major refactor

lib/components/pages/traction/traction_persistence.dart

@@ -0,0 +1,88 @@
+part of 'traction.dart';
+
+extension _TractionPersistence on _TractionPageState {
+  Future<void> _restoreSearchState() async {
+    if (widget.selectionMode) return;
+    if (_restoredFromPrefs) return;
+    _restoredFromPrefs = true;
+    try {
+      final prefs = await SharedPreferences.getInstance();
+      final raw = prefs.getString(_kTractionSearchPrefsKey);
+      if (raw == null || raw.trim().isEmpty) return;
+      final decoded = jsonDecode(raw);
+      if (decoded is! Map) return;
+
+      final classText = decoded['classText']?.toString();
+      final numberText = decoded['number']?.toString();
+      final nameText = decoded['name']?.toString();
+      final selectedClass = decoded['selectedClass']?.toString();
+      final mileageFirst = decoded['mileageFirst'];
+      final showAdvanced = decoded['showAdvancedFilters'];
+
+      if (classText != null) _classController.text = classText;
+      if (numberText != null) _numberController.text = numberText;
+      if (nameText != null) _nameController.text = nameText;
+
+      final dynamicValues = <String, String>{};
+      final enumValues = <String, String?>{};
+      final dynamicRaw = decoded['dynamic'];
+      if (dynamicRaw is Map) {
+        for (final entry in dynamicRaw.entries) {
+          final key = entry.key.toString();
+          final val = entry.value?.toString() ?? '';
+          dynamicValues[key] = val;
+        }
+      }
+      final enumRaw = decoded['enum'];
+      if (enumRaw is Map) {
+        for (final entry in enumRaw.entries) {
+          enumValues[entry.key.toString()] = entry.value?.toString();
+        }
+      }
+
+      for (final entry in dynamicValues.entries) {
+        _dynamicControllers.putIfAbsent(
+          entry.key,
+          () => TextEditingController(text: entry.value),
+        );
+        _dynamicControllers[entry.key]?.text = entry.value;
+      }
+      for (final entry in enumValues.entries) {
+        _enumSelections[entry.key] = entry.value;
+      }
+
+      if (!mounted) return;
+      _setState(() {
+        _selectedClass =
+            (selectedClass != null && selectedClass.trim().isNotEmpty)
+                ? selectedClass
+                : null;
+        if (mileageFirst is bool) _mileageFirst = mileageFirst;
+        if (showAdvanced is bool) _showAdvancedFilters = showAdvanced;
+      });
+    } catch (_) {
+      // Ignore preference restore failures.
+    }
+  }
+
+  Future<void> _persistSearchState() async {
+    if (widget.selectionMode) return;
+    final payload = <String, dynamic>{
+      'classText': _classController.text,
+      'number': _numberController.text,
+      'name': _nameController.text,
+      'selectedClass': _selectedClass,
+      'mileageFirst': _mileageFirst,
+      'showAdvancedFilters': _showAdvancedFilters,
+      'dynamic': _dynamicControllers.map((k, v) => MapEntry(k, v.text)),
+      'enum': _enumSelections,
+    };
+
+    try {
+      final prefs = await SharedPreferences.getInstance();
+      await prefs.setString(_kTractionSearchPrefsKey, jsonEncode(payload));
+    } catch (_) {
+      // Ignore persistence failures.
+    }
+  }
+}