import 'dart:typed_data';

import 'package:flutter/material.dart';
import 'package:tdesign_flutter/tdesign_flutter.dart';

import '../../core/i18n/app_localizations.dart';
import '../../core/navigation/host_app_channel.dart';
import '../models/bill_attachment.dart';
import '../widgets/loading_dialog.dart';

/// 附件下载辅助类，供详情页复用下载逻辑。
class AttachmentDownloadHelper {
  /// 根据扩展名返回 MIME 类型
  static String mimeType(String ext) {
    switch (ext.toLowerCase()) {
      case 'pdf':
        return 'application/pdf';
      case 'doc':
        return 'application/msword';
      case 'docx':
        return 'application/vnd.openxmlformats-officedocument.wordprocessingml.document';
      case 'xls':
        return 'application/vnd.ms-excel';
      case 'xlsx':
        return 'application/vnd.openxmlformats-officedocument.spreadsheetml.sheet';
      case 'jpg':
      case 'jpeg':
        return 'image/jpeg';
      case 'png':
        return 'image/png';
      case 'gif':
        return 'image/gif';
      case 'bmp':
        return 'image/bmp';
      case 'webp':
        return 'image/webp';
      default:
        return 'application/octet-stream';
    }
  }

  /// 下载附件并保存到公共目录，成功显示路径弹窗。
  static Future<void> downloadAndSave(
    BuildContext context,
    BillAttachment attachment,
    Future<Uint8List?> Function(String id) downloader,
  ) async {
    final l10n = AppLocalizations.of(context);
    try {
      LoadingDialog.show(context, text: l10n.get('downloading'));
      final bytes = await downloader(attachment.id);
      if (!context.mounted) return;
      LoadingDialog.hide(context);
      if (bytes == null) {
        TDToast.showText(l10n.get('downloadFailed'), context: context);
        return;
      }
      final path = await HostAppChannel.saveFileToDownloads(
        bytes,
        attachment.fileName,
        mimeType(attachment.ext),
      );
      if (!context.mounted) return;
      if (path != null) {
        _showSuccessDialog(context, l10n, path);
      } else {
        TDToast.showText(l10n.get('downloadFailed'), context: context);
      }
    } catch (_) {
      if (context.mounted) LoadingDialog.hide(context);
      if (context.mounted) {
        TDToast.showText(l10n.get('downloadFailed'), context: context);
      }
    }
  }

  static void _showSuccessDialog(
    BuildContext context,
    AppLocalizations l10n,
    String path,
  ) {
    showGeneralDialog(
      context: context,
      pageBuilder: (buildContext, animation, secondaryAnimation) {
        return TDConfirmDialog(
          title: l10n.get('downloadSuccess'),
          content: path,
          buttonStyle: TDDialogButtonStyle.text,
          buttonText: l10n.get('confirm'),
        );
      },
    );
  }
}