import 'package:app_settings/app_settings.dart';
import 'package:file_picker/file_picker.dart';
import 'package:flutter/material.dart';
import 'package:flutter/services.dart';
import 'package:image_picker/image_picker.dart';

import '../api/errors/error_mapper.dart';
import '../api/errors/permission_exception.dart';
import 'confirm_dialog.dart';
import 'info_dialog.dart';

/// Thin wrapper around the platform pickers. Every method resolves to `null`
/// when the user cancels **or** when picking failed; failures are reported to
/// the user right here (permission denial with a shortcut to the system
/// settings, everything else as a plain error dialog) so call sites can treat
/// the result like a cancel.
class FilePick {
  static final _picker = ImagePicker();

  static Future<List<XFile>?> multipleGalleryPick(BuildContext context) =>
      _guarded(context, () async {
        final pickedImages = await _picker.pickMultiImage();
        return pickedImages.isNotEmpty ? pickedImages : null;
      });

  static Future<XFile?> singleGalleryPick(BuildContext context) =>
      _guarded(context, () => _picker.pickImage(source: ImageSource.gallery));

  static Future<XFile?> cameraPick(BuildContext context) =>
      _guarded(context, () => _picker.pickImage(source: ImageSource.camera));

  static Future<List<String>?> documentPick() async {
    final result = await FilePicker.pickFiles(allowMultiple: true);
    return result?.files.map((e) => e.path).nonNulls.toList();
  }

  static Future<T?> _guarded<T>(
    BuildContext context,
    Future<T?> Function() pick,
  ) async {
    try {
      return await pick();
    } on PlatformException catch (e) {
      final denied = PermissionException.fromPlatform(e);
      if (!context.mounted) return null;
      if (denied != null) {
        _showPermissionDialog(context, denied);
      } else {
        _showErrorDialog(context, e);
      }
      return null;
    } catch (e) {
      if (context.mounted) _showErrorDialog(context, e);
      return null;
    }
  }

  static void _showPermissionDialog(
    BuildContext context,
    PermissionException denied,
  ) => ConfirmDialog(
    icon: Icons.block_outlined,
    title: 'Zugriff verweigert',
    content: denied.userMessage,
    confirmButton: 'Einstellungen öffnen',
    onConfirm: AppSettings.openAppSettings,
  ).asDialog(context);

  static void _showErrorDialog(BuildContext context, Object error) {
    final message = errorToUserMessage(error);
    final details = errorToTechnicalDetails(error);
    final body = details != null && details != message
        ? '$message\n\n$details'
        : message;
    InfoDialog.show(context, body, copyable: true, title: 'Fehler');
  }
}