import 'dart:typed_data';
import 'package:flutter/material.dart';
import 'package:shared_preferences/shared_preferences.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 '../core/utils/label_data.dart';

const _kPrinterKey = 'label_printer';

/// 标签打印预览弹窗：所见即所得预览（dart:ui 位图）+ 打印机选择 + 份数调整。
///
/// 单张模式（labels.length == 1）：隐藏缩略图条，直接显示大图。
/// 多张模式：左侧竖排缩略图（带勾选），右侧大图主视图。
class LabelPreviewDialog extends StatefulWidget {
  final List<LabelData> labels;

  /// 多张懒加载：按 productId 拉取 QR PNG 字节。单张场景可不传（qrBytes 已在 LabelData 中）。
  final Future<Uint8List> Function(int productId)? qrFetcher;

  const LabelPreviewDialog({
    super.key,
    required this.labels,
    this.qrFetcher,
  });

  @override
  State<LabelPreviewDialog> createState() => _LabelPreviewDialogState();
}

class _LabelPreviewDialogState extends State<LabelPreviewDialog> {
  int _selectedIndex = 0;
  late List<Uint8List?> _previews;
  late List<bool> _include;
  List<String> _printers = [];
  String? _printer;
  bool _printing = false;
  bool _printersChecked = false;
  String _status = '';

  @override
  void initState() {
    super.initState();
    _previews = List<Uint8List?>.filled(widget.labels.length, null,
        growable: false);
    _include = List<bool>.filled(widget.labels.length, true, growable: false);
    _init();
  }

  Future<void> _init() async {
    // ── 枚举打印机，读取上次记忆 ──
    final printers = await listLabelPrinters();
    final prefs = await SharedPreferences.getInstance();
    final saved = prefs.getString(_kPrinterKey);
    String? selected;
    if (saved != null && printers.contains(saved)) {
      selected = saved;
    } else {
      selected = await detectDefaultPrinter() ??
          (printers.isNotEmpty ? printers.first : null);
    }
    if (mounted) {
      setState(() {
        _printers = printers;
        _printer = selected;
        _printersChecked = true;
      });
    }

    // ── 逐张渲染预览（progressive）──
    for (int i = 0; i < widget.labels.length; i++) {
      final label = widget.labels[i];
      try {
        // 懒加载 QR
        if (label.qrBytes == null &&
            label.productId != null &&
            widget.qrFetcher != null) {
          label.qrBytes = await widget.qrFetcher!(label.productId!);
        }
        if (label.qrBytes == null) continue;
        final png = await renderLabelPreview(label);
        if (mounted && png != null) {
          setState(() => _previews[i] = png);
        }
      } catch (e, st) {
        debugPrint('[preview] 渲染第${i + 1}张失败: $e');
        reportError(e, st);
      }
    }
  }

  int get _totalPrintCount {
    int total = 0;
    for (int i = 0; i < widget.labels.length; i++) {
      if (_include[i]) total += widget.labels[i].copies;
    }
    return total;
  }

  Future<void> _doPrint() async {
    if (_printing) return;
    setState(() {
      _printing = true;
      _status = '正在打印...';
    });
    int done = 0;
    final total = _totalPrintCount;
    for (int i = 0; i < widget.labels.length; i++) {
      if (!_include[i]) continue;
      final label = widget.labels[i];
      for (int c = 0; c < label.copies; c++) {
        try {
          // 确保 QR 已拉取
          if (label.qrBytes == null &&
              label.productId != null &&
              widget.qrFetcher != null) {
            label.qrBytes = await widget.qrFetcher!(label.productId!);
          }
          if (label.qrBytes == null) continue;
          await printProductLabel(
            qrBytes: label.qrBytes!,
            name: label.name,
            code: label.code,
            spec: label.spec,
            series: label.series,
            batchNo: label.batchNo,
            productionDate: label.productionDate,
            remark: label.remark,
            shopName: label.shopName,
            shopAddress: label.shopAddress,
            shopPhone: label.shopPhone,
            printerName: _printer,
          );
          done++;
          if (mounted) {
            setState(() => _status = '已打印 $done/$total 张...');
          }
        } catch (e, st) {
          reportError(e, st);
          if (mounted) {
            setState(() => _status = '第${i + 1}张第${c + 1}份打印失败：$e');
          }
        }
      }
    }
    if (mounted) {
      setState(() {
        _printing = false;
        _status = '完成，共打印 $done 张';
      });
      Navigator.of(context).pop();
    }
  }

  // ── 缩略图列表项 ─────────────────────────────────────────────────────────────

  Widget _buildThumbnail(int i) {
    final isSelected = _selectedIndex == i;
    return GestureDetector(
      onTap: () => setState(() => _selectedIndex = i),
      child: Container(
        margin: const EdgeInsets.symmetric(vertical: 4, horizontal: 8),
        padding: const EdgeInsets.symmetric(horizontal: 6, vertical: 6),
        decoration: BoxDecoration(
          border: Border.all(
            color: isSelected ? AppTheme.primary : AppTheme.border,
            width: isSelected ? 2 : 1,
          ),
          borderRadius: BorderRadius.circular(6),
          color: isSelected
              ? AppTheme.primary.withOpacity(0.04)
              : AppTheme.surface,
        ),
        child: Row(
          children: [
            SizedBox(
              width: 20,
              height: 20,
              child: Checkbox(
                value: _include[i],
                onChanged: _printing
                    ? null
                    : (v) => setState(() => _include[i] = v ?? true),
                materialTapTargetSize: MaterialTapTargetSize.shrinkWrap,
                visualDensity: VisualDensity.compact,
              ),
            ),
            const SizedBox(width: 4),
            SizedBox(
              width: 76,
              height: 38,
              child: _previews[i] != null
                  ? Image.memory(_previews[i]!, fit: BoxFit.contain)
                  : const Center(
                      child: SizedBox(
                          width: 16,
                          height: 16,
                          child: CircularProgressIndicator(strokeWidth: 2))),
            ),
            const SizedBox(width: 6),
            Text(
              '${i + 1}',
              style: TextStyle(
                fontSize: 12,
                color: isSelected
                    ? AppTheme.primary
                    : AppTheme.textSecondary,
                fontWeight:
                    isSelected ? FontWeight.w600 : FontWeight.normal,
              ),
            ),
          ],
        ),
      ),
    );
  }

  // ── 大图 + 份数控件 ──────────────────────────────────────────────────────────

  Widget _buildMainPreview() {
    final preview = _previews[_selectedIndex];
    final label = widget.labels[_selectedIndex];
    return Column(
      children: [
        Expanded(
          child: Center(
            child: Container(
              constraints: const BoxConstraints(maxWidth: 420, maxHeight: 230),
              decoration: BoxDecoration(
                border: Border.all(color: AppTheme.border),
                borderRadius: BorderRadius.circular(4),
                color: Colors.white,
              ),
              child: ClipRRect(
                borderRadius: BorderRadius.circular(3),
                child: preview != null
                    ? Image.memory(preview, fit: BoxFit.contain)
                    : const Center(child: CircularProgressIndicator()),
              ),
            ),
          ),
        ),
        const SizedBox(height: 8),
        // 份数调节
        Row(
          mainAxisAlignment: MainAxisAlignment.center,
          children: [
            const Text('打印份数：', style: TextStyle(fontSize: 13)),
            IconButton(
              icon: const Icon(Icons.remove_circle_outline, size: 20),
              onPressed: (_printing || label.copies <= 1)
                  ? null
                  : () => setState(() => label.copies--),
              padding: EdgeInsets.zero,
              constraints: const BoxConstraints(),
            ),
            const SizedBox(width: 4),
            SizedBox(
              width: 32,
              child: Text(
                '${label.copies}',
                textAlign: TextAlign.center,
                style: const TextStyle(
                    fontSize: 15, fontWeight: FontWeight.w600),
              ),
            ),
            const SizedBox(width: 4),
            IconButton(
              icon: const Icon(Icons.add_circle_outline, size: 20),
              onPressed:
                  _printing ? null : () => setState(() => label.copies++),
              padding: EdgeInsets.zero,
              constraints: const BoxConstraints(),
            ),
          ],
        ),
      ],
    );
  }

  // ── build ────────────────────────────────────────────────────────────────────

  @override
  Widget build(BuildContext context) {
    final isMulti = widget.labels.length > 1;
    final totalCount = _totalPrintCount;

    return Dialog(
      shape: RoundedRectangleBorder(borderRadius: BorderRadius.circular(12)),
      child: Container(
        width: context.dialogWidth(isMulti ? 640 : 440),
        constraints: const BoxConstraints(maxHeight: 560),
        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: [
                  const Text('打印预览',
                      style: TextStyle(
                          fontSize: 16,
                          fontWeight: FontWeight.w600,
                          color: Colors.white)),
                  const Spacer(),
                  IconButton(
                    icon: const Icon(Icons.close, color: Colors.white),
                    onPressed: () => Navigator.of(context).pop(),
                    padding: EdgeInsets.zero,
                    constraints: const BoxConstraints(),
                  ),
                ],
              ),
            ),

            // ── 打印机选择行 ──────────────────────────────────────────────────
            Padding(
              padding: const EdgeInsets.fromLTRB(16, 12, 16, 0),
              child: Row(
                children: [
                  const Text('打印机：',
                      style: TextStyle(fontSize: 13)),
                  const SizedBox(width: 8),
                  Expanded(
                    child: _printers.isEmpty
                        ? Text(
                            _printersChecked ? '无打印机可用' : '正在检测打印机...',
                            style: const TextStyle(
                                fontSize: 13,
                                color: AppTheme.textSecondary))
                        : DropdownButtonHideUnderline(
                            child: Container(
                              padding: const EdgeInsets.symmetric(
                                  horizontal: 10, vertical: 4),
                              decoration: BoxDecoration(
                                border: Border.all(color: AppTheme.border),
                                borderRadius: BorderRadius.circular(6),
                              ),
                              child: DropdownButton<String>(
                                value: _printer,
                                isExpanded: true,
                                isDense: true,
                                style: const TextStyle(
                                    fontSize: 13,
                                    color: AppTheme.textPrimary),
                                items: _printers
                                    .map((p) => DropdownMenuItem(
                                          value: p,
                                          child: Text(p,
                                              overflow:
                                                  TextOverflow.ellipsis),
                                        ))
                                    .toList(),
                                onChanged: _printing
                                    ? null
                                    : (v) async {
                                        if (v == null) return;
                                        setState(() => _printer = v);
                                        final prefs = await SharedPreferences
                                            .getInstance();
                                        await prefs.setString(
                                            _kPrinterKey, v);
                                      },
                              ),
                            ),
                          ),
                  ),
                ],
              ),
            ),
            const SizedBox(height: 8),

            // ── 主体：缩略图条 + 大图 ─────────────────────────────────────────
            Expanded(
              child: Padding(
                padding: const EdgeInsets.symmetric(horizontal: 12),
                child: Row(
                  crossAxisAlignment: CrossAxisAlignment.start,
                  children: [
                    if (isMulti)
                      SizedBox(
                        width: 148,
                        child: ListView.builder(
                          itemCount: widget.labels.length,
                          itemBuilder: (_, i) => _buildThumbnail(i),
                        ),
                      ),
                    if (isMulti) const SizedBox(width: 8),
                    Expanded(child: _buildMainPreview()),
                  ],
                ),
              ),
            ),

            // ── 底栏 ─────────────────────────────────────────────────────────
            Padding(
              padding: const EdgeInsets.fromLTRB(16, 6, 16, 14),
              child: Row(
                children: [
                  if (_status.isNotEmpty)
                    Expanded(
                      child: Text(
                        _status,
                        style: const TextStyle(
                            fontSize: 12, color: AppTheme.textSecondary),
                      ),
                    )
                  else
                    const Spacer(),
                  TextButton(
                    onPressed:
                        _printing ? null : () => Navigator.of(context).pop(),
                    child: const Text('取消'),
                  ),
                  const SizedBox(width: 8),
                  FilledButton(
                    onPressed: (_printing || totalCount == 0 || _printer == null)
                        ? null
                        : _doPrint,
                    child: Text(
                        _printing ? '打印中...' : '打印 $totalCount 张'),
                  ),
                ],
              ),
            ),
          ],
        ),
      ),
    );
  }
}