tasq/lib/widgets/pdf_preview_dialog.dart

import 'dart:typed_data';
import 'package:flutter/material.dart';
import 'package:pdfrx/pdfrx.dart';
import 'package:printing/printing.dart';

/// Show a PDF preview dialog with Print and Download buttons.
///
/// [buildBytes] is called once and cached; the result is shared between the
/// preview viewer and the action buttons.
Future<void> showPdfPreviewDialog(
  BuildContext context, {
  required String title,
  required String filename,
  required Future<Uint8List> Function() buildBytes,
}) {
  return showDialog<void>(
    context: context,
    builder: (_) => _PdfPreviewDialog(
      title: title,
      filename: filename,
      buildBytes: buildBytes,
    ),
  );
}

class _PdfPreviewDialog extends StatefulWidget {
  const _PdfPreviewDialog({
    required this.title,
    required this.filename,
    required this.buildBytes,
  });

  final String title;
  final String filename;
  final Future<Uint8List> Function() buildBytes;

  @override
  State<_PdfPreviewDialog> createState() => _PdfPreviewDialogState();
}

class _PdfPreviewDialogState extends State<_PdfPreviewDialog> {
  late final Future<Uint8List> _future;

  @override
  void initState() {
    super.initState();
    _future = widget.buildBytes();
  }

  @override
  Widget build(BuildContext context) {
    return AlertDialog(
      contentPadding: EdgeInsets.zero,
      content: SizedBox(
        width: 800,
        height: 900,
        child: Column(
          children: [
            Padding(
              padding: const EdgeInsets.symmetric(horizontal: 12, vertical: 8),
              child: Row(
                children: [
                  Expanded(
                    child: Text(
                      widget.title,
                      style: const TextStyle(
                        fontSize: 16,
                        fontWeight: FontWeight.w600,
                      ),
                    ),
                  ),
                  IconButton(
                    tooltip: 'Print',
                    icon: const Icon(Icons.print),
                    onPressed: () async {
                      final bytes = await _future;
                      await Printing.layoutPdf(
                        onLayout: (_) async => bytes,
                        name: widget.filename,
                      );
                    },
                  ),
                  IconButton(
                    tooltip: 'Download',
                    icon: const Icon(Icons.download),
                    onPressed: () async {
                      final bytes = await _future;
                      await Printing.sharePdf(
                        bytes: bytes,
                        filename: widget.filename,
                      );
                    },
                  ),
                  IconButton(
                    tooltip: 'Close',
                    icon: const Icon(Icons.close),
                    onPressed: () => Navigator.of(context).pop(),
                  ),
                ],
              ),
            ),
            const Divider(height: 1),
            Expanded(
              child: FutureBuilder<Uint8List>(
                future: _future,
                builder: (context, snapshot) {
                  if (snapshot.connectionState == ConnectionState.waiting) {
                    return const Center(child: CircularProgressIndicator());
                  }
                  if (snapshot.hasError) {
                    return Center(child: Text(snapshot.error.toString()));
                  }
                  final data = snapshot.data;
                  if (data == null) return const SizedBox.shrink();
                  return PdfViewer.data(data, sourceName: widget.filename);
                },
              ),
            ),
          ],
        ),
      ),
    );
  }
}