DocumentOrganizer/Diligent.WebAPI.Business/Services/CategoryService.cs

using Diligent.WebAPI.Contracts.DTOs.Categories;
using System;
using System.Collections.Generic;
using System.Linq;
using System.Text;
using System.Threading.Tasks;

namespace Diligent.WebAPI.Business.Services
{
    public class CategoryService : ICategoryService
    {
        private readonly DatabaseContext _context;
        private readonly IMapper _mapper;

        public CategoryService(DatabaseContext context, IMapper mapper)
        {
            _context = context;
            _mapper = mapper;
        }

        public async Task<List<CategoriesNamesResponse>> GetCategoriesNamesAsync() =>
            _mapper.Map<List<CategoriesNamesResponse>>(await _context.Categories.ToListAsync());

        public async Task<Category> GetCategoryEntityById(int id) =>
            await _context.Categories.Where(x => x.Id == id).FirstOrDefaultAsync();

        public async Task<List<IsGrantedCategory>> GetCategories(int userId)
        {
            var grantedCategories = await _context.UserCategories.Where(k => k.UserId == userId).ToListAsync();
            var allCategories = await _context.Categories.ToListAsync();
            var result = new List<IsGrantedCategory>();
            for (int i = 0; i < allCategories.Count; i++)
            {
                var newCategory = new IsGrantedCategory
                {
                    Id = allCategories[i].Id,
                    Name = allCategories[i].Name,
                };
                bool isGranted = false;
                for (int j = 0; j < grantedCategories.Count; j++)
                {
                    if(grantedCategories[j].CategoryId == allCategories[i].Id && userId == grantedCategories[j].UserId)
                    {
                        isGranted = true;
                        break;
                    }
                }
                newCategory.IsChecked = isGranted;
                result.Add(newCategory);
                isGranted = false;
            }

            return result;
        }
    }
}