import 'package:flutter/material.dart';
import 'package:lucide_icons/lucide_icons.dart';
import '../../services/backup_service.dart';

class BackupSettingsSection extends StatefulWidget {
  final String title;

  const BackupSettingsSection({
    super.key,
    this.title = 'データバックアップ',
  });

  @override
  State<BackupSettingsSection> createState() => _BackupSettingsSectionState();
}

enum _BackupState { idle, signingIn, signingOut, backingUp, restoring }
 
 class _BackupSettingsSectionState extends State<BackupSettingsSection> {
   final BackupService _backupService = BackupService();
   _BackupState _state = _BackupState.idle;

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

   Future<void> _initBackupService() async {
     await _backupService.init();
     if (mounted) {
       setState(() {});
     }
   }

   Future<void> _signIn() async {
     setState(() => _state = _BackupState.signingIn);
     final account = await _backupService.signIn();
     if (mounted) {
       setState(() => _state = _BackupState.idle);
       if (account != null) {
         ScaffoldMessenger.of(context).showSnackBar(
           SnackBar(content: Text('${account.email} で連携しました')),
         );
       } else {
         ScaffoldMessenger.of(context).showSnackBar(
           const SnackBar(content: Text('連携がキャンセルされました')),
         );
       }
     }
   }

   Future<void> _signOut() async {
     final confirmed = await showDialog<bool>(
       context: context,
       builder: (context) => AlertDialog(
         title: const Text('連携解除'),
         content: const Text('Googleアカウントとの連携を解除しますか？'),
         actions: [
           TextButton(
             onPressed: () => Navigator.pop(context, false),
             child: const Text('キャンセル'),
           ),
           ElevatedButton(
             onPressed: () => Navigator.pop(context, true),
             child: const Text('解除'),
           ),
         ],
       ),
     );

     if (confirmed == true) {
       setState(() => _state = _BackupState.signingOut);
       await _backupService.signOut();
       if (mounted) {
         setState(() => _state = _BackupState.idle);
         ScaffoldMessenger.of(context).showSnackBar(
           const SnackBar(content: Text('連携を解除しました')),
         );
       }
     }
   }

   Future<void> _createBackup() async {
     setState(() => _state = _BackupState.backingUp);
     final success = await _backupService.createBackup();
     if (mounted) {
       setState(() => _state = _BackupState.idle);
       ScaffoldMessenger.of(context).showSnackBar(
         SnackBar(
           content: Text(success ? 'バックアップが完了しました' : 'バックアップに失敗しました'),
           backgroundColor: success ? Colors.green : Colors.red,
         ),
       );
     }
   }

   Future<void> _restoreBackup() async {
     final hasBackup = await _backupService.hasBackupOnDrive();
     if (!hasBackup && mounted) {
       ScaffoldMessenger.of(context).showSnackBar(
         const SnackBar(content: Text('バックアップファイルが見つかりません')),
       );
       return;
     }

     final confirmed = await showDialog<bool>(
       context: context,
       builder: (context) => AlertDialog(
         title: Row(
           children: [
             Icon(LucideIcons.alertTriangle, color: Colors.orange, size: 24),
             const SizedBox(width: 8),
             const Text('データ復元'),
           ],
         ),
         content: const Text('現在のデータは上書きされます。\n削除されたデータは元に戻りません。\n\n本当に続行しますか？'),
         actions: [
           TextButton(
             onPressed: () => Navigator.pop(context, false),
             child: const Text('キャンセル'),
           ),
           ElevatedButton(
             onPressed: () => Navigator.pop(context, true),
             style: ElevatedButton.styleFrom(
               backgroundColor: Theme.of(context).primaryColor,
               foregroundColor: Colors.white,
             ),
             child: const Text('復元'),
           ),
         ],
       ),
     );

     if (confirmed == true) {
       setState(() => _state = _BackupState.restoring);
       final success = await _backupService.restoreBackup();
       if (mounted) {
         setState(() => _state = _BackupState.idle);
         ScaffoldMessenger.of(context).showSnackBar(
           SnackBar(
             content: Text(success ? '復元が完了しました' : '復元に失敗しました'),
             backgroundColor: success ? Colors.green : Colors.red,
           ),
         );
       }
     }
   }

   @override
   Widget build(BuildContext context) {
     final currentUser = _backupService.currentUser;
     final isDark = Theme.of(context).brightness == Brightness.dark;
     final isAnyProcessing = _state != _BackupState.idle;

     return Column(
       children: [
         _buildSectionHeader(context, widget.title, LucideIcons.cloud),

         // Wi-Fi推奨の注意書き (v1.2)
         Container(
           margin: const EdgeInsets.only(bottom: 12),
           padding: const EdgeInsets.all(12),
           decoration: BoxDecoration(
             color: Colors.blue.withValues(alpha: 0.1),
             borderRadius: BorderRadius.circular(8),
             border: Border.all(color: Colors.blue.withValues(alpha: 0.3)),
           ),
           child: Row(
             crossAxisAlignment: CrossAxisAlignment.start,
             children: [
               Icon(LucideIcons.wifi, color: Colors.blue, size: 20),
               const SizedBox(width: 12),
               Expanded(
                 child: Text(
                   'バックアップにはWi-Fi環境を推奨します\n画像が多い場合、数百MB〜1GB以上になる可能性があります',
                   style: TextStyle(
                     fontSize: 12,
                     color: isDark ? Colors.blue[300] : Colors.blue[900],
                   ),
                 ),
               ),
             ],
           ),
         ),

         Card(
           color: isDark ? const Color(0xFF1E1E1E) : null,
           child: Column(
             children: [
               // Google Sign In Status
               ListTile(
                 leading: Icon(
                   currentUser != null ? LucideIcons.checkCircle2 : LucideIcons.user,
                   color: currentUser != null ? Colors.green : (isDark ? Colors.orange[300] : Theme.of(context).primaryColor),
                 ),
                 title: Text(currentUser == null ? 'Googleアカウント連携' : currentUser.email),
                 subtitle: Text(currentUser == null ? 'バックアップを利用するには連携が必要です' : '安全にログアウトできます'),
                 trailing: (_state == _BackupState.signingIn || _state == _BackupState.signingOut)
                     ? const SizedBox(width: 24, height: 24, child: CircularProgressIndicator(strokeWidth: 2))
                     : ElevatedButton(
                         style: ElevatedButton.styleFrom(
                           backgroundColor: currentUser == null ? Theme.of(context).primaryColor : Colors.grey[700],
                           foregroundColor: Colors.white,
                           padding: const EdgeInsets.symmetric(horizontal: 16),
                         ),
                         onPressed: isAnyProcessing ? null : (currentUser == null ? _signIn : _signOut),
                         child: Text(currentUser == null ? '連携' : '解除'),
                       ),
               ),
               if (currentUser != null) ...[
                 const Divider(height: 1),
                 ListTile(
                   leading: Icon(LucideIcons.uploadCloud, color: isDark ? Colors.blue[300] : Colors.blue),
                   title: const Text('バックアップ'),
                   subtitle: const Text('Google Driveに最新データのみ保存（過去分は上書き）'),
                   trailing: _state == _BackupState.backingUp
                       ? const SizedBox(width: 24, height: 24, child: CircularProgressIndicator(strokeWidth: 2))
                       : null,
                   onTap: isAnyProcessing ? null : _createBackup,
                 ),
                 const Divider(height: 1),
                 ListTile(
                   leading: Icon(LucideIcons.downloadCloud, color: isDark ? Colors.red[300] : Colors.red),
                   title: const Text('データ復元'),
                   subtitle: const Text('Google Driveからデータを読み込み（上書き）'),
                   trailing: _state == _BackupState.restoring
                       ? const SizedBox(width: 24, height: 24, child: CircularProgressIndicator(strokeWidth: 2))
                       : null,
                   onTap: isAnyProcessing ? null : _restoreBackup,
                 ),
               ],
             ],
           ),
         ),
       ],
     );
   }

  Widget _buildSectionHeader(BuildContext context, String title, IconData icon) {
    final isDark = Theme.of(context).brightness == Brightness.dark;
    return Padding(
      padding: const EdgeInsets.symmetric(vertical: 8, horizontal: 4),
      child: Row(
        children: [
          Icon(icon, size: 20, color: isDark ? Colors.orange[300] : Theme.of(context).primaryColor),
          const SizedBox(width: 8),
          Text(
            title,
            style: Theme.of(context).textTheme.titleMedium?.copyWith(
              fontWeight: FontWeight.bold,
              color: isDark ? Colors.grey[300] : Theme.of(context).primaryColor,
            ),
          ),
        ],
      ),
    );
  }
}