import 'package:flutter/material.dart' show ChangeNotifier;

import '../../model/repositories/interfaces/task_repository.dart';
import '../../model/task.dart';

class TaskController extends ChangeNotifier {
  TaskController(TaskRepository repository) : _repository = repository {
    Future.wait([
      _loadTaskOrder(),
      _loadTasks(),
    ]).whenComplete(() => notifyListeners());
  }

  final TaskRepository _repository;

  final List<Task> _tasks = [];
  final List<String> _taskOrder = [];

  List<Task> get orderedTasks {
    final lookup = {for (final task in _tasks) task.id: task};

    return _taskOrder.map((id) => lookup[id]!).toList();
  }

  Future<void> reorderTask(int oldIndex, int newIndex) async {
    final taskId = _taskOrder.removeAt(oldIndex);
    _taskOrder.insert(newIndex, taskId);
    _repository.updateTaskOrder(_taskOrder);
  }

  Future<void> saveTask(Task task) async {
    if (_tasks.contains(task)) {
      _tasks.remove(task);
      _tasks.add(task);
      _repository.updateTask(task);
    } else {
      _tasks.add(task);
      _taskOrder.add(task.id);
      _repository.createTask(task);
      _repository.updateTaskOrder(_taskOrder);
    }
    notifyListeners();
  }

  Future<void> deleteTask(Task task) async {
    _tasks.remove(task);
    _taskOrder.remove(task.id);
    notifyListeners();
    _repository.deleteTask(task);
    _repository.updateTaskOrder(_taskOrder);
  }

  Future<void> _loadTasks() async {
    _tasks.clear();
    return _repository.loadTasks().then((value) => _tasks.addAll(value));
  }

  Future<void> _loadTaskOrder() async {
    _taskOrder.clear();
    return _repository.loadTaskOrder().then(
      (value) => _taskOrder.addAll(value),
    );
  }
}