using System;
using System.Collections.Generic;
using System.Linq;
using System.Text;
using System.Threading.Tasks;
using TaskTrackerContracts.BindingModels;
using TaskTrackerContracts.BusinessLogicsContracts;
using TaskTrackerContracts.SearchModels;
using TaskTrackerContracts.StoragesContracts;
using TaskTrackerContracts.ViewModels;
using TaskTrackerDataModels.Enums;


namespace TaskTrackerBusinessLogics.BusinessLogic
{
    public class TaskLogic : ITaskLogic
    {

        private readonly ITaskStorage _taskStorage;

        public TaskLogic(ITaskStorage taskStorage)
        {
            _taskStorage = taskStorage;
        }

        public bool CreateTask(TaskBindingModel model)
        {
            CheckModel(model);
            if (model.Status != MyTaskStatus.Неизвестен)
            {
                return false;
            }
            model.Status = MyTaskStatus.Новый;
            if (_taskStorage.Insert(model) == null)
            {
                return false;
            }
            return true;
        }

        public List<TaskViewModel>? ReadList(TaskSearchModel? model)
        {
            var list = model == null ? _taskStorage.GetFullList() : _taskStorage.GetFilteredList(model);
            if (list == null)
            {
                return null;
            }
            return list;
        }

        public bool TakeTaskInWork(TaskBindingModel model)
        {
            return ChangeStatus(model, MyTaskStatus.Выполняется);
        }

        public bool FinishTask(TaskBindingModel model)
        {
            return ChangeStatus(model, MyTaskStatus.Готово);
        }

        public bool DeliveryTask(TaskBindingModel model)
        {
            return ChangeStatus(model, MyTaskStatus.Проверено);
        }

        private void CheckModel(TaskBindingModel model, bool withParams = true)
        {
            if (model == null)
            {
                throw new ArgumentNullException(nameof(model));
            }
            if (!withParams)
            {
                return;
            }
        }

        private bool ChangeStatus(TaskBindingModel model, MyTaskStatus newStatus)
        {
            CheckModel(model, false);
            var task = _taskStorage.GetElement(new TaskSearchModel { Id = model.Id });
            if (task == null)
            {
                return false;
            }
            if (task.Status + 1 != newStatus)
            {
                return false;
            }
            model.Status = newStatus;
            if (model.Status == MyTaskStatus.Готово)
            {
                model.DateImplement = DateTime.Now;
            }
            else
            {
                model.DateImplement = task.DateImplement;
            }
            if (_taskStorage.Update(model) == null)
            {
                return false;
            }
            return true;
        }
    }
}