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

import '../../../core/api/api_error_mapper.dart';
import '../../../core/api/api_exception.dart';
import '../../../core/ui/async_state_views.dart';
import '../../auth/data/auth_providers.dart';
import '../data/recipe_providers.dart';
import '../domain/recipe.dart';

class RecipeEditScreen extends ConsumerStatefulWidget {
  final int recipeId;

  const RecipeEditScreen({super.key, required this.recipeId});

  @override
  ConsumerState<RecipeEditScreen> createState() => _RecipeEditScreenState();
}

class _RecipeEditScreenState extends ConsumerState<RecipeEditScreen> {
  final _formKey = GlobalKey<FormState>();
  bool _initialized = false;

  late TextEditingController _nameCtrl;
  late TextEditingController _descCtrl;
  late TextEditingController _servingsCtrl;
  late TextEditingController _instructionsCtrl;

  bool _isSaving = false;
  String? _saveError;

  @override
  void dispose() {
    if (_initialized) {
      _nameCtrl.dispose();
      _descCtrl.dispose();
      _servingsCtrl.dispose();
      _instructionsCtrl.dispose();
    }
    super.dispose();
  }

  void _initControllers(Recipe recipe) {
    _nameCtrl = TextEditingController(text: recipe.title);
    _descCtrl = TextEditingController(text: recipe.description ?? '');
    _servingsCtrl =
        TextEditingController(text: recipe.servings?.toString() ?? '');
    _instructionsCtrl =
        TextEditingController(text: recipe.instructions ?? '');
    _initialized = true;
  }

  Future<void> _save() async {
    if (!(_formKey.currentState?.validate() ?? false)) return;

    setState(() {
      _isSaving = true;
      _saveError = null;
    });

    try {
      final token = await ref.read(authStateProvider.future);
      final servings = int.tryParse(_servingsCtrl.text.trim());
      await ref.read(recipeRepositoryProvider).updateRecipe(
        widget.recipeId,
        {
          'name': _nameCtrl.text.trim(),
          'description': _descCtrl.text.trim().isEmpty
              ? null
              : _descCtrl.text.trim(),
          if (servings != null) 'servings': servings,
          'instructions': _instructionsCtrl.text.trim().isEmpty
              ? null
              : _instructionsCtrl.text.trim(),
        },
        token: token,
      );
      ref.invalidate(recipeDetailProvider(widget.recipeId));
      ref.invalidate(recipesProvider);
      if (mounted) context.pop();
    } on ApiException catch (e) {
      if (e.type == ApiErrorType.unauthorized) {
        await ref.read(authStateProvider.notifier).logout();
        return;
      }
      setState(() {
        _saveError = mapErrorToUserMessage(e);
        _isSaving = false;
      });
    }
  }

  @override
  Widget build(BuildContext context) {
    final recipeAsync = ref.watch(recipeDetailProvider(widget.recipeId));

    return Scaffold(
      appBar: AppBar(
        title: const Text('Redigera recept'),
        actions: [
          if (_initialized)
            TextButton(
              onPressed: _isSaving ? null : _save,
              child: _isSaving
                  ? const SizedBox(
                      height: 16,
                      width: 16,
                      child: CircularProgressIndicator(strokeWidth: 2),
                    )
                  : const Text('Spara'),
            ),
        ],
      ),
      body: recipeAsync.when(
        loading: () => const LoadingStateView(label: 'Laddar recept...'),
        error: (error, _) => ErrorStateView(
          message: mapErrorToUserMessage(error),
          onRetry: () => ref.invalidate(recipeDetailProvider(widget.recipeId)),
        ),
        data: (recipe) {
          if (!_initialized) _initControllers(recipe);
          return _buildForm(context);
        },
      ),
    );
  }

  Widget _buildForm(BuildContext context) {
    return SingleChildScrollView(
      padding: const EdgeInsets.all(16),
      child: Form(
        key: _formKey,
        child: Column(
          crossAxisAlignment: CrossAxisAlignment.stretch,
          children: [
            TextFormField(
              controller: _nameCtrl,
              decoration: const InputDecoration(labelText: 'Receptnamn'),
              validator: (v) =>
                  (v == null || v.trim().isEmpty) ? 'Ange ett receptnamn.' : null,
            ),
            const SizedBox(height: 16),
            TextFormField(
              controller: _descCtrl,
              decoration:
                  const InputDecoration(labelText: 'Beskrivning (valfritt)'),
              maxLines: 3,
            ),
            const SizedBox(height: 16),
            TextFormField(
              controller: _servingsCtrl,
              decoration:
                  const InputDecoration(labelText: 'Antal portioner (valfritt)'),
              keyboardType: TextInputType.number,
              validator: (v) {
                if (v == null || v.trim().isEmpty) return null;
                if (int.tryParse(v.trim()) == null) {
                  return 'Ange ett heltal.';
                }
                return null;
              },
            ),
            const SizedBox(height: 16),
            TextFormField(
              controller: _instructionsCtrl,
              decoration:
                  const InputDecoration(labelText: 'Tillvägagångssätt (valfritt)'),
              maxLines: 10,
              textAlignVertical: TextAlignVertical.top,
            ),
            const SizedBox(height: 8),
            Text(
              'Ingredienser redigeras via Skapa recept-flödet.',
              style: Theme.of(context).textTheme.bodySmall?.copyWith(
                  color: Theme.of(context).colorScheme.onSurfaceVariant),
            ),
            if (_saveError != null) ...[
              const SizedBox(height: 16),
              Text(
                _saveError!,
                style:
                    TextStyle(color: Theme.of(context).colorScheme.error),
                textAlign: TextAlign.center,
              ),
            ],
            const SizedBox(height: 24),
            FilledButton(
              onPressed: _isSaving ? null : _save,
              child: _isSaving
                  ? const SizedBox(
                      height: 18,
                      width: 18,
                      child: CircularProgressIndicator(strokeWidth: 2),
                    )
                  : const Text('Spara ändringar'),
            ),
            const SizedBox(height: 40),
          ],
        ),
      ),
    );
  }
}