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 UserLogic : IUserLogic
    {
        private readonly IUserStorage _userStorage;

        public UserLogic(IUserStorage userStorage)
        {
            _userStorage = userStorage;
        }
        public bool Create(UserBindingModel model)
        {
            CheckModel(model);
            if (_userStorage.Insert(model) == null)
            {
                return false;
            }
            return true;
        }

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

        public UserViewModel? ReadElement(UserSearchModel model)
        {
            if (model == null)
            {
                throw new ArgumentNullException(nameof(model));
            }
            var user = _userStorage.GetElement(model);
            if (user == null)
            {
                return null;
            }
            return user;
        }

        public List<UserViewModel>? ReadList(UserSearchModel? model)
        {
            var list = model == null ? _userStorage.GetFullList() : _userStorage.GetFilteredList(model);
            if (list == null)
            {
                return null;
            }
            return list;
        }

        public bool Update(UserBindingModel model)
        {
            CheckModel(model, false);
            if (_userStorage.Update(model) == null)
            {
                return false;
            }
            return true;
        }
        private void CheckModel(UserBindingModel model, bool withParams = true)
        {
            if (model == null)
            {
                throw new ArgumentNullException(nameof(model));
            }
            if (!withParams)
            {
                return;
            }
            if (string.IsNullOrEmpty(model.Login))
            {
                throw new ArgumentNullException("Нет логина", nameof(model.Login));
            }

            var user = _userStorage.GetElement(new UserSearchModel{Login = model.Login});
            if (user != null)
            {
                throw new InvalidOperationException("Пользователь с таким логином уже есть");
            }
        }
    }
}