New: Validate that naming formats don't contain illegal characters

(cherry picked from commit 145c644c9d8f1636027da8a782a7e74f3182c678)

Closes #5382

src/NzbDrone.Core/Organizer/FileNameValidation.cs

@@ -1,5 +1,8 @@
+using System.IO;
+using System.Linq;
 using FluentValidation;
 using FluentValidation.Validators;
+using NzbDrone.Common.Extensions;
 
 namespace NzbDrone.Core.Organizer
 {
@@ -8,13 +11,42 @@ namespace NzbDrone.Core.Organizer
         public static IRuleBuilderOptions<T, string> ValidMovieFolderFormat<T>(this IRuleBuilder<T, string> ruleBuilder)
         {
             ruleBuilder.SetValidator(new NotEmptyValidator(null));
+            ruleBuilder.SetValidator(new IllegalCharactersValidator());
+
             return ruleBuilder.SetValidator(new RegularExpressionValidator(FileNameBuilder.MovieTitleRegex)).WithMessage("Must contain movie title");
         }
 
         public static IRuleBuilderOptions<T, string> ValidMovieFormat<T>(this IRuleBuilder<T, string> ruleBuilder)
         {
             ruleBuilder.SetValidator(new NotEmptyValidator(null));
+            ruleBuilder.SetValidator(new IllegalCharactersValidator());
+
             return ruleBuilder.SetValidator(new RegularExpressionValidator(FileNameBuilder.MovieTitleRegex)).WithMessage("Must contain movie title");
         }
     }
+
+    public class IllegalCharactersValidator : PropertyValidator
+    {
+        private static readonly char[] InvalidPathChars = Path.GetInvalidPathChars();
+
+        protected override string GetDefaultMessageTemplate() => "Contains illegal characters: {InvalidCharacters}";
+
+        protected override bool IsValid(PropertyValidatorContext context)
+        {
+            var value = context.PropertyValue as string;
+            if (value.IsNullOrWhiteSpace())
+            {
+                return true;
+            }
+
+            var invalidCharacters = InvalidPathChars.Where(i => value!.IndexOf(i) >= 0).ToList();
+            if (invalidCharacters.Any())
+            {
+                context.MessageFormatter.AppendArgument("InvalidCharacters", string.Join("", invalidCharacters));
+                return false;
+            }
+
+            return true;
+        }
+    }
 }