// version: 1.0.1 (Stable Standalone Edition)
import 'dart:io';
import 'dart:typed_data';
import 'package:flutter/material.dart';
import 'package:pdf/widgets.dart' as pw;
import 'package:path_provider/path_provider.dart';
import 'package:crypto/crypto.dart';
import 'package:intl/intl.dart';

void main() => runApp(const MaterialApp(home: InvoiceApp()));

class InvoiceApp extends StatefulWidget {
  const InvoiceApp({super.key});
  @override
  State<InvoiceApp> createState() => _InvoiceAppState();
}

class _InvoiceAppState extends State<InvoiceApp> {
  final _clientController = TextEditingController(text: "現場太郎 様");
  final _amountController = TextEditingController(text: "1500"); // 10%抜き単価
  String _status = "内容を入力してPDFを発行してください";

  Future<void> _generateInvoice() async {
    final pdf = pw.Document();
    final clientName = _clientController.text;
    final int unitPrice = int.tryParse(_amountController.text) ?? 0;
    
    // 【こだわり1】10%固定計算
    final int tax = (unitPrice * 0.1).floor();
    final int total = unitPrice + tax;
    final dateStr = DateFormat('yyyy/MM/dd HH:mm').format(DateTime.now());

    // PDFの内容（超シンプル）
    pdf.addPage(pw.Page(build: (context) => pw.Column(children: [
      pw.Text("Invoice / Receipt", style: pw.TextStyle(fontSize: 40)),
      pw.Divider(),
      pw.Text("Client: $clientName"),
      pw.Text("Date: $dateStr"),
      pw.SizedBox(height: 20),
      pw.Text("Subtotal: $unitPrice JPY"),
      pw.Text("Tax (10%): $tax JPY"),
      pw.Text("Total: $total JPY", style: pw.TextStyle(fontWeight: pw.FontWeight.bold)),
    ])));

    // PDFをバイトデータに変換
    final Uint8List bytes = await pdf.save();

    // 【こだわり2】SHA-256ハッシュ計算
    final hash = sha256.convert(bytes).toString().substring(0, 10);
    
    // 【こだわり3】ファイル名に情報を詰め込む
    final fileName = "${DateFormat('yyyyMMdd').format(DateTime.now())}_${clientName}_${total}円_hash_$hash.pdf";

    // 保存（Androidの書類フォルダなど）
    final directory = await getExternalStorageDirectory();
    final file = File("${directory!.path}/$fileName");
    await file.writeAsBytes(bytes);

    setState(() {
      _status = "保存完了！\n場所: ${file.path}\nハッシュ: $hash";
    });
  }

  @override
  Widget build(BuildContext context) {
    return Scaffold(
      appBar: AppBar(title: const Text("現場のじぇみエモン請求書")),
      body: Padding(
        padding: const EdgeInsets.all(16.0),
        child: Column(children: [
          TextField(controller: _clientController, decoration: const InputDecoration(labelText: "取引先名")),
          TextField(controller: _amountController, decoration: const InputDecoration(labelText: "単価(税抜)")),
          const SizedBox(height: 20),
          ElevatedButton(onPressed: _generateInvoice, child: const Text("PDF発行 & ハッシュ保存")),
          const SizedBox(height: 20),
          Text(_status, style: const TextStyle(color: Colors.blue)),
        ]),
      ),
    );
  }
}