import 'package:flutter/material.dart';
import 'package:go_router/go_router.dart';
import '../../core/theme/app_theme.dart';
import '../../core/widgets/step_indicator.dart';
import '../../data/models/models.dart';
import '../../data/services/order_service.dart';

class HandoffScreen extends StatefulWidget {
  final int orderId;
  const HandoffScreen({super.key, required this.orderId});

  @override
  State<HandoffScreen> createState() => _HandoffScreenState();
}

class _HandoffScreenState extends State<HandoffScreen> {
  final _service = MockOrderService();
  Order? _order;
  bool _loading = true;
  bool _finalizing = false;

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

  Future<void> _load() async {
    final order = await _service.getOrderDetail(widget.orderId);
    if (mounted) setState(() { _order = order; _loading = false; });
  }

  Future<void> _finalize() async {
    setState(() => _finalizing = true);
    await _service.finalizeOrder(widget.orderId);
    if (mounted) {
      ScaffoldMessenger.of(context).showSnackBar(
        const SnackBar(content: Text('Замовлення видано!'), backgroundColor: AppColors.success),
      );
      context.go('/orders');
    }
  }

  @override
  Widget build(BuildContext context) {
    return Scaffold(
      appBar: AppBar(
        title: Text(_order?.orderNumber ?? ''),
        leading: IconButton(icon: const Icon(Icons.arrow_back), onPressed: () => context.pop()),
      ),
      body: _loading
          ? const Center(child: CircularProgressIndicator())
          : Column(
              children: [
                const StepIndicator(currentStep: BatchStep.handoff),
                Expanded(
                  child: SingleChildScrollView(
                    padding: const EdgeInsets.all(16),
                    child: Column(
                      crossAxisAlignment: CrossAxisAlignment.start,
                      children: [
                        // Summary card
                        _SummaryCard(order: _order!),
                        const SizedBox(height: 16),
                        // Slots summary
                        if (_order!.assignedSlots.isNotEmpty) ...[
                          const Text('Ячейки зберігання',
                              style: TextStyle(fontSize: 15, fontWeight: FontWeight.bold)),
                          const SizedBox(height: 8),
                          ..._buildSlotChips(_order!.assignedSlots),
                          const SizedBox(height: 16),
                        ],
                        // Items summary
                        const Text('Підсумок збору',
                            style: TextStyle(fontSize: 15, fontWeight: FontWeight.bold)),
                        const SizedBox(height: 8),
                        _ItemsSummary(order: _order!),
                      ],
                    ),
                  ),
                ),
                SafeArea(
                  child: Padding(
                    padding: const EdgeInsets.all(16),
                    child: ElevatedButton(
                      onPressed: _finalizing ? null : _finalize,
                      style: ElevatedButton.styleFrom(backgroundColor: AppColors.success),
                      child: _finalizing
                          ? const SizedBox(height: 20, width: 20,
                              child: CircularProgressIndicator(color: Colors.white, strokeWidth: 2))
                          : const Text('Зібрано та видано'),
                    ),
                  ),
                ),
              ],
            ),
    );
  }

  List<Widget> _buildSlotChips(List<StorageSlot> slots) {
    return [
      Wrap(
        spacing: 8,
        runSpacing: 8,
        children: slots.map((slot) {
          final color = slot.type == StorageSlotType.freezer
              ? Colors.indigo
              : slot.type == StorageSlotType.fridge
                  ? AppColors.info
                  : AppColors.primary;
          return Chip(
            label: Text(slot.name, style: TextStyle(color: color, fontWeight: FontWeight.w600)),
            backgroundColor: color.withOpacity(0.1),
            side: BorderSide(color: color.withOpacity(0.4)),
          );
        }).toList(),
      ),
    ];
  }
}

class _SummaryCard extends StatelessWidget {
  final Order order;
  const _SummaryCard({required this.order});

  @override
  Widget build(BuildContext context) {
    final notPicked = order.segments
        .expand((s) => s.items)
        .where((i) => i.status == ItemStatus.notFound)
        .toList();
    final replaced = order.segments
        .expand((s) => s.items)
        .where((i) => i.status == ItemStatus.replaced)
        .toList();

    return Card(
      child: Padding(
        padding: const EdgeInsets.all(16),
        child: Column(
          crossAxisAlignment: CrossAxisAlignment.start,
          children: [
            Row(
              children: [
                const Icon(Icons.person, color: AppColors.primary),
                const SizedBox(width: 8),
                Expanded(
                  child: Column(
                    crossAxisAlignment: CrossAxisAlignment.start,
                    children: [
                      Text(order.customer.name,
                          style: const TextStyle(fontSize: 16, fontWeight: FontWeight.bold)),
                      Text(order.customer.phone, style: const TextStyle(color: AppColors.textSecondary)),
                    ],
                  ),
                ),
              ],
            ),
            const Divider(height: 20),
            Row(
              mainAxisAlignment: MainAxisAlignment.spaceBetween,
              children: [
                _stat('Зібрано', '${order.pickedItems}/${order.totalItems}', AppColors.success),
                if (replaced.isNotEmpty) _stat('Замінено', '${replaced.length}', AppColors.warning),
                if (notPicked.isNotEmpty) _stat('Відсутні', '${notPicked.length}', AppColors.error),
                _stat('Сума', '${order.amount.toStringAsFixed(0)} грн', AppColors.primary),
              ],
            ),
            if (order.customer.comment != null) ...[
              const Divider(height: 20),
              Row(
                crossAxisAlignment: CrossAxisAlignment.start,
                children: [
                  const Icon(Icons.comment, size: 16, color: AppColors.warning),
                  const SizedBox(width: 4),
                  Expanded(child: Text(order.customer.comment!,
                      style: const TextStyle(fontSize: 13, color: AppColors.warning))),
                ],
              ),
            ],
          ],
        ),
      ),
    );
  }

  Widget _stat(String label, String value, Color color) => Column(
        children: [
          Text(value, style: TextStyle(fontSize: 18, fontWeight: FontWeight.bold, color: color)),
          Text(label, style: const TextStyle(fontSize: 11, color: AppColors.textSecondary)),
        ],
      );
}

class _ItemsSummary extends StatelessWidget {
  final Order order;
  const _ItemsSummary({required this.order});

  @override
  Widget build(BuildContext context) {
    final allItems = order.segments.expand((s) => s.items).toList();
    return Column(
      children: allItems.map((item) {
        final icon = item.status == ItemStatus.picked
            ? Icons.check_circle
            : item.status == ItemStatus.replaced
                ? Icons.swap_horiz
                : Icons.cancel;
        final color = item.status == ItemStatus.picked
            ? AppColors.success
            : item.status == ItemStatus.replaced
                ? AppColors.warning
                : AppColors.error;
        return Padding(
          padding: const EdgeInsets.symmetric(vertical: 4),
          child: Row(
            children: [
              Icon(icon, size: 18, color: color),
              const SizedBox(width: 8),
              Expanded(child: Text(item.name, style: const TextStyle(fontSize: 14))),
              Text('${item.actualQty}/${item.planQty}',
                  style: const TextStyle(fontSize: 13, color: AppColors.textSecondary)),
            ],
          ),
        );
      }).toList(),
    );
  }
}