import 'package:flutter/material.dart';
import 'package:flutter/services.dart';
import 'package:flutter_riverpod/flutter_riverpod.dart';
import 'package:go_router/go_router.dart';
import '../../core/theme/app_theme.dart';
import '../../models/inventory.dart';
import '../../models/warehouse.dart';
import '../../providers/inventory_provider.dart';
import '../../providers/warehouse_provider.dart';

class InventoryCheckScreen extends ConsumerStatefulWidget {
  const InventoryCheckScreen({super.key});

  @override
  ConsumerState<InventoryCheckScreen> createState() =>
      _InventoryCheckScreenState();
}

class _InventoryCheckScreenState extends ConsumerState<InventoryCheckScreen> {
  Warehouse? _selectedWarehouse;
  String _checkType = '全盘';
  bool _submitting = false;
  bool _loadingItems = false;

  // Editable check items built from real inventory
  final List<_CheckItem> _checkItems = [];

  String get _checkNo {
    final now = DateTime.now();
    final date =
        '${now.year}${now.month.toString().padLeft(2, '0')}${now.day.toString().padLeft(2, '0')}';
    return 'PD$date${_selectedWarehouse?.id.toString().padLeft(3, '0') ?? '001'}';
  }

  @override
  void dispose() {
    for (final item in _checkItems) {
      item.dispose();
    }
    super.dispose();
  }

  Future<void> _loadInventory(Warehouse wh) async {
    setState(() {
      _loadingItems = true;
      for (final item in _checkItems) {
        item.dispose();
      }
      _checkItems.clear();
    });
    try {
      final result = await ref
          .read(inventoryRepositoryProvider)
          .listInventory(warehouseId: wh.id, pageSize: 200);
      final items = result.data
          .where((inv) => inv.productId != null)
          .map((inv) => _CheckItem(inventory: inv))
          .toList();
      if (mounted) {
        setState(() {
          _checkItems.addAll(items);
          _loadingItems = false;
        });
      }
    } catch (e) {
      if (mounted) {
        setState(() => _loadingItems = false);
        ScaffoldMessenger.of(context).showSnackBar(
          SnackBar(
              content: Text('加载库存失败：$e'),
              backgroundColor: AppTheme.danger),
        );
      }
    }
  }

  Future<void> _submit() async {
    if (_selectedWarehouse == null) {
      ScaffoldMessenger.of(context)
          .showSnackBar(const SnackBar(content: Text('请先选择仓库')));
      return;
    }
    setState(() => _submitting = true);
    try {
      final now = DateTime.now();
      final dateStr =
          '${now.year}-${now.month.toString().padLeft(2, '0')}-${now.day.toString().padLeft(2, '0')}';

      final items = _checkItems.map((item) {
        final actual =
            double.tryParse(item.actualQtyCtrl.text) ?? item.inventory.quantity;
        return {
          'product_id': item.inventory.productId!,
          'actual_qty': actual,
          'remark': item.remarkCtrl.text.trim(),
        };
      }).toList();

      await ref.read(inventoryRepositoryProvider).createCheck({
        'check_no': _checkNo,
        'warehouse_id': _selectedWarehouse!.id,
        'check_date': dateStr,
        'items': items,
      });

      if (mounted) {
        ScaffoldMessenger.of(context).showSnackBar(
          const SnackBar(
            content: Text('盘点单已提交'),
            backgroundColor: AppTheme.success,
          ),
        );
        context.go('/inventory');
      }
    } catch (e) {
      if (mounted) {
        ScaffoldMessenger.of(context).showSnackBar(
          SnackBar(
              content: Text('提交失败：$e'),
              backgroundColor: AppTheme.danger),
        );
      }
    } finally {
      if (mounted) setState(() => _submitting = false);
    }
  }

  int _getDiff(_CheckItem item) {
    final actual =
        double.tryParse(item.actualQtyCtrl.text) ?? item.inventory.quantity;
    return (actual - item.inventory.quantity).round();
  }

  @override
  Widget build(BuildContext context) {
    final asyncWarehouses = ref.watch(warehouseListProvider);

    return Scaffold(
      backgroundColor: AppTheme.background,
      body: Column(
        children: [
          // Header
          Container(
            height: 52,
            color: AppTheme.surface,
            padding: const EdgeInsets.symmetric(horizontal: 16),
            child: Row(
              children: [
                IconButton(
                  icon: const Icon(Icons.arrow_back, size: 20),
                  onPressed: () => context.go('/inventory'),
                ),
                const SizedBox(width: 8),
                const Text('库存盘点',
                    style: TextStyle(
                        fontSize: 16, fontWeight: FontWeight.w600)),
                const Spacer(),
                OutlinedButton(
                  onPressed: () => context.go('/inventory'),
                  child: const Text('取消'),
                ),
                const SizedBox(width: 8),
                ElevatedButton.icon(
                  onPressed: (_submitting || _checkItems.isEmpty)
                      ? null
                      : _submit,
                  icon: _submitting
                      ? const SizedBox(
                          width: 14,
                          height: 14,
                          child: CircularProgressIndicator(
                              strokeWidth: 2, color: Colors.white))
                      : const Icon(Icons.check_circle_outline, size: 16),
                  label: const Text('提交盘点'),
                ),
              ],
            ),
          ),
          const Divider(height: 1),
          Expanded(
            child: SingleChildScrollView(
              padding: const EdgeInsets.all(16),
              child: Column(
                children: [
                  // Basic info
                  Card(
                    child: Padding(
                      padding: const EdgeInsets.all(16),
                      child: Column(
                        crossAxisAlignment: CrossAxisAlignment.start,
                        children: [
                          const Text('盘点基本信息',
                              style: TextStyle(
                                  fontSize: 14,
                                  fontWeight: FontWeight.w600,
                                  color: AppTheme.primaryDark)),
                          const SizedBox(height: 16),
                          Wrap(
                            spacing: 16,
                            runSpacing: 16,
                            children: [
                              _InfoField(
                                label: '盘点单号',
                                child: InputDecorator(
                                  decoration: const InputDecoration(),
                                  child: Text(
                                    _checkNo,
                                    style: const TextStyle(
                                        fontFamily: 'monospace',
                                        fontSize: 13),
                                  ),
                                ),
                              ),
                              _InfoField(
                                label: '盘点仓库',
                                child: asyncWarehouses.when(
                                  loading: () =>
                                      const LinearProgressIndicator(),
                                  error: (e, _) => Text('$e',
                                      style: const TextStyle(
                                          color: AppTheme.danger,
                                          fontSize: 12)),
                                  data: (warehouses) =>
                                      DropdownButtonFormField<Warehouse>(
                                    value: _selectedWarehouse,
                                    hint: const Text('请选择仓库'),
                                    items: warehouses
                                        .map((w) => DropdownMenuItem(
                                            value: w,
                                            child: Text(w.name,
                                                style: const TextStyle(
                                                    fontSize: 13))))
                                        .toList(),
                                    onChanged: (w) {
                                      setState(
                                          () => _selectedWarehouse = w);
                                      if (w != null) _loadInventory(w);
                                    },
                                    decoration: const InputDecoration(),
                                  ),
                                ),
                              ),
                              _InfoField(
                                label: '盘点类型',
                                child: DropdownButtonFormField<String>(
                                  value: _checkType,
                                  items: ['全盘', '抽盘', '循环盘点']
                                      .map((s) => DropdownMenuItem(
                                          value: s,
                                          child: Text(s,
                                              style: const TextStyle(
                                                  fontSize: 13))))
                                      .toList(),
                                  onChanged: (v) =>
                                      setState(() => _checkType = v!),
                                  decoration: const InputDecoration(),
                                ),
                              ),
                              _InfoField(
                                label: '盘点日期',
                                child: InputDecorator(
                                  decoration: const InputDecoration(),
                                  child: Builder(builder: (ctx) {
                                    final now = DateTime.now();
                                    return Text(
                                      '${now.year}-${now.month.toString().padLeft(2, '0')}-${now.day.toString().padLeft(2, '0')}',
                                      style:
                                          const TextStyle(fontSize: 13),
                                    );
                                  }),
                                ),
                              ),
                            ],
                          ),
                        ],
                      ),
                    ),
                  ),
                  const SizedBox(height: 12),
                  // Check items table
                  Card(
                    child: Padding(
                      padding: const EdgeInsets.all(16),
                      child: Column(
                        crossAxisAlignment: CrossAxisAlignment.start,
                        children: [
                          Row(
                            children: [
                              const Text('盘点明细',
                                  style: TextStyle(
                                      fontSize: 14,
                                      fontWeight: FontWeight.w600,
                                      color: AppTheme.primaryDark)),
                              const SizedBox(width: 12),
                              if (_checkItems.isNotEmpty)
                                Container(
                                  padding: const EdgeInsets.symmetric(
                                      horizontal: 8, vertical: 2),
                                  decoration: BoxDecoration(
                                    color:
                                        AppTheme.accent.withOpacity(0.1),
                                    borderRadius:
                                        BorderRadius.circular(3),
                                  ),
                                  child: Text(
                                    '差异 ${_checkItems.where((i) => _getDiff(i) != 0).length} 项',
                                    style: const TextStyle(
                                        fontSize: 12,
                                        color: AppTheme.accent),
                                  ),
                                ),
                            ],
                          ),
                          const SizedBox(height: 12),
                          if (_selectedWarehouse == null)
                            const Center(
                              child: Padding(
                                padding: EdgeInsets.all(32),
                                child: Text('请先选择盘点仓库',
                                    style: TextStyle(
                                        color: AppTheme.textSecondary)),
                              ),
                            )
                          else if (_loadingItems)
                            const Center(
                              child: Padding(
                                padding: EdgeInsets.all(32),
                                child: CircularProgressIndicator(),
                              ),
                            )
                          else if (_checkItems.isEmpty)
                            const Center(
                              child: Padding(
                                padding: EdgeInsets.all(32),
                                child: Text('该仓库暂无库存记录',
                                    style: TextStyle(
                                        color: AppTheme.textSecondary)),
                              ),
                            )
                          else
                            Table(
                              columnWidths: const {
                                0: FixedColumnWidth(36),
                                1: FixedColumnWidth(80),
                                2: FlexColumnWidth(3),
                                3: FixedColumnWidth(50),
                                4: FixedColumnWidth(80),
                                5: FixedColumnWidth(120),
                                6: FixedColumnWidth(80),
                                7: FlexColumnWidth(2),
                              },
                              children: [
                                TableRow(
                                  decoration: const BoxDecoration(
                                      color: Color(0xFFF0F4FF)),
                                  children: [
                                    '序号',
                                    '商品编码',
                                    '商品名称',
                                    '单位',
                                    '账面数量',
                                    '实际数量',
                                    '差异',
                                    '备注',
                                  ]
                                      .map((h) => Padding(
                                            padding: const EdgeInsets
                                                .symmetric(
                                                horizontal: 8,
                                                vertical: 10),
                                            child: Text(h,
                                                style: const TextStyle(
                                                    fontSize: 13,
                                                    fontWeight:
                                                        FontWeight.w600,
                                                    color: AppTheme
                                                        .primaryDark)),
                                          ))
                                      .toList(),
                                ),
                                ...List.generate(
                                    _checkItems.length,
                                    (i) => _buildCheckRow(i)),
                              ],
                            ),
                          if (_checkItems.isNotEmpty) ...[
                            const Divider(height: 1),
                            Padding(
                              padding: const EdgeInsets.only(top: 12),
                              child: Row(
                                children: [
                                  _SummaryItem(
                                    label: '盘点商品',
                                    value: '${_checkItems.length}种',
                                    color: AppTheme.primary,
                                  ),
                                  const SizedBox(width: 24),
                                  _SummaryItem(
                                    label: '盘盈',
                                    value:
                                        '${_checkItems.where((i) => _getDiff(i) > 0).length}种',
                                    color: AppTheme.success,
                                  ),
                                  const SizedBox(width: 24),
                                  _SummaryItem(
                                    label: '盘亏',
                                    value:
                                        '${_checkItems.where((i) => _getDiff(i) < 0).length}种',
                                    color: AppTheme.danger,
                                  ),
                                  const SizedBox(width: 24),
                                  _SummaryItem(
                                    label: '相符',
                                    value:
                                        '${_checkItems.where((i) => _getDiff(i) == 0).length}种',
                                    color: AppTheme.textSecondary,
                                  ),
                                ],
                              ),
                            ),
                          ],
                        ],
                      ),
                    ),
                  ),
                ],
              ),
            ),
          ),
        ],
      ),
    );
  }

  TableRow _buildCheckRow(int index) {
    final item = _checkItems[index];
    final diff = _getDiff(item);
    final inv = item.inventory;

    return TableRow(
      decoration: BoxDecoration(
        color: diff != 0
            ? (diff > 0
                ? AppTheme.success.withOpacity(0.04)
                : AppTheme.danger.withOpacity(0.04))
            : (index.isEven ? Colors.white : const Color(0xFFFAFAFA)),
      ),
      children: [
        Padding(
          padding:
              const EdgeInsets.symmetric(horizontal: 8, vertical: 10),
          child: Text('${index + 1}',
              style: const TextStyle(
                  fontSize: 13, color: AppTheme.textSecondary)),
        ),
        Padding(
          padding:
              const EdgeInsets.symmetric(horizontal: 8, vertical: 10),
          child: Text(inv.productCode.isEmpty ? '-' : inv.productCode,
              style: const TextStyle(
                  fontFamily: 'monospace',
                  fontSize: 12,
                  color: AppTheme.textSecondary)),
        ),
        Padding(
          padding:
              const EdgeInsets.symmetric(horizontal: 8, vertical: 10),
          child: Text(inv.productName.isEmpty ? '-' : inv.productName,
              style: const TextStyle(fontSize: 13),
              overflow: TextOverflow.ellipsis),
        ),
        Padding(
          padding:
              const EdgeInsets.symmetric(horizontal: 8, vertical: 10),
          child: Text(inv.unit.isEmpty ? '-' : inv.unit,
              style: const TextStyle(fontSize: 13)),
        ),
        Padding(
          padding:
              const EdgeInsets.symmetric(horizontal: 8, vertical: 10),
          child: Text(inv.quantity.toStringAsFixed(0),
              style: const TextStyle(fontSize: 13)),
        ),
        Padding(
          padding: const EdgeInsets.all(4),
          child: TextFormField(
            controller: item.actualQtyCtrl,
            decoration: const InputDecoration(),
            style: const TextStyle(fontSize: 13),
            keyboardType: TextInputType.number,
            inputFormatters: [FilteringTextInputFormatter.digitsOnly],
            onChanged: (_) => setState(() {}),
          ),
        ),
        Padding(
          padding:
              const EdgeInsets.symmetric(horizontal: 8, vertical: 10),
          child: Text(
            diff == 0 ? '0' : (diff > 0 ? '+$diff' : '$diff'),
            style: TextStyle(
              fontSize: 13,
              fontWeight: FontWeight.w600,
              color: diff == 0
                  ? AppTheme.textSecondary
                  : (diff > 0 ? AppTheme.success : AppTheme.danger),
            ),
          ),
        ),
        Padding(
          padding: const EdgeInsets.all(4),
          child: TextFormField(
            controller: item.remarkCtrl,
            decoration: const InputDecoration(hintText: '备注'),
            style: const TextStyle(fontSize: 13),
          ),
        ),
      ],
    );
  }
}

class _CheckItem {
  final Inventory inventory;
  final TextEditingController actualQtyCtrl;
  final TextEditingController remarkCtrl;

  _CheckItem({required this.inventory})
      : actualQtyCtrl = TextEditingController(
            text: inventory.quantity.toStringAsFixed(0)),
        remarkCtrl = TextEditingController();

  void dispose() {
    actualQtyCtrl.dispose();
    remarkCtrl.dispose();
  }
}

class _InfoField extends StatelessWidget {
  final String label;
  final Widget child;

  const _InfoField({required this.label, required this.child});

  @override
  Widget build(BuildContext context) {
    return SizedBox(
      width: 220,
      child: Column(
        crossAxisAlignment: CrossAxisAlignment.start,
        children: [
          Text(label,
              style: const TextStyle(
                  fontSize: 13, color: AppTheme.textSecondary)),
          const SizedBox(height: 6),
          child,
        ],
      ),
    );
  }
}

class _SummaryItem extends StatelessWidget {
  final String label;
  final String value;
  final Color color;

  const _SummaryItem(
      {required this.label, required this.value, required this.color});

  @override
  Widget build(BuildContext context) {
    return Row(
      children: [
        Text(label,
            style: const TextStyle(
                fontSize: 13, color: AppTheme.textSecondary)),
        const SizedBox(width: 4),
        Text(value,
            style: TextStyle(
                fontSize: 14,
                fontWeight: FontWeight.w600,
                color: color)),
      ],
    );
  }
}