import 'package:flutter/foundation.dart';
import 'package:uuid/uuid.dart';

import '../../../../core/errors/failures.dart';
import '../../../../core/logging/app_logger.dart';
import '../../domain/entities/task_entity.dart';
import '../../domain/enums/priority.dart';
import '../../domain/repositories/task_repository.dart';

enum FormStatus { initial, loading, success, error }

class TaskFormViewModel extends ChangeNotifier {
  final TaskRepository repository;
  final AppLogger logger;

  TaskFormViewModel({
    required this.repository,
    required this.logger,
  });

  FormStatus _status = FormStatus.initial;
  Failure? _failure;
  TaskEntity? _existingTask;

  String _title = '';
  String _description = '';
  DateTime _date = DateTime.now();
  String? _time;
  Priority _priority = Priority.medium;

  String? _titleError;

  FormStatus get status => _status;
  Failure? get failure => _failure;
  bool get isEditing => _existingTask != null;

  String get title => _title;
  String get description => _description;
  DateTime get date => _date;
  String? get time => _time;
  Priority get priority => _priority;
  String? get titleError => _titleError;

  void initForCreate(DateTime? initialDate) {
    _existingTask = null;
    _title = '';
    _description = '';
    _date = initialDate ?? DateTime.now();
    _time = null;
    _priority = Priority.medium;
    _status = FormStatus.initial;
    notifyListeners();
  }

  Future<void> initForEdit(String taskId) async {
    _status = FormStatus.loading;
    notifyListeners();

    final result = await repository.getTaskById(taskId);

    result.when(
      success: (task) {
        _existingTask = task;
        _title = task.title;
        _description = task.description ?? '';
        _date = task.date;
        _time = task.time;
        _priority = task.priority;
        _status = FormStatus.initial;
      },
      error: (failure) {
        _failure = failure;
        _status = FormStatus.error;
      },
    );

    notifyListeners();
  }

  void setTitle(String value) {
    _title = value;
    _titleError = null;
    notifyListeners();
  }

  void setDescription(String value) {
    _description = value;
    notifyListeners();
  }

  void setDate(DateTime value) {
    _date = value;
    notifyListeners();
  }

  void setTime(String? value) {
    _time = value;
    notifyListeners();
  }

  void setPriority(Priority value) {
    _priority = value;
    notifyListeners();
  }

  bool validate() {
    if (_title.trim().isEmpty) {
      _titleError = 'Title is required';
      notifyListeners();
      return false;
    }
    return true;
  }

  Future<bool> save() async {
    if (!validate()) return false;

    _status = FormStatus.loading;
    notifyListeners();

    final task = TaskEntity(
      id: _existingTask?.id ?? const Uuid().v4(),
      title: _title.trim(),
      description: _description.trim().isEmpty ? null : _description.trim(),
      date: _date,
      time: _time,
      priority: _priority,
      isDone: _existingTask?.isDone ?? false,
      createdAt: _existingTask?.createdAt,
    );

    final result = isEditing
        ? await repository.updateTask(task)
        : await repository.createTask(task);

    return result.when(
      success: (_) {
        _status = FormStatus.success;
        logger.info(isEditing ? 'Task updated' : 'Task created');
        notifyListeners();
        return true;
      },
      error: (failure) {
        _failure = failure;
        _status = FormStatus.error;
        notifyListeners();
        return false;
      },
    );
  }
}