using BlogContracts.BindingModel;
using BlogContracts.BusinessLogicContracts;
using BlogContracts.SearchModels;
using BlogContracts.StorageContracts;
using BlogContracts.ViewModels;
using System;
using System.Collections.Generic;
using System.Linq;
using System.Text;
using System.Threading.Tasks;

namespace BusinessLogic
{
    public class NewsLogic : INewsLogic
    {
        private readonly INewsStorage _newsStorage;
        public NewsLogic(INewsStorage newsStorage)
        {
            _newsStorage = newsStorage ?? throw new ArgumentNullException(nameof(newsStorage));
        }

        public bool Create(NewsBindingModel model)
        {
            CheckModel(model);
            if (_newsStorage.Insert(model) == null)
            {
                return false;
            }
            return true;
        }

        public bool Delete(NewsBindingModel model)
        {
            CheckModel(model);
            if (_newsStorage.Delete(model) == null)
            {
                return false;
            }
            return true;
        }

        public NewsViewModel? ReadElement(NewsSearchModel model)
        {
            if (model == null)
            {
                throw new ArgumentNullException(nameof(model));
            }
            var element = _newsStorage.GetElement(model);
            if (element == null)
            {
                return null;
            }
            return element;
        }

        public List<NewsViewModel>? ReadList(NewsSearchModel? model)
        {
            var list = model == null ? _newsStorage.GetFullList() : _newsStorage.GetFilteredList(model);
            if (list == null)
            {
                return null;
            }
            return list;
        }

        public bool Update(NewsBindingModel model)
        {
            CheckModel(model);
            if (_newsStorage.Update(model) == null)
            {
                return false;
            }
            return true;
        }
        private void CheckModel(NewsBindingModel model)
        {
            if (model == null)
            {
                throw new ArgumentNullException(nameof(model));
            }
            if (string.IsNullOrEmpty(model.Title))
            {
                throw new ArgumentException("Отсутвует название",
                    nameof(model.Title));
            }
            if (string.IsNullOrEmpty(model.Text))
            {
                throw new ArgumentException("Отсутвует текст",
                    nameof(model.Text));
            }
            if (string.IsNullOrEmpty(model.UserId.ToString()))
            {
                throw new ArgumentException("Отсутвует автор",
                    nameof(model.UserId));
            }
            if (_newsStorage.GetElement(new NewsSearchModel
            {
                Title = model.Title,
                UserId = model.UserId,

            }) != null)
            {
                throw new InvalidOperationException("Такая новость уже существует");
            }
        }
    }
}