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/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();

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

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

  @override
  void initState() {
    super.initState();
    _scannerService.scanResults.listen(_onScan);
    WidgetsBinding.instance.addPostFrameCallback((_) {
      _focusNode.requestFocus();
    });
  }

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

  void _onKeyEvent(KeyEvent event) {
    if (event is KeyDownEvent &&
        event.logicalKey == LogicalKeyboardKey.enter) {
      _submit();
    }
  }

  void _onScan(ScanResult result) {
    final parsed = CodeParser.parse(result.barcode);
    switch (parsed.type) {
      case CodeType.zongpaiNo:
        _feedbackService.trigger(FeedbackEvent.scanValid);
        setState(() {
          if (_isLocked) {
            final idx = _zongpaiNos.indexOf(parsed.value);
            if (idx >= 0) {
              _zongpaiNos[idx] = parsed.value;
            } else {
              _zongpaiNos.add(parsed.value);
            }
          } else {
            if (_zongpaiNos.isNotEmpty) {
              _zongpaiNos[0] = parsed.value;
            } else {
              _zongpaiNos.add(parsed.value);
            }
          }
          _clearStatusOverride();
        });
      case CodeType.locationNormal:
      case CodeType.locationTransit:
        if (!_isLocked) {
          _feedbackService.trigger(FeedbackEvent.scanValid);
          setState(() {
            _locationCode = parsed.value;
            _locationType = parsed.type;
            _clearStatusOverride();
          });
        }
      case CodeType.invalid:
        _feedbackService.trigger(FeedbackEvent.scanInvalid);
        _showStatusOverride(
          '无效码：${result.barcode}',
          StatusDotColor.red,
          const Duration(seconds: 2),
        );
    }
  }

  void _removeZongpai(int index) {
    setState(() {
      _zongpaiNos.removeAt(index);
    });
  }

  // --- Status bar management ---

  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 hasZ = _zongpaiNos.isNotEmpty;
    final hasL = _locationCode != null;
    if (hasZ && hasL) {
      _statusDot = StatusDotColor.blue;
      _statusText = '请确认信息并提交';
    } else if (hasZ && !hasL) {
      _statusDot = StatusDotColor.blue;
      _statusText = '请扫描目标货位号';
    } else if (!hasZ && hasL) {
      _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;

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

    final configService = AppConfigService();
    final baseUrl = await configService.getString('api_url') ?? '';
    if (baseUrl.isEmpty) {
      _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) {
      await _submitBatch(baseUrl);
    } else {
      await _submitOne(baseUrl, _zongpaiNos.first);
    }
  }

  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);
      setState(() {
        _zongpaiNos.remove(zongpaiNo);
        if (!_isLocked) {
          _locationCode = null;
          _locationType = null;
        }
      });
      final msg = _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));
    } else if (result.isDuplicate) {
      _feedbackService.trigger(FeedbackEvent.duplicateError);
      _showDuplicateDialog(zongpaiNo, result.duplicateInfo);
    } 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;
    final failed = <String>[];
    final toRemove = <String>[];

    for (final zp in List.of(_zongpaiNos)) {
      final result = await _apiService.registerLocation(
        baseUrl: baseUrl,
        zongpaiNo: zp,
        locationCode: _locationCode!,
      );
      if (result.success) {
        successCount++;
        toRemove.add(zp);
      } else {
        failed.add(zp);
        if (result.isDuplicate) {
          setState(() {
            _zongpaiNos.removeWhere((e) => toRemove.contains(e));
            _isSubmitting = false;
          });
          _feedbackService.trigger(FeedbackEvent.duplicateError);
          _showDuplicateDialog(zp, result.duplicateInfo);
          return;
        }
      }
    }

    if (!mounted) return;

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

    if (failed.isEmpty) {
      _feedbackService.trigger(FeedbackEvent.submitSuccess);
      _showStatusOverride(
        '批量上架成功（$successCount 条）',
        StatusDotColor.green,
        const Duration(milliseconds: 1500),
      );
    } else {
      _feedbackService.trigger(FeedbackEvent.submitFailure);
      _showStatusOverride(
        '成功 $successCount 条，失败 ${failed.length} 条',
        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 _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) {
        if (_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;

    // Compute effective status
    _updateBaseStatus();
    final effectiveDot = _statusOverrideDot ?? _statusDot;
    final effectiveText = _statusOverrideText ?? _statusText;

    return KeyboardListener(
      focusNode: _focusNode,
      onKeyEvent: _onKeyEvent,
      child: Scaffold(
        appBar: AppBar(
          title: const Text('上架登记'),
          actions: [
            Padding(
              padding: const EdgeInsets.only(right: 4),
              child: Row(
                children: [
                  const Text('锁定货位', style: TextStyle(fontSize: 13)),
                  Switch(value: _isLocked, onChanged: _toggleLock),
                ],
              ),
            ),
          ],
        ),
        body: Column(
          children: [
            // Main form area (no top banner)
            Expanded(
              child: Padding(
                padding: const EdgeInsets.all(16),
                child: Column(
                  children: [
                    // ---- 目标货位 (上方) ----
                    Row(
                      children: [
                        const Text(
                          '目标货位',
                          style: TextStyle(
                            fontSize: 14,
                            fontWeight: FontWeight.w500,
                          ),
                        ),
                        if (_locationCode != null) ...[
                          const SizedBox(width: 8),
                          Container(
                            padding: const EdgeInsets.symmetric(
                              horizontal: 6,
                              vertical: 2,
                            ),
                            decoration: BoxDecoration(
                              color: _locationLabelColor(
                                _locationType,
                              ).withValues(alpha: 0.15),
                              borderRadius: BorderRadius.circular(4),
                            ),
                            child: Text(
                              _locationLabel(_locationType),
                              style: TextStyle(
                                fontSize: 11,
                                color: _locationLabelColor(_locationType),
                                fontWeight: FontWeight.bold,
                              ),
                            ),
                          ),
                        ],
                      ],
                    ),
                    const SizedBox(height: 6),
                    Container(
                      width: double.infinity,
                      padding: const EdgeInsets.symmetric(
                        horizontal: 12,
                        vertical: 14,
                      ),
                      decoration: BoxDecoration(
                        border: Border.all(
                          color: _locationCode != null
                              ? Colors.green
                              : Colors.grey.shade400,
                          width: _locationCode != null ? 2 : 1,
                        ),
                        borderRadius: BorderRadius.circular(8),
                      ),
                      child: Row(
                        children: [
                          Expanded(
                            child: Text(
                              _locationCode ?? '',
                              style: TextStyle(
                                fontSize: 20,
                                fontWeight: FontWeight.bold,
                                color: _locationCode != null
                                    ? Colors.black87
                                    : Colors.grey,
                              ),
                            ),
                          ),
                          if (_isLocked)
                            const Icon(
                              Icons.lock,
                              color: Colors.orange,
                              size: 20,
                            ),
                        ],
                      ),
                    ),

                    const SizedBox(height: 16),

                    // ---- 总排号 (下方) ----
                    Row(
                      children: [
                        const Text(
                          '总排号',
                          style: TextStyle(
                            fontSize: 14,
                            fontWeight: FontWeight.w500,
                          ),
                        ),
                        if (_isLocked && _zongpaiNos.isNotEmpty) ...[
                          const SizedBox(width: 8),
                          Container(
                            padding: const EdgeInsets.symmetric(
                              horizontal: 6,
                              vertical: 2,
                            ),
                            decoration: BoxDecoration(
                              color: Colors.blue.withValues(alpha: 0.15),
                              borderRadius: BorderRadius.circular(4),
                            ),
                            child: Text(
                              '${_zongpaiNos.length} 条',
                              style: const TextStyle(
                                fontSize: 11,
                                color: Colors.blue,
                                fontWeight: FontWeight.bold,
                              ),
                            ),
                          ),
                        ],
                      ],
                    ),
                    const SizedBox(height: 6),

                    if (_isLocked) ...[
                      // 锁定模式：列表显示多条总排号
                      Expanded(
                        child: _zongpaiNos.isEmpty
                            ? Container(
                                width: double.infinity,
                                padding: const EdgeInsets.all(14),
                                decoration: BoxDecoration(
                                  border: Border.all(color: Colors.grey.shade400),
                                  borderRadius: BorderRadius.circular(8),
                                ),
                                child: const Text(
                                  '',
                                  style: TextStyle(
                                    fontSize: 20,
                                    color: Colors.grey,
                                  ),
                                ),
                              )
                            : ListView.separated(
                                itemCount: _zongpaiNos.length,
                                separatorBuilder: (_, __) =>
                                    const SizedBox(height: 6),
                                itemBuilder: (context, index) {
                                  return Dismissible(
                                    key: ValueKey('${_zongpaiNos[index]}-$index'),
                                    direction: DismissDirection.endToStart,
                                    onDismissed: (_) => _removeZongpai(index),
                                    background: Container(
                                      alignment: Alignment.centerRight,
                                      padding: const EdgeInsets.only(right: 16),
                                      decoration: BoxDecoration(
                                        color: Colors.red.shade100,
                                        borderRadius: BorderRadius.circular(8),
                                      ),
                                      child: const Icon(
                                        Icons.delete,
                                        color: Colors.red,
                                      ),
                                    ),
                                    child: Container(
                                      padding: const EdgeInsets.symmetric(
                                        horizontal: 12,
                                        vertical: 12,
                                      ),
                                      decoration: BoxDecoration(
                                        border: Border.all(
                                          color: Colors.green,
                                          width: 2,
                                        ),
                                        borderRadius: BorderRadius.circular(8),
                                      ),
                                      child: Row(
                                        children: [
                                          Expanded(
                                            child: Text(
                                              _zongpaiNos[index],
                                              style: const TextStyle(
                                                fontSize: 20,
                                                fontWeight: FontWeight.bold,
                                                color: Colors.black87,
                                              ),
                                            ),
                                          ),
                                          IconButton(
                                            icon: const Icon(
                                              Icons.close,
                                              size: 20,
                                            ),
                                            onPressed: () =>
                                                _removeZongpai(index),
                                            padding: EdgeInsets.zero,
                                            constraints: const BoxConstraints(),
                                          ),
                                        ],
                                      ),
                                    ),
                                  );
                                },
                              ),
                      ),
                    ] else ...[
                      // 单次模式：单个显示
                      Container(
                        width: double.infinity,
                        padding: const EdgeInsets.symmetric(
                          horizontal: 12,
                          vertical: 14,
                        ),
                        decoration: BoxDecoration(
                          border: Border.all(
                            color: _zongpaiNos.isNotEmpty
                                ? Colors.green
                                : Colors.grey.shade400,
                            width: _zongpaiNos.isNotEmpty ? 2 : 1,
                          ),
                          borderRadius: BorderRadius.circular(8),
                        ),
                        child: Text(
                          _zongpaiNos.isNotEmpty ? _zongpaiNos.first : '',
                          style: TextStyle(
                            fontSize: 20,
                            fontWeight: FontWeight.bold,
                            color: _zongpaiNos.isNotEmpty
                                ? Colors.black87
                                : Colors.grey,
                          ),
                        ),
                      ),
                    ],

                    const SizedBox(height: 16),

                    // Submit button
                    SizedBox(
                      width: double.infinity,
                      height: 48,
                      child: ElevatedButton(
                        onPressed: _canSubmit ? _submit : null,
                        style: ElevatedButton.styleFrom(
                          backgroundColor: _canSubmit
                              ? colorScheme.primary
                              : Colors.grey.shade300,
                          foregroundColor: _canSubmit
                              ? Colors.white
                              : Colors.grey.shade600,
                          shape: RoundedRectangleBorder(
                            borderRadius: BorderRadius.circular(8),
                          ),
                        ),
                        child: _isSubmitting
                            ? const SizedBox(
                                width: 22,
                                height: 22,
                                child: CircularProgressIndicator(
                                  strokeWidth: 2,
                                  color: Colors.white,
                                ),
                              )
                            : Text(
                                _isLocked && _zongpaiNos.length > 1
                                    ? '批量上架（${_zongpaiNos.length} 条）'
                                    : '确认上架(P1)',
                                style: const TextStyle(fontSize: 18),
                              ),
                      ),
                    ),
                  ],
                ),
              ),
            ),

            // Bottom status bar
            StatusBar(dotColor: effectiveDot, text: effectiveText),
          ],
        ),
      ),
    );
  }
}