import 'package:flutter/material.dart';
import 'package:uuid/uuid.dart';

import '../models/department_model.dart';
import '../services/department_repository.dart';

class DepartmentMasterScreen extends StatefulWidget {
  const DepartmentMasterScreen({super.key});

  @override
  State<DepartmentMasterScreen> createState() => _DepartmentMasterScreenState();
}

class _DepartmentMasterScreenState extends State<DepartmentMasterScreen> {
  final DepartmentRepository _repository = DepartmentRepository();
  final Uuid _uuid = const Uuid();

  bool _isLoading = true;
  bool _includeInactive = true;
  List<Department> _departments = const [];

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

  Future<void> _loadDepartments() async {
    setState(() => _isLoading = true);
    final list = await _repository.fetchDepartments(includeInactive: _includeInactive);
    if (!mounted) return;
    setState(() {
      _departments = list;
      _isLoading = false;
    });
  }

  Future<void> _openForm({Department? department}) async {
    final result = await showDialog<Department>(
      context: context,
      builder: (ctx) => _DepartmentFormDialog(
        department: department,
        onSubmit: (data) => Navigator.of(ctx).pop(data),
      ),
    );
    if (result == null) return;
    final saving = result.copyWith(id: result.id.isEmpty ? _uuid.v4() : result.id, updatedAt: DateTime.now());
    await _repository.saveDepartment(saving);
    if (!mounted) return;
    ScaffoldMessenger.of(context).showSnackBar(const SnackBar(content: Text('部門を保存しました')));
    _loadDepartments();
  }

  Future<void> _deleteDepartment(Department department) async {
    final confirmed = await showDialog<bool>(
      context: context,
      builder: (ctx) => AlertDialog(
        title: const Text('部門を削除'),
        content: Text('${department.name} を削除しますか？'),
        actions: [
          TextButton(onPressed: () => Navigator.pop(ctx, false), child: const Text('キャンセル')),
          TextButton(onPressed: () => Navigator.pop(ctx, true), child: const Text('削除', style: TextStyle(color: Colors.red))),
        ],
      ),
    );
    if (confirmed != true) return;
    await _repository.deleteDepartment(department.id);
    if (!mounted) return;
    ScaffoldMessenger.of(context).showSnackBar(const SnackBar(content: Text('部門を削除しました')));
    _loadDepartments();
  }

  @override
  Widget build(BuildContext context) {
    return Scaffold(
      appBar: AppBar(
        leading: const BackButton(),
        title: const Text('M4:部門マスター'),
        actions: [
          SwitchListTile.adaptive(
            value: _includeInactive,
            onChanged: (value) {
              setState(() => _includeInactive = value);
              _loadDepartments();
            },
            contentPadding: const EdgeInsets.only(right: 12),
            title: const Text('無効を表示'),
          ),
        ],
      ),
      floatingActionButton: FloatingActionButton(
        onPressed: () => _openForm(),
        child: const Icon(Icons.add),
      ),
      body: _isLoading
          ? const Center(child: CircularProgressIndicator())
          : _departments.isEmpty
              ? const _EmptyState(message: '部門が登録されていません')
              : ListView.separated(
                  padding: const EdgeInsets.all(16),
                  itemCount: _departments.length,
                  separatorBuilder: (context, _) => const SizedBox(height: 8),
                  itemBuilder: (context, index) {
                    final department = _departments[index];
                    return Card(
                      child: ListTile(
                        title: Text(department.name, style: const TextStyle(fontWeight: FontWeight.bold)),
                        subtitle: Text([
                          if (department.code?.isNotEmpty == true) 'コード: ${department.code}',
                          department.description ?? '',
                          department.isActive ? '稼働中' : '無効',
                        ].where((v) => v.isNotEmpty).join('\n')),
                        trailing: PopupMenuButton<String>(
                          onSelected: (value) {
                            switch (value) {
                              case 'edit':
                                _openForm(department: department);
                                break;
                              case 'delete':
                                _deleteDepartment(department);
                                break;
                            }
                          },
                          itemBuilder: (context) => const [
                            PopupMenuItem(value: 'edit', child: Text('編集')),
                            PopupMenuItem(value: 'delete', child: Text('削除')),
                          ],
                        ),
                      ),
                    );
                  },
                ),
    );
  }
}

class _DepartmentFormDialog extends StatefulWidget {
  const _DepartmentFormDialog({required this.onSubmit, this.department});

  final Department? department;
  final ValueChanged<Department> onSubmit;

  @override
  State<_DepartmentFormDialog> createState() => _DepartmentFormDialogState();
}

class _DepartmentFormDialogState extends State<_DepartmentFormDialog> {
  late final TextEditingController _nameController;
  late final TextEditingController _codeController;
  late final TextEditingController _descriptionController;
  bool _isActive = true;

  @override
  void initState() {
    super.initState();
    final department = widget.department;
    _nameController = TextEditingController(text: department?.name ?? '');
    _codeController = TextEditingController(text: department?.code ?? '');
    _descriptionController = TextEditingController(text: department?.description ?? '');
    _isActive = department?.isActive ?? true;
  }

  void _submit() {
    if (_nameController.text.trim().isEmpty) {
      ScaffoldMessenger.of(context).showSnackBar(const SnackBar(content: Text('部門名は必須です')));
      return;
    }
    widget.onSubmit(
      Department(
        id: widget.department?.id ?? '',
        name: _nameController.text.trim(),
        code: _codeController.text.trim().isEmpty ? null : _codeController.text.trim(),
        description: _descriptionController.text.trim().isEmpty ? null : _descriptionController.text.trim(),
        isActive: _isActive,
        updatedAt: DateTime.now(),
      ),
    );
  }

  @override
  Widget build(BuildContext context) {
    return AlertDialog(
      title: Text(widget.department == null ? '部門を追加' : '部門を編集'),
      content: SingleChildScrollView(
        child: Column(
          mainAxisSize: MainAxisSize.min,
          children: [
            TextField(controller: _nameController, decoration: const InputDecoration(labelText: '部門名 *')),
            TextField(controller: _codeController, decoration: const InputDecoration(labelText: '部門コード')),
            TextField(controller: _descriptionController, decoration: const InputDecoration(labelText: '説明'), maxLines: 2),
            SwitchListTile(
              title: const Text('稼働中'),
              value: _isActive,
              onChanged: (value) => setState(() => _isActive = value),
            ),
          ],
        ),
      ),
      actions: [
        TextButton(onPressed: () => Navigator.pop(context), child: const Text('キャンセル')),
        FilledButton(onPressed: _submit, child: const Text('保存')),
      ],
    );
  }
}

class _EmptyState extends StatelessWidget {
  const _EmptyState({required this.message});

  final String message;

  @override
  Widget build(BuildContext context) {
    return Center(
      child: Column(
        mainAxisAlignment: MainAxisAlignment.center,
        children: [
          const Icon(Icons.view_list, size: 64, color: Colors.grey),
          const SizedBox(height: 16),
          Text(message),
        ],
      ),
    );
  }
}