import 'package:flutter/material.dart';
import 'package:flutter_riverpod/flutter_riverpod.dart';
import 'package:kifi_app/core/widgets/smart_search_dropdown.dart';
import 'package:kifi_app/features/inventory/providers/products_provider.dart';
import 'package:kifi_app/features/inventory/domain/product_bom.dart';
import 'package:kifi_app/features/inventory/domain/product.dart';

class BomTab extends ConsumerStatefulWidget {
  final int productId;

  const BomTab({super.key, required this.productId});

  @override
  ConsumerState<BomTab> createState() => _BomTabState();
}

class _BomTabState extends ConsumerState<BomTab> {
  bool _isLoading = true;
  List<ProductBom> _bomItems = [];

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

  Future<void> _loadBom() async {
    setState(() => _isLoading = true);
    try {
      final items = await ref.read(productsProvider.notifier).fetchProductBom(widget.productId);
      setState(() {
        _bomItems = items;
      });
    } catch (e) {
      if (mounted) {
        ScaffoldMessenger.of(context).showSnackBar(SnackBar(content: Text('Error loading BOM: $e')));
      }
    } finally {
      if (mounted) setState(() => _isLoading = false);
    }
  }

  void _showAddComponentSheet() {
    final productsState = ref.read(productsProvider);
    final availableProducts = (productsState.value ?? []).where((p) => p.id != widget.productId).toList();

    Product? selectedProduct;
    final qtyCtrl = TextEditingController(text: '1');

    showModalBottomSheet(
      context: context,
      isScrollControlled: true,
      builder: (context) => StatefulBuilder(
        builder: (context, setSheetState) {
          return Padding(
            padding: EdgeInsets.only(
              bottom: MediaQuery.of(context).viewInsets.bottom,
              left: 24,
              right: 24,
              top: 24,
            ),
            child: Column(
              mainAxisSize: MainAxisSize.min,
              crossAxisAlignment: CrossAxisAlignment.start,
              children: [
                const Text("Add Component", style: TextStyle(fontSize: 20, fontWeight: FontWeight.bold)),
                const SizedBox(height: 16),
                SmartSearchDropdown<Product>(
                  hintText: 'Select Product',
                  value: selectedProduct,
                  items: availableProducts,
                  itemAsString: (p) => p.name,
                  onChanged: (val) {
                    setSheetState(() {
                      selectedProduct = val;
                    });
                  },
                ),
                const SizedBox(height: 16),
                TextField(
                  controller: qtyCtrl,
                  keyboardType: const TextInputType.numberWithOptions(decimal: true),
                  decoration: const InputDecoration(
                    labelText: 'Quantity Required',
                    border: OutlineInputBorder(),
                  ),
                ),
                const SizedBox(height: 24),
                SizedBox(
                  width: double.infinity,
                  child: ElevatedButton(
                    onPressed: () async {
                      if (selectedProduct == null) return;
                      final qty = double.tryParse(qtyCtrl.text) ?? 1.0;
                      
                      final bomItem = ProductBom(
                        parentProductId: widget.productId,
                        componentProductId: selectedProduct!.id!,
                        quantity: qty,
                      );
                      
                      try {
                        await ref.read(productsProvider.notifier).addBomItem(widget.productId, bomItem);
                        if (context.mounted) Navigator.pop(context);
                        _loadBom();
                      } catch (e) {
                        if (context.mounted) {
                          ScaffoldMessenger.of(context).showSnackBar(SnackBar(content: Text('Error adding component: $e')));
                        }
                      }
                    },
                    style: ElevatedButton.styleFrom(
                      padding: const EdgeInsets.symmetric(vertical: 16),
                      backgroundColor: Colors.blue,
                      foregroundColor: Colors.white,
                    ),
                    child: const Text('Add to BOM'),
                  ),
                ),
                const SizedBox(height: 24),
              ],
            ),
          );
        }
      ),
    );
  }

  @override
  Widget build(BuildContext context) {
    if (_isLoading) {
      return const Center(child: CircularProgressIndicator());
    }
    
    final productsState = ref.watch(productsProvider);
    final allProducts = productsState.value ?? [];

    return Stack(
      children: [
        if (_bomItems.isEmpty)
          const Center(child: Text("No components added yet.", style: TextStyle(color: Colors.grey)))
        else
          ListView.builder(
            padding: const EdgeInsets.all(16).copyWith(bottom: 80),
            itemCount: _bomItems.length,
            itemBuilder: (context, index) {
              final item = _bomItems[index];
              final component = allProducts.firstWhere(
                (p) => p.id == item.componentProductId, 
                orElse: () => Product(name: 'Unknown Product', priceCalcRule: 'MANUAL'),
              );
              
              return Card(
                margin: const EdgeInsets.only(bottom: 12),
                shape: RoundedRectangleBorder(borderRadius: BorderRadius.circular(12)),
                child: ListTile(
                  title: Text(component.name, style: const TextStyle(fontWeight: FontWeight.bold)),
                  subtitle: Text('Quantity Required: ${item.quantity}'),
                  trailing: IconButton(
                    icon: const Icon(Icons.delete, color: Colors.red),
                    onPressed: () async {
                      try {
                        await ref.read(productsProvider.notifier).deleteBomItem(item.id!);
                        _loadBom();
                      } catch (e) {
                        if (context.mounted) {
                          ScaffoldMessenger.of(context).showSnackBar(SnackBar(content: Text('Error deleting component: $e')));
                        }
                      }
                    },
                  ),
                ),
              );
            },
          ),
        
        Positioned(
          bottom: 90,
          right: 16,
          child: FloatingActionButton.extended(
            heroTag: 'add_bom_btn',
            onPressed: _showAddComponentSheet,
            backgroundColor: Colors.indigo,
            icon: const Icon(Icons.add),
            label: const Text("Add Component"),
          ),
        ),
      ],
    );
  }
}