iv_and/create_invoice_screen.dart

import 'package:flutter/material.dart';
import 'package:provider/provider.dart';
import 'customer_provider.dart';
import 'product_provider.dart';
import 'invoice_provider.dart';

class CreateInvoiceScreen extends StatefulWidget {
  @override
  _CreateInvoiceScreenState createState() => _CreateInvoiceScreenState();
}

class _CreateInvoiceScreenState extends State<CreateInvoiceScreen> {
  final TextEditingController _quantityController = TextEditingController();

  int? _selectedCustomerId;
  int? _selectedProductId;

  @override
  Widget build(BuildContext context) {
    final customerProvider = Provider.of<CustomerProvider>(context);
    final productProvider = Provider.of<ProductProvider>(context);
    final invoiceProvider = Provider.of<InvoiceProvider>(context);

    return Scaffold(
      appBar: AppBar(
        title: Text('請求書作成'),
      ),
      body: Padding(
        padding: const EdgeInsets.all(16.0),
        child: Column(
          children: [
            DropdownButtonFormField<int>(
              value: _selectedCustomerId,
              items: customerProvider.customers.map((customer) {
                return DropdownMenuItem<int>(
                  value: customer.id,
                  child: Text(customer.name),
                );
              }).toList(),
              onChanged: (value) {
                setState(() {
                  _selectedCustomerId = value;
                });
              },
              decoration: InputDecoration(labelText: '顧客選択'),
            ),
            SizedBox(height: 20),
            DropdownButtonFormField<int>(
              value: _selectedProductId,
              items: productProvider.products.map((product) {
                return DropdownMenuItem<int>(
                  value: product.id,
                  child: Text(product.name),
                );
              }).toList(),
              onChanged: (value) {
                setState(() {
                  _selectedProductId = value;
                });
              },
              decoration: InputDecoration(labelText: '商品選択'),
            ),
            SizedBox(height: 20),
            TextField(
              controller: _quantityController,
              keyboardType: TextInputType.number,
              decoration: InputDecoration(labelText: '数量'),
            ),
            SizedBox(height: 20),
            ElevatedButton(
              onPressed: () async {
                if (_selectedCustomerId != null &&
                    _selectedProductId != null &&
                    _quantityController.text.isNotEmpty) {
                  final quantity = int.parse(_quantityController.text);
                  final product = productProvider.products.firstWhere((p) => p.id == _selectedProductId);

                  final invoiceItem = InvoiceItem(
                    invoiceId: 0, // 後で生成される ID
                    productId: _selectedProductId!,
                    quantity: quantity,
                    unitPrice: product.unitPrice,
                    discount: product.discount,
                  );

                  final total = (product.unitPrice * quantity) - (product.unitPrice * quantity * product.discount);
                  final tax = total * 0.1; // 簡易的な税率
                  final discountTotal = product.unitPrice * quantity * product.discount;

                  final invoice = Invoice(
                    customerId: _selectedCustomerId!,
                    date: DateTime.now().toIso8601String(),
                    total: total,
                    tax: tax,
                    discountTotal: discountTotal,
                  );

                  await invoiceProvider.addInvoice(invoice);
                  // 追加の処理（PDF生成など）

                  Navigator.pop(context);
                }
              },
              child: Text('PDF生成'),
            ),
          ],
        ),
      ),
    );
  }
}