Ignore older episodes in latest season

New: Ignore episodes that aired more than 90 days ago when adding with Latest Season
Closes #826

src/NzbDrone.Core.Test/TvTests/EpisodeMonitoredServiceTests/SetEpisodeMontitoredFixture.cs

@@ -207,6 +207,22 @@ namespace NzbDrone.Core.Test.TvTests.EpisodeMonitoredServiceTests
             VerifyNotMonitored(e => e.HasFile);
         }
 
+        [Test]
+        public void should_not_monitor_latest_season_if_all_episodes_aired_more_than_90_days_ago()
+        {
+            _episodes.ForEach(e => e.AirDateUtc = DateTime.UtcNow.AddDays(-100));
+
+            var monitoringOptions = new MonitoringOptions
+                                    {
+                                        Monitor = MonitorTypes.LatestSeason
+                                    };
+
+            Subject.SetEpisodeMonitoredStatus(_series, monitoringOptions);
+
+            Mocker.GetMock<IEpisodeService>()
+                  .Verify(v => v.UpdateEpisodes(It.Is<List<Episode>>(l => l.All(e => !e.Monitored))));
+        }
+
         private void VerifyMonitored(Func<Episode, bool> predicate)
         {
             Mocker.GetMock<IEpisodeService>()

src/NzbDrone.Core/Tv/EpisodeMonitoredService.cs

@@ -77,7 +77,17 @@ namespace NzbDrone.Core.Tv
                     break;
 
                 case MonitorTypes.LatestSeason:
+
+                    if (episodes.Where(e => e.SeasonNumber == lastSeason)
+                                .All(e => e.AirDateUtc.HasValue && !e.AirDateUtc.Value.InLastDays(90)))
+                    {
+                        _logger.Debug("[{0}] Unmonitoring all episodes because latest season aired more than 90 days ago", series.Title);
+                        ToggleEpisodesMonitoredState(episodes, e => false);
+                        break;
+                    }
+
                     _logger.Debug("[{0}] Monitoring latest season episodes", series.Title);
+
                     ToggleEpisodesMonitoredState(episodes, e => e.SeasonNumber > 0 && e.SeasonNumber == lastSeason);
 
                     break;