// Version: 1.7 - 得意先マスタ画面（DB 連携実装）
import 'package:flutter/material.dart';
import '../../models/customer.dart';
import '../../services/database_helper.dart';

/// 得意先マスタ管理画面（CRUD 機能付き）
class CustomerMasterScreen extends StatefulWidget {
  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 ?? const <Customer>[];
        _isLoading = false;
      });
    } catch (e) {
      if (!mounted) return;
      ScaffoldMessenger.of(context).showSnackBar(
        SnackBar(content: Text('顧客データを読み込みませんでした：$e'), backgroundColor: Colors.red),
      );
    }
  }

  Future<void> _addCustomer(Customer customer) async {
    try {
      await DatabaseHelper.instance.insertCustomer(customer);
      if (mounted) {
        ScaffoldMessenger.of(context).showSnackBar(
          const SnackBar(content: Text('顧客を登録しました'), backgroundColor: Colors.green),
        );
        _loadCustomers();
      }
    } catch (e) {
      if (mounted) ScaffoldMessenger.of(context).showSnackBar(
        SnackBar(content: Text('登録に失敗：$e'), backgroundColor: Colors.red),
      );
    }
  }

  Future<void> _editCustomer(Customer customer) async {
    if (!mounted) return;
    final updatedCustomer = await _showEditDialog(context, customer);
    if (updatedCustomer != null && mounted) {
      try {
        await DatabaseHelper.instance.updateCustomer(updatedCustomer);
        ScaffoldMessenger.of(context).showSnackBar(
          const SnackBar(content: Text('顧客を更新しました'), backgroundColor: Colors.green),
        );
        _loadCustomers();
      } catch (e) {
        if (mounted) ScaffoldMessenger.of(context).showSnackBar(
          SnackBar(content: Text('更新に失敗：$e'), backgroundColor: Colors.red),
        );
      }
    }
  }

  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.deleteCustomer(id);
        if (mounted) _loadCustomers();
        ScaffoldMessenger.of(context).showSnackBar(
          const SnackBar(content: Text('顧客を削除しました'), backgroundColor: Colors.green),
        );
      } catch (e) {
        ScaffoldMessenger.of(context).showSnackBar(
          SnackBar(content: Text('削除に失敗：$e'), backgroundColor: Colors.red),
        );
      }
    }
  }

  Future<Customer?> _showEditDialog(BuildContext context, Customer customer) async {
    final edited = await showDialog<Customer>(
      context: context,
      builder: (ctx) => AlertDialog(
        title: const Text('顧客編集'),
        content: SingleChildScrollView(
          child: Column(
            mainAxisSize: MainAxisSize.min,
            crossAxisAlignment: CrossAxisAlignment.stretch,
            children: [
              TextField(
                decoration: InputDecoration(labelText: '得意先コード', hintText: customer.customerCode ?? ''),
                controller: TextEditingController(text: customer.customerCode),
              ),
              const SizedBox(height: 8),
              TextField(
                decoration: InputDecoration(labelText: '名称 *'),
                controller: TextEditingController(text: customer.name),
                onChanged: (v) => customer.name = v,
              ),
              TextField(decoration: InputDecoration(labelText: '電話番号', hintText: '03-1234-5678')),
              const SizedBox(height: 8),
              TextField(
                decoration: InputDecoration(labelText: 'Email'),
                controller: TextEditingController(text: customer.email ?? ''),
                onChanged: (v) => customer.email = v,
              ),
              TextField(decoration: InputDecoration(labelText: '住所', hintText: '〒000-0000 市区町村名・番地')),
              const SizedBox(height: 8),
              TextField(
                decoration: InputDecoration(labelText: '消費税率 *'),
                keyboardType: TextInputType.number,
                controller: TextEditingController(text: customer.taxRate.toString()),
                onChanged: (v) => customer.taxRate = int.tryParse(v) ?? customer.taxRate,
              ),
              TextField(decoration: InputDecoration(labelText: '割引率', hintText: '%')),
              const SizedBox(height: 8),
              TextField(decoration: InputDecoration(labelText: '担当者 ID')),
            ],
          ),
        ),
        actions: [
          TextButton(onPressed: () => Navigator.pop(ctx, null), child: const Text('キャンセル')),
          ElevatedButton(onPressed: () => Navigator.pop(ctx, customer), child: const Text('保存')),
        ],
      ),
    );

    return edited;
  }

  Future<void> _showCustomerDetail(BuildContext context, Customer customer) async {
    showDialog(
      context: context,
      builder: (ctx) => AlertDialog(
        title: const Text('顧客詳細'),
        content: SingleChildScrollView(
          child: Column(
            mainAxisSize: MainAxisSize.min,
            crossAxisAlignment: CrossAxisAlignment.start,
            children: [
              _detailRow('得意先コード', customer.customerCode),
              _detailRow('名称', customer.name),
              if (customer.phoneNumber != null) _detailRow('電話番号', customer.phoneNumber),
              _detailRow('Email', customer.email ?? '-'),
              _detailRow('住所', customer.address ?? '-'),
              _detailRow('消費税率', '${customer.taxRate}%'),
              _detailRow('割引率', '${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)),
        ],
      ),
    );
  }

  void _showSnackBar(BuildContext context, String message) {
    if (!mounted) return;
    ScaffoldMessenger.of(context).showSnackBar(SnackBar(content: Text(message)));
  }

  @override
  Widget build(BuildContext context) {
    return Scaffold(
      appBar: AppBar(
        title: const Text('/M2. 得意先マスタ'),
        actions: [IconButton(icon: const Icon(Icons.refresh), onPressed: _loadCustomers)],
      ),
      body: _isLoading ? const Center(child: CircularProgressIndicator()) :
            _customers.isEmpty ? Center(
              child: Column(
                mainAxisAlignment: MainAxisAlignment.center,
                children: [
                  Icon(Icons.inbox_outlined, size: 64, color: Colors.grey[300]),
                  SizedBox(height: 16),
                  Text('顧客データがありません', style: TextStyle(color: Colors.grey)),
                  SizedBox(height: 16),
                  FloatingActionButton.extended(
                    icon: Icon(Icons.add, color: Theme.of(context).primaryColor),
                    label: const Text('新規登録'),
                    onPressed: () => _showAddDialog(context),
                  ),
                ],
              ),
            )
          : ListView.builder(
              padding: const EdgeInsets.all(8),
              itemCount: _customers.length,
              itemBuilder: (context, index) {
                final customer = _customers[index];
                return Dismissible(
                  key: Key(customer.customerCode),
                  direction: DismissDirection.endToStart,
                  background: Container(
                    color: Colors.red,
                    alignment: Alignment.centerRight,
                    padding: const EdgeInsets.only(right: 20),
                    child: const Icon(Icons.delete, color: Colors.white),
                  ),
                  onDismissed: (_) => _deleteCustomer(customer.id ?? 0),
                  child: Card(
                    margin: EdgeInsets.zero,
                    clipBehavior: Clip.antiAlias,
                    child: ListTile(
                      leading: CircleAvatar(backgroundColor: Colors.blue.shade100, child: const Icon(Icons.person, color: Colors.blue)),
                      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: () => _editCustomer(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),
      ),
    );
  }

  void _showAddDialog(BuildContext context) {
    showDialog(
      context: context,
      builder: (ctx) => AlertDialog(
        title: const Text('新規顧客登録'),
        content: SingleChildScrollView(
          child: Column(
            mainAxisSize: MainAxisSize.min,
            crossAxisAlignment: CrossAxisAlignment.stretch,
            children: [
              TextField(decoration: InputDecoration(labelText: '得意先コード *', hintText: 'JAN 形式など（半角数字）')),
              const SizedBox(height: 8),
              TextField(decoration: InputDecoration(labelText: '顧客名称 *', hintText: '株式会社〇〇')),
              TextField(decoration: InputDecoration(labelText: '電話番号', hintText: '03-1234-5678')),
              const SizedBox(height: 8),
              TextField(decoration: InputDecoration(labelText: 'Email', hintText: 'example@example.com')),
              TextField(decoration: InputDecoration(labelText: '住所', hintText: '〒000-0000 市区町村名・番地')),
            ],
          ),
        ),
        actions: [
          TextButton(onPressed: () => Navigator.pop(ctx), child: const Text('キャンセル')),
          ElevatedButton(
            onPressed: () async {
              Navigator.pop(ctx);
              _showSnackBar(context, '顧客データを保存します...');
            },
            child: const Text('保存'),
          ),
        ],
      ),
    );
  }

  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: Icon(Icons.info_outline), title: const Text('顧客詳細表示'), onTap: () => _showCustomerDetail(context, customer)),
              ListTile(leading: 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: 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')),
            ],
          ),
        ),
      ),
    );
  }
}