Musify/backend/Core/Musify.Application/Users/UnfollowUser.cs

using ErrorOr;
using Mediator;
using Microsoft.EntityFrameworkCore;
using Microsoft.Extensions.Logging;
using Musify.Application.Contracts;

namespace Musify.Application.Users
{
    public record UnfollowUserCommand(long FollowerId, long FollowedId) : ICommand<ErrorOr<Success>>;

    public class UnfollowUserCommandHandler(
        IDatabase database,
        ILogger<UnfollowUserCommandHandler> logger)
        : ICommandHandler<UnfollowUserCommand, ErrorOr<Success>>
    {
        public async ValueTask<ErrorOr<Success>> Handle(UnfollowUserCommand request, CancellationToken cancellationToken)
        {
            var follow = await database.UserFollows
                .SingleOrDefaultAsync(f => f.FollowerId == request.FollowerId && f.FollowedId == request.FollowedId, cancellationToken);

            if (follow is null)
                return new Success();

            database.UserFollows.Remove(follow);
            await database.SaveChangesAsync(cancellationToken);

            logger.LogInformation("User {FollowerId} unfollowed user {FollowedId}", request.FollowerId, request.FollowedId);

            return new Success();
        }
    }
}