import 'package:get/get.dart';
import 'package:intl/intl.dart';

import '../models/backup_model.dart';
import '../services/backup_file_service.dart';
import '../services/get_storage_services.dart';
import 'home_controller.dart';
import 'abfall_controller.dart';

class ExportController extends GetxController {
  ExportController({BackupFileService? fileService})
    : fileService = fileService ?? BackupFileService();

  final BackupFileService fileService;
  final storage = Get.find<GetStorageService>();
  final isBusy = false.obs;
  final message = RxnString();
  final hasError = false.obs;
  final pendingBackup = Rxn<BackupModel>();

  Future<void> exportData() async {
    if (isBusy.value) return;
    isBusy.value = true;
    message.value = null;
    try {
      final backup = BackupModel({
        for (final key in BackupModel.keys) key: storage.getModelList(key),
      });
      final name =
          'filament_backup_${DateFormat('yyyy-MM-dd_HH-mm-ss').format(DateTime.now())}.json';
      if (await fileService.save(backup.encode(), name)) {
        hasError.value = false;
        message.value = 'Datensicherung als JSON-Datei exportiert.';
      }
    } catch (_) {
      _error('Export fehlgeschlagen. Bitte erneut versuchen.');
    } finally {
      isBusy.value = false;
    }
  }

  Future<void> selectImport() async {
    if (isBusy.value) return;
    isBusy.value = true;
    message.value = null;
    pendingBackup.value = null;
    try {
      final source = await fileService.open();
      if (source != null) pendingBackup.value = BackupModel.decode(source);
    } on FormatException catch (error) {
      _error(error.message);
    } catch (_) {
      _error('Datei konnte nicht gelesen werden. Bitte erneut versuchen.');
    } finally {
      isBusy.value = false;
    }
  }

  Future<void> importData() async {
    final backup = pendingBackup.value;
    if (isBusy.value || backup == null) return;
    isBusy.value = true;
    message.value = null;
    final previous = <String, List<Map<String, dynamic>>>{};
    final attempted = <String>[];
    try {
      for (final key in BackupModel.keys) {
        previous[key] = storage.getModelList(key);
      }
      for (final key in BackupModel.keys) {
        attempted.add(key);
        await storage.saveModelList(key, backup.data[key]!);
      }
      if (Get.isRegistered<HomeController>()) {
        final home = Get.find<HomeController>();
        home.loadFilamente();
        home.loadMaterialien();
        home.resetForm();
      }
      if (Get.isRegistered<AbfallController>()) {
        Get.find<AbfallController>().loadAbfaelle();
      }
      pendingBackup.value = null;
      hasError.value = false;
      message.value = 'Alle Daten wurden importiert.';
    } catch (_) {
      var restored = true;
      for (final key in attempted.reversed) {
        try {
          await storage.saveModelList(key, previous[key]!);
        } catch (_) {
          restored = false;
        }
      }
      _error(
        restored
            ? 'Import fehlgeschlagen. Die bisherigen Daten wurden beibehalten.'
            : 'Import und Wiederherstellung fehlgeschlagen. Bitte die Datensicherung erneut importieren.',
      );
    } finally {
      isBusy.value = false;
    }
  }

  void _error(String text) {
    hasError.value = true;
    message.value = text;
  }
}