Fix #28: author audiobook/ebook path edits are silently dropped

src/Chaptarr.Api.V1/Author/AuthorController.cs

@@ -213,6 +213,8 @@ public AuthorController(IBroadcastSignalRMessage signalRBroadcaster,
             PostValidator.RuleFor(s => s.ForeignAuthorId).NotEmpty().SetValidator(authorExistsValidator);
 
 	            PutValidator.RuleFor(s => s.Path).IsValidPath();
+	            PutValidator.RuleFor(s => s.AudiobookPath).IsValidPath().When(s => s.AudiobookPath.IsNotNullOrWhiteSpace());
+	            PutValidator.RuleFor(s => s.EbookPath).IsValidPath().When(s => s.EbookPath.IsNotNullOrWhiteSpace());
 	        }
 
 	        private bool IsImportActive()

src/Chaptarr.Api.V1/Author/AuthorResource.cs

@@ -67,6 +67,10 @@ public class AuthorResource : RestResource
         // Readarr/Seerr compatibility (monitor mode string, e.g. "none")
         public string MonitorNewItems { get; set; }
         public string Folder { get; set; }
+        // Writable per-media author paths. The edit UI submits these; AudiobookFolder/
+        // EbookFolder below remain the read-only display values set by the controller.
+        public string AudiobookPath { get; set; }
+        public string EbookPath { get; set; }
         public string AudiobookFolder { get; set; }
         public string EbookFolder { get; set; }
         public List<string> Genres { get; set; }
@@ -131,6 +135,8 @@ public static AuthorResource ToResource(this NzbDrone.Core.Books.Author model, R
                 Images = displayImages.JsonClone(),
 
                 Path = model.Path,
+                AudiobookPath = model.AudiobookPath,
+                EbookPath = model.EbookPath,
                 AudiobookQualityProfileId = model.AudiobookQualityProfileId,
                 EbookQualityProfileId = model.EbookQualityProfileId,
                 MetadataProfileId = model.MetadataProfileId,
@@ -463,6 +469,8 @@ public static NzbDrone.Core.Books.Author ToModel(this AuthorResource resource, R
 
                 //AlternateTitles
                 Path = resource.Path,
+                AudiobookPath = resource.AudiobookPath,
+                EbookPath = resource.EbookPath,
                 AudiobookQualityProfileId = audiobookQualityProfileId,
                 EbookQualityProfileId = ebookQualityProfileId,
                 MetadataProfileId = resource.MetadataProfileId,
@@ -568,6 +576,16 @@ private static void PreserveStoredAuthorStateForFacadeUpdate(AuthorResource reso
                 updatedAuthor.Path = storedAuthor.Path;
             }
 
+            if (resource.AudiobookPath == null)
+            {
+                updatedAuthor.AudiobookPath = storedAuthor.AudiobookPath;
+            }
+
+            if (resource.EbookPath == null)
+            {
+                updatedAuthor.EbookPath = storedAuthor.EbookPath;
+            }
+
             if (resource.AddOptions == null)
             {
                 updatedAuthor.AddOptions = storedAuthor.AddOptions;

src/Chaptarr.Core.Test/Books/AuthorResourceMapperFixture.cs

@@ -99,6 +99,53 @@ public void should_not_wipe_tri_state_monitoring_fields_when_not_provided_on_put
             Assert.That(updated.EbookSettingsManuallyOverridden, Is.False);
         }
 
+        [Test]
+        public void should_apply_media_paths_on_put_update()
+        {
+            var existing = new NzbDrone.Core.Books.Author
+            {
+                Id = 1,
+                Name = "J.R.R. Tolkien",
+                AudiobookPath = "/audiobooks/J.R.R. Tolkien",
+                EbookPath = "/ebooks/J.R.R. Tolkien"
+            };
+
+            var resource = new AuthorResource
+            {
+                Id = 1,
+                AuthorName = "J.R.R. Tolkien",
+                AudiobookPath = "/audiobooks/J. R. R. Tolkien"
+            };
+
+            var updated = resource.ToModel(existing);
+
+            Assert.That(updated.AudiobookPath, Is.EqualTo("/audiobooks/J. R. R. Tolkien"));
+            Assert.That(updated.EbookPath, Is.EqualTo("/ebooks/J.R.R. Tolkien"), "an omitted media path must keep its stored value");
+        }
+
+        [Test]
+        public void should_not_wipe_media_paths_when_not_provided_on_put_update()
+        {
+            var existing = new NzbDrone.Core.Books.Author
+            {
+                Id = 1,
+                Name = "J.R.R. Tolkien",
+                AudiobookPath = "/audiobooks/J.R.R. Tolkien",
+                EbookPath = "/ebooks/J.R.R. Tolkien"
+            };
+
+            var resource = new AuthorResource
+            {
+                Id = 1,
+                AuthorName = "J.R.R. Tolkien"
+            };
+
+            var updated = resource.ToModel(existing);
+
+            Assert.That(updated.AudiobookPath, Is.EqualTo("/audiobooks/J.R.R. Tolkien"));
+            Assert.That(updated.EbookPath, Is.EqualTo("/ebooks/J.R.R. Tolkien"));
+        }
+
         [Test]
         public void should_apply_per_type_metadata_profiles_on_put_update()
         {

src/NzbDrone.Core/Books/Model/Author.cs

@@ -328,6 +328,11 @@ public override void ApplyChanges(Author other)
             AddOptions = other.AddOptions;
             AudiobookRootFolderPath = other.AudiobookRootFolderPath;
             EbookRootFolderPath = other.EbookRootFolderPath;
+
+            // Per-media author paths: null means the caller did not provide a value,
+            // so keep the stored one (an explicit clear arrives as an empty string).
+            AudiobookPath = other.AudiobookPath ?? AudiobookPath;
+            EbookPath = other.EbookPath ?? EbookPath;
             Monitored = other.Monitored;
             // TRI-STATE MONITORING SYSTEM - Copy only when explicitly provided (not null).
             // This prevents partial updates from wiping existing monitoring values.