source: ChapterX.Application/Story/Commands/AddHandler.cs@ 0b502c2

using ChapterX.Application.Abstractions;
using ChapterX.Domain.Repositories;
using MediatR;
using Microsoft.Extensions.Logging;

namespace ChapterX.Application.Story.Commands
{
    public class AddHandler : IRequestHandler<AddRequest, AddResponse>
    {
        private readonly IStoryRepository _storyRepository;
        private readonly IGenreRepository _genreRepository;
        private readonly IHasGenreRepository _hasGenreRepository;
        private readonly IApplicationDbContext _context;
        private readonly ILogger<AddHandler> _logger;

        public AddHandler(IStoryRepository storyRepository, IGenreRepository genreRepository, IHasGenreRepository hasGenreRepository, IApplicationDbContext context, ILogger<AddHandler> logger)
        {
            _storyRepository = storyRepository;
            _genreRepository = genreRepository;
            _hasGenreRepository = hasGenreRepository;
            _context = context;
            _logger = logger;
        }

        public async Task<AddResponse> Handle(AddRequest request, CancellationToken cancellationToken)
        {
            await using var transaction = await _context.BeginTransactionAsync(cancellationToken);
            try
            {
                var story = new Domain.Entities.Story
                {
                    MatureContent = request.MatureContent,
                    ShortDescription = request.ShortDescription,
                    Image = request.Image,
                    Content = request.Content,
                    UserId = request.UserId,
                    CreatedAt = DateTime.UtcNow,
                    UpdatedAt = DateTime.UtcNow
                };

                await _storyRepository.AddAsync(story, cancellationToken);

                foreach (var genreName in request.Genres ?? [])
                {
                    var genre = await _genreRepository.GetByNameAsync(genreName, cancellationToken);
                    if (genre == null) continue;
                    await _hasGenreRepository.AddAsync(new Domain.Entities.HasGenre { StoryId = story.Id, GenreId = genre.Id }, cancellationToken);
                }

                await transaction.CommitAsync(cancellationToken);
                return new AddResponse(story.Id);
            }
            catch
            {
                await transaction.RollbackAsync(cancellationToken);
                throw;
            }
        }
    }
}