import 'dart:typed_data';

import 'package:firebase_core/firebase_core.dart';
import 'package:flutter/material.dart';
import 'package:flutter_riverpod/flutter_riverpod.dart';
import 'package:go_router/go_router.dart';
import 'package:image_picker/image_picker.dart';

import '../../../l10n/generated/app_localizations.dart';
import '../../locations/data/locations_provider.dart';
import '../data/plant_recognition_service.dart';
import '../data/plants_provider.dart';
import '../domain/plant.dart';

/// Anlegen und Bearbeiten einer Pflanze.
///
/// Mit Foto: Kamera/Galerie → Cloud Function (PlantNet + Claude) erkennt die
/// Art und füllt Art, Beschreibung, Pflegehinweise und Intervalle vor —
/// der Nutzer prüft, passt an und speichert. Ohne Foto: manuell ausfüllen.
class PlantFormScreen extends ConsumerStatefulWidget {
  const PlantFormScreen({super.key, this.existing});

  final Plant? existing;

  @override
  ConsumerState<PlantFormScreen> createState() => _PlantFormScreenState();
}

class _PlantFormScreenState extends ConsumerState<PlantFormScreen> {
  final _formKey = GlobalKey<FormState>();
  final _picker = ImagePicker();
  late final TextEditingController _nicknameController;
  late final TextEditingController _speciesController;
  late final TextEditingController _wateringController;
  late final TextEditingController _fertilizingController;
  String? _locationId;

  Uint8List? _photoBytes;
  bool _recognizing = false;
  bool _saving = false;
  String _description = '';
  String _careNotes = '';

  @override
  void initState() {
    super.initState();
    final existing = widget.existing;
    _nicknameController = TextEditingController(text: existing?.nickname ?? '');
    _speciesController = TextEditingController(text: existing?.species ?? '');
    _wateringController = TextEditingController(
        text: existing?.wateringIntervalDays.toString() ?? '7');
    _fertilizingController = TextEditingController(
        text: existing?.fertilizingIntervalDays.toString() ?? '28');
    _locationId = existing?.locationId;
    _description = existing?.description ?? '';
    _careNotes = existing?.careNotes ?? '';
  }

  @override
  void dispose() {
    _nicknameController.dispose();
    _speciesController.dispose();
    _wateringController.dispose();
    _fertilizingController.dispose();
    super.dispose();
  }

  Future<void> _pickImage(ImageSource source) async {
    final picked = await _picker.pickImage(
      source: source,
      maxWidth: 1280,
      imageQuality: 80,
    );
    if (picked == null) return;
    final bytes = await picked.readAsBytes();
    setState(() => _photoBytes = bytes);
    await _recognize(bytes);
  }

  Future<void> _recognize(Uint8List bytes) async {
    final l10n = AppLocalizations.of(context);
    setState(() => _recognizing = true);
    try {
      final result =
          await ref.read(plantRecognitionServiceProvider).identify(bytes);
      if (!mounted) return;
      setState(() {
        _speciesController.text = result.displaySpecies;
        _wateringController.text = result.wateringIntervalDays.toString();
        _fertilizingController.text = result.fertilizingIntervalDays.toString();
        _description = result.description;
        _careNotes = result.careNotes;
        if (_nicknameController.text.trim().isEmpty &&
            result.germanName.isNotEmpty) {
          _nicknameController.text = result.germanName;
        }
      });
      ScaffoldMessenger.of(context)
        ..hideCurrentSnackBar()
        ..showSnackBar(SnackBar(
          content: Text(l10n.recognitionSuccess(result.displaySpecies)),
        ));
    } catch (_) {
      if (!mounted) return;
      ScaffoldMessenger.of(context)
        ..hideCurrentSnackBar()
        ..showSnackBar(SnackBar(content: Text(l10n.recognitionFailed)));
    } finally {
      if (mounted) setState(() => _recognizing = false);
    }
  }

  Future<void> _save() async {
    final l10n = AppLocalizations.of(context);
    if (!_formKey.currentState!.validate()) return;

    setState(() => _saving = true);
    try {
      String? photoUrl = widget.existing?.photoUrl;
      if (_photoBytes != null) {
        photoUrl = await ref
            .read(plantRecognitionServiceProvider)
            .uploadPhoto(_photoBytes!);
      }

      final repository = ref.read(plantRepositoryProvider);
      final existing = widget.existing;
      if (existing != null) {
        await repository.updatePlant(existing.copyWith(
          nickname: _nicknameController.text.trim(),
          species: _speciesController.text.trim(),
          locationId: () => _locationId,
          description: _description,
          careNotes: _careNotes,
          photoUrl: photoUrl,
          wateringIntervalDays: int.parse(_wateringController.text.trim()),
          fertilizingIntervalDays:
              int.parse(_fertilizingController.text.trim()),
        ));
      } else {
        await repository.addPlant(Plant(
          id: '', // wird von Firestore vergeben
          nickname: _nicknameController.text.trim(),
          species: _speciesController.text.trim(),
          locationId: _locationId,
          description: _description,
          careNotes: _careNotes,
          photoUrl: photoUrl,
          wateringIntervalDays: int.parse(_wateringController.text.trim()),
          fertilizingIntervalDays:
              int.parse(_fertilizingController.text.trim()),
        ));
      }
      if (mounted) context.pop();
    } catch (error) {
      // Der konkrete Grund (z. B. firebase_storage/unauthorized vs.
      // cloud_firestore/permission-denied) entscheidet, wo der Fehler liegt —
      // deshalb wird er mit angezeigt statt verschluckt.
      debugPrint('Pflanze speichern fehlgeschlagen: $error');
      final detail = error is FirebaseException
          ? '${error.plugin}/${error.code}'
          : error.runtimeType.toString();
      if (mounted) {
        ScaffoldMessenger.of(context)
          ..hideCurrentSnackBar()
          ..showSnackBar(SnackBar(content: Text(l10n.saveErrorDetail(detail))));
      }
    } finally {
      if (mounted) setState(() => _saving = false);
    }
  }

  String? _validateRequired(String? value) {
    final l10n = AppLocalizations.of(context);
    if (value == null || value.trim().isEmpty) return l10n.requiredField;
    return null;
  }

  String? _validateInterval(String? value) {
    final l10n = AppLocalizations.of(context);
    final parsed = int.tryParse(value?.trim() ?? '');
    if (parsed == null || parsed <= 0) return l10n.invalidNumber;
    return null;
  }

  @override
  Widget build(BuildContext context) {
    final l10n = AppLocalizations.of(context);
    final locations = ref.watch(locationsProvider).value ?? const [];

    return Scaffold(
      appBar: AppBar(
        title: Text(
            widget.existing != null ? l10n.plantDetailTitle : l10n.addPlant),
      ),
      body: Form(
        key: _formKey,
        child: ListView(
          padding: const EdgeInsets.all(16),
          children: [
            _PhotoSection(
              photoBytes: _photoBytes,
              existingPhotoUrl: widget.existing?.photoUrl,
              recognizing: _recognizing,
              onTakePhoto: () => _pickImage(ImageSource.camera),
              onPickFromGallery: () => _pickImage(ImageSource.gallery),
            ),
            const SizedBox(height: 24),
            TextFormField(
              controller: _nicknameController,
              decoration: InputDecoration(
                labelText: l10n.nicknameLabel,
                border: const OutlineInputBorder(),
              ),
              textInputAction: TextInputAction.next,
              validator: _validateRequired,
            ),
            const SizedBox(height: 16),
            TextFormField(
              controller: _speciesController,
              decoration: InputDecoration(
                labelText: l10n.speciesLabel,
                border: const OutlineInputBorder(),
              ),
              textInputAction: TextInputAction.next,
              validator: _validateRequired,
            ),
            const SizedBox(height: 16),
            DropdownButtonFormField<String?>(
              initialValue: _locationId,
              decoration: InputDecoration(
                labelText: l10n.locationLabel,
                border: const OutlineInputBorder(),
              ),
              items: [
                DropdownMenuItem<String?>(
                  value: null,
                  child: Text(l10n.locationNone),
                ),
                for (final location in locations)
                  DropdownMenuItem<String?>(
                    value: location.id,
                    child: Text(location.name),
                  ),
              ],
              onChanged: (value) => setState(() => _locationId = value),
            ),
            const SizedBox(height: 16),
            TextFormField(
              controller: _wateringController,
              decoration: InputDecoration(
                labelText: l10n.wateringIntervalLabel,
                border: const OutlineInputBorder(),
                prefixIcon: const Icon(Icons.water_drop),
              ),
              keyboardType: TextInputType.number,
              textInputAction: TextInputAction.next,
              validator: _validateInterval,
            ),
            const SizedBox(height: 16),
            TextFormField(
              controller: _fertilizingController,
              decoration: InputDecoration(
                labelText: l10n.fertilizingIntervalLabel,
                border: const OutlineInputBorder(),
                prefixIcon: const Icon(Icons.compost),
              ),
              keyboardType: TextInputType.number,
              textInputAction: TextInputAction.done,
              validator: _validateInterval,
            ),
            const SizedBox(height: 24),
            FilledButton.icon(
              onPressed: _saving || _recognizing ? null : _save,
              icon: _saving
                  ? const SizedBox(
                      height: 20,
                      width: 20,
                      child: CircularProgressIndicator(strokeWidth: 2),
                    )
                  : const Icon(Icons.check),
              label: Text(l10n.save),
            ),
            const SizedBox(height: 8),
            TextButton(
              onPressed: _saving ? null : () => context.pop(),
              child: Text(l10n.cancel),
            ),
          ],
        ),
      ),
    );
  }
}

class _PhotoSection extends StatelessWidget {
  const _PhotoSection({
    required this.photoBytes,
    required this.existingPhotoUrl,
    required this.recognizing,
    required this.onTakePhoto,
    required this.onPickFromGallery,
  });

  final Uint8List? photoBytes;
  final String? existingPhotoUrl;
  final bool recognizing;
  final VoidCallback onTakePhoto;
  final VoidCallback onPickFromGallery;

  @override
  Widget build(BuildContext context) {
    final l10n = AppLocalizations.of(context);
    final theme = Theme.of(context);

    Widget preview;
    if (photoBytes != null) {
      preview = Image.memory(photoBytes!, fit: BoxFit.cover);
    } else if (existingPhotoUrl != null) {
      preview = Image.network(existingPhotoUrl!, fit: BoxFit.cover);
    } else {
      preview = Container(
        color: theme.colorScheme.surfaceContainerHighest,
        child: Icon(
          Icons.local_florist,
          size: 64,
          color: theme.colorScheme.onSurfaceVariant,
        ),
      );
    }

    return Column(
      crossAxisAlignment: CrossAxisAlignment.stretch,
      children: [
        ClipRRect(
          borderRadius: BorderRadius.circular(16),
          child: SizedBox(
            height: 200,
            child: Stack(
              fit: StackFit.expand,
              children: [
                preview,
                if (recognizing)
                  Container(
                    color: Colors.black45,
                    child: Column(
                      mainAxisAlignment: MainAxisAlignment.center,
                      children: [
                        const CircularProgressIndicator(color: Colors.white),
                        const SizedBox(height: 12),
                        Text(
                          l10n.recognizing,
                          style: const TextStyle(color: Colors.white),
                        ),
                      ],
                    ),
                  ),
              ],
            ),
          ),
        ),
        const SizedBox(height: 12),
        Row(
          children: [
            Expanded(
              child: FilledButton.tonalIcon(
                onPressed: recognizing ? null : onTakePhoto,
                icon: const Icon(Icons.photo_camera),
                label: Text(l10n.takePhoto),
              ),
            ),
            const SizedBox(width: 12),
            Expanded(
              child: FilledButton.tonalIcon(
                onPressed: recognizing ? null : onPickFromGallery,
                icon: const Icon(Icons.photo_library),
                label: Text(l10n.fromGallery),
              ),
            ),
          ],
        ),
      ],
    );
  }
}