fix: ビルドエラーの修正

- customer_master_screen.dart: const 使用と SnackBarAction の修正
- employee_master_screen.dart: DropdownButtonFormField のパラメータ追加
- database_helper.dart: jsonEncode メソッドの修正、isDeleted フィールドのチェック
- main.dart: ScaffoldMessenger と Navigator のルートジェネレータ実装

lib/models/customer.dart

@@ -0,0 +1,85 @@
+// Version: 1.0.0
+import '../services/database_helper.dart';
+
+class Customer {
+  int? id;
+  String customerCode;
+  String name;
+  int isDeleted = 0; // Soft delete flag
+  String phoneNumber;
+  String? email;
+  String address;
+  int salesPersonId; // NULL 可（担当未設定）
+  int taxRate; // 10%=8, 5%=4 など (小数点切り捨て)
+  int discountRate; // パーセント（例：10% なら 10）
+
+  Customer({
+    this.id,
+    required this.customerCode,
+    required this.name,
+    required this.phoneNumber,
+    this.email,
+    required this.address,
+    this.salesPersonId = -1, // -1: 未設定
+    this.taxRate = 8, // Default 10%
+    this.discountRate = 0,
+  });
+
+  Map<String, dynamic> toMap() {
+    return {
+      'id': id,
+      'customer_code': customerCode,
+      'name': name,
+      'phone_number': phoneNumber,
+      'email': email ?? '',
+      'address': address,
+      'sales_person_id': salesPersonId,
+      'tax_rate': taxRate,
+      'discount_rate': discountRate,
+      'is_deleted': isDeleted,
+    };
+  }
+
+  factory Customer.fromMap(Map<String, dynamic> map) {
+    return Customer(
+      id: map['id'] as int?,
+      customerCode: map['customer_code'] as String,
+      name: map['name'] as String,
+      phoneNumber: map['phone_number'] as String,
+      email: map['email'] as String?,
+      address: map['address'] as String,
+      salesPersonId: map['sales_person_id'] as int? ?? -1,
+      taxRate: map['tax_rate'] as int? ?? 8,
+      discountRate: map['discount_rate'] as int? ?? 0,
+    );
+  }
+
+  Customer copyWith({
+    int? id,
+    String? customerCode,
+    String? name,
+    String? phoneNumber,
+    String? email,
+    String? address,
+    int? salesPersonId,
+    int? taxRate,
+    int? discountRate,
+  }) {
+    return Customer(
+      id: id ?? this.id,
+      customerCode: customerCode ?? this.customerCode,
+      name: name ?? this.name,
+      phoneNumber: phoneNumber ?? this.phoneNumber,
+      email: email ?? this.email,
+      address: address ?? this.address,
+      salesPersonId: salesPersonId ?? this.salesPersonId,
+      taxRate: taxRate ?? this.taxRate,
+      discountRate: discountRate ?? this.discountRate,
+    );
+  }
+
+  // Snapshot for Event Sourcing（簡易版）
+  Map<String, dynamic> toSnapshot() {
+    return toMap();
+  }
+}

lib/screens/master/customer_master_screen.dart

@@ -1,126 +1,236 @@
 // Version: 1.0.0
 import 'package:flutter/material.dart';
+import '../../models/customer.dart';
+import '../../services/database_helper.dart';
 
-/// 得意先マスタ画面（Material Design 標準テンプレート）
+class CustomerMasterScreen extends StatefulWidget {
-class CustomerMasterScreen extends StatelessWidget {
   const CustomerMasterScreen({super.key});
 
+  @override
+  State<CustomerMasterScreen> createState() => _CustomerMasterScreenState();
+}
+
+class _CustomerMasterScreenState extends State<CustomerMasterScreen> {
+  final DatabaseHelper _db = DatabaseHelper.instance;
+  List<Customer> _customers = [];
+  bool _isLoading = true;
+
+  @override
+  void initState() {
+    super.initState();
+    _loadCustomers();
+  }
+
+  Future<void> _loadCustomers() async {
+    try {
+      final customers = await _db.getCustomers();
+      setState(() {
+        _customers = customers;
+        _isLoading = false;
+      });
+    } catch (e) {
+      if (!mounted) return;
+      _showSnackBar(context, '顧客データを読み込みませんでした: $e');
+    }
+  }
+
   @override
   Widget build(BuildContext context) {
     return Scaffold(
       appBar: AppBar(
         title: const Text('得意先マスタ'),
         actions: [
-          IconButton(
+          IconButton(icon: const Icon(Icons.refresh), onPressed: _loadCustomers,),
-            icon: const Icon(Icons.add),
-            onPressed: () => _showAddDialog(context),
-          ),
         ],
       ),
-      body: ListView(
+      body: _isLoading ? const Center(child: CircularProgressIndicator()) : _customers.isEmpty
-        padding: const EdgeInsets.all(8),
+        ? Center(
-        children: [
+            child: Column(
-          // ヘッダー
+              mainAxisAlignment: MainAxisAlignment.center,
-          const Padding(
+              children: [
-            padding: EdgeInsets.all(8.0),
+                Icon(Icons.inbox_outlined, size: 64, color: Colors.grey[300]),
-            child: Text(
+                SizedBox(height: 16),
-              '得意先名称',
+                Text('顧客データがありません', style: TextStyle(color: Colors.grey)),
-              style: TextStyle(fontWeight: FontWeight.bold),
+                SizedBox(height: 16),
+                IconButton(
+                  icon: Icon(Icons.add, color: Theme.of(context).primaryColor),
+                  onPressed: () => _showAddDialog(context),
+                ),
+              ],
             ),
-          ),
+          )
-          // カードリスト形式（標準 Material 部品）
+        : ListView.builder(
-          ListView.builder(
+            padding: const EdgeInsets.all(8),
-            shrinkWrap: true,
+            itemCount: _customers.length,
-            padding: EdgeInsets.zero,
-            itemCount: 5, // デモ用データ数
             itemBuilder: (context, index) {
-              return Card(
+              final customer = _customers[index];
-                margin: const EdgeInsets.symmetric(vertical: 4),
+              return Dismissible(
-                child: ListTile(
+                key: Key(customer.customerCode),
-                  leading: CircleAvatar(
+                direction: DismissDirection.endToStart,
-                    backgroundColor: Colors.teal.shade100,
+                background: Container(
-                    child: Icon(Icons.person, color: Colors.teal),
+                  color: Colors.red,
-                  ),
+                  alignment: Alignment.centerRight,
-                  title: Text('会社${index + 1}株式会社'),
+                  padding: const EdgeInsets.only(right: 20),
-                  subtitle: Text('担当者：山田花子'),
+                  child: const Icon(Icons.delete, color: Colors.white),
-                  trailing: Row(
+                ),
-                    mainAxisSize: MainAxisSize.min,
+                onDismissed: (_) => _deleteCustomer(customer.id!),
-                    children: [
+                child: Card(
-                      IconButton(
+                  margin: EdgeInsets.zero,
-                        icon: const Icon(Icons.edit),
+                  clipBehavior: Clip.antiAlias,
-                        onPressed: () => _showEditDialog(context, index),
+                  child: ListTile(
-                      ),
+                    leading: CircleAvatar(
-                      IconButton(
+                      backgroundColor: Colors.blue.shade100,
-                        icon: const Icon(Icons.delete),
+                      child: const Icon(Icons.person, color: Colors.blue),
-                        onPressed: () => _showDeleteDialog(context, index),
+                    ),
-                      ),
+                    title: Text(customer.name),
-                    ],
+                    subtitle: Column(
+                      crossAxisAlignment: CrossAxisAlignment.start,
+                      children: [
+                        if (customer.email != null)
+                          Text('Email: ${customer.email}', style: const TextStyle(fontSize: 12)),
+                        Text('税抜：${(customer.taxRate / 8 * 100).toStringAsFixed(1)}%'),
+                        Text('割引：${customer.discountRate}%'),
+                      ],
+                    ),
+                    trailing: Row(
+                      mainAxisSize: MainAxisSize.min,
+                      children: [
+                        IconButton(icon: const Icon(Icons.edit), onPressed: () => _showEditDialog(context, customer),),
+                        IconButton(icon: const Icon(Icons.more_vert), onPressed: () => _showMoreOptions(context, customer),),
+                      ],
+                    ),
                   ),
                 ),
               );
             },
           ),
+      floatingActionButton: FloatingActionButton.extended(
+        icon: const Icon(Icons.add),
+        label: const Text('新規登録'),
+        onPressed: () => _showAddDialog(context),
+      ),
+    );
+  }
+
+  Future<void> _addCustomer(Customer customer) async {
+    final db = await DatabaseHelper.instance.database;
+
+    // 既存顧客リストを取得
+    final existingCustomers = (await db.query('customers')) as List<Map<String, dynamic>>;
+    final customerCodes = existingCustomers.map((e) => e['customer_code'] as String).toList();
+
+    if (customerCodes.contains(customer.customerCode)) {
+      _showSnackBar(context, '既に同じコードを持つ顧客が登録されています');
+      return;
+    }
+
+    try {
+      await db.insert('customers', customer.toMap());
+      await DatabaseHelper.instance.saveSnapshot(customer); // Event sourcing snapshot
+      await _loadCustomers();
+
+      if (mounted) {
+        ScaffoldMessenger.of(context).showSnackBar(
+          const SnackBar(content: Text('顧客を登録しました')),
+        );
+      }
+    } catch (e) {
+      _showSnackBar(context, '登録に失敗：$e');
+    }
+  }
+
+  Future<void> _editCustomer(Customer customer) async {
+    if (!mounted) return;
+    ScaffoldMessenger.of(context).showSnackBar(
+      SnackBar(
+        content: Text('編集機能：${customer.name}'),
+        action: const SnackBarAction(label: 'キャンセル', onPressed: () {}),
+      ),
+    );
+  }
+
+  Future<void> _deleteCustomer(int id) async {
+    final confirmed = await showDialog<bool>(
+      context: context,
+      builder: (ctx) => AlertDialog(
+        title: const Text('顧客削除'),
+        content: Text('この顧客を削除しますか？履歴データも消去されます。'),
+        actions: [
+          TextButton(onPressed: () => Navigator.pop(ctx, false), child: const Text('キャンセル'),),
+          ElevatedButton(
+            onPressed: () => Navigator.pop(ctx, true),
+            style: ElevatedButton.styleFrom(backgroundColor: Colors.red),
+            child: const Text('削除'),
+          ),
         ],
       ),
     );
+
+    if (confirmed == true) {
+      try {
+        await DatabaseHelper.instance.delete(id);
+        await _loadCustomers();
+        if (mounted) {
+          ScaffoldMessenger.of(context).showSnackBar(
+            const SnackBar(content: Text('顧客を削除しました')),
+          );
+        }
+      } catch (e) {
+        _showSnackBar(context, '削除に失敗：$e');
+      }
+    }
   }
 
   void _showAddDialog(BuildContext context) {
     showDialog(
       context: context,
       builder: (ctx) => AlertDialog(
-        title: const Text('新規得意先登録'),
+        title: const Text('新規顧客登録'),
         content: SingleChildScrollView(
           child: Column(
             mainAxisSize: MainAxisSize.min,
             children: [
-              TextField(
+              ListTile(
-                decoration: const InputDecoration(
+                title: const Text('得意先コード *'),
-                  labelText: '会社名',
+                subtitle: const Text('JAN 形式など（半角数字）'),
-                  hintText: '株式会社名を入力',
+                onLongPress: () => _showSnackBar(context, '登録機能（プレースホルダ）'),
-                ),
               ),
-              const SizedBox(height: 8),
+              ListTile(
-              TextField(
+                title: const Text('顧客名称 *'),
-                decoration: const InputDecoration(
+                subtitle: const Text('株式会社〇〇'),
-                  labelText: '代表者名',
+                onLongPress: () => _showSnackBar(context, '登録機能（プレースホルダ）'),
-                ),
               ),
-              const SizedBox(height: 8),
+              ListTile(
-              TextField(
+                title: const Text('電話番号'),
-                decoration: const InputDecoration(
+                subtitle: const Text('03-1234-5678'),
-                  labelText: '住所',
+                onLongPress: () => _showSnackBar(context, '登録機能（プレースホルダ）'),
-                  hintText: '〒000-0000 北海道...',
-                ),
               ),
-              const SizedBox(height: 8),
+              ListTile(
-              TextField(
+                title: const Text('Email'),
-                decoration: const InputDecoration(
+                subtitle: const Text('example@example.com'),
-                  labelText: '電話番号',
+                onLongPress: () => _showSnackBar(context, '登録機能（プレースホルダ）'),
-                  hintText: '0123-456789',
-                ),
-                keyboardType: TextInputType.phone,
               ),
-              const SizedBox(height: 8),
+              ListTile(
-              TextField(
+                title: const Text('住所'),
-                decoration: const InputDecoration(
+                subtitle: const Text('〒000-0000 市区町村名・番地'),
-                  labelText: '担当者名',
+                onLongPress: () => _showSnackBar(context, '登録機能（プレースホルダ）'),
-                ),
+              ),
+              const SizedBox(height: 12),
+              Text(
+                '※ 保存ボタンを押すと、上記の値から作成された顧客データが登録されます',
+                textAlign: TextAlign.center,
+                style: TextStyle(fontStyle: FontStyle.italic),
               ),
             ],
           ),
         ),
         actions: [
-          TextButton(
+          TextButton(onPressed: () => Navigator.pop(ctx), child: const Text('キャンセル'),),
-            onPressed: () => Navigator.pop(ctx),
-            child: const Text('キャンセル'),
-          ),
           ElevatedButton(
             onPressed: () {
               Navigator.pop(ctx);
-              ScaffoldMessenger.of(context).showSnackBar(
+              // 実際の登録処理は後期開発（プレースホルダ）
-                const SnackBar(content: Text('得意先登録しました')),
+              _showSnackBar(context, '顧客データを保存します...');
-              );
             },
             child: const Text('保存'),
           ),
@@ -129,33 +239,139 @@ class CustomerMasterScreen extends StatelessWidget {
     );
   }
 
-  void _showEditDialog(BuildContext context, int index) {
+  void _showEditDialog(BuildContext context, Customer customer) {
-    // 編集ダイアログ（構造は新規と同様）
+    if (!mounted) return;
-  }
-
-  void _showDeleteDialog(BuildContext context, int index) {
     showDialog(
       context: context,
       builder: (ctx) => AlertDialog(
-        title: const Text('得意先削除'),
+        title: const Text('顧客編集'),
-        content: Text('会社${index + 1}株式会社を削除しますか？'),
+        content: Column(
+          mainAxisSize: MainAxisSize.min,
+          children: [
+            ListTile(
+              title: const Text('顧客コード'),
+              subtitle: Text(customer.customerCode),
+              onLongPress: () => _showSnackBar(context, '編集機能（プレースホルダ）'),
+            ),
+            ListTile(
+              title: const Text('名称'),
+              subtitle: Text(customer.name),
+              onLongPress: () => _showSnackBar(context, '編集機能（プレースホルダ）'),
+            ),
+            ListTile(
+              title: const Text('電話番号'),
+              subtitle: Text(customer.phoneNumber),
+              onLongPress: () => _showSnackBar(context, '編集機能（プレースホルダ）'),
+            ),
+            ListTile(
+              title: const Text('税抜率'),
+              subtitle: Text('${customer.taxRate}%'),
+              onLongPress: () => _showSnackBar(context, '編集機能（プレースホルダ）'),
+            ),
+          ],
+        ),
         actions: [
-          TextButton(
+          TextButton(onPressed: () => Navigator.pop(ctx), child: const Text('キャンセル'),),
-            onPressed: () => Navigator.pop(ctx),
-            child: const Text('キャンセル'),
-          ),
           ElevatedButton(
             onPressed: () {
+              // 実際の保存処理は後期開発（プレースホルダ）
+              _showSnackBar(context, '編集を保存します...');
               Navigator.pop(ctx);
-              ScaffoldMessenger.of(context).showSnackBar(
-                const SnackBar(content: Text('得意先削除しました')),
-              );
             },
-            style: ElevatedButton.styleFrom(backgroundColor: Colors.red),
+            child: const Text('保存'),
-            child: const Text('削除'),
           ),
         ],
       ),
     );
   }
+
+  void _showMoreOptions(BuildContext context, Customer customer) {
+    showModalBottomSheet(
+      context: context,
+      builder: (ctx) => SafeArea(
+        child: Padding(
+          padding: const EdgeInsets.all(16),
+          child: Column(
+            mainAxisSize: MainAxisSize.min,
+            crossAxisAlignment: CrossAxisAlignment.start,
+            children: [
+              Text('『${customer.name}』のオプション機能', style: Theme.of(context).textTheme.titleLarge),
+              ListTile(
+                leading: const Icon(Icons.info_outline),
+                title: const Text('顧客詳細表示'),
+                onTap: () => _showCustomerDetail(context, customer),
+              ),
+              ListTile(
+                leading: const Icon(Icons.history_edu),
+                title: const Text('履歴表示（イベントソーシング）', style: TextStyle(color: Colors.grey)),
+                onTap: () => _showSnackBar(context, 'イベント履歴機能は後期開発'),
+              ),
+              ListTile(
+                leading: const Icon(Icons.copy),
+                title: const Text('QR コード発行（未実装）', style: TextStyle(color: Colors.grey)),
+                onTap: () => _showSnackBar(context, 'QR コード機能は後期開発で'),
+              ),
+            ],
+          ),
+        ),
+      ),
+    );
+  }
+
+  void _showCustomerDetail(BuildContext context, Customer customer) {
+    if (!mounted) return;
+    showDialog(
+      context: context,
+      builder: (ctx) => AlertDialog(
+        title: const Text('顧客詳細'),
+        content: SingleChildScrollView(
+          child: Column(
+            mainAxisSize: MainAxisSize.min,
+            children: [
+              _detailRow('得意先コード', customer.customerCode),
+              _detailRow('名称', customer.name),
+              _detailRow('電話番号', customer.phoneNumber),
+              _detailRow('Email', customer.email ?? '-'),
+              _detailRow('住所', customer.address),
+              if (customer.salesPersonId > 0) _detailRow('担当者 ID', customer.salesPersonId.toString()),
+              _detailRow('税抜率', '${customer.taxRate}%'),
+              _detailRow('割引率', '${customer.discountRate}%'),
+            ],
+          ),
+        ),
+        actions: [
+          TextButton(onPressed: () => Navigator.pop(ctx), child: const Text('閉じる'),),
+        ],
+      ),
+    );
+  }
+
+  Widget _detailRow(String label, String value) {
+    return Padding(
+      padding: const EdgeInsets.only(bottom: 8),
+      child: Row(
+        crossAxisAlignment: CrossAxisAlignment.start,
+        children: [
+          SizedBox(width: 100),
+          Expanded(child: Text(value)),
+        ],
+      ),
+    );
+  }
+
+  Future<void> _showEventHistory(BuildContext context, Customer customer) async {
+    if (!mounted) return;
+    ScaffoldMessenger.of(context).showSnackBar(
+      const SnackBar(content: Text('イベント履歴表示（未実装：後期開発）')),
+    );
+  }
+
+  void _showSnackBar(BuildContext context, String message) {
+    if (!mounted) return;
+    ScaffoldMessenger.of(context).showSnackBar(
+      SnackBar(
+        content: Text(message),
+      ),
+    );
+  }
 }

lib/services/database_helper.dart

@@ -0,0 +1,139 @@
+// Version: 1.0.0
+import 'package:sqflite/sqflite.dart';
+import 'package:path/path.dart';
+import 'dart:convert';
+import '../models/customer.dart';
+
+class DatabaseHelper {
+  static final DatabaseHelper instance = DatabaseHelper._init();
+  static Database? _database;
+
+  DatabaseHelper._init();
+
+  Future<Database> get database async {
+    if (_database != null) return _database!;
+    _database = await _initDB('customer_assist.db');
+    return _database!;
+  }
+
+  Future<Database> _initDB(String filePath) async {
+    final dbPath = await getDatabasesPath();
+    final path = join(dbPath, filePath);
+
+    return await openDatabase(
+      path,
+      version: 1,
+      onCreate: _createDB,
+    );
+  }
+
+  Future<void> _createDB(Database db, int version) async {
+    const idType = 'INTEGER PRIMARY KEY AUTOINCREMENT';
+    const textType = 'TEXT NOT NULL';
+    const intType = 'INTEGER';
+
+    await db.execute('''
+      CREATE TABLE customers (
+        id INTEGER PRIMARY KEY AUTOINCREMENT,
+        customer_code TEXT NOT NULL,
+        name TEXT NOT NULL,
+        phone_number TEXT NOT NULL,
+        email TEXT NOT NULL,
+        address TEXT NOT NULL,
+        sales_person_id INTEGER,
+        tax_rate INTEGER DEFAULT 8, // Default 10%
+        discount_rate INTEGER DEFAULT 0, // Default 0%
+        created_at TEXT NOT NULL,
+        updated_at TEXT NOT NULL
+      )
+    ''');
+
+    await db.execute('''
+      CREATE TABLE customer_snapshots (
+        id INTEGER PRIMARY KEY AUTOINCREMENT,
+        customer_id INTEGER NOT NULL,
+        data_json TEXT NOT NULL,
+        created_at TEXT NOT NULL
+      )
+    ''');
+  }
+
+  Future<int> insert(Customer customer) async {
+    final db = await instance.database;
+    return await db.insert('customers', customer.toMap());
+  }
+
+  Future<List<Customer>> getCustomers() async {
+    final db = await instance.database;
+    final List<Map<String, dynamic>> maps = await db.query('customers');
+    
+    return (maps as List)
+        .map((json) => Customer.fromMap(json))
+        .where((c) => c.isDeleted == 0)
+        .toList();
+  }
+
+  Future<Customer?> getCustomer(int id) async {
+    final db = await instance.database;
+    final maps = await db.query(
+      'customers',
+      where: 'id = ?',
+      whereArgs: [id],
+    );
+    
+    if (maps.isEmpty) return null;
+    return Customer.fromMap(maps.first);
+  }
+
+  Future<int> update(Customer customer) async {
+    final db = await instance.database;
+    return await db.update(
+      'customers',
+      customer.toMap(),
+      where: 'id = ?',
+      whereArgs: [customer.id],
+    );
+  }
+
+  Future<int> delete(int id) async {
+    final db = await instance.database;
+    return await db.update(
+      'customers',
+      {'is_deleted': 1}, // Soft delete
+      where: 'id = ?',
+      whereArgs: [id],
+    );
+  }
+
+  Future<void> saveSnapshot(Customer customer) async {
+    final db = await instance.database;
+    final id = customer.id;
+    final now = DateTime.now().toIso8601String();
+
+    // Check if snapshot already exists for this customer (keep last 5 snapshots)
+    final existing = await db.query(
+      'customer_snapshots',
+      where: 'customer_id = ?',
+      whereArgs: [id],
+      limit: 6,
+    );
+
+    if (existing.length > 5) {
+      // Delete oldest snapshot
+      final oldestId = existing.first['id'] as int;
+      await db.delete('customer_snapshots', where: 'id = ?', whereArgs: [oldestId]);
+    }
+
+    // Insert new snapshot
+    await db.insert('customer_snapshots', {
+      'customer_id': id,
+      'data_json': jsonEncode(customer.toMap()),
+      'created_at': now,
+    });
+  }
+
+  Future<void> close() async {
+    final db = await instance.database;
+    db.close();
+  }
+}

pubspec.yaml

@@ -2,7 +2,7 @@ name: sales_assist_1
 description: オフライン単体で見積・納品・請求・レジ業務まで完結できる販売アシスタント
 publish_to: 'none'
 
-version: 1.0.0+4
+version: 1.0.0+5
 
 environment:
   sdk: '>=3.0.0 <4.0.0'
@@ -11,25 +11,21 @@ dependencies:
   flutter:
     sdk: flutter
   cupertino_icons: ^1.0.6
-  
+
   # SQLite データ永続化
   sqflite: ^2.3.3
   path_provider: ^2.1.1
-  
+
   # Google エコシステム連携
   google_sign_in: ^6.1.0
   http: ^1.1.0
-  googleapis_auth: ^1.4.0
-  googleapis: ^12.0.0
   googleapis_auth: ^1.5.0
-  
+  googleapis: ^12.0.0
+
 dev_dependencies:
   flutter_test:
     sdk: flutter
   flutter_lints: ^3.0.0
 
 flutter:
-  uses-material-design: true
+  uses-material-design: true
-  
-  assets:
-    - assets/