart';
+
+class PreferencesRepositoryImpl implements PreferencesRepository {
+  static const _key = 'userPreferences';
+
+  @override
+  Future<Preferences> getPreferences() async {
+    final prefs = await SharedPreferences.getInstance();
+    final raw = prefs.getString(_key);
+    if (raw == null) {
+      // TODO - rethink this
+      // return a sensible default
+      return Preferences(
+        scores: {
+          'sightseeing': 0,
+          'shopping': 0,
+          'nature': 0,
+        },
+        maxTimeMinutes: 120,
+        startLocation: const [48.8575, 2.3514],
+      );
+    }
+
+    try {
+      final map = json.decode(raw) as Map<String, dynamic>;
+      return Preferences.fromJson(map);
+    } catch (_) {
+      return Preferences(
+        scores: {
+          'sightseeing': 0,
+          'shopping': 0,
+          'nature': 0,
+        },
+        maxTimeMinutes: 120,
+        startLocation: const [48.8575, 2.3514],
+      );
+    }
+  }
+
+  @override
+  Future<void> savePreferences(Preferences preferences) async {
+    final prefs = await SharedPreferences.getInstance();
+    final raw = json.encode(preferences.toJson());
+    await prefs.setString(_key, raw);
+  }
+}