some preliminary work to move decision engine to use the visitor pattern.

NzbDrone.Core/DecisionEngine/Specifications/AcceptableSizeSpecification.cs

@@ -0,0 +1,76 @@
+using NLog;
+using NzbDrone.Core.Model;
+using NzbDrone.Core.Qualities;
+using NzbDrone.Core.Tv;
+
+namespace NzbDrone.Core.DecisionEngine.Specifications
+{
+    public class AcceptableSizeSpecification : IFetchableSpecification
+    {
+        private readonly IQualitySizeService _qualityTypeProvider;
+        private readonly IEpisodeService _episodeService;
+        private readonly Logger _logger;
+
+        public AcceptableSizeSpecification(IQualitySizeService qualityTypeProvider, IEpisodeService episodeService, Logger logger)
+        {
+            _qualityTypeProvider = qualityTypeProvider;
+            _episodeService = episodeService;
+            _logger = logger;
+        }
+
+        public string RejectionReason
+        {
+            get { return "File size too big or small"; }
+        }
+
+        public virtual bool IsSatisfiedBy(EpisodeParseResult subject)
+        {
+            _logger.Trace("Beginning size check for: {0}", subject);
+
+            if (subject.Quality.Quality == Quality.RAWHD)
+            {
+                _logger.Trace("Raw-HD release found, skipping size check.");
+                return true;
+            }
+
+            var qualityType = _qualityTypeProvider.Get((int)subject.Quality.Quality);
+
+            if (qualityType.MaxSize == 0)
+            {
+                _logger.Trace("Max size is 0 (unlimited) - skipping check.");
+                return true;
+            }
+
+            var maxSize = qualityType.MaxSize.Megabytes();
+            var series = subject.Series;
+
+            //Multiply maxSize by Series.Runtime
+            maxSize = maxSize * series.Runtime;
+
+            //Multiply maxSize by the number of episodes parsed (if EpisodeNumbers is null it will be treated as a single episode)
+            //TODO: is this check really necessary? shouldn't we blowup?
+            if (subject.EpisodeNumbers != null)
+                maxSize = maxSize * subject.EpisodeNumbers.Count;
+
+            //Check if there was only one episode parsed
+            //and it is the first or last episode of the season
+            if (subject.EpisodeNumbers != null && subject.EpisodeNumbers.Count == 1 &&
+                _episodeService.IsFirstOrLastEpisodeOfSeason(series.Id,
+                subject.SeasonNumber, subject.EpisodeNumbers[0]))
+            {
+                maxSize = maxSize * 2;
+            }
+
+            //If the parsed size is greater than maxSize we don't want it
+            if (subject.Size > maxSize)
+            {
+                _logger.Trace("Item: {0}, Size: {1} is greater than maximum allowed size ({2}), rejecting.", subject, subject.Size, maxSize);
+                return false;
+            }
+
+            _logger.Trace("Item: {0}, meets size constraints.", subject);
+            return true;
+        }
+
+    }
+}