Fixed: Lists are fetched much more efficiently. (Up to 40x loading time improvement with large lists!)

src/NzbDrone.Api/NetImport/NetImportModule.cs

@@ -9,7 +9,7 @@ namespace NzbDrone.Api.NetImport
     {
         public NetImportModule(NetImportFactory netImportFactory) : base(netImportFactory, "netimport")
         {
-            PostValidator.RuleFor(c => c.RootFolderPath).NotNull();
+            PostValidator.RuleFor(c => c.RootFolderPath).IsValidPath();
             PostValidator.RuleFor(c => c.MinimumAvailability).NotNull();
             PostValidator.RuleFor(c => c.ProfileId).NotNull();
         }

src/NzbDrone.Core/NetImport/NetImportSearchService.cs

@@ -63,7 +63,7 @@ namespace NzbDrone.Core.NetImport
         {
             var movies = MovieListSearch(listId, onlyEnableAuto);
 
-            return movies.Where(x => !_movieService.MovieExists(x)).ToList();
+            return _movieService.FilterExistingMovies(movies);
         }
 
         public List<Movie> MovieListSearch(int listId, bool onlyEnableAuto = false)

src/NzbDrone.Core/Tv/MovieService.cs

@@ -1,4 +1,5 @@
 using System;
+using System.Collections;
 using System.Collections.Generic;
 using System.IO;
 using System.Linq;
@@ -39,6 +40,7 @@ namespace NzbDrone.Core.Tv
         List<Movie> GetAllMovies();
         Movie UpdateMovie(Movie movie);
         List<Movie> UpdateMovie(List<Movie> movie);
+        List<Movie> FilterExistingMovies(List<Movie> movies);
         bool MoviePathExists(string folder);
         void RemoveAddOptions(Movie movie);
         List<Movie> MoviesWithFiles(int movieId);
@@ -444,5 +446,21 @@ namespace NzbDrone.Core.Tv
 
             return false;
         }
+
+        public List<Movie> FilterExistingMovies(List<Movie> movies)
+        {
+            var allMovies = GetAllMovies();
+
+            var withTmdbid = movies.Where(m => m.TmdbId != 0).ToList();
+            var withoutTmdbid = movies.Where(m => m.TmdbId == 0).ToList();
+            var withImdbid = withoutTmdbid.Where(m => m.ImdbId.IsNotNullOrWhiteSpace());
+            var rest = withoutTmdbid.Where(m => m.ImdbId.IsNullOrWhiteSpace());
+
+            var ret = withTmdbid.ExceptBy(m => m.TmdbId, allMovies, m => m.TmdbId, EqualityComparer<int>.Default)
+                .Union(withImdbid.ExceptBy(m => m.ImdbId, allMovies, m => m.ImdbId, EqualityComparer<string>.Default))
+                .Union(rest.ExceptBy(m => m.Title.CleanSeriesTitle(), allMovies, m => m.CleanTitle, EqualityComparer<string>.Default)).ToList();
+
+            return ret;
+        }
     }
 }