using System;
using System.Collections.Generic;
using System.Linq;
using System.Text;
using System.Threading.Tasks;
using UniversityContracts.BindingModels;
using UniversityContracts.BusinessLogicContracts;
using UniversityContracts.SearchModels;
using UniversityContracts.StoragesContracts;
using UniversityContracts.ViewModels;

namespace UniversityBusinessLogic.BusinessLogics
{
    public class DisciplineLogic : IDisciplineLogic
    {
        private readonly IDisciplineStorage _disciplineStorage;

        public DisciplineLogic(IDisciplineStorage disciplineStorage)
        {
            _disciplineStorage = disciplineStorage;
        }
        public bool Create(DisciplineBindingModel model)
        {
            CheckModel(model);
            if (_disciplineStorage.Insert(model) == null)
            {
                return false;
            }
            return true;
        }

        public bool Delete(DisciplineBindingModel model)
        {
            CheckModel(model, false);
            if (_disciplineStorage.Delete(model) == null)
            {
                return false;
            }
            return true;
        }

        public DisciplineViewModel? ReadElement(DisciplineSearchModel model)
        {
            if (model == null)
            {
                throw new ArgumentNullException(nameof(model));
            }
            var discipline = _disciplineStorage.GetElement(model);
            if (discipline == null)
            {
                return null;
            }
            return discipline;
        }

        public List<DisciplineViewModel>? ReadList(DisciplineSearchModel? model)
        {
            var list = model == null ? _disciplineStorage.GetFullList() : _disciplineStorage.GetFilteredList(model);
            if (list == null)
            {
                return null;
            }
            return list;
        }

        public bool Update(DisciplineBindingModel model)
        {
            CheckModel(model, false);
            if (_disciplineStorage.Update(model) == null)
            {
                return false;
            }
            return true;
        }

        public int GetNumberOfPages(int userId, int pageSize = 10)
        {
            return _disciplineStorage.GetNumberOfPages(userId, pageSize);
        }

        private void CheckModel(DisciplineBindingModel model, bool withParams = true)
        {
            if (model == null)
            {
                throw new ArgumentNullException(nameof(model));
            }
            if (!withParams)
            {
                return;
            }
            if (string.IsNullOrEmpty(model.Name))
            {
                throw new ArgumentNullException("Нет Имени", nameof(model.Name));
            }

            var discipline = _disciplineStorage.GetElement(new DisciplineSearchModel { Name = model.Name });
            if (discipline != null)
            {
                throw new InvalidOperationException("Дисциплина с таким названием уже есть");
            }
        }
    }
}