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

import '../../../../core/utils/date_time_utils.dart';
import '../../domain/entities/pantry_category.dart';
import '../../domain/value_objects/measurement_units.dart';
import '../controllers/pantry_inventory_controller.dart';

/// Opens the "Add Pantry Item" dialog.
///
/// Resolves to `true` when the item was persisted, `false` when saving
/// failed, and `null` when the user dismissed the dialog.
Future<bool?> showAddPantryItemDialog(BuildContext context) => showDialog<bool>(
      context: context,
      builder: (context) => const AddPantryItemDialog(),
    );

/// Form for stocking the pantry: name, quantity, unit, grocery aisle, and an
/// optional expiration date.
class AddPantryItemDialog extends ConsumerStatefulWidget {
  const AddPantryItemDialog({super.key});

  @override
  ConsumerState<AddPantryItemDialog> createState() =>
      _AddPantryItemDialogState();
}

class _AddPantryItemDialogState extends ConsumerState<AddPantryItemDialog> {
  final GlobalKey<FormState> _formKey = GlobalKey<FormState>();
  final TextEditingController _nameController = TextEditingController();
  final TextEditingController _quantityController = TextEditingController();

  late String _unit = pantryUnitOptions.first;
  PantryCategory _category = PantryCategory.other;
  DateTime? _expirationDate;
  bool _isSaving = false;

  @override
  Widget build(BuildContext context) {
    return AlertDialog(
      title: const Text('Add Pantry Item'),
      content: SizedBox(
        width: 440,
        child: Form(
          key: _formKey,
          child: SingleChildScrollView(
            child: Column(
              mainAxisSize: MainAxisSize.min,
              crossAxisAlignment: CrossAxisAlignment.stretch,
              children: [
                TextFormField(
                  controller: _nameController,
                  decoration: const InputDecoration(
                    labelText: 'Name',
                    hintText: 'e.g. chicken breast',
                    border: OutlineInputBorder(),
                  ),
                  textCapitalization: TextCapitalization.sentences,
                  validator: _nameValidator,
                ),
                const SizedBox(height: 16),
                Row(
                  children: [
                    Expanded(
                      child: TextFormField(
                        controller: _quantityController,
                        decoration: const InputDecoration(
                          labelText: 'Quantity',
                          border: OutlineInputBorder(),
                        ),
                        keyboardType:
                            const TextInputType.numberWithOptions(decimal: true),
                        validator: _quantityValidator,
                      ),
                    ),
                    const SizedBox(width: 12),
                    Expanded(
                      child: DropdownButtonFormField<String>(
                        initialValue: _unit,
                        decoration: const InputDecoration(
                          labelText: 'Unit',
                          border: OutlineInputBorder(),
                        ),
                        items: [
                          for (final unit in pantryUnitOptions)
                            DropdownMenuItem(value: unit, child: Text(unit)),
                        ],
                        onChanged: (unit) {
                          if (unit == null) return;
                          setState(() => _unit = unit);
                        },
                      ),
                    ),
                  ],
                ),
                const SizedBox(height: 16),
                DropdownButtonFormField<PantryCategory>(
                  initialValue: _category,
                  decoration: const InputDecoration(
                    labelText: 'Aisle',
                    border: OutlineInputBorder(),
                  ),
                  items: [
                    for (final category in PantryCategory.values)
                      DropdownMenuItem(
                        value: category,
                        child: Text(category.displayName),
                      ),
                  ],
                  onChanged: (category) {
                    if (category == null) return;
                    setState(() => _category = category);
                  },
                ),
                const SizedBox(height: 8),
                Row(
                  children: [
                    Expanded(
                      child: Text(
                        _expirationDate == null
                            ? 'No expiration date'
                            : 'Expires ${formatMonthDay(_expirationDate!)}',
                        style: Theme.of(context).textTheme.bodyMedium,
                      ),
                    ),
                    if (_expirationDate != null)
                      IconButton(
                        tooltip: 'Clear date',
                        icon: const Icon(Icons.clear),
                        onPressed: () =>
                            setState(() => _expirationDate = null),
                      ),
                    TextButton(
                      onPressed: _pickExpirationDate,
                      child: const Text('Pick Date'),
                    ),
                  ],
                ),
              ],
            ),
          ),
        ),
      ),
      actions: [
        TextButton(
          onPressed: _isSaving ? null : () => Navigator.of(context).pop(),
          child: const Text('Cancel'),
        ),
        FilledButton.icon(
          onPressed: _isSaving ? null : _save,
          icon: _isSaving
              ? const SizedBox(
                  width: 16,
                  height: 16,
                  child: CircularProgressIndicator(strokeWidth: 2),
                )
              : const Icon(Icons.add),
          label: const Text('Add Item'),
        ),
      ],
    );
  }

  Future<void> _pickExpirationDate() async {
    final now = DateTime.now();
    final picked = await showDatePicker(
      context: context,
      initialDate: _expirationDate ?? now,
      firstDate: DateTime(now.year - 1),
      lastDate: DateTime(now.year + 5),
    );
    if (picked == null || !mounted) return;
    setState(() => _expirationDate = picked);
  }

  Future<void> _save() async {
    if (!(_formKey.currentState?.validate() ?? false)) return;
    setState(() => _isSaving = true);
    final saved =
        await ref.read(pantryInventoryControllerProvider.notifier).addItem(
              name: _nameController.text,
              quantityOnHand: double.parse(_quantityController.text.trim()),
              unit: _unit,
              category: _category,
              expirationDate: _expirationDate,
            );
    if (!mounted) return;
    Navigator.of(context).pop(saved);
  }

  String? _nameValidator(String? value) {
    final trimmed = (value ?? '').trim();
    if (trimmed.isEmpty) return 'Enter a name';
    if (trimmed.length > 128) return 'Name is too long (max 128)';
    return null;
  }

  String? _quantityValidator(String? value) {
    final parsed = double.tryParse((value ?? '').trim());
    if (parsed == null || parsed < 0) return 'Enter a valid quantity';
    return null;
  }

  @override
  void dispose() {
    _nameController.dispose();
    _quantityController.dispose();
    super.dispose();
  }
}