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

namespace BlogBusinessLogic
{
    public class CategoryLogic : ICategoryLogic
    {
        private readonly ICategoryStorage _categoryStorage;

        public CategoryLogic(ICategoryStorage categoryStorage)
        {
            _categoryStorage = categoryStorage;
        }

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

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

        public CategoryViewModel? ReadElement(CategorySearchModel model)
        {
            if (model == null)
            {
                throw new ArgumentNullException(nameof(model));
            }
            var element = _categoryStorage.GetElement(model);
            if (element == null)
            {
                return null;
            }
            return element;
        }

        public List<CategoryViewModel>? ReadList(CategorySearchModel? model)
        {
            var list = model == null ? _categoryStorage.GetFullList() : _categoryStorage.GetFilteredList(model);
            if (list == null)
            {
                return null;
            }
            return list;
        }

        public bool Update(CategoryBindingModel model)
        {
            CheckModel(model);
            if (_categoryStorage.Update(model) == null)
            {
                return false;
            }
            return true;
        }

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

            var element = _categoryStorage.GetElement(new CategorySearchModel
                {
                    Name = model.Name
                }
            );
            if (element != null && element.Id != model.Id)
            {
                throw new InvalidOperationException("Категория с таким названием уже есть");
            }
        }
    }
}