Lidarr/src/NzbDrone.Core/DecisionEngine/Specifications/UpgradeDiskSpecification.cs

using System.Linq;
using NLog;
using NzbDrone.Core.IndexerSearch.Definitions;
using NzbDrone.Core.Parser.Model;

namespace NzbDrone.Core.DecisionEngine.Specifications
{
    public class UpgradeDiskSpecification : IDecisionEngineSpecification
    {
        private readonly QualityUpgradableSpecification _qualityUpgradableSpecification;
        private readonly Logger _logger;

        public UpgradeDiskSpecification(QualityUpgradableSpecification qualityUpgradableSpecification, Logger logger)
        {
            _qualityUpgradableSpecification = qualityUpgradableSpecification;
            _logger = logger;
        }

        public RejectionType Type => RejectionType.Permanent;

        public virtual Decision IsSatisfiedBy(RemoteEpisode subject, SearchCriteriaBase searchCriteria)
        {
            foreach (var file in subject.Episodes.Where(c => c.EpisodeFileId != 0).Select(c => c.EpisodeFile.Value))
            {
                if(file == null)
                {
                    _logger.Debug("File is no longer available, skipping this file.");
                    continue;
                }

                _logger.Debug("Comparing file quality with report. Existing file is {0}", file.Quality);

                if (!_qualityUpgradableSpecification.IsUpgradable(subject.Series.Profile, file.Quality, subject.ParsedEpisodeInfo.Quality))
                {
                    return Decision.Reject("Quality for existing file on disk is of equal or higher preference: {0}", file.Quality);
                }
            }

            return Decision.Accept();
        }
    }
}