Musify/Application/PlayLists/Handlers/UpdatePlayListCommandHandler.cs

using Ardalis.Result;
using Mediator;
using Microsoft.EntityFrameworkCore;
using Microsoft.Extensions.Logging;
using Musify.Application.Configuration;
using Musify.Application.Abstractions.Infrastructure;
using Musify.Application.Events;
using Musify.Application.PlayLists.Commands;
using Musify.Application.PlayLists.Responses;

namespace Musify.Application.PlayLists.Handlers
{
    public class UpdatePlayListCommandHandler(
        IEventBus eventBus,
        IDatabase database,
        ILogger<UpdatePlayListCommandHandler> logger,
        ApplicationStorageConfiguration storageConfiguration,
        PlayListConfiguration playListConfiguration)
        : ICommandHandler<UpdatePlayListCommand, Result<PlayListApplicationResponse>>
    {
        public async ValueTask<Result<PlayListApplicationResponse>> Handle(UpdatePlayListCommand request, CancellationToken cancellationToken)
        {
            var playListEntity = await database.PlayLists.SingleOrDefaultAsync(pl => pl.Id == request.PlayListId, cancellationToken);
            if (playListEntity is null)
            {
                logger.LogInformation("Playlist {PlayListId} not found", request.PlayListId);
                return Result.NotFound();
            }

            if (playListEntity.UserId != request.UserId)
            {
                logger.LogWarning("User {UserId} is not the owner of playlist {PlayListId}", request.UserId, request.PlayListId);
                return Result.Unauthorized();
            }

            if (request.NewName is not null)
            {
                playListEntity.Name = request.NewName;
                playListEntity.NormalizedName = request.NewName.Trim().ToUpperInvariant();
            }

            if (request.NewDescription is not null)
            {
                playListEntity.Description = request.NewDescription;
            }

            if (request.NewOriginalPictureName is not null)
            {
                playListEntity.OriginalPictureName = request.NewOriginalPictureName;

                var publishResult = await PublishPlayListPictureEvent(playListEntity.UserId, playListEntity.Id, playListEntity.OriginalPictureName, cancellationToken);
                if (!publishResult.IsSuccess)
                    return publishResult;
            }

            try
            {
                database.PlayLists.Update(playListEntity);
                await database.SaveChangesAsync(cancellationToken);
            }
            catch (Exception exception)
            {
                logger.LogError(exception, "Failed to update playlist {PlayListId}", playListEntity.Id);
                return Result.Error($"Failed to update playlist {playListEntity.Id}");
            }

            logger.LogInformation("Updated playlist {PlayListId}", playListEntity.Id);
            return Result.Success(PlayListApplicationResponse.FromEntity(playListEntity));
        }

        async Task<Result> PublishPlayListPictureEvent(Guid userId, Guid playListId, string originalPictureName, CancellationToken cancellationToken)
        {
            try
            {
                await eventBus.PublishAsync(new UpdatePlayListPictureEvent(
                    playListId,
                    storageConfiguration.Bucket,
                    playListConfiguration.Routes.BuildOriginalPicturePath(userId, originalPictureName),
                    new ImageSize(
                        playListConfiguration.Routes.SmallPicturesPath,
                        playListConfiguration.PicturesSizes.SmallPictureWidth,
                        playListConfiguration.PicturesSizes.SmallPictureHeight),
                    new ImageSize(
                        playListConfiguration.Routes.MediumPicturesPath,
                        playListConfiguration.PicturesSizes.MediumPictureWidth,
                        playListConfiguration.PicturesSizes.MediumPictureHeight),
                    new ImageSize(
                        playListConfiguration.Routes.LargePicturesPath,
                        playListConfiguration.PicturesSizes.LargePictureWidth,
                        playListConfiguration.PicturesSizes.LargePictureHeight)),
                    cancellationToken);
                return Result.Success();
            }
            catch (Exception exception)
            {
                logger.LogError(exception, "Failed to publish playlist picture update event for playlist {PlayListId}", playListId);
                return Result.Error($"Failed to publish playlist {playListId} picture update event");
            }
        }
    }
}