import 'package:flutter/material.dart';
import 'package:provider/provider.dart';
import '../models/instruction.dart';
import '../providers/instruction_provider.dart';
import '../widgets/tag_selection_dialog.dart';

class AddEditInstructionPage extends StatefulWidget {
  final Instruction? initialInstruction;

  const AddEditInstructionPage({super.key, this.initialInstruction});

  @override
  State<AddEditInstructionPage> createState() => _AddEditInstructionPageState();
}

class _AddEditInstructionPageState extends State<AddEditInstructionPage> {
  final _formKey = GlobalKey<FormState>();
  late TextEditingController _titleController;
  late TextEditingController _contentController;
  late List<String> _selectedTags;

  bool get _isEditing => widget.initialInstruction != null;

  @override
  void initState() {
    super.initState();
    _titleController = TextEditingController(text: widget.initialInstruction?.title ?? '');
    _contentController = TextEditingController(text: widget.initialInstruction?.content ?? '');
    _selectedTags = List<String>.from(widget.initialInstruction?.tags ?? []);
  }
  
  @override
  void dispose() {
    _titleController.dispose();
    _contentController.dispose();
    super.dispose();
  }

  Future<void> _showTagSelectionDialog() async {
    final provider = context.read<InstructionProvider>();
    final result = await showDialog<List<String>>(
      context: context,
      builder: (ctx) => TagSelectionDialog(
        allTags: provider.allAvailableTags,
        initialSelectedTags: _selectedTags.toSet(),
      ),
    );

    if (result != null) {
      setState(() {
        _selectedTags = result;
      });
    }
  }

  Future<void> _saveForm() async {
    if (_formKey.currentState!.validate()) {
      final provider = context.read<InstructionProvider>();
      final title = _titleController.text;
      final content = _contentController.text;

      showDialog(
          context: context,
          barrierDismissible: false,
          builder: (ctx) => const Center(child: CircularProgressIndicator()));

      try {
        if (_isEditing) {
          final updatedInstruction = widget.initialInstruction!.copyWith(
            title: title,
            content: content,
            tags: _selectedTags,
          );
          await provider.updateInstruction(updatedInstruction);
        } else {
          await provider.addInstruction(title, content, _selectedTags);
        }
        if (mounted) {
           Navigator.of(context)..pop()..pop();
        }
      } catch (e) {
        if(mounted) {
          Navigator.of(context).pop();
          ScaffoldMessenger.of(context).showSnackBar(
            SnackBar(content: Text('Ошибка сохранения: $e')),
          );
        }
      }
    }
  }

  @override
  Widget build(BuildContext context) {
    return Scaffold(
      appBar: AppBar(
        title: Text(_isEditing ? 'Редактировать' : 'Новый инструктаж'),
        actions: [IconButton(icon: const Icon(Icons.save), onPressed: _saveForm)],
      ),
      body: Padding(
        padding: const EdgeInsets.all(16.0),
        child: Form(
          key: _formKey,
          child: ListView(
            children: [
              TextFormField(
                controller: _titleController,
                decoration: const InputDecoration(labelText: 'Название', border: OutlineInputBorder()),
                validator: (v) => v == null || v.isEmpty ? 'Название не может быть пустым' : null,
              ),
              const SizedBox(height: 16),
              TextFormField(
                controller: _contentController,
                decoration: const InputDecoration(labelText: 'Содержание', border: OutlineInputBorder()),
                maxLines: 8,
                validator: (v) => v == null || v.isEmpty ? 'Содержание не может быть пустым' : null,
              ),
              const SizedBox(height: 24),
              Row(
                mainAxisAlignment: MainAxisAlignment.spaceBetween,
                children: [
                  const Text('Теги:', style: TextStyle(fontSize: 16)),
                  OutlinedButton.icon(
                    icon: const Icon(Icons.edit_note),
                    label: const Text('Изменить теги'),
                    onPressed: _showTagSelectionDialog,
                  ),
                ],
              ),
              const SizedBox(height: 8),
              Container(
                padding: const EdgeInsets.all(12),
                decoration: BoxDecoration(
                  border: Border.all(color: Colors.grey.shade400),
                  borderRadius: BorderRadius.circular(4),
                ),
                child: Wrap(
                  spacing: 8.0,
                  runSpacing: 4.0,
                  children: _selectedTags.isEmpty
                      ? [const Text('Теги не выбраны')]
                      : _selectedTags.map((tag) => Chip(label: Text(tag))).toList(),
                ),
              ),
            ],
          ),
        ),
      ),
    );
  }
}