New: Already Imported Decision Specification (#661)

src/NzbDrone.Core/DecisionEngine/Specifications/AlreadyImportedSpecification.cs

@@ -0,0 +1,106 @@
+using System;
+using System.Linq;
+using NLog;
+using NzbDrone.Core.Configuration;
+using NzbDrone.Core.History;
+using NzbDrone.Core.Indexers;
+using NzbDrone.Core.IndexerSearch.Definitions;
+using NzbDrone.Core.MediaFiles;
+using NzbDrone.Core.Parser.Model;
+
+namespace NzbDrone.Core.DecisionEngine.Specifications
+{
+    public class AlreadyImportedSpecification : IDecisionEngineSpecification
+    {
+        private readonly IHistoryService _historyService;
+        private readonly IConfigService _configService;
+        private readonly IMediaFileService _mediaFileService;
+        private readonly Logger _logger;
+
+        public AlreadyImportedSpecification(IHistoryService historyService,
+                                            IConfigService configService,
+                                            IMediaFileService mediaFileService,
+                                            Logger logger)
+        {
+            _historyService = historyService;
+            _mediaFileService = mediaFileService;
+            _configService = configService;
+            _logger = logger;
+        }
+
+        public SpecificationPriority Priority => SpecificationPriority.Database;
+        public RejectionType Type => RejectionType.Permanent;
+
+        public Decision IsSatisfiedBy(RemoteAlbum subject, SearchCriteriaBase searchCriteria)
+        {
+            var cdhEnabled = _configService.EnableCompletedDownloadHandling;
+
+            if (!cdhEnabled)
+            {
+                _logger.Debug("Skipping already imported check because CDH is disabled");
+                return Decision.Accept();
+            }
+
+            _logger.Debug("Performing already imported check on report");
+            foreach (var album in subject.Albums)
+            {
+                var trackFiles = _mediaFileService.GetFilesByAlbum(album.Id);
+
+                if (trackFiles.Count() == 0)
+                {
+                    _logger.Debug("Skipping already imported check for album without files");
+                    continue;
+                }
+
+                var historyForAlbum = _historyService.GetByAlbum(album.Id, null);
+                var lastGrabbed = historyForAlbum.FirstOrDefault(h => h.EventType == HistoryEventType.Grabbed);
+
+                if (lastGrabbed == null)
+                {
+                    continue;
+                }
+
+                var imported = historyForAlbum.FirstOrDefault(h =>
+                    h.EventType == HistoryEventType.DownloadImported &&
+                    h.DownloadId == lastGrabbed.DownloadId);
+
+                if (imported == null)
+                {
+                    continue;
+                }
+
+                // This is really only a guard against redownloading the same release over
+                // and over when the grabbed and imported qualities do not match, if they do
+                // match skip this check.
+                if (lastGrabbed.Quality.Equals(imported.Quality))
+                {
+                    continue;
+                }
+
+                var release = subject.Release;
+
+                if (release.DownloadProtocol == DownloadProtocol.Torrent)
+                {
+                    var torrentInfo = release as TorrentInfo;
+
+                    if (torrentInfo != null && torrentInfo.InfoHash.ToUpper() == lastGrabbed.DownloadId)
+                    {
+                        _logger.Debug("Has same torrent hash as a grabbed and imported release");
+                        return Decision.Reject("Has same torrent hash as a grabbed and imported release");
+                    }
+                }
+
+                // Only based on title because a release with the same title on another indexer/released at
+                // a different time very likely has the exact same content and we don't need to also try it.
+
+                if (release.Title.Equals(lastGrabbed.SourceTitle, StringComparison.InvariantCultureIgnoreCase))
+                {
+                    _logger.Debug("Has same release name as a grabbed and imported release");
+                    return Decision.Reject("Has same release name as a grabbed and imported release");
+                }
+            }
+
+            return Decision.Accept();
+        }
+    }
+}