jiu/client/lib/widgets/order_print_preview_dialog.dart

import 'dart:typed_data';
import 'package:flutter/foundation.dart' show kIsWeb;
import 'package:flutter/material.dart';
import 'package:printing/printing.dart';
import '../core/errors/error_reporter.dart';
import '../core/theme/app_theme.dart';
import '../core/responsive/responsive.dart';
import '../core/utils/print_util.dart';
import '../models/stock_in.dart';
import '../models/stock_out.dart';

/// 单据打印预览弹窗：把待打印的 A4 PDF 光栅化成图片（所见即所得）逐页展示，
/// 页内点「打印」再调系统打印。解决部分 Windows 系统打印对话框无预览的问题。
///
/// 仅桌面端使用；Web 端走浏览器自带的打印预览（见 [showStockInOrderPrint]）。
class OrderPrintPreviewDialog extends StatefulWidget {
  /// 标题，如「入库单打印预览」。
  final String title;

  /// 系统打印任务名（也作另存默认文件名前缀）。
  final String printName;

  /// 惰性生成 PDF 字节。
  final Future<Uint8List> Function() pdfBuilder;

  const OrderPrintPreviewDialog({
    super.key,
    required this.title,
    required this.printName,
    required this.pdfBuilder,
  });

  @override
  State<OrderPrintPreviewDialog> createState() =>
      _OrderPrintPreviewDialogState();
}

class _OrderPrintPreviewDialogState extends State<OrderPrintPreviewDialog> {
  Uint8List? _pdfBytes;
  final List<Uint8List> _pages = [];
  bool _rendering = true;
  bool _printing = false;
  String _error = '';

  @override
  void initState() {
    super.initState();
    _render();
  }

  Future<void> _render() async {
    try {
      final bytes = await widget.pdfBuilder();
      if (!mounted) return;
      setState(() => _pdfBytes = bytes);
      // 逐页光栅化（progressive），DPI 取 110 兼顾清晰与速度。
      await for (final raster in Printing.raster(bytes, dpi: 110)) {
        final png = await raster.toPng();
        if (!mounted) return;
        setState(() => _pages.add(png));
      }
    } catch (e, st) {
      reportError(e, st);
      if (mounted) setState(() => _error = '预览生成失败：$e');
    } finally {
      if (mounted) setState(() => _rendering = false);
    }
  }

  Future<void> _doPrint() async {
    final bytes = _pdfBytes;
    if (bytes == null || _printing) return;
    setState(() => _printing = true);
    try {
      await Printing.layoutPdf(
        name: '${widget.printName}_${_ts()}',
        dynamicLayout: false,
        onLayout: (_) async => bytes,
      );
      if (mounted) Navigator.of(context).pop();
    } catch (e, st) {
      reportError(e, st);
      if (mounted) {
        setState(() {
          _printing = false;
          _error = '打印失败，请检查打印机连接和驱动是否正常。\n详情：$e';
        });
      }
    }
  }

  String _ts() {
    final n = DateTime.now();
    String p(int v) => v.toString().padLeft(2, '0');
    return '${n.year}${p(n.month)}${p(n.day)}_${p(n.hour)}${p(n.minute)}${p(n.second)}';
  }

  @override
  Widget build(BuildContext context) {
    return Dialog(
      shape: RoundedRectangleBorder(borderRadius: BorderRadius.circular(12)),
      child: Container(
        width: context.dialogWidth(720),
        constraints: const BoxConstraints(maxHeight: 720),
        child: Column(
          children: [
            // ── 顶栏 ──────────────────────────────────────────────────────────
            Container(
              padding:
                  const EdgeInsets.symmetric(horizontal: 20, vertical: 14),
              decoration: const BoxDecoration(
                color: AppTheme.primary,
                borderRadius: BorderRadius.only(
                  topLeft: Radius.circular(12),
                  topRight: Radius.circular(12),
                ),
              ),
              child: Row(
                children: [
                  Text(widget.title,
                      style: const TextStyle(
                          fontSize: 16,
                          fontWeight: FontWeight.w600,
                          color: Colors.white)),
                  const Spacer(),
                  IconButton(
                    icon: const Icon(Icons.close, color: Colors.white),
                    onPressed:
                        _printing ? null : () => Navigator.of(context).pop(),
                    padding: EdgeInsets.zero,
                    constraints: const BoxConstraints(),
                  ),
                ],
              ),
            ),

            // ── 预览区 ─────────────────────────────────────────────────────────
            Expanded(
              child: Container(
                width: double.infinity,
                color: const Color(0xFFE9ECF1),
                child: _buildBody(),
              ),
            ),

            // ── 底栏 ──────────────────────────────────────────────────────────
            Padding(
              padding: const EdgeInsets.fromLTRB(16, 10, 16, 14),
              child: Row(
                children: [
                  Expanded(
                    child: Text(
                      _error.isNotEmpty
                          ? _error
                          : (_rendering
                              ? '正在生成预览…'
                              : '共 ${_pages.length} 页'),
                      style: TextStyle(
                          fontSize: 12,
                          color: _error.isNotEmpty
                              ? Colors.red
                              : AppTheme.textSecondary),
                    ),
                  ),
                  TextButton(
                    onPressed:
                        _printing ? null : () => Navigator.of(context).pop(),
                    child: const Text('取消'),
                  ),
                  const SizedBox(width: 8),
                  FilledButton.icon(
                    icon: const Icon(Icons.print, size: 18),
                    onPressed: (_pdfBytes == null || _printing)
                        ? null
                        : _doPrint,
                    label: Text(_printing ? '打印中…' : '打印'),
                  ),
                ],
              ),
            ),
          ],
        ),
      ),
    );
  }

  Widget _buildBody() {
    if (_pages.isEmpty) {
      if (_error.isNotEmpty) {
        return Center(
          child: Padding(
            padding: const EdgeInsets.all(24),
            child: Text(_error,
                textAlign: TextAlign.center,
                style: const TextStyle(color: Colors.red, fontSize: 13)),
          ),
        );
      }
      return const Center(child: CircularProgressIndicator());
    }
    return ListView.separated(
      padding: const EdgeInsets.symmetric(horizontal: 20, vertical: 16),
      itemCount: _pages.length,
      separatorBuilder: (_, __) => const SizedBox(height: 16),
      itemBuilder: (_, i) => Center(
        child: Container(
          decoration: BoxDecoration(
            color: Colors.white,
            boxShadow: [
              BoxShadow(
                color: Colors.black.withOpacity(0.18),
                blurRadius: 8,
                offset: const Offset(0, 2),
              ),
            ],
          ),
          child: Image.memory(_pages[i], fit: BoxFit.contain),
        ),
      ),
    );
  }
}

/// 打印入库单：桌面端先弹应用内预览，Web 端走浏览器自带打印预览。
Future<void> showStockInOrderPrint(
    BuildContext context, StockInOrder order) async {
  if (kIsWeb) {
    await safePrint(context, () => printStockInOrder(order));
    return;
  }
  await showDialog<void>(
    context: context,
    barrierDismissible: false,
    builder: (_) => OrderPrintPreviewDialog(
      title: '入库单打印预览',
      printName: '入库单',
      pdfBuilder: () => buildStockInOrderPdf(order),
    ),
  );
}

/// 打印出库单：桌面端先弹应用内预览，Web 端走浏览器自带打印预览。
Future<void> showStockOutOrderPrint(
    BuildContext context, StockOutOrder order) async {
  if (kIsWeb) {
    await safePrint(context, () => printStockOutOrder(order));
    return;
  }
  await showDialog<void>(
    context: context,
    barrierDismissible: false,
    builder: (_) => OrderPrintPreviewDialog(
      title: '出库单打印预览',
      printName: '出库单',
      pdfBuilder: () => buildStockOutOrderPdf(order),
    ),
  );
}