Prowlarr/src/NzbDrone.Core/Validation/Paths/MovieExistsValidator.cs

using FluentValidation.Validators;
using NzbDrone.Core.Movies;

namespace NzbDrone.Core.Validation.Paths
{
    public class MovieExistsValidator : PropertyValidator
    {
        private readonly IMovieService _movieService;

        public MovieExistsValidator(IMovieService movieService)
            : base("This movie has already been added")
        {
            _movieService = movieService;
        }

        protected override bool IsValid(PropertyValidatorContext context)
        {
            if (context.PropertyValue == null) return true;

            int tmdbId = (int)context.PropertyValue;

            return (_movieService.FindByTmdbId(tmdbId) == null);
        }
    }
}