import 'dart:io';

import 'package:file_picker/file_picker.dart';
import 'package:flutter/material.dart';
import 'package:path_provider/path_provider.dart';
import 'package:provider/provider.dart';
import 'package:share_plus/share_plus.dart' show Share, XFile;

import '../../estado/estado_radio.dart';
import '../../l10n/gen/app_localizations.dart';
import '../../widgets/pluri_glass_surface.dart';
import '../../widgets/pluri_layout.dart';
import '../../widgets/pluri_push_scaffold.dart';

/// APLICACIÓN group · "Copia de seguridad" (design ADR-3). Body moved
/// verbatim from the former `_SeccionBackup` in `pantalla_ajustes.dart` —
/// only the panel header's icon and title were removed (the pushed screen's
/// title now carries them); every method below is unchanged.
class PantallaAjustesBackup extends StatelessWidget {
  const PantallaAjustesBackup({super.key});

  @override
  Widget build(BuildContext context) {
    final l10n = AppLocalizations.of(context);
    return PluriPushScaffold(
      title: l10n.backupSectionTitle,
      body: ListView(
        padding: PluriLayout.pageContentPadding,
        children: const [_CuerpoBackup()],
      ),
    );
  }
}

class _CuerpoBackup extends StatelessWidget {
  const _CuerpoBackup();

  Future<void> _exportar(BuildContext context) async {
    final l10n = AppLocalizations.of(context);
    try {
      final estado = context.read<EstadoRadio>();
      // JSON serialization is owned by ServicioExportImport (S4-R4).
      final json = await estado.exportarConfigJson();

      final dir = await getTemporaryDirectory();
      final file = File('${dir.path}/pluriwave-backup.json');
      await file.writeAsString(json);

      await Share.shareXFiles(
        [XFile(file.path)],
        subject: l10n.backupShareSubject,
        text: l10n.backupShareText(DateTime.now().toLocal()),
      );
    } catch (e) {
      if (context.mounted) {
        ScaffoldMessenger.of(context).showSnackBar(
          SnackBar(content: Text(l10n.backupExportError(e.toString()))),
        );
      }
    }
  }

  Future<void> _importar(BuildContext context) async {
    final l10n = AppLocalizations.of(context);
    try {
      final result = await FilePicker.platform.pickFiles(
        type: FileType.custom,
        allowedExtensions: ['json'],
      );
      if (result == null || result.files.single.path == null) return;

      final file = File(result.files.single.path!);
      final contenido = await file.readAsString();
      if (!context.mounted) return;
      // Parsing is owned by ServicioExportImport (S4-R4): null = malformed.
      final json = context.read<EstadoRadio>().parsearConfigJson(contenido);
      if (json == null) {
        throw const FormatException('invalid backup file');
      }

      if (context.mounted) {
        final confirmar = await showDialog<bool>(
          context: context,
          builder:
              (ctx) => AlertDialog(
                title: Text(AppLocalizations.of(ctx).backupImportTitle),
                content: Text(
                  AppLocalizations.of(ctx).backupImportConfirmMessage,
                ),
                actions: [
                  TextButton(
                    onPressed: () => Navigator.pop(ctx, false),
                    child: Text(AppLocalizations.of(ctx).cancelAction),
                  ),
                  FilledButton(
                    onPressed: () => Navigator.pop(ctx, true),
                    child: Text(AppLocalizations.of(ctx).backupImportTitle),
                  ),
                ],
              ),
        );
        if (confirmar != true) return;
        if (context.mounted) {
          final estado = context.read<EstadoRadio>();
          final messenger = ScaffoldMessenger.of(context);
          await estado.importarConfig(json);
          messenger.showSnackBar(
            SnackBar(content: Text(l10n.backupImportSuccess)),
          );
        }
      }
    } catch (e) {
      if (context.mounted) {
        ScaffoldMessenger.of(context).showSnackBar(
          SnackBar(content: Text(l10n.backupImportError(e.toString()))),
        );
      }
    }
  }

  @override
  Widget build(BuildContext context) {
    return PluriGlassSurface(
      child: Column(
        crossAxisAlignment: CrossAxisAlignment.start,
        children: [
          ListTile(
            contentPadding: EdgeInsets.zero,
            leading: const Icon(Icons.upload_outlined),
            title: Text(AppLocalizations.of(context).backupExportTitle),
            subtitle: Text(AppLocalizations.of(context).backupExportSubtitle),
            onTap: () => _exportar(context),
          ),
          ListTile(
            contentPadding: EdgeInsets.zero,
            leading: const Icon(Icons.download_outlined),
            title: Text(AppLocalizations.of(context).backupImportTitle),
            subtitle: Text(AppLocalizations.of(context).backupImportSubtitle),
            onTap: () => _importar(context),
          ),
        ],
      ),
    );
  }
}