import 'dart:async';

import 'package:flutter/material.dart';
import 'package:flutter/services.dart';
import 'package:pad_scanner/services/app_config_service.dart';
import 'package:pad_scanner/services/scanner_service.dart';
import 'package:pad_scanner/services/code_parser.dart';
import 'package:pad_scanner/services/api_service.dart';
import 'package:pad_scanner/services/feedback_service.dart';
import 'package:pad_scanner/services/registration_linking.dart';
import 'package:vibration/vibration.dart';
import 'package:pad_scanner/pages/boxing_page.dart';
import 'package:pad_scanner/widgets/status_bar.dart';

class RegistrationPage extends StatefulWidget {
  const RegistrationPage({super.key});

  @override
  State<RegistrationPage> createState() => _RegistrationPageState();
}

class _RegistrationPageState extends State<RegistrationPage> {
  final _scannerService = ScannerService();
  final _apiService = ApiService();
  final _feedbackService = FeedbackService();
  final _focusNode = FocusNode();

  StreamSubscription<ScanResult>? _scanSubscription;
  final _zongpaiNos = <String>[];
  String? _locationCode;
  CodeType? _locationType;
  bool _isLocked = false;
  bool _isSubmitting = false;

  StatusDotColor _statusDot = StatusDotColor.blue;
  String _statusText = '等待扫描总排号或货位号…';
  String? _statusOverrideText;
  StatusDotColor? _statusOverrideDot;

  bool _overviewLoading = false;
  bool _overviewNotFound = false;
  String? _overviewError;
  String? _overviewZongpaiNo;
  PaichaOverviewResult? _overview;
  int _overviewRequestId = 0;

  /// Whether a cross-paicha warning dialog is currently showing.
  bool _crossPaichaPending = false;

  @override
  void initState() {
    super.initState();
    _startScanListening();
    WidgetsBinding.instance.addPostFrameCallback((_) {
      _focusNode.requestFocus();
    });
  }

  @override
  void dispose() {
    _scanSubscription?.cancel();
    _focusNode.dispose();
    _feedbackService.dispose();
    super.dispose();
  }

  void _startScanListening() {
    _scanSubscription ??= _scannerService.scanResults.listen(_onScan);
  }

  Future<void> _stopScanListening() async {
    final subscription = _scanSubscription;
    _scanSubscription = null;
    await subscription?.cancel();
  }

  void _restartScanListening() {
    _scanSubscription?.cancel();
    _scanSubscription = null;
    _startScanListening();
    WidgetsBinding.instance.addPostFrameCallback((_) {
      if (mounted) {
        _focusNode.requestFocus();
      }
    });
  }

  void _onKeyEvent(KeyEvent event) {
    if (event is! KeyDownEvent) return;
    if (_isLockToggleKey(event)) {
      _toggleLock(!_isLocked);
      return;
    }
    if (event.logicalKey == LogicalKeyboardKey.enter) {
      _submit();
    }
  }

  bool _isLockToggleKey(KeyEvent event) {
    final key = event.logicalKey;
    return key == LogicalKeyboardKey.select ||
        key == LogicalKeyboardKey.gameButtonRight1;
  }

  void _onScan(ScanResult result) {
    final parsed = CodeParser.parse(result.barcode);
    switch (parsed.type) {
      case CodeType.zongpaiNo:
        _handleZongpaiScan(parsed.value);
      case CodeType.locationNormal:
      case CodeType.locationTransit:
        if (!_isLocked) {
          _feedbackService.trigger(FeedbackEvent.scanValid);
          setState(() {
            _locationCode = parsed.value;
            _locationType = parsed.type;
            _clearStatusOverride();
          });
        } else {}
      case CodeType.invalid:
        _feedbackService.trigger(FeedbackEvent.scanInvalid);
        _showStatusOverride(
          '无效码：${result.barcode}',
          StatusDotColor.red,
          const Duration(seconds: 2),
        );
    }
  }

  void _handleZongpaiScan(String zongpaiNo) {
    // If cross-paicha dialog is showing, just vibrate and discard
    if (_crossPaichaPending) {
      _triggerDoubleVibration();
      return;
    }

    // In locked mode with existing data, check for cross-paicha scan
    if (_isLocked &&
        _zongpaiNos.isNotEmpty &&
        _overview?.success == true &&
        !_overview!.items.any((item) => item.zongpaiNo == zongpaiNo)) {
      _crossPaichaPending = true;
      _triggerDoubleVibration();
      _showCrossPaichaDialog(zongpaiNo);
      return;
    }

    final shouldRefresh = _overviewZongpaiNo != zongpaiNo;
    _feedbackService.trigger(FeedbackEvent.scanValid);
    setState(() {
      if (_isLocked) {
        if (!_zongpaiNos.contains(zongpaiNo)) {
          _zongpaiNos.add(zongpaiNo);
        }
      } else {
        if (_zongpaiNos.isEmpty) {
          _zongpaiNos.add(zongpaiNo);
        } else {
          _zongpaiNos[0] = zongpaiNo;
        }
      }
      _clearStatusOverride();
    });
    if (shouldRefresh) {
      _loadOverview(zongpaiNo);
    }
  }

  void _triggerDoubleVibration() {
    Vibration.vibrate(pattern: [0, 200, 100, 200]);
  }

  void _removeZongpai(String zongpaiNo) {
    setState(() {
      _zongpaiNos.remove(zongpaiNo);
    });
  }

  void _clearStatusOverride() {
    _statusOverrideText = null;
    _statusOverrideDot = null;
  }

  void _showStatusOverride(String text, StatusDotColor dot, Duration duration) {
    setState(() {
      _statusOverrideText = text;
      _statusOverrideDot = dot;
    });
    Future.delayed(duration, () {
      if (mounted) setState(() => _clearStatusOverride());
    });
  }

  void _updateBaseStatus() {
    if (_isSubmitting) {
      _statusDot = StatusDotColor.orange;
      _statusText = '正在提交…';
      return;
    }
    if (_isLocked && _locationCode != null && _zongpaiNos.isEmpty) {
      _statusDot = StatusDotColor.blue;
      _statusText = '货位已锁定，请扫描下一张执行卡';
      return;
    }
    final hasZongpai = _zongpaiNos.isNotEmpty;
    final hasLocation = _locationCode != null;
    if (hasZongpai && hasLocation) {
      _statusDot = StatusDotColor.blue;
      _statusText = '请确认信息并提交';
    } else if (hasZongpai) {
      _statusDot = StatusDotColor.blue;
      _statusText = '请扫描目标货位号';
    } else if (hasLocation) {
      _statusDot = StatusDotColor.blue;
      _statusText = '请扫描执行卡';
    } else {
      _statusDot = StatusDotColor.blue;
      _statusText = '等待扫描总排号或货位号…';
    }
  }

  bool get _canSubmit =>
      _zongpaiNos.isNotEmpty && _locationCode != null && !_isSubmitting;

  bool get _isTransitTarget => isTransitTarget(_locationType, _locationCode);

  /// Find the first scanned item that is already on shelf (for batch submit blocking).
  PaichaOverviewItem? _findOnShelfInScanned() {
    if (_overview?.success != true) return null;
    final scannedSet = _zongpaiNos.toSet();
    for (final item in _overview!.items) {
      if (scannedSet.contains(item.zongpaiNo) && item.status == 'on_shelf') {
        return item;
      }
    }
    return null;
  }

  Future<String?> _baseUrl() async {
    final configService = AppConfigService();
    final baseUrl = await configService.getString('api_url') ?? '';
    if (baseUrl.isEmpty) {
      return null;
    }
    return baseUrl;
  }

  Future<void> _loadOverview(String zongpaiNo, {bool force = false}) async {
    if (!force && _overviewZongpaiNo == zongpaiNo && _overview != null) {
      return;
    }
    final requestId = ++_overviewRequestId;
    setState(() {
      _overviewZongpaiNo = zongpaiNo;
      _overviewLoading = true;
      _overviewNotFound = false;
      _overviewError = null;
    });

    final baseUrl = await _baseUrl();
    if (!mounted || requestId != _overviewRequestId) return;
    if (baseUrl == null) {
      setState(() {
        _overviewLoading = false;
        _overviewError = '未配置 API 地址，请前往设置';
      });
      return;
    }

    final result = await _apiService.fetchPaichaOverview(
      baseUrl: baseUrl,
      zongpaiNo: zongpaiNo,
    );
    if (!mounted || requestId != _overviewRequestId) return;

    setState(() {
      _overviewLoading = false;
      if (result.success) {
        _overview = result;
        _overviewNotFound = false;
        _overviewError = null;
      } else if (result.notFound) {
        _overview = null;
        _overviewNotFound = true;
        _overviewError = null;
      } else {
        _overviewError = result.errorMessage ?? '加载失败，点击重试';
      }
    });
  }

  Future<void> _refreshCurrentOverview() async {
    final zongpaiNo = _overviewZongpaiNo;
    if (zongpaiNo == null) return;
    await _loadOverview(zongpaiNo, force: true);
  }

  Future<void> _submit() async {
    if (!_canSubmit) return;

    final baseUrl = await _baseUrl();
    if (baseUrl == null) {
      _feedbackService.trigger(FeedbackEvent.submitFailure);
      _showStatusOverride(
        '未配置 API 地址，请前往设置',
        StatusDotColor.red,
        const Duration(seconds: 2),
      );
      return;
    }

    setState(() => _isSubmitting = true);

    if (_isLocked && _zongpaiNos.length > 1) {
      if (_isTransitTarget && !await _ensureBatchSamePaicha(baseUrl)) {
        if (!mounted) return;
        setState(() => _isSubmitting = false);
        _feedbackService.trigger(FeedbackEvent.submitFailure);
        _showStatusOverride(
          batchPaichaMismatchMessage,
          StatusDotColor.red,
          const Duration(seconds: 2),
        );
        return;
      }
      // Pre-check: block entire batch if any item is already on shelf (normal shelf)
      if (!_isTransitTarget) {
        final onShelfItem = _findOnShelfInScanned();
        if (onShelfItem != null) {
          setState(() => _isSubmitting = false);
          _feedbackService.trigger(FeedbackEvent.duplicateError);
          _showDuplicateDialog(
            onShelfItem.zongpaiNo,
            {'location_code': onShelfItem.locationCode ?? '未知'},
          );
          return;
        }
      }
      await _submitBatch(baseUrl);
    } else {
      await _submitOne(baseUrl, _zongpaiNos.first);
    }
  }

  Future<bool> _ensureBatchSamePaicha(String baseUrl) async {
    final paichaByCode = <String, String>{};
    final cachedOverview = _overview;
    if (cachedOverview?.success == true && cachedOverview!.paichaNo != null) {
      for (final item in cachedOverview.items) {
        paichaByCode[item.zongpaiNo] = cachedOverview.paichaNo!;
      }
    }

    for (final zongpaiNo in _zongpaiNos) {
      if (paichaByCode.containsKey(zongpaiNo)) continue;
      final result = await _apiService.fetchPaichaOverview(
        baseUrl: baseUrl,
        zongpaiNo: zongpaiNo,
      );
      if (!result.success || result.paichaNo == null) {
        return false;
      }
      for (final item in result.items) {
        paichaByCode[item.zongpaiNo] = result.paichaNo!;
      }
    }

    return allSamePaicha(_zongpaiNos.map((code) => paichaByCode[code]));
  }

  Future<void> _submitOne(String baseUrl, String zongpaiNo) async {
    final result = await _apiService.registerLocation(
      baseUrl: baseUrl,
      zongpaiNo: zongpaiNo,
      locationCode: _locationCode!,
    );

    if (!mounted) return;

    setState(() => _isSubmitting = false);

    if (result.success) {
      _feedbackService.trigger(FeedbackEvent.submitSuccess);
      if (_isTransitTarget) {
        setState(() => _isSubmitting = false);
        await _navigateToBoxing(
          mode: BoxingMode.singleCode,
          codes: [zongpaiNo],
          codesToClear: [zongpaiNo],
          clearLocation: !_isLocked,
        );
        return;
      }
      setState(() {
        _zongpaiNos.remove(zongpaiNo);
        if (!_isLocked) {
          _locationCode = null;
          _locationType = null;
        }
      });
      final msg = result.isOffShelfSuccess
          ? '下架成功'
          : (_isLocked ? '货位已锁定，请扫描下一张执行卡' : '上架成功');
      _showStatusOverride(
        msg,
        StatusDotColor.green,
        const Duration(milliseconds: 1500),
      );
      await _refreshCurrentOverview();
    } else if (result.isDuplicate) {
      _feedbackService.trigger(FeedbackEvent.duplicateError);
      _showDuplicateDialog(zongpaiNo, result.duplicateInfo);
    } else if (result.isAlreadyOffShelf) {
      _feedbackService.trigger(FeedbackEvent.submitFailure);
      _showStatusOverride(
        result.errorMessage ?? '该总排号已下架至转运区域，不可重新上架',
        StatusDotColor.red,
        const Duration(seconds: 2),
      );
    } else {
      final isNetwork = result.errorMessage == '网络异常，请检查网络连接';
      _feedbackService.trigger(
        isNetwork ? FeedbackEvent.networkError : FeedbackEvent.submitFailure,
      );
      _showStatusOverride(
        result.errorMessage ?? '提交失败',
        isNetwork ? StatusDotColor.yellow : StatusDotColor.red,
        const Duration(seconds: 2),
      );
    }
  }

  Future<void> _submitBatch(String baseUrl) async {
    int successCount = 0;
    int offShelfCount = 0;
    final failed = <String>[];
    final toRemove = <String>[];
    final transitCodes = <String>[];

    for (final zongpaiNo in List.of(_zongpaiNos)) {
      final result = await _apiService.registerLocation(
        baseUrl: baseUrl,
        zongpaiNo: zongpaiNo,
        locationCode: _locationCode!,
      );
      if (result.success) {
        successCount++;
        if (result.isOffShelfSuccess) {
          offShelfCount++;
        }
        toRemove.add(zongpaiNo);
        if (_isTransitTarget) {
          transitCodes.add(zongpaiNo);
        }
      } else {
        failed.add(zongpaiNo);
        if (result.isDuplicate) {
          if (_isTransitTarget && transitCodes.isNotEmpty) {
            setState(() {
              _zongpaiNos.removeWhere((item) => toRemove.contains(item));
              _isSubmitting = false;
            });
            await _navigateToBoxing(
              mode: BoxingMode.multiCode,
              codes: transitCodes,
              codesToClear: toRemove,
              clearLocation: false,
              returnMessage: '成功 $successCount 条，失败 ${failed.length} 条',
            );
            return;
          }
          setState(() {
            _zongpaiNos.removeWhere((item) => toRemove.contains(item));
            _isSubmitting = false;
          });
          _feedbackService.trigger(FeedbackEvent.duplicateError);
          _showDuplicateDialog(zongpaiNo, result.duplicateInfo);
          return;
        }
        if (result.isAlreadyOffShelf) {
          if (_isTransitTarget && transitCodes.isNotEmpty) {
            setState(() {
              _zongpaiNos.removeWhere((item) => toRemove.contains(item));
              _isSubmitting = false;
            });
            await _navigateToBoxing(
              mode: BoxingMode.multiCode,
              codes: transitCodes,
              codesToClear: toRemove,
              clearLocation: false,
              returnMessage: '成功 $successCount 条，失败 ${failed.length} 条',
            );
            return;
          }
          setState(() {
            _zongpaiNos.removeWhere((item) => toRemove.contains(item));
            _isSubmitting = false;
          });
          _feedbackService.trigger(FeedbackEvent.submitFailure);
          _showStatusOverride(
            result.errorMessage ?? '该总排号已下架至转运区域，不可重新上架',
            StatusDotColor.red,
            const Duration(seconds: 2),
          );
          return;
        }
      }
    }

    if (!mounted) return;

    setState(() {
      _zongpaiNos.removeWhere((item) => toRemove.contains(item));
      _isSubmitting = false;
    });

    if (_isTransitTarget && transitCodes.isNotEmpty) {
      await _navigateToBoxing(
        mode: BoxingMode.multiCode,
        codes: transitCodes,
        codesToClear: toRemove,
        clearLocation: failed.isEmpty,
        returnMessage: failed.isEmpty
            ? null
            : '成功 $successCount 条，失败 ${failed.length} 条',
      );
      return;
    }

    if (failed.isEmpty) {
      _feedbackService.trigger(FeedbackEvent.submitSuccess);
      final msg = offShelfCount == successCount
          ? '批量下架成功（$successCount 条）'
          : '批量上架成功（$successCount 条）';
      _showStatusOverride(
        msg,
        StatusDotColor.green,
        const Duration(milliseconds: 1500),
      );
      await _refreshCurrentOverview();
    } else {
      _feedbackService.trigger(FeedbackEvent.submitFailure);
      _showStatusOverride(
        '成功 $successCount 条，失败 ${failed.length} 条',
        StatusDotColor.red,
        const Duration(seconds: 2),
      );
    }
  }

  Future<void> _navigateToBoxing({
    required BoxingMode mode,
    required List<String> codes,
    required List<String> codesToClear,
    required bool clearLocation,
    String? returnMessage,
  }) async {
    await _refreshCurrentOverview();
    if (!mounted) return;
    final navigator = Navigator.of(context);
    await _stopScanListening();
    await navigator.push(
      MaterialPageRoute(
        builder: (_) => BoxingPage(
          arguments: BoxingPageArguments(
            initialMode: mode,
            autoScanCodes: codes,
          ),
        ),
      ),
    );
    if (!mounted) return;
    await Future<void>.delayed(const Duration(milliseconds: 120));
    if (!mounted) return;
    _restartScanListening();
    setState(() {
      _zongpaiNos.removeWhere((item) => codesToClear.contains(item));
      if (clearLocation) {
        _locationCode = null;
        _locationType = null;
      }
    });
    await _refreshCurrentOverview();
    if (!mounted) return;
    if (returnMessage != null) {
      _showStatusOverride(
        returnMessage,
        StatusDotColor.red,
        const Duration(seconds: 2),
      );
    }
  }

  void _showDuplicateDialog(String zongpaiNo, Map<String, dynamic>? info) {
    showDialog(
      context: context,
      barrierDismissible: false,
      builder: (ctx) => AlertDialog(
        backgroundColor: Colors.red.shade50,
        title: const Row(
          children: [
            Icon(Icons.warning, color: Colors.red),
            SizedBox(width: 8),
            Text('重复上架', style: TextStyle(color: Colors.red)),
          ],
        ),
        content: Column(
          mainAxisSize: MainAxisSize.min,
          crossAxisAlignment: CrossAxisAlignment.start,
          children: [
            Text('总排号：$zongpaiNo'),
            const SizedBox(height: 4),
            Text('已登记货位：${info?["location_code"] ?? "未知"}'),
            const SizedBox(height: 4),
            Text('登记时间：${info?["registered_at"] ?? "未知"}'),
            const SizedBox(height: 12),
            const Text(
              '请核查实物，确认是否操作错误。',
              style: TextStyle(fontWeight: FontWeight.bold),
            ),
          ],
        ),
        actions: [
          TextButton(
            onPressed: () {
              _feedbackService.stopAlert();
              Navigator.pop(ctx);
            },
            child: const Text('关闭'),
          ),
        ],
      ),
    );
  }

  void _showCrossPaichaDialog(String newZongpaiNo) {
    final currentPaicha = _overview?.paichaNo ?? '--';
    final dialogFocus = FocusNode();
    var dismissed = false;
    var selectedIndex = 0; // 0 = "否" (default), 1 = "是"

    void dismissAsNo() {
      if (dismissed) return;
      dismissed = true;
      Navigator.of(context).pop();
      setState(() {
        _crossPaichaPending = false;
      });
    }

    void confirmSwitch() {
      if (dismissed) return;
      dismissed = true;
      Navigator.of(context).pop();
      _switchToNewPaicha(newZongpaiNo);
    }

    showDialog(
      context: context,
      barrierDismissible: false,
      builder: (ctx) => StatefulBuilder(
        builder: (ctx, setDialogState) {
          return KeyboardListener(
            focusNode: dialogFocus,
            onKeyEvent: (event) {
              if (event is! KeyDownEvent) return;
              if (event.logicalKey == LogicalKeyboardKey.arrowUp) {
                setDialogState(() => selectedIndex = 0);
              } else if (event.logicalKey == LogicalKeyboardKey.arrowDown) {
                setDialogState(() => selectedIndex = 1);
              } else if (event.logicalKey == LogicalKeyboardKey.enter) {
                selectedIndex == 0 ? dismissAsNo() : confirmSwitch();
              } else if (event.logicalKey == LogicalKeyboardKey.escape) {
                dismissAsNo();
              }
            },
            child: PopScope(
              canPop: false,
              onPopInvokedWithResult: (didPop, _) {
                if (!didPop) dismissAsNo();
              },
              child: AlertDialog(
                backgroundColor: Colors.orange.shade50,
                title: Row(
                  children: [
                    Icon(Icons.warning_amber, color: Colors.orange.shade800),
                    const SizedBox(width: 8),
                    Text(
                      '跨排产号扫描',
                      style: TextStyle(color: Colors.orange.shade900),
                    ),
                  ],
                ),
                content: Column(
                  mainAxisSize: MainAxisSize.min,
                  crossAxisAlignment: CrossAxisAlignment.stretch,
                  children: [
                    Text(
                      '总排号 $newZongpaiNo 不属于当前排产号（$currentPaicha），'
                      '是否切换到新的排产号？\n\n'
                      '选择「是」将放弃当前已扫描的所有数据。',
                      style: const TextStyle(fontSize: 14),
                    ),
                    const SizedBox(height: 16),
                    _dialogOptionBtn(
                      label: '否',
                      selected: selectedIndex == 0,
                      onTap: dismissAsNo,
                    ),
                    const SizedBox(height: 8),
                    _dialogOptionBtn(
                      label: '是，切换排产号',
                      selected: selectedIndex == 1,
                      onTap: confirmSwitch,
                    ),
                  ],
                ),
              ),
            ),
          );
        },
      ),
    );

    WidgetsBinding.instance.addPostFrameCallback((_) {
      dialogFocus.requestFocus();
    });
  }

  Widget _dialogOptionBtn({
    required String label,
    required bool selected,
    required VoidCallback onTap,
  }) {
    return SizedBox(
      width: double.infinity,
      height: 40,
      child: ElevatedButton(
        onPressed: onTap,
        style: ElevatedButton.styleFrom(
          backgroundColor:
              selected ? Colors.blue.shade700 : Colors.grey.shade200,
          foregroundColor: selected ? Colors.white : Colors.black87,
          shape: RoundedRectangleBorder(borderRadius: BorderRadius.circular(8)),
        ),
        child: Text(
          label,
          style: TextStyle(
            fontWeight: selected ? FontWeight.w800 : FontWeight.w600,
          ),
        ),
      ),
    );
  }

  void _switchToNewPaicha(String newZongpaiNo) {
    _feedbackService.trigger(FeedbackEvent.paichanSwitch);
    setState(() {
      _crossPaichaPending = false;
      _zongpaiNos.clear();
      _zongpaiNos.add(newZongpaiNo);
      _overview = null;
      _overviewNotFound = false;
      _overviewError = null;
      _clearStatusOverride();
    });
    _loadOverview(newZongpaiNo);
  }

  void _toggleLock(bool value) {
    if (value && _locationCode == null) {
      _feedbackService.trigger(FeedbackEvent.submitFailure);
      _showStatusOverride(
        '请先扫描货位号',
        StatusDotColor.red,
        const Duration(seconds: 2),
      );
      return;
    }
    setState(() {
      _isLocked = value;
      if (!value && _zongpaiNos.length > 1) {
        _zongpaiNos.removeRange(0, _zongpaiNos.length - 1);
      }
    });
  }

  String _locationLabel(CodeType? type) {
    if (type == CodeType.locationTransit) return '转运区域';
    return '普通货架';
  }

  Color _locationLabelColor(CodeType? type) {
    if (type == CodeType.locationTransit) return Colors.orange;
    return Colors.blue;
  }

  @override
  Widget build(BuildContext context) {
    final colorScheme = Theme.of(context).colorScheme;
    _updateBaseStatus();
    final effectiveDot = _statusOverrideDot ?? _statusDot;
    final effectiveText = _statusOverrideText ?? _statusText;

    return KeyboardListener(
      focusNode: _focusNode,
      onKeyEvent: _onKeyEvent,
      child: Scaffold(
        appBar: AppBar(
          title: Row(
            children: [
              const Text('上架登记'),
              const SizedBox(width: 12),
              Expanded(child: _buildLockHeader()),
            ],
          ),
          titleSpacing: 12,
        ),
        body: Column(
          children: [
            _buildPaichaHeader(),
            if (_overview?.success == true) _buildTableHead(),
            Expanded(child: _buildListBody()),
            _buildBottomBar(colorScheme),
            StatusBar(dotColor: effectiveDot, text: effectiveText),
          ],
        ),
      ),
    );
  }

  Widget _buildLockHeader() {
    final backgroundColor =
        _isLocked ? Colors.orange.shade700 : Colors.blue.shade700;
    final label = _isLocked ? '货位锁定' : '未锁定';

    return Material(
      borderRadius: BorderRadius.circular(8),
      color: backgroundColor,
      child: InkWell(
        borderRadius: BorderRadius.circular(8),
        onTap: () => _toggleLock(!_isLocked),
        child: Container(
          width: double.infinity,
          height: 36,
          padding: const EdgeInsets.symmetric(horizontal: 10),
          child: Row(
            mainAxisAlignment: MainAxisAlignment.center,
            children: [
              const Icon(Icons.swap_horiz, color: Colors.white, size: 18),
              const SizedBox(width: 6),
              Flexible(
                child: FittedBox(
                  fit: BoxFit.scaleDown,
                  child: Text(
                    label,
                    maxLines: 1,
                    style: const TextStyle(
                      color: Colors.white,
                      fontSize: 18,
                      fontWeight: FontWeight.w800,
                    ),
                  ),
                ),
              ),
              const SizedBox(width: 8),
              Text(
                'P2',
                style: TextStyle(
                  color: Colors.white.withValues(alpha: 0.88),
                  fontSize: 12,
                  fontWeight: FontWeight.w700,
                ),
              ),
            ],
          ),
        ),
      ),
    );
  }

  Widget _buildLocationChip() {
    final color = _locationLabelColor(_locationType);
    return Container(
      padding: const EdgeInsets.symmetric(horizontal: 6, vertical: 2),
      decoration: BoxDecoration(
        color: color.withValues(alpha: 0.15),
        borderRadius: BorderRadius.circular(4),
      ),
      child: Text(
        _locationLabel(_locationType),
        style: TextStyle(
          fontSize: 11,
          color: color,
          fontWeight: FontWeight.bold,
        ),
      ),
    );
  }

  // === Paicha Header ===

  Widget _buildPaichaHeader() {
    final overview = _overview;
    final hasData = overview?.success == true;
    final hasLoc = _locationCode != null;

    int totalCount = 0, shelvedCount = 0, transferredCount = 0;
    if (hasData && overview != null) {
      totalCount = overview.totalCount;
      for (final item in overview.items) {
        switch (item.status) {
          case 'on_shelf':
            shelvedCount++;
          case 'transferred':
            transferredCount++;
        }
      }
    }

    return Container(
      padding: const EdgeInsets.fromLTRB(12, 8, 12, 6),
      decoration: BoxDecoration(
        color: Colors.grey.shade50,
        border: Border(bottom: BorderSide(color: Colors.grey.shade300)),
      ),
      child: Row(
        crossAxisAlignment: CrossAxisAlignment.center,
        children: [
          Text(
            hasData ? (overview!.paichaNo ?? '--') : '--',
            style: TextStyle(
              fontSize: 24,
              fontWeight: FontWeight.w800,
              color: hasData ? Colors.black87 : Colors.grey.shade400,
            ),
          ),
          const SizedBox(width: 12),
          Expanded(
            child: Column(
              crossAxisAlignment: CrossAxisAlignment.end,
              children: [
                if (hasLoc)
                  Row(
                    mainAxisSize: MainAxisSize.min,
                    children: [
                      Text(
                        _locationCode!,
                        style: const TextStyle(
                          fontSize: 13,
                          fontWeight: FontWeight.w600,
                          color: Colors.black54,
                        ),
                      ),
                      const SizedBox(width: 5),
                      _buildLocationChip(),
                    ],
                  ),
                Row(
                  mainAxisSize: MainAxisSize.min,
                  children: [
                    _buildStatTag(
                      '共 $totalCount',
                      const Color(0xFFE3F2FD),
                      const Color(0xFF1565C0),
                      hasData,
                    ),
                    _buildStatTag(
                      '上架 $shelvedCount',
                      const Color(0xFFE8F5E9),
                      const Color(0xFF2E7D32),
                      hasData,
                    ),
                    _buildStatTag(
                      '转运 $transferredCount',
                      const Color(0xFFFFF3E0),
                      const Color(0xFFE65100),
                      hasData,
                    ),
                  ],
                ),
              ],
            ),
          ),
        ],
      ),
    );
  }

  Widget _buildStatTag(String text, Color bg, Color fg, bool hasData) {
    return Container(
      padding: const EdgeInsets.symmetric(horizontal: 7, vertical: 1),
      margin: const EdgeInsets.only(left: 5),
      decoration: BoxDecoration(
        color: hasData ? bg : const Color(0xFFF5F5F5),
        borderRadius: BorderRadius.circular(10),
      ),
      child: Text(
        text,
        style: TextStyle(
          fontSize: 10,
          fontWeight: FontWeight.w700,
          color: hasData ? fg : Colors.grey.shade400,
        ),
      ),
    );
  }

  // === Table Head ===

  Widget _buildTableHead() {
    return Container(
      height: 28,
      padding: const EdgeInsets.symmetric(horizontal: 12),
      decoration: BoxDecoration(
        color: Colors.grey.shade200,
        border: Border(bottom: BorderSide(color: Colors.grey.shade400)),
      ),
      child: const Row(
        children: [
          Expanded(flex: 22, child: Text('总排号', style: _headerStyle)),
          Expanded(flex: 18, child: Text('工令号', style: _headerStyle)),
          Expanded(
            flex: 12,
            child: Text(
              '数量',
              textAlign: TextAlign.center,
              style: _headerStyle,
            ),
          ),
          Expanded(
            flex: 28,
            child: Text(
              '货位号',
              textAlign: TextAlign.right,
              style: _headerStyle,
            ),
          ),
        ],
      ),
    );
  }

  // === List Body ===

  Widget _buildListBody() {
    if (_overviewZongpaiNo == null) {
      return _buildListMessage('扫描总排号后自动显示排产号上架情况');
    }
    if (_overviewLoading && _overview == null) {
      return _buildListMessage('正在加载排产号上架情况…');
    }
    if (_overviewNotFound) {
      return _buildListMessage('暂无排产信息');
    }
    if (_overviewError != null && _overview == null) {
      return _buildListError(_overviewError!);
    }
    final overview = _overview;
    if (overview == null || !overview.success) {
      return _buildListMessage('扫描总排号后自动显示排产号上架情况');
    }

    final scannedSet = _zongpaiNos.toSet();
    final scanned = <PaichaOverviewItem>[];
    final unscanned = <PaichaOverviewItem>[];
    for (final item in overview.items) {
      if (scannedSet.contains(item.zongpaiNo)) {
        scanned.add(item);
      } else {
        unscanned.add(item);
      }
    }

    final hasDivider = scanned.isNotEmpty && unscanned.isNotEmpty;

    return Column(
      children: [
        if (_overviewError != null)
          Container(
            padding: const EdgeInsets.symmetric(horizontal: 12, vertical: 4),
            color: Colors.red.shade50,
            child: Row(
              children: [
                Expanded(
                  child: Text(
                    _overviewError!,
                    style: const TextStyle(fontSize: 12, color: Colors.red),
                  ),
                ),
                TextButton(
                  onPressed: _overviewZongpaiNo == null
                      ? null
                      : () => _loadOverview(_overviewZongpaiNo!, force: true),
                  child: const Text('重试'),
                ),
              ],
            ),
          ),
        Expanded(
          child: ListView.builder(
            itemCount: scanned.length +
                (hasDivider ? 1 : 0) +
                unscanned.length,
            itemBuilder: (context, index) {
              if (index < scanned.length) {
                return _buildListRow(scanned[index], isScanned: true);
              }
              if (index == scanned.length && hasDivider) {
                return _buildSectionDivider(unscanned.length);
              }
              final unscannedIdx =
                  index - scanned.length - (hasDivider ? 1 : 0);
              return _buildListRow(unscanned[unscannedIdx], isScanned: false);
            },
          ),
        ),
      ],
    );
  }

  Widget _buildSectionDivider(int count) {
    return Container(
      height: 24,
      padding: const EdgeInsets.symmetric(horizontal: 12),
      decoration: BoxDecoration(
        border: Border(bottom: BorderSide(color: Colors.grey.shade200)),
      ),
      child: Row(
        children: [
          const Expanded(child: Divider(height: 0)),
          Padding(
            padding: const EdgeInsets.symmetric(horizontal: 8),
            child: Text(
              '以下 $count 项未操作',
              style: TextStyle(
                fontSize: 10,
                fontWeight: FontWeight.w600,
                color: Colors.grey.shade500,
              ),
            ),
          ),
          const Expanded(child: Divider(height: 0)),
        ],
      ),
    );
  }

  Widget _buildListRow(PaichaOverviewItem item, {required bool isScanned}) {
    final rowStyle = TextStyle(
      fontSize: 12,
      fontWeight: isScanned ? FontWeight.w700 : FontWeight.w500,
      color: Colors.black87,
    );

    final Color barColor;
    final Color bgColor;
    if (isScanned) {
      final alreadyOnShelf = item.status == 'on_shelf' && !_isTransitTarget;
      if (alreadyOnShelf) {
        barColor = Colors.red;
        bgColor = Colors.red.shade50;
      } else {
        barColor = const Color(0xFF43A047);
        bgColor = const Color(0xFFF1F8E9);
      }
    } else {
      barColor = _barColor(item.status);
      bgColor = _rowBgColor(item.status);
    }

    return Container(
      constraints: const BoxConstraints(minHeight: 36),
      padding: const EdgeInsets.symmetric(horizontal: 12, vertical: 6),
      decoration: BoxDecoration(
        color: bgColor,
        border: Border(
          left: BorderSide(color: barColor, width: 3),
          bottom: BorderSide(color: Colors.grey.shade200),
        ),
      ),
      child: Row(
        children: [
          Expanded(
            flex: 22,
            child: Text(
              item.zongpaiNo,
              overflow: TextOverflow.ellipsis,
              style: rowStyle,
            ),
          ),
          Expanded(
            flex: 18,
            child: Text(
              item.workOrderNo ?? '--',
              overflow: TextOverflow.ellipsis,
              style: rowStyle,
            ),
          ),
          Expanded(
            flex: 12,
            child: Text(
              item.quantity.toString(),
              textAlign: TextAlign.center,
              overflow: TextOverflow.ellipsis,
              style: rowStyle,
            ),
          ),
          Expanded(
            flex: 28,
            child: Text(
              item.locationCode ?? '\u2014',
              textAlign: TextAlign.right,
              overflow: TextOverflow.ellipsis,
              style: rowStyle,
            ),
          ),
          if (isScanned && _isLocked) ...[
            const SizedBox(width: 6),
            SizedBox(
              width: 28,
              height: 28,
              child: IconButton(
                icon: Icon(Icons.delete_outline, size: 16),
                color: Colors.red,
                onPressed: () => _removeZongpai(item.zongpaiNo),
                padding: EdgeInsets.zero,
                constraints: const BoxConstraints(minWidth: 28, minHeight: 28),
              ),
            ),
          ],
        ],
      ),
    );
  }

  Color _barColor(String status) {
    switch (status) {
      case 'on_shelf':
        return const Color(0xFF2196F3);
      case 'transferred':
        return const Color(0xFFFF9800);
      default:
        return Colors.grey.shade400;
    }
  }

  Color _rowBgColor(String status) {
    switch (status) {
      case 'on_shelf':
        return const Color(0xFFE3F2FD);
      case 'transferred':
        return const Color(0xFFFFF3E0);
      default:
        return const Color(0xFFF5F5F5);
    }
  }

  Widget _buildListMessage(String text) {
    return Center(
      child: Text(
        text,
        textAlign: TextAlign.center,
        style: TextStyle(fontSize: 13, color: Colors.grey.shade600),
      ),
    );
  }

  Widget _buildListError(String text) {
    return Center(
      child: Column(
        mainAxisSize: MainAxisSize.min,
        children: [
          Text(
            text,
            textAlign: TextAlign.center,
            style: const TextStyle(fontSize: 13, color: Colors.red),
          ),
          const SizedBox(height: 6),
          TextButton(
            onPressed: _overviewZongpaiNo == null
                ? null
                : () => _loadOverview(_overviewZongpaiNo!, force: true),
            child: const Text('重试'),
          ),
        ],
      ),
    );
  }

  // === Bottom Bar ===

  Widget _buildBottomBar(ColorScheme colorScheme) {
    return Container(
      decoration: BoxDecoration(
        color: Colors.white,
        border: Border(top: BorderSide(color: Colors.grey.shade300)),
      ),
      padding: const EdgeInsets.symmetric(horizontal: 12, vertical: 8),
      child: SizedBox(
        width: double.infinity,
        height: 34,
        child: ElevatedButton(
          onPressed: _canSubmit ? _submit : null,
          style: ElevatedButton.styleFrom(
            backgroundColor: registrationSubmitColor(
              canSubmit: _canSubmit,
              isTransitTarget: _isTransitTarget,
              primaryColor: colorScheme.primary,
            ),
            foregroundColor:
                _canSubmit ? Colors.white : Colors.grey.shade600,
            shape: RoundedRectangleBorder(
              borderRadius: BorderRadius.circular(6),
            ),
          ),
          child: _isSubmitting
              ? const SizedBox(
                  width: 18,
                  height: 18,
                  child: CircularProgressIndicator(
                    strokeWidth: 2,
                    color: Colors.white,
                  ),
                )
              : Text(
                  registrationSubmitLabel(
                    isTransitTarget: _isTransitTarget,
                    isLocked: _isLocked,
                    zongpaiCount: _zongpaiNos.length,
                  ),
                  style: const TextStyle(
                    fontSize: 14,
                    fontWeight: FontWeight.w700,
                  ),
                ),
        ),
      ),
    );
  }
}

const _headerStyle = TextStyle(fontSize: 10, fontWeight: FontWeight.w700);