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

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

/// Manuelles Anlegen und Bearbeiten einer Pflanze.
///
/// Im KI-Block von V1 wird dieser Screen um den Foto-Flow ergänzt:
/// Foto → PlantNet-Erkennung → Claude befüllt Art, Beschreibung und
/// Intervall-Vorschläge vor – der Nutzer bestätigt hier nur noch.
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>();
  late final TextEditingController _nicknameController;
  late final TextEditingController _speciesController;
  late final TextEditingController _wateringController;
  late final TextEditingController _fertilizingController;
  String? _locationId;

  @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;
  }

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

  void _save() {
    if (!_formKey.currentState!.validate()) return;

    final notifier = ref.read(plantsProvider.notifier);
    final existing = widget.existing;
    if (existing != null) {
      notifier.updatePlant(existing.copyWith(
        nickname: _nicknameController.text.trim(),
        species: _speciesController.text.trim(),
        locationId: () => _locationId,
        wateringIntervalDays: int.parse(_wateringController.text.trim()),
        fertilizingIntervalDays: int.parse(_fertilizingController.text.trim()),
      ));
    } else {
      notifier.addPlant(Plant(
        id: 'plant-${DateTime.now().millisecondsSinceEpoch}',
        nickname: _nicknameController.text.trim(),
        species: _speciesController.text.trim(),
        locationId: _locationId,
        wateringIntervalDays: int.parse(_wateringController.text.trim()),
        fertilizingIntervalDays: int.parse(_fertilizingController.text.trim()),
      ));
    }
    context.pop();
  }

  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);

    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: [
            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: _save,
              icon: const Icon(Icons.check),
              label: Text(l10n.save),
            ),
            const SizedBox(height: 8),
            TextButton(
              onPressed: () => context.pop(),
              child: Text(l10n.cancel),
            ),
          ],
        ),
      ),
    );
  }
}