import 'dart:io';
import 'package:flutter/material.dart';
import 'package:image_picker/image_picker.dart';
import 'package:permission_handler/permission_handler.dart';
import 'package:device_info_plus/device_info_plus.dart';

import 'package:provider/provider.dart';
import '../../core/constants/app_constants.dart';
import '../../core/theme/app_theme.dart';
import '../../data/models/target_type.dart';
import '../crop/crop_screen.dart';
import '../session/session_provider.dart';
import 'widgets/image_source_button.dart';
import '../../services/image_crop_service.dart';
import '../../services/document_scanner_service.dart'; // Scanner ML Kit : redresse la cible de face

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

  @override
  State<CaptureScreen> createState() => _CaptureScreenState();
}

class _CaptureScreenState extends State<CaptureScreen> {
  final ImagePicker _picker = ImagePicker();
  final ImageCropService _cropService = ImageCropService();
  final TargetType _selectedType = TargetType.concentric;

  // Scanner de documents Google ML Kit (redresse la cible de face automatiquement)
  final DocumentScannerService _docScanner = DocumentScannerService();

  String? _selectedImagePath;
  bool _isLoading = false;

  // ─────────────────────────────────────────────────────────────────────────
  // Build principal
  // ─────────────────────────────────────────────────────────────────────────
  @override
  Widget build(BuildContext context) {
    final sessionProvider = context.watch<SessionProvider>();
    final title = sessionProvider.isSessionActive
        ? 'Cible ${sessionProvider.targetCount + 1}'
        : 'Source';

    return Scaffold(
      appBar: AppBar(title: Text(title)),
      body: SingleChildScrollView(
        padding: const EdgeInsets.all(AppConstants.defaultPadding),
        child: Column(
          crossAxisAlignment: CrossAxisAlignment.stretch,
          children: [
            const SizedBox(height: AppConstants.largePadding),
            _buildSectionTitle('Source de l\'Image'),
            const SizedBox(height: 12),
            Row(
              children: [
                Expanded(
                  child: ImageSourceButton(
                    icon: Icons.document_scanner,
                    label: 'Scanner',
                    onPressed: _isLoading ? null : _scanWithDocumentScanner,
                  ),
                ),
                const SizedBox(width: 12),
                Expanded(
                  child: ImageSourceButton(
                    icon: Icons.photo_library,
                    label: 'Galerie',
                    onPressed: _isLoading ? null : _handleGallerySelection,
                  ),
                ),
              ],
            ),
            const SizedBox(height: AppConstants.largePadding),
            if (_isLoading)
              const Center(
                child: Padding(
                  padding: EdgeInsets.all(32),
                  child: CircularProgressIndicator(),
                ),
              )
            else
              _buildGuide(),
          ],
        ),
      ),
    );
  }

  // ─────────────────────────────────────────────────────────────────────────
  // Déclic → lance le scanner de documents Google ML Kit qui redresse
  // automatiquement la cible (feuille rectangulaire) de face.
  // ─────────────────────────────────────────────────────────────────────────
  Future<void> _scanWithDocumentScanner() async {
    setState(() => _isLoading = true);
    try {
      final result = await _docScanner.scanTarget();

      if (!result.success) {
        // L'utilisateur a annulé le scan : on ne fait rien de plus.
        if (mounted) setState(() => _isLoading = false);
        return;
      }

      setState(() {
        _selectedImagePath = result.imagePath;
      });

      _analyzeImage();
    } catch (e) {
      debugPrint('Erreur scanner document: $e');
      if (mounted) {
        ScaffoldMessenger.of(context).showSnackBar(
          const SnackBar(
            content: Text('Le scan a échoué. Réessayez.'),
          ),
        );
      }
    } finally {
      if (mounted) setState(() => _isLoading = false);
    }
  }

  // ─────────────────────────────────────────────────────────────────────────
  // Galerie (inchangée)
  // ─────────────────────────────────────────────────────────────────────────
  Future<void> _handleGallerySelection() async {
    PermissionStatus status;

    if (Platform.isAndroid) {
      final deviceInfo = DeviceInfoPlugin();
      final androidInfo = await deviceInfo.androidInfo;
      status = androidInfo.version.sdkInt >= 33
          ? await Permission.photos.request()
          : await Permission.storage.request();
    } else {
      status = await Permission.photos.request();
    }

    if (status.isGranted) {
      _captureImageFromGallery();
    } else if (status.isPermanentlyDenied) {
      _showSettingsDialog();
    } else {
      if (mounted) {
        ScaffoldMessenger.of(context).showSnackBar(
          const SnackBar(
            content: Text('Accès à la galerie requis pour continuer'),
          ),
        );
      }
    }
  }

  void _showSettingsDialog() {
    showDialog(
      context: context,
      builder: (context) => AlertDialog(
        title: const Text('Permission requise'),
        content: const Text(
          'L\'accès aux photos est nécessaire. Veuillez l\'activer dans les paramètres.',
        ),
        actions: [
          TextButton(
            onPressed: () => Navigator.pop(context),
            child: const Text('Annuler'),
          ),
          TextButton(
            onPressed: () => openAppSettings(),
            child: const Text('Paramètres'),
          ),
        ],
      ),
    );
  }

  Future<void> _captureImageFromGallery() async {
    setState(() => _isLoading = true);
    try {
      final XFile? image = await _picker.pickImage(
        source: ImageSource.gallery,
        maxWidth: 2048,
        maxHeight: 2048,
        imageQuality: 90,
      );
      if (image != null) {
        setState(() {
          _selectedImagePath = image.path;
        });
        _analyzeImage();
      }
    } catch (e) {
      debugPrint('Erreur galerie: $e');
    } finally {
      if (mounted) setState(() => _isLoading = false);
    }
  }

  void _analyzeImage() {
    if (_selectedImagePath == null) return;

    Navigator.push(
      context,
      MaterialPageRoute(
        builder: (_) => CropScreen(
          imagePath: _selectedImagePath!,
          targetType: _selectedType,
        ),
      ),
    );
  }

  // ─────────────────────────────────────────────────────────────────────────
  // Helpers UI
  // ─────────────────────────────────────────────────────────────────────────
  Widget _buildSectionTitle(String title) {
    return Text(
      title,
      style: Theme.of(context)
          .textTheme
          .titleMedium
          ?.copyWith(fontWeight: FontWeight.bold),
    );
  }

  Widget _buildGuide() {
    return Card(
      child: Padding(
        padding: const EdgeInsets.all(AppConstants.defaultPadding),
        child: Column(
          children: [
            Icon(Icons.help_outline, size: 48, color: Colors.grey[400]),
            const SizedBox(height: 12),
            Text(
              'Conseils pour une bonne analyse',
              style: Theme.of(context)
                  .textTheme
                  .titleSmall
                  ?.copyWith(fontWeight: FontWeight.bold),
            ),
            const SizedBox(height: 12),
            _buildGuideItem(
              Icons.crop_free,
              'Cadrez la cible entière dans l\'image',
            ),
            _buildGuideItem(Icons.wb_sunny, 'Utilisez un bon éclairage'),
            _buildGuideItem(Icons.straighten, 'Prenez la photo de face'),
            _buildGuideItem(Icons.blur_off, 'Évitez les images floues'),
            _buildGuideItem(
              Icons.cleaning_services,
              'Nettoyer votre objectif avec une chiffonnette',
            ),
          ],
        ),
      ),
    );
  }

  Widget _buildGuideItem(IconData icon, String text) {
    return Padding(
      padding: const EdgeInsets.symmetric(vertical: 4),
      child: Row(
        children: [
          Icon(icon, size: 20, color: AppTheme.primaryColor),
          const SizedBox(width: 12),
          Expanded(child: Text(text)),
        ],
      ),
    );
  }
}