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

import '../../../nutrition/domain/entities/meal_type.dart';
import '../../domain/entities/meal_plan_slot.dart';
import '../../domain/entities/recipe.dart';
import '../controllers/meal_plan_calendar_controller.dart';

/// Opens the quick-assign modal for a specific day/meal slot.
///
/// Shows the saved recipes to pick from, plus a free-text override for
/// meals without a saved recipe. Resolves to `true` when a slot was
/// written, otherwise `null`/`false`.
Future<bool?> showAssignSlotDialog(
  BuildContext context, {
  required DateTime day,
  required MealType mealType,
  required List<Recipe> savedRecipes,
  MealPlanSlot? existingSlot,
}) {
  return showDialog<bool>(
    context: context,
    builder: (context) => AssignSlotDialog(
      day: day,
      mealType: mealType,
      savedRecipes: savedRecipes,
      existingSlot: existingSlot,
    ),
  );
}

/// Modal used by the weekly calendar's "+" affordance: assign a saved
/// recipe (via dropdown) or type a quick custom description for the slot.
class AssignSlotDialog extends ConsumerStatefulWidget {
  const AssignSlotDialog({
    super.key,
    required this.day,
    required this.mealType,
    required this.savedRecipes,
    this.existingSlot,
  });

  final DateTime day;
  final MealType mealType;
  final List<Recipe> savedRecipes;
  final MealPlanSlot? existingSlot;

  @override
  ConsumerState<AssignSlotDialog> createState() => _AssignSlotDialogState();
}

class _AssignSlotDialogState extends ConsumerState<AssignSlotDialog> {
  final GlobalKey<FormState> _formKey = GlobalKey<FormState>();
  late final TextEditingController _descriptionController;

  Recipe? _selectedRecipe;
  bool _isSaving = false;

  @override
  void initState() {
    super.initState();
    _descriptionController = TextEditingController(
      text: widget.existingSlot?.customDescription ?? '',
    );
    // Pre-select the currently assigned recipe, if any.
    final recipeId = widget.existingSlot?.recipeId;
    if (recipeId != null) {
      for (final recipe in widget.savedRecipes) {
        if (recipe.id == recipeId) {
          _selectedRecipe = recipe;
          break;
        }
      }
    }
  }

  @override
  Widget build(BuildContext context) {
    final dayLabel = MaterialLocalizations.of(context).formatCompactDate(widget.day);

    return AlertDialog(
      title: Text('Assign ${widget.mealType.displayName} — $dayLabel'),
      content: SizedBox(
        width: 420,
        child: Form(
          key: _formKey,
          child: SingleChildScrollView(
            child: Column(
              mainAxisSize: MainAxisSize.min,
              crossAxisAlignment: CrossAxisAlignment.stretch,
              children: [
                DropdownButtonFormField<Recipe>(
                  initialValue: _selectedRecipe,
                  decoration: const InputDecoration(
                    labelText: 'Saved recipe',
                    border: OutlineInputBorder(),
                  ),
                  items: [
                    for (final recipe in widget.savedRecipes)
                      DropdownMenuItem<Recipe>(
                        value: recipe,
                        child: Text(
                          recipe.title,
                          maxLines: 1,
                          overflow: TextOverflow.ellipsis,
                        ),
                      ),
                  ],
                  onChanged: (recipe) => setState(() => _selectedRecipe = recipe),
                ),
                const SizedBox(height: 16),
                TextFormField(
                  controller: _descriptionController,
                  decoration: const InputDecoration(
                    labelText: 'Description (optional)',
                    hintText: 'e.g. Leftover chicken & greens',
                    border: OutlineInputBorder(),
                  ),
                  textCapitalization: TextCapitalization.sentences,
                  validator: _validate,
                ),
              ],
            ),
          ),
        ),
      ),
      actions: [
        TextButton(
          onPressed: _isSaving ? null : () => Navigator.of(context).pop(),
          child: const Text('Cancel'),
        ),
        FilledButton.icon(
          onPressed: _isSaving ? null : _assign,
          icon: _isSaving
              ? const SizedBox(
                  width: 16,
                  height: 16,
                  child: CircularProgressIndicator(strokeWidth: 2),
                )
              : const Icon(Icons.event_available_outlined),
          label: const Text('Assign'),
        ),
      ],
    );
  }

  String? _validate(String? value) {
    // A description is only required when no saved recipe is selected.
    if (_selectedRecipe == null && (value == null || value.trim().isEmpty)) {
      return 'Select a recipe or enter a description';
    }
    return null;
  }

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

    setState(() => _isSaving = true);
    final controller = ref.read(mealPlanCalendarControllerProvider.notifier);
    final description = _descriptionController.text.trim();

    final bool saved;
    final recipe = _selectedRecipe;
    if (recipe != null) {
      saved = await controller.assignRecipe(
        day: widget.day,
        mealType: widget.mealType,
        recipeId: recipe.id,
        note: description.isEmpty ? null : description,
      );
    } else {
      saved = await controller.saveCustomEntry(
        day: widget.day,
        mealType: widget.mealType,
        description: description,
      );
    }

    if (!mounted) return;
    Navigator.of(context).pop(saved);
  }

  @override
  void dispose() {
    _descriptionController.dispose();
    super.dispose();
  }
}