Series and Season folder format validation/error handling

src/NzbDrone.Api/Config/NamingConfigModule.cs

@@ -4,6 +4,7 @@ using System.Linq;
 using FluentValidation;
 using FluentValidation.Results;
 using Nancy.Responses;
+using NzbDrone.Common;
 using NzbDrone.Core.Organizer;
 using Nancy.ModelBinding;
 using NzbDrone.Api.Mapping;
@@ -39,6 +40,7 @@ namespace NzbDrone.Api.Config
             SharedValidator.RuleFor(c => c.StandardEpisodeFormat).ValidEpisodeFormat();
             SharedValidator.RuleFor(c => c.DailyEpisodeFormat).ValidDailyEpisodeFormat();
             SharedValidator.RuleFor(c => c.SeriesFolderFormat).ValidSeriesFolderFormat();
+            SharedValidator.RuleFor(c => c.SeasonFolderFormat).ValidSeasonFolderFormat();
         }
 
         private void UpdateNamingConfig(NamingConfigResource resource)
@@ -72,7 +74,6 @@ namespace NzbDrone.Api.Config
 
         private JsonResponse<NamingSampleResource> GetExamples(NamingConfigResource config)
         {
-            //TODO: Validate that the format is valid
             var nameSpec = config.InjectTo<NamingConfig>();
             var sampleResource = new NamingSampleResource();
             
@@ -92,8 +93,13 @@ namespace NzbDrone.Api.Config
                     ? "Invalid format"
                     : dailyEpisodeSampleResult.Filename;
 
-            sampleResource.SeriesFolderExample = _filenameSampleService.GetSeriesFolderSample(nameSpec);
-            sampleResource.SeasonFolderExample = _filenameSampleService.GetSeasonFolderSample(nameSpec);
+            sampleResource.SeriesFolderExample = nameSpec.SeriesFolderFormat.IsNullOrWhiteSpace()
+                ? "Invalid format"
+                : _filenameSampleService.GetSeriesFolderSample(nameSpec);
+
+            sampleResource.SeasonFolderExample = nameSpec.SeasonFolderFormat.IsNullOrWhiteSpace()
+                ? "Invalid format"
+                : _filenameSampleService.GetSeasonFolderSample(nameSpec);
 
             return sampleResource.AsResponse();
         }

src/NzbDrone.Core/Organizer/FileNameValidation.cs

@@ -1,4 +1,5 @@
 using System;
+using System.Text.RegularExpressions;
 using FluentValidation;
 using FluentValidation.Validators;
 
@@ -6,6 +7,9 @@ namespace NzbDrone.Core.Organizer
 {
     public static class FileNameValidation
     {
+        private static readonly Regex SeasonFolderRegex = new Regex(@"(\{season(\:\d+)?\})",
+                                                                            RegexOptions.Compiled | RegexOptions.IgnoreCase);
+
         public static IRuleBuilderOptions<T, string> ValidEpisodeFormat<T>(this IRuleBuilder<T, string> ruleBuilder)
         {
             ruleBuilder.SetValidator(new NotEmptyValidator(null));
@@ -23,6 +27,12 @@ namespace NzbDrone.Core.Organizer
             ruleBuilder.SetValidator(new NotEmptyValidator(null));
             return ruleBuilder.SetValidator(new RegularExpressionValidator(FileNameBuilder.SeriesTitleRegex)).WithMessage("Must contain series title");
         }
+
+        public static IRuleBuilderOptions<T, string> ValidSeasonFolderFormat<T>(this IRuleBuilder<T, string> ruleBuilder)
+        {
+            ruleBuilder.SetValidator(new NotEmptyValidator(null));
+            return ruleBuilder.SetValidator(new RegularExpressionValidator(SeasonFolderRegex)).WithMessage("Must contain season number");
+        }
     }
 
     public class ValidDailyEpisodeFormatValidator : PropertyValidator