Use MinBy and MaxBy instead of OrderBy + First

(cherry picked from commit 6ea3d8c127eafbcf9d1b6e9338b737e91e256875)

Closes #2323

src/NzbDrone.Common/Disk/DiskProviderBase.cs

@@ -473,12 +473,11 @@ namespace NzbDrone.Common.Disk
 
                 return mounts.Where(drive => drive.RootDirectory.PathEquals(path) ||
                                              drive.RootDirectory.IsParentPath(path))
-                          .OrderByDescending(drive => drive.RootDirectory.Length)
-                          .FirstOrDefault();
+                          .MaxBy(drive => drive.RootDirectory.Length);
             }
             catch (Exception ex)
             {
-                Logger.Debug(ex, string.Format("Failed to get mount for path {0}", path));
+                Logger.Debug(ex, $"Failed to get mount for path {path}");
                 return null;
             }
         }

src/NzbDrone.Core/Books/Services/MonitorNewBookService.cs

@@ -33,7 +33,7 @@ namespace NzbDrone.Core.Books
 
             if (monitorNewItems == NewItemMonitorTypes.New)
             {
-                var newest = existingBooks.OrderByDescending(x => x.ReleaseDate ?? DateTime.MinValue).FirstOrDefault()?.ReleaseDate ?? DateTime.MinValue;
+                var newest = existingBooks.MaxBy(x => x.ReleaseDate ?? DateTime.MinValue)?.ReleaseDate ?? DateTime.MinValue;
 
                 return (addedBook.ReleaseDate ?? DateTime.MinValue) >= newest;
             }

src/NzbDrone.Core/Books/Utilities/ShouldRefreshAuthor.cs

@@ -40,7 +40,7 @@ namespace NzbDrone.Core.Books
                 return true;
             }
 
-            var lastBook = _bookService.GetBooksByAuthor(author.Id).OrderByDescending(e => e.ReleaseDate).FirstOrDefault();
+            var lastBook = _bookService.GetBooksByAuthor(author.Id).MaxBy(e => e.ReleaseDate);
 
             if (lastBook != null && lastBook.ReleaseDate > DateTime.UtcNow.AddDays(-30))
             {

src/NzbDrone.Core/Download/Pending/PendingReleaseService.cs

@@ -96,7 +96,7 @@ namespace NzbDrone.Core.Download.Pending
 
                     var bookIds = decision.RemoteBook.Books.Select(e => e.Id);
 
-                    var existingReports = bookIds.SelectMany(v => alreadyPendingByBook[v] ?? Enumerable.Empty<PendingRelease>())
+                    var existingReports = bookIds.SelectMany(v => alreadyPendingByBook[v])
                                                     .Distinct().ToList();
 
                     var matchingReports = existingReports.Where(MatchingReleasePredicate(decision.RemoteBook.Release)).ToList();
@@ -239,8 +239,7 @@ namespace NzbDrone.Core.Download.Pending
 
             return authorReleases.Select(r => r.RemoteBook)
                                  .Where(r => r.Books.Select(e => e.Id).Intersect(bookIds).Any())
-                                 .OrderByDescending(p => p.Release.AgeHours)
-                                 .FirstOrDefault();
+                                 .MaxBy(p => p.Release.AgeHours);
         }
 
         private ILookup<int, PendingRelease> CreateBookLookup(IEnumerable<PendingRelease> alreadyPending)

src/NzbDrone.Core/History/HistoryRepository.cs

@@ -29,16 +29,12 @@ namespace NzbDrone.Core.History
 
         public EntityHistory MostRecentForBook(int bookId)
         {
-            return Query(h => h.BookId == bookId)
-                .OrderByDescending(h => h.Date)
-                .FirstOrDefault();
+            return Query(h => h.BookId == bookId).MaxBy(h => h.Date);
         }
 
         public EntityHistory MostRecentForDownloadId(string downloadId)
         {
-            return Query(h => h.DownloadId == downloadId)
-                .OrderByDescending(h => h.Date)
-                .FirstOrDefault();
+            return Query(h => h.DownloadId == downloadId).MaxBy(h => h.Date);
         }
 
         public List<EntityHistory> FindByDownloadId(string downloadId)

src/NzbDrone.Core/MetadataSource/BookInfo/BookInfoProxy.cs

@@ -881,7 +881,7 @@ namespace NzbDrone.Core.MetadataSource.BookInfo
                 book.Editions = resource.Books.Select(x => MapEdition(x)).ToList();
 
                 // monitor the most popular release
-                var mostPopular = book.Editions.Value.OrderByDescending(x => x.Ratings.Popularity).FirstOrDefault();
+                var mostPopular = book.Editions.Value.MaxBy(x => x.Ratings.Popularity);
                 if (mostPopular != null)
                 {
                     mostPopular.Monitored = true;

src/NzbDrone.Core/RootFolders/RootFolderService.cs

@@ -153,8 +153,7 @@ namespace NzbDrone.Core.RootFolders
         public RootFolder GetBestRootFolder(string path, List<RootFolder> allRootFolders)
         {
             return allRootFolders.Where(r => PathEqualityComparer.Instance.Equals(r.Path, path) || r.Path.IsParentPath(path))
-                .OrderByDescending(r => r.Path.Length)
-                .FirstOrDefault();
+                .MaxBy(r => r.Path.Length);
         }
 
         public string GetBestRootFolderPath(string path)