system-praktyk-api/src/InternshipSystem.Api/Services/InternshipService.cs

using System;
using System.Threading;
using System.Threading.Tasks;
using AutoMapper;
using InternshipSystem.Api.Queries;
using InternshipSystem.Api.Security;
using InternshipSystem.Core;
using InternshipSystem.Repository;
using Microsoft.AspNetCore.Mvc;
using Microsoft.EntityFrameworkCore;

namespace InternshipSystem.Api.Services
{
    public class InternshipService : IInternshipService
    {
        private readonly InternshipDbContext _context;
        private IMapper Mapper { get; }

        public InternshipService(InternshipDbContext context, IMapper mapper)
        {
            _context = context;
            Mapper = mapper;
        }
        
        public async Task<ActionResult> AddDocumentToInternship(DocumentPublishRequest documentRequest, User user,
            CancellationToken cancellationToken)
        {
            var edition = await _context.Editions.FindAsync(user.EditionId);

            var internship = await _context.Entry(edition)
                .Collection(e => e.Internships)
                .Query()
                .Include(i => i.Documentation)
                .SingleAsync(i => i.Student.Id == user.PersonNumber, cancellationToken);

            var document = Mapper.Map<Document>(documentRequest);
            
            if (documentRequest.Id.HasValue)
            {                
                try
                {
                    internship.UpdateDocument(document);
                }
                catch (InvalidOperationException)
                {
                    return new NotFoundResult();
                }
            }
            else
            {
                internship.AddNewDocument(document);
            }

            await _context.SaveChangesAsync(cancellationToken);
            return new OkResult();
        }
    }
}