incr ver

Add feature to scan library for higher quality books

.vitepress/config.js

@@ -3,7 +3,8 @@ import { defineConfig } from "vitepress";
 // https://vitepress.dev/reference/site-config
 export default defineConfig({
   title: "Libation",
-  description: "Libation: Liberate your Library - A free application for downloading your Audible audiobooks",
+  description:
+    "Libation: Liberate your Library - A free application for downloading your Audible audiobooks",
   head: [["link", { rel: "icon", href: "/favicon.ico" }]],
   cleanUrls: true,
   themeConfig: {
@@ -26,14 +27,20 @@ export default defineConfig({
     nav: [
       { text: "Getting Started", link: "/docs/getting-started" },
       { text: "Docs", link: "/docs/index" },
-      { text: "Download", link: "https://github.com/rmcrackan/Libation/releases/latest" },
-      { text: "Issues & Requests", link: "https://github.com/rmcrackan/Libation/issues" },
+      {
+        text: "Download",
+        link: "https://github.com/rmcrackan/Libation/releases/latest",
+      },
+      {
+        text: "Issues & Requests",
+        link: "https://github.com/rmcrackan/Libation/issues",
+      },
       { text: "Donate", link: "https://www.paypal.com/paypalme/mcrackan" },
     ],
     sidebar: [
       {
         items: [
-          { text: "Overview", link: "/docs/index"},
+          { text: "Overview", link: "/docs/index" },
           { text: "Getting Started", link: "/docs/getting-started" },
           { text: "FAQ", link: "/docs/frequently-asked-questions" },
           {
@@ -56,7 +63,10 @@ export default defineConfig({
         text: "Features",
         collapsed: false,
         items: [
-          { text: "Audio File Formats", link: "/docs/features/audio-file-formats" },
+          {
+            text: "Audio File Formats",
+            link: "/docs/features/audio-file-formats",
+          },
           { text: "Naming Templates", link: "/docs/features/naming-templates" },
           {
             text: "Searching & Filtering",
@@ -67,12 +77,19 @@ export default defineConfig({
       {
         text: "Advanced",
         collapsed: false,
+        items: [{ text: "Advanced Topics", link: "/docs/advanced/advanced" }],
+      },
+      {
+        text: "Development",
+        collapsed: false,
         items: [
-          { text: "Advanced Topics", link: "/docs/advanced/advanced" },
           {
-            text: "Linux Development Setup",
-            link: "/docs/advanced/linux-development-setup-using-nix",
+            text: "Getting Started",
+            link: "/docs/development/getting-started",
           },
+          { text: "Contribute", link: "/docs/development/contribute" },
+          { text: "Website & Docs", link: "/docs/development/website" },
+          { text: "Linux Setup (Nix)", link: "/docs/development/nix-linux-setup" },
         ],
       },
     ],
@@ -81,7 +98,9 @@ export default defineConfig({
       level: "deep",
     },
 
-    socialLinks: [{ icon: "github", link: "https://github.com/rmcrackan/Libation" }],
+    socialLinks: [
+      { icon: "github", link: "https://github.com/rmcrackan/Libation" },
+    ],
 
     search: {
       provider: "local",

Documentation/Advanced.md

@@ -0,0 +1 @@
+# This page has been moved to https://getlibation.com/docs/advanced/advanced

Documentation/AudioFileFormats.md

@@ -0,0 +1 @@
+# This page has been moved to https://getlibation.com/docs/features/audio-file-formats

Documentation/Docker.md

@@ -0,0 +1 @@
+# This page has been moved to https://getlibation.com/docs/installation/docker

Documentation/FrequentlyAskedQuestions.md

@@ -0,0 +1 @@
+# This page has been moved to https://getlibation.com/docs/frequently-asked-questions

Documentation/GettingStarted.md

@@ -0,0 +1 @@
+# This page has been moved to https://getlibation.com/docs/getting-started

Documentation/InstallOnLinux.md

@@ -0,0 +1 @@
+# This page has been moved to https://getlibation.com/docs/installation/linux

Documentation/InstallOnMac.md

@@ -0,0 +1 @@
+# This page has been moved to https://getlibation.com/docs/installation/mac

Documentation/LinuxDevelopmentSetupUsingNix.md

@@ -0,0 +1 @@
+# This page has been moved to https://getlibation.com/docs/development/nix-linux-setup

Documentation/NamingTemplates.md

@@ -0,0 +1 @@
+# This page has been moved to https://getlibation.com/docs/features/naming-templates

Documentation/SearchingAndFiltering.md

@@ -0,0 +1 @@
+# This page has been moved to https://getlibation.com/docs/features/searching-and-filtering

README.md

@@ -1,10 +1,15 @@
 # Libation: Liberate your Library
 
-## [Download Libation](https://github.com/rmcrackan/Libation/releases/latest)
+**Libation** is a free, open-source application for downloading and managing your Audible audiobooks. It decrypts your library, removes DRM, and lets you own your audiobooks forever.
 
-### If you found this useful, tell a friend. If you found this REALLY useful, you can click here to [PayPal.me](https://paypal.me/mcrackan?locale.x=en_us)
+## Features
 
-...or just tell more friends. As long as I'm maintaining this software, it will remain **free** and **open source**.
+- **Unlock Your Library**: Download and remove DRM from your audiobooks.
+- **Cross-Platform**: Fully supported on Windows, macOS, and Linux.
+- **Region Support**: Works with Audible regions US, UK, Canada, Germany, France, Australia, Japan, India, and Spain.
+- **Advanced Organization**: Search, filter, and tag your books.
+- **Fast & Efficient**: Powered by AAXClean for fast decryption without heavy dependencies like ffmpeg.
+- **Import**: Easily import your existing library, including cover art.
 
 ## Getting started with Libation
 
@@ -17,26 +22,34 @@ All documentation has been moved to our new site: [getlibation.com](https://getl
 
 ## Development
 
-### Documentation
+Grab the latest release for your platform from the [Releases Page](https://github.com/rmcrackan/Libation/releases/latest).
 
-The documentation is built with [VitePress](https://vitepress.dev/) and located in the `docs` directory. For more information like [markdown syntax](https://vitepress.dev/guide/markdown#advanced-configuration) and [routing](https://vitepress.dev/guide/routing) or other features, refer [VitePress documentation](https://vitepress.dev/guide).
+## Documentation
 
-**Prerequisites**: Node.js 18+
+Comprehensive documentation is available in the `docs` directory and on our [Documentation Site](https://getlibation.com/docs).
 
-**Commands**:
+- [Getting Started](https://getlibation.com/docs/getting-started)
+- [FAQ](https://getlibation.com/docs/frequently-asked-questions)
 
-```bash
-# Install dependencies
-npm install
+## Development & Contributing
 
-# Start local dev server (http://localhost:5173)
-npm run docs:dev
+We welcome contributions!
 
-# Build for production (output: docs/.vitepress/dist)
-npm run docs:build
+- **[Development Getting Started](https://getlibation.com/docs/development/getting-started)**: Setup your environment.
+- **[Contribute](https://getlibation.com/docs/development/contribute)**: How to contribute code.
+- **[Website & Docs](https://getlibation.com/docs/development/website)**: How to run and improve the documentation.
+- **[Linux Setup (Nix)](https://getlibation.com/docs/development/nix-linux-setup)**: Nix-based environment setup.
 
-# Preview production build
-npm run docs:preview
-```
+## Community & Support
 
-**Note**: New pages are automatically routed based on their folder structure (e.g., `docs/docs/index.md` maps to `/docs/index`). To add them to the sidebar, update the `sidebar` configuration in `.vitepress/config.js`.
+- **[Issues](https://github.com/rmcrackan/Libation/issues)**: Report bugs or request features.
+- **[PayPal](https://paypal.me/mcrackan?locale.x=en_us)**: Support the project if you find it useful.
+
+## License
+
+Libation is released under the GPL-3.0 License
+
+---
+
+If you found this useful, tell a friend. If you found this REALLY useful, you can click here to PayPal.me
+...or just tell more friends. As long as I'm maintaining this software, it will remain free and open source.

Source/AaxDecrypter/AaxcDownloadMultiConverter.cs

@@ -25,12 +25,19 @@ namespace AaxDecrypter
 		{
 			//Finishing configuring lame encoder.
 			if (DownloadOptions.OutputFormat == OutputFormat.Mp3)
+			{
+				if (AaxFile is null)
+					throw new InvalidOperationException($"AaxFile is null during {nameof(OnInitialized)} in {nameof(AaxcDownloadConvertBase)}.");
+				if (DownloadOptions.LameConfig is null)
+					throw new InvalidOperationException($"LameConfig is null during {nameof(OnInitialized)} in {nameof(DownloadOptions)}.");
+
 				MpegUtil.ConfigureLameOptions(
 					AaxFile,
 					DownloadOptions.LameConfig,
 					DownloadOptions.Downsample,
 					DownloadOptions.MatchSourceBitrate,
 					chapters: null);
+			}
 		}
 
 		/*

Source/AaxDecrypter/AaxcDownloadSingleConverter.cs

@@ -31,12 +31,19 @@ namespace AaxDecrypter
 		{
 			//Finishing configuring lame encoder.
 			if (DownloadOptions.OutputFormat == OutputFormat.Mp3)
+			{
+				if (AaxFile is null)
+					throw new InvalidOperationException($"AaxFile is null during {nameof(OnInitialized)} in {nameof(AaxcDownloadConvertBase)}.");
+				if (DownloadOptions.LameConfig is null)
+					throw new InvalidOperationException($"LameConfig is null during {nameof(OnInitialized)} in {nameof(DownloadOptions)}.");
+
 				MpegUtil.ConfigureLameOptions(
 					AaxFile,
 					DownloadOptions.LameConfig,
 					DownloadOptions.Downsample,
 					DownloadOptions.MatchSourceBitrate,
 					DownloadOptions.ChapterInfo);
+			}
 		}
 
 		protected async override Task<bool> Step_DownloadAndDecryptAudiobookAsync()

Source/AaxDecrypter/MpegUtil.cs

@@ -2,7 +2,9 @@
 using AAXClean.Codecs;
 using NAudio.Lame;
 using System;
+using System.Linq;
 
+#nullable enable
 namespace AaxDecrypter
 {
 	public static class MpegUtil
@@ -13,7 +15,7 @@ namespace AaxDecrypter
 			LameConfig lameConfig,
 			bool downsample,
 			bool matchSourceBitrate,
-			ChapterInfo chapters)
+			ChapterInfo? chapters)
 		{
 			double bitrateMultiple = 1;
 
@@ -50,20 +52,22 @@ namespace AaxDecrypter
 			if (mp4File.AppleTags.AppleListBox.GetFreeformTagString(TagDomain, "SUBTITLE") is string subtitle)
 				lameConfig.ID3.Subtitle = subtitle;
 
-			if (mp4File.AppleTags.AppleListBox.GetFreeformTagString(TagDomain, "LANGUAGE") is string lang)
-				lameConfig.ID3.UserDefinedText.Add("LANGUAGE", lang);
-
-			if (mp4File.AppleTags.AppleListBox.GetFreeformTagString(TagDomain, "SERIES") is string series)
-				lameConfig.ID3.UserDefinedText.Add("SERIES", series);
-
-			if (mp4File.AppleTags.AppleListBox.GetFreeformTagString(TagDomain, "PART") is string part)
-				lameConfig.ID3.UserDefinedText.Add("PART", part);
-
 			if (chapters?.Count > 0)
 			{
 				var cue = Cue.CreateContents(lameConfig.ID3.Title + ".mp3", chapters);
 				lameConfig.ID3.UserDefinedText.Add("CUESHEET", cue);
 			}
+
+			//Copy over all other freeform tags
+			foreach (var t in mp4File.AppleTags.AppleListBox.Tags.OfType<Mpeg4Lib.Boxes.FreeformTagBox>())
+			{
+				if (t.Name?.Name is string name &&
+					t.Mean?.ReverseDnsDomain is string domain &&
+					!lameConfig.ID3.UserDefinedText.ContainsKey(name) &&
+					mp4File.AppleTags.AppleListBox.GetFreeformTagString(domain, name) is string tagStr &&
+					!string.IsNullOrWhiteSpace(tagStr))
+					lameConfig.ID3.UserDefinedText.Add(name, tagStr);
+			}
 		}
 	}
 }

Source/AppScaffolding/AppScaffolding.csproj

@@ -2,7 +2,7 @@
 <Project Sdk="Microsoft.NET.Sdk">
   <PropertyGroup>
     <TargetFramework>net10.0</TargetFramework>
-    <Version>13.0.0.1</Version>
+    <Version>13.1.0.1</Version>
   </PropertyGroup>
   <ItemGroup>
     <PackageReference Include="Octokit" Version="14.0.0" />

Source/AppScaffolding/LibationScaffolding.cs

@@ -136,10 +136,13 @@ namespace AppScaffolding
 				}
 			}
 		}
+		static bool migrationsRun = false;
 
 		/// <summary>Initialize logging. Wire-up events. Run after migration</summary>
 		public static void RunPostMigrationScaffolding(Variety variety, Configuration config)
 		{
+			if (System.Threading.Interlocked.CompareExchange(ref migrationsRun, true, false))
+				return;
 			Variety = Enum.IsDefined(variety) ? variety : Variety.None;
 
 			var releaseID = (ReleaseIdentifier)((int)variety | (int)Configuration.OS | (int)RuntimeInformation.ProcessArchitecture);

Source/ApplicationServices/LibraryCommands.cs

@@ -376,8 +376,8 @@ namespace ApplicationServices
         #endregion
 
         #region remove/restore books
-        public static Task<int> RemoveBooksAsync(this IEnumerable<LibraryBook> idsToRemove) => Task.Run(() => removeBooks(idsToRemove));
-        private static int removeBooks(IEnumerable<LibraryBook> removeLibraryBooks)
+        public static Task<int> RemoveBooksAsync(this IEnumerable<LibraryBook?>? idsToRemove) => Task.Run(() => removeBooks(idsToRemove));
+        private static int removeBooks(IEnumerable<LibraryBook?>? removeLibraryBooks)
 		{
 			if (removeLibraryBooks is null || !removeLibraryBooks.Any())
 				return 0;
@@ -385,7 +385,7 @@ namespace ApplicationServices
 			return DoDbSizeChangeOperation(ctx =>
 			{
 				// Entry() NoTracking entities before SaveChanges()
-				foreach (var lb in removeLibraryBooks)
+				foreach (var lb in removeLibraryBooks.OfType<LibraryBook>())
 				{
 					lb.IsDeleted = true;
 					ctx.Entry(lb).State = Microsoft.EntityFrameworkCore.EntityState.Modified;
@@ -417,8 +417,8 @@ namespace ApplicationServices
             }
         }
 
-		public static Task<int> PermanentlyDeleteBooksAsync(this IEnumerable<LibraryBook> idsToRemove) => Task.Run(() => permanentlyDeleteBooks(idsToRemove));
-		private static int permanentlyDeleteBooks(this IEnumerable<LibraryBook> libraryBooks)
+		public static Task<int> PermanentlyDeleteBooksAsync(this IEnumerable<LibraryBook?>? idsToRemove) => Task.Run(() => permanentlyDeleteBooks(idsToRemove));
+		private static int permanentlyDeleteBooks(this IEnumerable<LibraryBook?>? libraryBooks)
 		{
 			if (libraryBooks is null || !libraryBooks.Any())
 				return 0;
@@ -426,8 +426,8 @@ namespace ApplicationServices
             {
 				return DoDbSizeChangeOperation(ctx =>
                 {
-					ctx.LibraryBooks.RemoveRange(libraryBooks);
-					ctx.Books.RemoveRange(libraryBooks.Select(lb => lb.Book));
+					ctx.LibraryBooks.RemoveRange(libraryBooks.OfType<LibraryBook>());
+					ctx.Books.RemoveRange(libraryBooks.OfType<LibraryBook>().Select(lb => lb.Book));
 				});
             }
             catch (Exception ex)
@@ -514,7 +514,7 @@ namespace ApplicationServices
                         udi.UpdateRating(rating.OverallRating, rating.PerformanceRating, rating.StoryRating);
 				});
 
-        public static async Task<int> UpdateBookStatusAsync(this LibraryBook lb, LiberatedStatus bookStatus, Version? libationVersion, AudioFormat audioFormat, string audioVersion)
+        public static async Task<int> UpdateBookStatusAsync(this LibraryBook lb, LiberatedStatus bookStatus, Version? libationVersion, AudioFormat? audioFormat, string audioVersion)
             => await lb.UpdateUserDefinedItemAsync(udi => { udi.BookStatus = bookStatus; udi.SetLastDownloaded(libationVersion, audioFormat, audioVersion); });
 
         public static async Task<int> UpdateBookStatusAsync(this LibraryBook libraryBook, LiberatedStatus bookStatus)
@@ -529,27 +529,31 @@ namespace ApplicationServices
 
         public static async Task<int> UpdateTagsAsync(this LibraryBook libraryBook, string tags)
             => await libraryBook.UpdateUserDefinedItemAsync(udi => udi.Tags = tags);
-        public static async Task<int> UpdateTagsAsync(this IEnumerable<LibraryBook> libraryBooks, string tags)
-            => await libraryBooks.UpdateUserDefinedItemAsync(udi => udi.Tags = tags);
+        public static async Task<int> UpdateTagsAsync(this IEnumerable<LibraryBook> libraryBooks, string? tags)
+            => await libraryBooks.UpdateUserDefinedItemAsync(udi => udi.Tags = tags ?? string.Empty);
 
 		public static async Task<int> UpdateUserDefinedItemAsync(this LibraryBook libraryBook, Action<UserDefinedItem> action)
             => await UpdateUserDefinedItemAsync([libraryBook], action);
 
-		public static Task<int> UpdateUserDefinedItemAsync(this IEnumerable<LibraryBook> libraryBooks, Action<UserDefinedItem> action)
+		public static Task<int> UpdateUserDefinedItemAsync(this IEnumerable<LibraryBook?>? libraryBooks, Action<UserDefinedItem> action)
             => Task.Run(() => libraryBooks.updateUserDefinedItem(action));
 
-		private static int updateUserDefinedItem(this IEnumerable<LibraryBook> libraryBooks, Action<UserDefinedItem> action)
+		private static int updateUserDefinedItem(this IEnumerable<LibraryBook?>? libraryBooks, Action<UserDefinedItem> action)
         {
             try
             {
                 if (libraryBooks is null || !libraryBooks.Any())
                     return 0;
 
-                int qtyChanges;
+                var nonNullBooks = libraryBooks.OfType<LibraryBook>();
+				if (!nonNullBooks.Any())
+					return 0;
+
+				int qtyChanges;
                 using (var context = DbContexts.GetContext())
                 {
                     // Entry() instead of Attach() due to possible stack overflow with large tables
-                    foreach (var book in libraryBooks)
+                    foreach (var book in nonNullBooks)
                     {
                         action?.Invoke(book.Book.UserDefinedItem);
 
@@ -563,7 +567,7 @@ namespace ApplicationServices
                     qtyChanges = context.SaveChanges();
                 }
                 if (qtyChanges > 0)
-                    BookUserDefinedItemCommitted?.Invoke(null, libraryBooks);
+                    BookUserDefinedItemCommitted?.Invoke(null, nonNullBooks);
 
                 return qtyChanges;
             }

Source/ApplicationServices/LibraryExporter.cs

@@ -108,19 +108,22 @@ namespace ApplicationServices
 		[Name("Language")]
         public string Language { get; set; }
 
-		[Name("LastDownloaded")]
+		[Name("Last Downloaded")]
 		public DateTime? LastDownloaded { get; set; }
 
-		[Name("LastDownloadedVersion")]
+		[Name("Last Downloaded Version")]
         public string LastDownloadedVersion { get; set; }
 
-		[Name("IsFinished")]
+		[Name("Is Finished?")]
         public bool IsFinished { get; set; }
 
-		[Name("IsSpatial")]
+		[Name("Is Spatial?")]
 		public bool IsSpatial { get; set; }
 
-		[Name("Last Downloaded File Version")]
+		[Name("Included Until")]
+		public DateTime? IncludedUntil { get; set; }
+
+        [Name("Last Downloaded File Version")]
 		public string LastDownloadedFileVersion { get; set; }
 
 		[Ignore /* csv ignore */]
@@ -177,6 +180,7 @@ namespace ApplicationServices
 				LastDownloadedVersion = a.Book.UserDefinedItem.LastDownloadedVersion?.ToString() ?? "",
 				IsFinished = a.Book.UserDefinedItem.IsFinished,
 				IsSpatial = a.Book.IsSpatial,
+				IncludedUntil = a.IncludedUntil,
 				LastDownloadedFileVersion = a.Book.UserDefinedItem.LastDownloadedFileVersion ?? "",
 				LastDownloadedFormat = a.Book.UserDefinedItem.LastDownloadedFormat
 			}).ToList();
@@ -248,6 +252,7 @@ namespace ApplicationServices
                 nameof(ExportDto.LastDownloadedVersion),
                 nameof(ExportDto.IsFinished),
                 nameof(ExportDto.IsSpatial),
+				nameof(ExportDto.IncludedUntil),
                 nameof(ExportDto.LastDownloadedFileVersion),
                 nameof(ExportDto.CodecString),
                 nameof(ExportDto.SampleRate),
@@ -305,7 +310,8 @@ namespace ApplicationServices
 				row.Cell(col++).Value = dto.LastDownloadedVersion;
 				row.Cell(col++).Value = dto.IsFinished;
 				row.Cell(col++).Value = dto.IsSpatial;
-				row.Cell(col++).Value = dto.LastDownloadedFileVersion;
+                row.Cell(col++).Value = dto.IncludedUntil;
+                row.Cell(col++).Value = dto.LastDownloadedFileVersion;
 				row.Cell(col++).Value = dto.CodecString;
 				row.Cell(col++).Value = dto.SampleRate;
 				row.Cell(col++).Value = dto.ChannelCount;

Source/AudibleUtilities/AccountsSettings.cs

@@ -79,7 +79,7 @@ namespace AudibleUtilities
 		// more common naming convention alias for internal collection
 		public IReadOnlyList<Account> GetAll() => Accounts;
 
-		public Account Upsert(string accountId, string locale)
+		public Account Upsert(string accountId, string? locale)
 		{
 			var acct = GetAccount(accountId, locale);
 

Source/AudibleUtilities/ApiExtended.cs

@@ -1,16 +1,17 @@
-using System;
-using System.Collections.Generic;
-using System.Linq;
-using System.Threading.Channels;
-using System.Threading.Tasks;
-using System.Diagnostics;
-using AudibleApi;
+using AudibleApi;
 using AudibleApi.Common;
 using Dinah.Core;
+using LibationFileManager;
+using Newtonsoft.Json.Linq;
 using Polly;
 using Polly.Retry;
+using System;
+using System.Collections.Generic;
+using System.Diagnostics;
+using System.Linq;
 using System.Threading;
-using LibationFileManager;
+using System.Threading.Channels;
+using System.Threading.Tasks;
 
 #nullable enable
 namespace AudibleUtilities
@@ -82,6 +83,23 @@ namespace AudibleUtilities
 			return policy.ExecuteAsync(() => getItemsAsync(libraryOptions));
 		}
 
+		/// <summary>
+		/// A debugging method used to simulate a library scan from a LibraryScans.zip json file.
+		/// Simply replace the Api call to GetLibraryItemsPagesAsync() with a call to this method.
+		/// </summary>
+		private static async IAsyncEnumerable<Item[]> GetItemsFromJsonFile()
+		{
+			var libraryScanJsonPath = @"Path/to/libraryscan.json";
+			using var jsonFile = System.IO.File.OpenText(libraryScanJsonPath);
+
+			var json = await JToken.ReadFromAsync(new Newtonsoft.Json.JsonTextReader(jsonFile));
+			if (json?["Items"] is not JArray items)
+				yield break;
+
+			foreach (var batch in items.Select(i => Item.FromJson(i as JObject)).Chunk(BatchSize))
+				yield return batch;
+		}
+
 		private async Task<List<Item>> getItemsAsync(LibraryOptions libraryOptions)
 		{
 			Serilog.Log.Logger.Debug("Beginning library scan.");
@@ -162,6 +180,7 @@ namespace AudibleUtilities
 			Serilog.Log.Logger.Information("Completed indexing series episodes after {elappsed_ms} ms.", sw.ElapsedMilliseconds);
 			Serilog.Log.Logger.Information($"Completed library scan in {totalTime.TotalMilliseconds:F0} ms.");
 
+			Array.ForEach(ISanitizer.GetAllSanitizers(), s => s.Sanitize(items));
 			var allExceptions = IValidator.GetAllValidators().SelectMany(v => v.Validate(items)).ToList();
 			if (allExceptions?.Count > 0)
 				throw new ImportValidationException(items, allExceptions);

Source/AudibleUtilities/AudibleApiSanitizers.cs

@@ -0,0 +1,33 @@
+using AudibleApi.Common;
+using System.Collections.Generic;
+using System.Linq;
+
+#nullable enable
+namespace AudibleUtilities;
+
+public interface ISanitizer
+{
+	void Sanitize(IEnumerable<Item> items);
+
+	public static ISanitizer[] GetAllSanitizers() => [
+		new ContributorSanitizer()
+	];
+}
+
+public class ContributorSanitizer : ISanitizer
+{
+	public void Sanitize(IEnumerable<Item> items)
+	{
+		foreach (var item in items)
+		{
+			item.Authors = SanitizePersonArray(item.Authors);
+			item.Narrators = SanitizePersonArray(item.Narrators);
+		}
+	}
+
+	private static Person[]? SanitizePersonArray(Person?[]? contributors)
+		=> contributors
+		?.OfType<Person>()
+		.Where(c => !string.IsNullOrWhiteSpace(c.Asin) && !string.IsNullOrWhiteSpace(c.Name))
+		.ToArray();
+}

Source/AudibleUtilities/AudibleApiValidators.cs

@@ -9,17 +9,21 @@ namespace AudibleUtilities
 	{
 		IEnumerable<Exception> Validate(IEnumerable<Item> items);
 
-		public static IValidator[] GetAllValidators()
-			=> new IValidator[]
-			{
-				new LibraryValidator(),
-				new BookValidator(),
-				new CategoryValidator(),
-				new ContributorValidator(),
-				new SeriesValidator(),
-			};
+		public static IValidator[] GetAllValidators() => [
+			new LibraryValidator(),
+			new BookValidator(),
+			new CategoryValidator(),
+			new SeriesValidator(),
+		];
 	}
 
+	/// <summary>
+	/// To be used when no validation is desired
+	/// </summary>
+	public class ClearValidator : IValidator
+	{
+		public IEnumerable<Exception> Validate(IEnumerable<Item> items) => [];
+	}
 	public class LibraryValidator : IValidator
 	{
 		public IEnumerable<Exception> Validate(IEnumerable<Item> items)
@@ -68,20 +72,6 @@ namespace AudibleUtilities
 			return exceptions;
 		}
 	}
-	public class ContributorValidator : IValidator
-	{
-		public IEnumerable<Exception> Validate(IEnumerable<Item> items)
-		{
-			var exceptions = new List<Exception>();
-
-			if (items.GetAuthorsDistinct().Any(a => string.IsNullOrWhiteSpace(a.Name)))
-				exceptions.Add(new ArgumentException($"Collection contains {nameof(Item.Authors)} with null {nameof(Person.Name)}", nameof(items)));
-			if (items.GetNarratorsDistinct().Any(a => string.IsNullOrWhiteSpace(a.Name)))
-				exceptions.Add(new ArgumentException($"Collection contains {nameof(Item.Narrators)} with null {nameof(Person.Name)}", nameof(items)));
-
-			return exceptions;
-		}
-	}
 	public class SeriesValidator : IValidator
 	{
 		public IEnumerable<Exception> Validate(IEnumerable<Item> items)

Source/DataLayer/EfClasses/Rating.cs

@@ -1,11 +1,10 @@
 using System;
-using System.Collections.Generic;
-using Dinah.Core;
 
+#nullable enable
 namespace DataLayer
 {
     /// <summary>Parameterless ctor and setters should be used by EF only. Everything else should treat it as immutable</summary>
-    public class Rating : ValueObject_Static<Rating>, IComparable<Rating>, IComparable
+    public record Rating : IComparable<Rating>, IComparable
     {
         public float OverallRating { get; private set; }
         public float PerformanceRating { get; private set; }
@@ -31,23 +30,17 @@ namespace DataLayer
             StoryRating = storyRating;
         }
 
-        protected override IEnumerable<object> GetEqualityComponents()
-        {
-            yield return OverallRating;
-            yield return PerformanceRating;
-            yield return StoryRating;
-        }
-
         public override string ToString() => $"Overall={OverallRating} Perf={PerformanceRating} Story={StoryRating}";
 
-        public int CompareTo(Rating other)
+        public int CompareTo(Rating? other)
         {
-            var compare = OverallRating.CompareTo(other.OverallRating);
+            if (other is null) return 1;
+			var compare = OverallRating.CompareTo(other.OverallRating);
             if (compare != 0) return compare;
             compare = PerformanceRating.CompareTo(other.PerformanceRating);
             if (compare != 0) return compare;
             return StoryRating.CompareTo(other.StoryRating);
         }
-        public int CompareTo(object obj) => obj is Rating second ? CompareTo(second) : -1;
+        public int CompareTo(object? obj) => obj is Rating second ? CompareTo(second) : 1;
     }
 }

Source/DataLayer/EfClasses/UserDefinedItem.cs

@@ -4,6 +4,7 @@ using System.Linq;
 using System.Text.RegularExpressions;
 using Dinah.Core;
 
+#nullable enable
 namespace DataLayer
 {
     /// <summary>
@@ -31,17 +32,17 @@ namespace DataLayer
 		/// <summary>
 		/// Version of Libation used the last time the audio file was downloaded.
 		/// </summary>
-		public Version LastDownloadedVersion { get; private set; }
+		public Version? LastDownloadedVersion { get; private set; }
 		/// <summary>
 		/// Audio format of the last downloaded audio file.
 		/// </summary>
-		public AudioFormat LastDownloadedFormat { get; private set; }
+		public AudioFormat? LastDownloadedFormat { get; private set; }
 		/// <summary>
 		/// Version of the audio file that was last downloaded.
 		/// </summary>
-		public string LastDownloadedFileVersion { get; private set; }
+		public string? LastDownloadedFileVersion { get; private set; }
 
-        public void SetLastDownloaded(Version libationVersion, AudioFormat audioFormat, string audioVersion)
+        public void SetLastDownloaded(Version? libationVersion, AudioFormat? audioFormat, string? audioVersion)
         {
             if (LastDownloadedVersion != libationVersion)
             {
@@ -71,9 +72,13 @@ namespace DataLayer
                 OnItemChanged(nameof(LastDownloaded));
             }
 		}
+		private UserDefinedItem()
+        {
+			// for EF
+			Book = null!;
+		}
 
-		private UserDefinedItem() { }
-        internal UserDefinedItem(Book book)
+		internal UserDefinedItem(Book book)
 		{
 			ArgumentValidator.EnsureNotNull(book, nameof(book));
             Book = book;
@@ -162,7 +167,7 @@ namespace DataLayer
         /// Occurs when <see cref="Tags"/>, <see cref="BookStatus"/>, or <see cref="PdfStatus"/> values change.
         /// This signals the change of the in-memory value; it does not ensure that the new value has been persisted.
         /// </summary>
-        public static event EventHandler<string> ItemChanged;
+        public static event EventHandler<string>? ItemChanged;
 
         private void OnItemChanged(string e)
         {

Source/DataLayer/MockLibraryBook.cs

@@ -86,7 +86,11 @@ public class MockLibraryBook : LibraryBook
 		string localeName = "us",
 		bool isAbridged = false,
 		bool isSpatial = false,
-		string language = "English")
+		string language = "English",
+		LiberatedStatus bookStatus = LiberatedStatus.Liberated,
+		LiberatedStatus? pdfStatus = null,
+		AudioFormat? lastDlFormat = null,
+		Version? lastDlVersion = null)
 	{
 		var book = new Book(
 			new AudibleProductId(CalculateAsin(title + subtitle)),
@@ -99,6 +103,12 @@ public class MockLibraryBook : LibraryBook
 			[new Contributor(firstNarrator, CalculateAsin(firstNarrator))],
 			localeName);
 
+		lastDlFormat ??= new AudioFormat(Codec.AAC_LC, 128, 44100, 2);
+		lastDlVersion ??= new Version(13, 0);
+		book.UserDefinedItem.SetLastDownloaded(lastDlVersion, lastDlFormat, "1");
+		book.UserDefinedItem.PdfStatus = pdfStatus;
+		book.UserDefinedItem.BookStatus = bookStatus;
+
 		book.UpdateBookDetails(isAbridged, isSpatial, datePublished ?? DateTime.Now, language);
 
 		return new MockLibraryBook(

Source/DtoImporterService/ContributorImporter.cs

@@ -10,7 +10,7 @@ namespace DtoImporterService
 {
 	public class ContributorImporter : ItemsImporterBase
 	{
-		protected override IValidator Validator => new ContributorValidator();
+		protected override IValidator Validator => new ClearValidator();
 
 		public Dictionary<string, Contributor> Cache { get; private set; } = new();
 

Source/FileLiberator/AudioFormatDecoder.cs

@@ -12,7 +12,7 @@ using System.IO;
 namespace AaxDecrypter;
 
 /// <summary> Read audio codec, bitrate, sample rate, and channel count from MP4 and MP3 audio files. </summary>
-internal static class AudioFormatDecoder
+public static class AudioFormatDecoder
 {
 	public static AudioFormat FromMpeg4(string filename)
 	{

Source/FileLiberator/ConvertToMp3.cs

@@ -63,10 +63,6 @@ namespace FileLiberator
 					using var m4bFileStream = File.Open(entry.m4bPath, FileMode.Open, FileAccess.Read, FileShare.Read);
 					var m4bBook = new Mp4File(m4bFileStream);
 
-					//AAXClean.Codecs only supports decoding AAC and E-AC-3 audio.
-					if (m4bBook.AudioSampleEntry.Esds is null && m4bBook.AudioSampleEntry.Dec3 is null)
-						continue;
-
 					OnTitleDiscovered(m4bBook.AppleTags.Title);
 					OnAuthorsDiscovered(m4bBook.AppleTags.FirstAuthor);
 					OnNarratorsDiscovered(m4bBook.AppleTags.Narrator);

Source/FileLiberator/DownloadDecryptBook.cs

@@ -254,6 +254,11 @@ namespace FileLiberator
 				tags.Year ??= pubDate.Year.ToString();
 				tags.ReleaseDate ??= pubDate.ToString("dd-MMM-yyyy");
 			}
+
+			const string tagDomain = "org.libation";
+			aaxFile.AppleTags.AppleListBox.EditOrAddFreeformTag(tagDomain, "AUDIBLE_ACR", tags.Acr);
+			aaxFile.AppleTags.AppleListBox.EditOrAddFreeformTag(tagDomain, "AUDIBLE_DRM_TYPE", options.DrmType.ToString());
+			aaxFile.AppleTags.AppleListBox.EditOrAddFreeformTag(tagDomain, "AUDIBLE_LOCALE", options.LibraryBook.Book.Locale);
 		}
 
 		private void AaxcDownloader_RetrievedCoverArt(object? sender, byte[]? e)

Source/FileManager/NamingTemplate/NamingTemplate.cs

@@ -51,7 +51,7 @@ public class NamingTemplate
 	/// <param name="template">The template string to parse</param>
 	/// <param name="tagCollections">A collection of <see cref="TagCollection"/> with
 	/// properties registered to match to the <paramref name="template"/></param>
-	public static NamingTemplate Parse(string template, IEnumerable<TagCollection> tagCollections)
+	public static NamingTemplate Parse(string? template, IEnumerable<TagCollection> tagCollections)
 	{
 		var namingTemplate = new NamingTemplate(tagCollections);
 		try

Source/HangoverAvalonia/App.axaml

@@ -2,9 +2,6 @@
              xmlns:x="http://schemas.microsoft.com/winfx/2006/xaml"
              xmlns:local="using:HangoverAvalonia"
              x:Class="HangoverAvalonia.App">
-    <Application.DataTemplates>
-        <local:ViewLocator/>
-    </Application.DataTemplates>
 
 	<Application.Styles>
 		<FluentTheme>

Source/HangoverAvalonia/ViewLocator.cs

@@ -1,30 +0,0 @@
-using Avalonia.Controls;
-using Avalonia.Controls.Templates;
-using HangoverAvalonia.ViewModels;
-using System;
-
-namespace HangoverAvalonia
-{
-	public class ViewLocator : IDataTemplate
-	{
-		public Control Build(object data)
-		{
-			var name = data.GetType().FullName!.Replace("ViewModel", "View");
-			var type = Type.GetType(name);
-
-			if (type != null)
-			{
-				return (Control)Activator.CreateInstance(type)!;
-			}
-			else
-			{
-				return new TextBlock { Text = "Not Found: " + name };
-			}
-		}
-
-		public bool Match(object data)
-		{
-			return data is ViewModelBase;
-		}
-	}
-}

Source/LibationAvalonia/App.axaml

@@ -6,10 +6,6 @@
 			 x:Class="LibationAvalonia.App"
              Name="Libation">
 
-	<Application.DataTemplates>
-		<local:ViewLocator/>
-	</Application.DataTemplates>
-
 	<Application.Resources>
 
 		<ResourceDictionary>

Source/LibationAvalonia/App.axaml.cs

@@ -21,7 +21,6 @@ using System.IO;
 using System.Linq;
 using System.Threading.Tasks;
 
-#nullable enable
 namespace LibationAvalonia;
 
 public class App : Application

Source/LibationAvalonia/AvaloniaUtils.cs

@@ -5,9 +5,9 @@ using Avalonia.Media.Imaging;
 using Avalonia.VisualTree;
 using LibationFileManager;
 using LibationUiBase.Forms;
+using System;
 using System.Threading.Tasks;
 
-#nullable enable
 namespace LibationAvalonia
 {
 	internal static class AvaloniaUtils
@@ -23,7 +23,9 @@ namespace LibationAvalonia
 			? dialogWindow.ShowDialog<DialogResult>(window)
 			: Task.FromResult(DialogResult.None);
 
-		public static Window? GetParentWindow(this Control control) => control.GetVisualRoot() as Window;
+		public static Window GetParentWindow(this Control control)
+			=> control.GetVisualRoot() as Window ?? App.MainWindow
+			?? throw new InvalidOperationException("Cannot find parent window.");
 
 
 		private static Bitmap? defaultImage;

Source/LibationAvalonia/Controls/CheckedListBox.axaml.cs

@@ -22,6 +22,6 @@ namespace LibationAvalonia.Controls
 	public class CheckBoxViewModel : ViewModelBase
 	{
 		public bool IsChecked { get => field; set => this.RaiseAndSetIfChanged(ref field, value); }
-		public object Item { get => field; set => this.RaiseAndSetIfChanged(ref field, value); }
+		public object? Item { get => field; set => this.RaiseAndSetIfChanged(ref field, value); }
 	}
 }

Source/LibationAvalonia/Controls/DataGridCheckBoxColumnExt.cs

@@ -5,11 +5,11 @@ namespace LibationAvalonia.Controls
 {
 	public class DataGridCheckBoxColumnExt : DataGridCheckBoxColumn
 	{
-		protected override Control GenerateEditingElementDirect(DataGridCell cell, object dataItem)
+		protected override Control? GenerateEditingElementDirect(DataGridCell cell, object dataItem)
 		{
 			//Only SeriesEntry types have three-state checks, individual LibraryEntry books are binary.
 			var ele = base.GenerateEditingElementDirect(cell, dataItem) as CheckBox;
-			ele.IsThreeState = dataItem is SeriesEntry;
+			ele?.IsThreeState = dataItem is SeriesEntry;
 			return ele;
 		}
 	}

Source/LibationAvalonia/Controls/DataGridContextMenus.cs

@@ -9,17 +9,19 @@ namespace LibationAvalonia.Controls
 {
 	internal static class DataGridContextMenus
 	{
-		public static event EventHandler<DataGridCellContextMenuStripNeededEventArgs> CellContextMenuStripNeeded;
+		public static event EventHandler<DataGridCellContextMenuStripNeededEventArgs>? CellContextMenuStripNeeded;
 		private static readonly ContextMenu ContextMenu = new();
-		private static readonly AvaloniaList<Control> MenuItems = new();
+		public static readonly AvaloniaList<Control> MenuItems = new();
 		private static readonly PropertyInfo OwningColumnProperty;
 		private static readonly PropertyInfo OwningGridProperty;
 
 		static DataGridContextMenus()
 		{
 			ContextMenu.ItemsSource = MenuItems;
-			OwningColumnProperty = typeof(DataGridCell).GetProperty("OwningColumn", BindingFlags.Instance | BindingFlags.NonPublic);
-			OwningGridProperty = typeof(DataGridColumn).GetProperty("OwningGrid", BindingFlags.Instance | BindingFlags.NonPublic);
+			OwningColumnProperty = typeof(DataGridCell).GetProperty("OwningColumn", BindingFlags.Instance | BindingFlags.NonPublic)
+				?? throw new InvalidOperationException("Could not find OwningColumn property on DataGridCell");
+			OwningGridProperty = typeof(DataGridColumn).GetProperty("OwningGrid", BindingFlags.Instance | BindingFlags.NonPublic)
+				?? throw new InvalidOperationException("Could not find OwningGrid property on DataGridColumn");
 		}
 
 		public static void AttachContextMenu(this DataGridCell cell)
@@ -31,7 +33,7 @@ namespace LibationAvalonia.Controls
 			}
 		}
 
-		private static void Cell_ContextRequested(object sender, ContextRequestedEventArgs e)
+		private static void Cell_ContextRequested(object? sender, ContextRequestedEventArgs e)
 		{
 			if (sender is DataGridCell cell &&
 				cell.DataContext is GridEntry clickedEntry &&
@@ -74,7 +76,8 @@ namespace LibationAvalonia.Controls
 		private static readonly MethodInfo GetCellValueMethod;
 		static DataGridCellContextMenuStripNeededEventArgs()
 		{
-			GetCellValueMethod = typeof(DataGridColumn).GetMethod("GetCellValue", BindingFlags.NonPublic | BindingFlags.Instance);
+			GetCellValueMethod = typeof(DataGridColumn).GetMethod("GetCellValue", BindingFlags.NonPublic | BindingFlags.Instance)
+				?? throw new InvalidOperationException("Could not find GetCellValue method on DataGridColumn");
 		}
 
 		private static string GetCellValue(DataGridColumn column, object item)
@@ -96,7 +99,7 @@ namespace LibationAvalonia.Controls
 				Grid.Columns
 				.Where(c => c.IsVisible)
 				.OrderBy(c => c.DisplayIndex)
-				.Select(c => RemoveLineBreaks(c.Header.ToString())));
+				.Select(c => RemoveLineBreaks(c.Header.ToString() ?? "")));
 
 		private static string RemoveLineBreaks(string text)
 			=> text.Replace("\r\n", "").Replace('\r', ' ').Replace('\n', ' ');
@@ -111,7 +114,6 @@ namespace LibationAvalonia.Controls
 		public required DataGridColumn Column { get; init; }
 		public required GridEntry[] GridEntries { get; init; }
 		public required ContextMenu ContextMenu { get; init; }
-		public AvaloniaList<Control> ContextMenuItems
-			=> ContextMenu.ItemsSource as AvaloniaList<Control>;
+		public AvaloniaList<Control> ContextMenuItems => DataGridContextMenus.MenuItems;
 	}
 }

Source/LibationAvalonia/Controls/DataGridMyRatingColumn.cs

@@ -9,8 +9,8 @@ namespace LibationAvalonia.Controls
 {
 	public class DataGridMyRatingColumn : DataGridBoundColumn
 	{
-		[AssignBinding] public IBinding BackgroundBinding { get; set; }
-		[AssignBinding] public IBinding OpacityBinding { get; set; }
+		[AssignBinding] public IBinding? BackgroundBinding { get; set; }
+		[AssignBinding] public IBinding? OpacityBinding { get; set; }
 		private static Rating DefaultRating => new Rating(0, 0, 0);
 		public DataGridMyRatingColumn()
 		{

Source/LibationAvalonia/Controls/DirectoryOrCustomSelectControl.axaml.cs

@@ -9,7 +9,6 @@ using System.Collections.Generic;
 using System.IO;
 using System.Linq;
 
-#nullable enable
 namespace LibationAvalonia.Controls
 {
 	public partial class DirectoryOrCustomSelectControl : UserControl

Source/LibationAvalonia/Controls/DirectorySelectControl.axaml.cs

@@ -13,27 +13,27 @@ namespace LibationAvalonia.Controls
 {
 	public class KnownDirectoryConverter : IValueConverter
 	{
-		public object Convert(object value, Type targetType, object parameter, CultureInfo culture)
+		public object? Convert(object? value, Type targetType, object? parameter, CultureInfo culture)
 		{
 			if (value is Configuration.KnownDirectories dir)
 				return dir.GetDescription();
 			return new BindingNotification(new InvalidCastException(), BindingErrorType.Error);
 		}
 
-		public object ConvertBack(object value, Type targetType, object parameter, CultureInfo culture)
+		public object? ConvertBack(object? value, Type targetType, object? parameter, CultureInfo culture)
 		{
 			return new BindingNotification(new InvalidCastException(), BindingErrorType.Error);
 		}
 	}
 	public class KnownDirectoryPath : IMultiValueConverter
 	{
-		public object Convert(IList<object> values, Type targetType, object parameter, CultureInfo culture)
+		public object? Convert(IList<object?> values, Type targetType, object? parameter, CultureInfo culture)
 		{
 			if (values?.Count == 2 && values[0] is Configuration.KnownDirectories kdir && kdir is not Configuration.KnownDirectories.None)
 			{
 				var subdir = values[1] as string ?? "";
 				var path = kdir is Configuration.KnownDirectories.AppDir ? Configuration.AppDir_Absolute : Configuration.GetKnownDirectoryPath(kdir);
-				return Path.Combine(path, subdir);
+				return path is null ? "" : Path.Combine(path, subdir);
 			}
 			return "";
 		}

Source/LibationAvalonia/Controls/LinkLabel.axaml.cs

@@ -58,7 +58,7 @@ namespace LibationAvalonia.Controls
 			Tapped += LinkLabel_Tapped;
 		}
 
-		private void LinkLabel_Tapped(object sender, TappedEventArgs e)
+		private void LinkLabel_Tapped(object? sender, TappedEventArgs e)
 		{
 			Foreground = ForegroundVisited;
 			if (IsEffectivelyEnabled)
@@ -87,7 +87,7 @@ namespace LibationAvalonia.Controls
 		}
 		protected override bool IsEnabledCore => base.IsEnabledCore && _commandCanExecute;
 
-		protected override void UpdateDataValidation(AvaloniaProperty property, BindingValueType state, Exception error)
+		protected override void UpdateDataValidation(AvaloniaProperty property, BindingValueType state, Exception? error)
 		{
 			base.UpdateDataValidation(property, state, error);
 			if (property == CommandProperty)

Source/LibationAvalonia/Controls/MyRatingCellEditor.axaml.cs

@@ -61,18 +61,20 @@ namespace LibationAvalonia.Controls
 
 		public void Panel_PointerExited(object sender, Avalonia.Input.PointerEventArgs e)
 		{
-			var panel = sender as Panel;
+			if (sender is not Panel panel)
+				return;
 			var stackPanel = panel.Children.OfType<StackPanel>().Single();
 
 			//Restore defaults
 			foreach (TextBlock child in stackPanel.Children)
-				child.Text = (string)child.Tag;
+				child.Text = child.Tag as string;
 		}
 
 		public void Star_PointerEntered(object sender, Avalonia.Input.PointerEventArgs e)
 		{
 			var thisTbox = sender as TextBlock;
-			var stackPanel = thisTbox.Parent as StackPanel;
+			if (thisTbox?.Parent is not StackPanel stackPanel)
+				return;
 			var star = SOLID_STAR;
 
 			foreach (TextBlock child in stackPanel.Children)
@@ -89,7 +91,8 @@ namespace LibationAvalonia.Controls
 			var story = Rating.StoryRating;
 
 			var thisTbox = sender as TextBlock;
-			var stackPanel = thisTbox.Parent as StackPanel;
+			if (thisTbox?.Parent is not StackPanel stackPanel)
+				return;
 
 			int newRatingValue = 0;
 			foreach (var tbox in stackPanel.Children)

Source/LibationAvalonia/Controls/Settings/Audio.axaml.cs

@@ -5,7 +5,6 @@ using LibationAvalonia.ViewModels.Settings;
 using LibationFileManager;
 using LibationFileManager.Templates;
 using LibationUiBase.Forms;
-using ReactiveUI;
 using System.Linq;
 using System.Threading.Tasks;
 
@@ -13,7 +12,7 @@ namespace LibationAvalonia.Controls.Settings
 {
 	public partial class Audio : UserControl
 	{
-		private AudioSettingsVM _viewModel => DataContext as AudioSettingsVM; 
+		private AudioSettingsVM? _viewModel => DataContext as AudioSettingsVM; 
 		public Audio()
 		{
 			InitializeComponent();
@@ -56,12 +55,12 @@ namespace LibationAvalonia.Controls.Settings
 						}
 					}
 
-					_viewModel.UseWidevine = false;
+					_viewModel?.UseWidevine = false;
 				}
 			}
 			else
 			{
-				_viewModel.Request_xHE_AAC = _viewModel.RequestSpatial = false;
+				_viewModel?.Request_xHE_AAC = _viewModel.RequestSpatial = false;
 			}
 		}
 
@@ -73,7 +72,7 @@ namespace LibationAvalonia.Controls.Settings
 				_viewModel.ChapterTitleTemplate = newTemplate;
 		}
 
-		private async Task<string> editTemplate(ITemplateEditor template)
+		private async Task<string?> editTemplate(ITemplateEditor template)
 		{
 			var form = new EditTemplateDialog(template);
 			if (await form.ShowDialog<DialogResult>(this.GetParentWindow()) == DialogResult.OK)

Source/LibationAvalonia/Controls/Settings/DownloadDecrypt.axaml.cs

@@ -1,4 +1,5 @@
 using Avalonia.Controls;
+using FileManager;
 using LibationAvalonia.Dialogs;
 using LibationAvalonia.ViewModels.Settings;
 using LibationFileManager;
@@ -10,7 +11,7 @@ namespace LibationAvalonia.Controls.Settings
 {
 	public partial class DownloadDecrypt : UserControl
 	{
-		private DownloadDecryptSettingsVM _viewModel => DataContext as DownloadDecryptSettingsVM;
+		private DownloadDecryptSettingsVM? _viewModel => DataContext as DownloadDecryptSettingsVM;
 		public DownloadDecrypt()
 		{
 			InitializeComponent();
@@ -22,24 +23,24 @@ namespace LibationAvalonia.Controls.Settings
 
 		public async void EditFolderTemplateButton_Click(object sender, Avalonia.Interactivity.RoutedEventArgs e)
 		{
-			if (_viewModel is null) return;
-			var newTemplate = await editTemplate(TemplateEditor<Templates.FolderTemplate>.CreateFilenameEditor(_viewModel.Config.Books, _viewModel.FolderTemplate));
+			if (_viewModel is null || _viewModel.Config.Books is not LongPath books) return;
+			var newTemplate = await editTemplate(TemplateEditor<Templates.FolderTemplate>.CreateFilenameEditor(books, _viewModel.FolderTemplate));
 			if (newTemplate is not null)
 				_viewModel.FolderTemplate = newTemplate;
 		}
 
 		public async void EditFileTemplateButton_Click(object sender, Avalonia.Interactivity.RoutedEventArgs e)
 		{
-			if (_viewModel is null) return;
-			var newTemplate = await editTemplate(TemplateEditor<Templates.FileTemplate>.CreateFilenameEditor(_viewModel.Config.Books, _viewModel.FileTemplate));
+			if (_viewModel is null || _viewModel.Config.Books is not LongPath books) return;
+			var newTemplate = await editTemplate(TemplateEditor<Templates.FileTemplate>.CreateFilenameEditor(books, _viewModel.FileTemplate));
 			if (newTemplate is not null)
 				_viewModel.FileTemplate = newTemplate;
 		}
 
 		public async void EditChapterFileTemplateButton_Click(object sender, Avalonia.Interactivity.RoutedEventArgs e)
 		{
-			if (_viewModel is null) return;
-			var newTemplate = await editTemplate(TemplateEditor<Templates.ChapterFileTemplate>.CreateFilenameEditor(_viewModel.Config.Books, _viewModel.ChapterFileTemplate));
+			if (_viewModel is null || _viewModel.Config.Books is not LongPath books) return;
+			var newTemplate = await editTemplate(TemplateEditor<Templates.ChapterFileTemplate>.CreateFilenameEditor(books, _viewModel.ChapterFileTemplate));
 			if (newTemplate is not null)
 				_viewModel.ChapterFileTemplate = newTemplate;
 		}
@@ -52,7 +53,7 @@ namespace LibationAvalonia.Controls.Settings
 		}
 
 
-		private async Task<string> editTemplate(ITemplateEditor template)
+		private async Task<string?> editTemplate(ITemplateEditor template)
 		{
 			var form = new EditTemplateDialog(template);
 			if (await form.ShowDialog<DialogResult>(this.GetParentWindow()) == DialogResult.OK)

Source/LibationAvalonia/Controls/Settings/Important.axaml.cs

@@ -1,13 +1,10 @@
 using Avalonia.Controls;
 using Avalonia.Controls.ApplicationLifetimes;
-using Dinah.Core;
-using FileManager;
 using LibationAvalonia.Dialogs;
 using LibationAvalonia.ViewModels.Settings;
 using LibationFileManager;
 using System.Linq;
 
-#nullable enable
 namespace LibationAvalonia.Controls.Settings
 {
 	public partial class Important : UserControl

Source/LibationAvalonia/Controls/ThemePreviewControl.axaml.cs

@@ -43,7 +43,7 @@ public partial class ThemePreviewControl : UserControl
 		QueuedBook.AddDownloadPdf();
 		WorkingBook.AddDownloadPdf();
 
-		typeof(ProcessBookViewModel).GetProperty(nameof(ProcessBookViewModel.Progress)).SetValue(WorkingBook, 50);
+		typeof(ProcessBookViewModel).GetProperty(nameof(ProcessBookViewModel.Progress))!.SetValue(WorkingBook, 50);
 
 		ProductsDisplay = new ProductsDisplayViewModel();
 		_ = ProductsDisplay.BindToGridAsync(sampleEntries);

Source/LibationAvalonia/Dialogs/AboutDialog.axaml.cs

@@ -26,11 +26,11 @@ namespace LibationAvalonia.Dialogs
 			var mainWindow = Owner as Views.MainWindow;
 
 			var upgrader = new Upgrader();
-			upgrader.DownloadProgress += async (_, e) => await Avalonia.Threading.Dispatcher.UIThread.InvokeAsync(() => mainWindow.ViewModel.DownloadProgress = e.ProgressPercentage);
-			upgrader.DownloadCompleted += async (_, _) => await Avalonia.Threading.Dispatcher.UIThread.InvokeAsync(() => mainWindow.ViewModel.DownloadProgress = null);
+			upgrader.DownloadProgress += async (_, e) => await Avalonia.Threading.Dispatcher.UIThread.InvokeAsync(() => mainWindow?.ViewModel?.DownloadProgress = e.ProgressPercentage);
+			upgrader.DownloadCompleted += async (_, _) => await Avalonia.Threading.Dispatcher.UIThread.InvokeAsync(() => mainWindow?.ViewModel?.DownloadProgress = null);
 
 			_viewModel.CanCheckForUpgrade = false;
-			Version latestVersion = null;
+			Version? latestVersion = null;
 			await upgrader.CheckForUpgradeAsync(OnUpgradeAvailable);
 
 			_viewModel.CanCheckForUpgrade = latestVersion is null;

Source/LibationAvalonia/Dialogs/AccountsDialog.axaml.cs

@@ -21,7 +21,7 @@ namespace LibationAvalonia.Dialogs
 		{
 			public IReadOnlyList<Locale> Locales => AccountsDialog.Locales;
 			public bool LibraryScan { get; set; } = true;
-			public string AccountId
+			public string? AccountId
 			{
 				get => field;
 				set
@@ -31,8 +31,8 @@ namespace LibationAvalonia.Dialogs
 				}
 			}
 
-			public Locale SelectedLocale { get; set; }
-			public string AccountName { get; set; }
+			public Locale? SelectedLocale { get; set; }
+			public string? AccountName { get; set; }
 			public bool IsDefault => string.IsNullOrEmpty(AccountId);
 
 			public AccountDto() { }
@@ -65,7 +65,7 @@ namespace LibationAvalonia.Dialogs
 			addBlankAccount();
 		}
 
-		private void Accounts_CollectionChanged(object sender, NotifyCollectionChangedEventArgs e)
+		private void Accounts_CollectionChanged(object? sender, NotifyCollectionChangedEventArgs e)
 		{
 			if (e.Action is NotifyCollectionChangedAction.Add && e.NewItems?.Count > 0)
 			{
@@ -81,13 +81,13 @@ namespace LibationAvalonia.Dialogs
 
 		private void addBlankAccount() => Accounts.Insert(Accounts.Count, new AccountDto());
 
-		private void AccountDto_PropertyChanged(object sender, System.ComponentModel.PropertyChangedEventArgs e)
+		private void AccountDto_PropertyChanged(object? sender, System.ComponentModel.PropertyChangedEventArgs e)
 		{
 			if (!Accounts.Any(a => a.IsDefault))
 				addBlankAccount();
 		}
 
-		public void DeleteButton_Clicked(object sender, Avalonia.Interactivity.RoutedEventArgs e)
+		public void DeleteButton_Clicked(object? sender, Avalonia.Interactivity.RoutedEventArgs e)
 		{
 			if (e.Source is Button expBtn && expBtn.DataContext is AccountDto acc)
 				Accounts.Remove(acc);
@@ -200,9 +200,9 @@ namespace LibationAvalonia.Dialogs
 			}
 
 			// upsert each. validation occurs through Account and AccountsSettings
-			foreach (var dto in Accounts)
+			foreach (var dto in Accounts.Where(a => a.AccountId is not null))
 			{
-				var acct = accountsSettings.Upsert(dto.AccountId, dto.SelectedLocale?.Name);
+				var acct = accountsSettings.Upsert(dto.AccountId!, dto.SelectedLocale?.Name);
 				acct.LibraryScan = dto.LibraryScan;
 				acct.AccountName
 					= string.IsNullOrWhiteSpace(dto.AccountName)

Source/LibationAvalonia/Dialogs/BookDetailsDialog.axaml.cs

@@ -17,26 +17,27 @@ namespace LibationAvalonia.Dialogs
 {
 	public partial class BookDetailsDialog : DialogWindow
 	{
-		private BookDetailsDialogViewModel _viewModel;
-		public LibraryBook LibraryBook
+		private BookDetailsDialogViewModel? _viewModel;
+		public LibraryBook? LibraryBook
 		{
 			get => field;
 			set
 			{
 				field = value;
-				Title = field.Book.TitleWithSubtitle;
-				DataContext = _viewModel = new BookDetailsDialogViewModel(field);
+				Title = field?.Book.TitleWithSubtitle;
+				if (field is not null)
+					DataContext = _viewModel = new BookDetailsDialogViewModel(field);
 			}
 		}
 
-		public string NewTags => _viewModel.Tags;
-		public LiberatedStatus BookLiberatedStatus => _viewModel.BookLiberatedSelectedItem.Status;
-		public LiberatedStatus? PdfLiberatedStatus => _viewModel.PdfLiberatedSelectedItem?.Status;
+		public string? NewTags => _viewModel?.Tags;
+		public LiberatedStatus BookLiberatedStatus => _viewModel?.BookLiberatedSelectedItem?.Status ?? default;
+		public LiberatedStatus? PdfLiberatedStatus => _viewModel?.PdfLiberatedSelectedItem?.Status;
 
 		public BookDetailsDialog()
 		{
 			InitializeComponent();
-			ControlToFocusOnShow = this.Find<TextBox>(nameof(tagsTbox));
+			ControlToFocusOnShow = tagsTbox;
 
 			if (Design.IsDesignMode)
 			{
@@ -60,14 +61,15 @@ namespace LibationAvalonia.Dialogs
 
 		protected override async Task SaveAndCloseAsync()
 		{
-			await LibraryBook.UpdateUserDefinedItemAsync(NewTags, bookStatus: BookLiberatedStatus, pdfStatus: PdfLiberatedStatus);
+			if (LibraryBook is not null)
+				await LibraryBook.UpdateUserDefinedItemAsync(NewTags, bookStatus: BookLiberatedStatus, pdfStatus: PdfLiberatedStatus);
 			await base.SaveAndCloseAsync();
 		}
 
 		public void BookStatus_SelectionChanged(object sender, SelectionChangedEventArgs e)
 		{
 			if (sender is not WheelComboBox { SelectedItem: liberatedComboBoxItem { Status: LiberatedStatus.Error } } &&
-				_viewModel.BookLiberatedItems.SingleOrDefault(s => s.Status == LiberatedStatus.Error) is liberatedComboBoxItem errorItem)
+				_viewModel?.BookLiberatedItems.SingleOrDefault(s => s.Status == LiberatedStatus.Error) is liberatedComboBoxItem errorItem)
 			{
 				_viewModel.BookLiberatedItems.Remove(errorItem);
 			}
@@ -78,8 +80,8 @@ namespace LibationAvalonia.Dialogs
 		public class liberatedComboBoxItem
 		{
 			public LiberatedStatus Status { get; set; }
-			public string Text { get; set; }
-			public override string ToString() => Text;
+			public string? Text { get; set; }
+			public override string? ToString() => Text;
 		}
 
 		public class BookDetailsDialogViewModel : ViewModelBase
@@ -92,8 +94,8 @@ namespace LibationAvalonia.Dialogs
 			public bool HasPDF => PdfLiberatedItems?.Count > 0;
 			public AvaloniaList<liberatedComboBoxItem> BookLiberatedItems { get; } = new();
 			public List<liberatedComboBoxItem> PdfLiberatedItems { get; } = new();
-			public liberatedComboBoxItem PdfLiberatedSelectedItem { get; set; }
-			public liberatedComboBoxItem BookLiberatedSelectedItem { get; set; }
+			public liberatedComboBoxItem? PdfLiberatedSelectedItem { get; set; }
+			public liberatedComboBoxItem? BookLiberatedSelectedItem { get; set; }
 			public ICommand OpenInAudibleCommand { get; }
 
 			public BookDetailsDialogViewModel(LibraryBook libraryBook)

Source/LibationAvalonia/Dialogs/BookRecordsDialog.axaml.cs

@@ -24,6 +24,7 @@ namespace LibationAvalonia.Dialogs
 		public BookRecordsDialog()
 		{
 			InitializeComponent();
+			libraryBook = MockLibraryBook.CreateBook();
 
 			if (Design.IsDesignMode)
 			{
@@ -43,7 +44,7 @@ namespace LibationAvalonia.Dialogs
 			Loaded += BookRecordsDialog_Loaded;
 		}
 
-		private async void BookRecordsDialog_Loaded(object sender, Avalonia.Interactivity.RoutedEventArgs e)
+		private async void BookRecordsDialog_Loaded(object? sender, Avalonia.Interactivity.RoutedEventArgs e)
 		{
 			try
 			{
@@ -211,8 +212,8 @@ namespace LibationAvalonia.Dialogs
 			public string Created => Record.Created.ToString(DateFormat);
 			public string Modified => Record is IAnnotation annotation ? annotation.Created.ToString(DateFormat) : string.Empty;
 			public string End => Record is IRangeAnnotation range ? formatTimeSpan(range.End) : string.Empty;
-			public string Note => Record is IRangeAnnotation range ? range.Text : string.Empty;
-			public string Title => Record is Clip range ? range.Title : string.Empty;
+			public string Note => (Record as IRangeAnnotation)?.Text ?? string.Empty;
+			public string Title => (Record as Clip)?.Title ?? string.Empty;
 			public BookRecordEntry(IRecord record) => Record = record;
 
 			private static string formatTimeSpan(TimeSpan timeSpan)

Source/LibationAvalonia/Dialogs/DescriptionDisplayDialog.axaml.cs

@@ -3,7 +3,6 @@ using Avalonia.Controls;
 using System;
 using System.Linq;
 
-#nullable enable
 namespace LibationAvalonia.Dialogs
 {
 	public partial class DescriptionDisplayDialog : Window

Source/LibationAvalonia/Dialogs/DialogWindow.cs

@@ -14,7 +14,7 @@ namespace LibationAvalonia.Dialogs
 		protected bool CancelOnEscape { get; set; } = true;
 		protected bool SaveOnEnter { get; set; } = true;
 		public bool SaveAndRestorePosition { get; set; }
-		public Control ControlToFocusOnShow { get; set; }
+		public Control? ControlToFocusOnShow { get; set; }
 		protected override Type StyleKeyOverride => typeof(DialogWindow);
 		public DialogResult DialogResult { get; private set; } = DialogResult.None;
 
@@ -39,7 +39,7 @@ namespace LibationAvalonia.Dialogs
 			}
 		}
 
-		private void DialogWindow_Loaded(object sender, Avalonia.Interactivity.RoutedEventArgs e)
+		private void DialogWindow_Loaded(object? sender, Avalonia.Interactivity.RoutedEventArgs e)
 		{
 			if (!CanResize)
 				this.HideMinMaxBtns();
@@ -57,20 +57,20 @@ namespace LibationAvalonia.Dialogs
 			}
 		}
 
-		private void DialogWindow_Initialized(object sender, EventArgs e)
+		private void DialogWindow_Initialized(object? sender, EventArgs e)
 		{
 			this.WindowStartupLocation = WindowStartupLocation.CenterOwner;
 			if (SaveAndRestorePosition)
 				this.RestoreSizeAndLocation(Configuration.Instance);
 		}
 
-		private void DialogWindow_Closing(object sender, System.ComponentModel.CancelEventArgs e)
+		private void DialogWindow_Closing(object? sender, System.ComponentModel.CancelEventArgs e)
 		{
 			if (SaveAndRestorePosition)
 				this.SaveSizeAndLocation(Configuration.Instance);
 		}
 
-		private void DialogWindow_Opened(object sender, EventArgs e)
+		private void DialogWindow_Opened(object? sender, EventArgs e)
 		{
 			ControlToFocusOnShow?.Focus();
 		}
@@ -86,7 +86,7 @@ namespace LibationAvalonia.Dialogs
 		protected virtual void CancelAndClose() => Close(DialogResult.Cancel);
 		protected virtual async Task CancelAndCloseAsync() => await Avalonia.Threading.Dispatcher.UIThread.InvokeAsync(CancelAndClose);
 
-		private async void DialogWindow_KeyDown(object sender, Avalonia.Input.KeyEventArgs e)
+		private async void DialogWindow_KeyDown(object? sender, Avalonia.Input.KeyEventArgs e)
 		{
 			if (CancelOnEscape && e.Key == Avalonia.Input.Key.Escape)
 				await CancelAndCloseAsync();

Source/LibationAvalonia/Dialogs/EditQuickFilters.axaml.cs

@@ -13,13 +13,13 @@ namespace LibationAvalonia.Dialogs
 
 		public class Filter : ViewModels.ViewModelBase
 		{ 
-            public string Name
+            public string? Name
             {
                 get => field;
                 set => this.RaiseAndSetIfChanged(ref field, value);
 			}
 
-			public string FilterString
+			public string? FilterString
 			{
 				get => field;
 				set
@@ -33,7 +33,7 @@ namespace LibationAvalonia.Dialogs
 			public bool IsTop { get => field; set => this.RaiseAndSetIfChanged(ref field, value); }
 			public bool IsBottom { get => field; set => this.RaiseAndSetIfChanged(ref field, value); }
 
-			public QuickFilters.NamedFilter AsNamedFilter() => new(FilterString, Name);
+			public QuickFilters.NamedFilter? AsNamedFilter() => FilterString is null ? null : new(FilterString, Name);
 
 		}
 		public EditQuickFilters()
@@ -76,7 +76,7 @@ namespace LibationAvalonia.Dialogs
 			DataContext = this;
 		}
 
-		private void Filter_PropertyChanged(object sender, System.ComponentModel.PropertyChangedEventArgs e)
+		private void Filter_PropertyChanged(object? sender, System.ComponentModel.PropertyChangedEventArgs e)
 		{
 			if (Filters.Any(f => f.IsDefault))
 				return;
@@ -88,7 +88,7 @@ namespace LibationAvalonia.Dialogs
 
 		protected override void SaveAndClose()
 		{
-			QuickFilters.ReplaceAll(Filters.Where(f => !f.IsDefault).Select(x => x.AsNamedFilter()));
+			QuickFilters.ReplaceAll(Filters.Select(x => x.AsNamedFilter()).OfType<QuickFilters.NamedFilter>());
 			base.SaveAndClose();
 		}
 

Source/LibationAvalonia/Dialogs/EditReplacementChars.axaml.cs

@@ -6,7 +6,6 @@ using ReactiveUI;
 using System.Collections.Generic;
 using System.Linq;
 
-#nullable enable
 namespace LibationAvalonia.Dialogs
 {
 	public partial class EditReplacementChars : DialogWindow

Source/LibationAvalonia/Dialogs/EditTemplateDialog.axaml.cs

@@ -17,7 +17,7 @@ namespace LibationAvalonia.Dialogs;
 
 public partial class EditTemplateDialog : DialogWindow
 {
-	private EditTemplateViewModel _viewModel;
+	private EditTemplateViewModel? _viewModel;
 
 	public EditTemplateDialog()
 	{
@@ -51,18 +51,18 @@ public partial class EditTemplateDialog : DialogWindow
 	{
 		var dataGrid = sender as DataGrid;
 
-		var item = (dataGrid.SelectedItem as Tuple<string, string, string>).Item3;
+		var item = (dataGrid?.SelectedItem as Tuple<string, string, string>)?.Item3;
 		if (string.IsNullOrWhiteSpace(item)) return;
 
 		var text = userEditTbox.Text;
 
-		userEditTbox.Text = text.Insert(Math.Min(Math.Max(0, userEditTbox.CaretIndex), text.Length), item);
+		userEditTbox.Text = text?.Insert(Math.Min(Math.Max(0, userEditTbox.CaretIndex), text.Length), item);
 		userEditTbox.CaretIndex += item.Length;
 	}
 
 	protected override async Task SaveAndCloseAsync()
 	{
-		if (!await _viewModel.Validate())
+		if (_viewModel is null || !await _viewModel.Validate())
 			return;
 
 		await base.SaveAndCloseAsync();
@@ -101,7 +101,7 @@ public partial class EditTemplateDialog : DialogWindow
 			=> Go.To.Url(@"ht" + "tps://github.com/rmcrackan/Libation/blob/master/Documentation/NamingTemplates.md");
 
 		// hold the work-in-progress value. not guaranteed to be valid
-		public string UserTemplateText
+		public string? UserTemplateText
 		{
 			get => field;
 			set
@@ -111,7 +111,7 @@ public partial class EditTemplateDialog : DialogWindow
 			}
 		}
 
-		public string WarningText { get => field; set => this.RaiseAndSetIfChanged(ref field, value); }
+		public string? WarningText { get => field; set => this.RaiseAndSetIfChanged(ref field, value); }
 
 		public string Description { get; }
 
@@ -147,7 +147,7 @@ public partial class EditTemplateDialog : DialogWindow
 			// \books\author with a very     <= normal line break on space between words
 			// long name\narrator narrator   
 			// \title                        <= line break on the zero-with space we added before slashes
-			string slashWrap(string val) => val.Replace(sing, $"{ZERO_WIDTH_SPACE}{sing}");
+			string slashWrap(string? val) => val?.Replace(sing, $"{ZERO_WIDTH_SPACE}{sing}") ?? string.Empty;
 
 			WarningText
 				= !TemplateEditor.EditingTemplate.HasWarnings

Source/LibationAvalonia/Dialogs/FindBetterQualityBooksDialog.axaml

@@ -0,0 +1,94 @@
+<Window xmlns="https://github.com/avaloniaui"
+        xmlns:x="http://schemas.microsoft.com/winfx/2006/xaml"
+        xmlns:d="http://schemas.microsoft.com/expression/blend/2008"
+        xmlns:mc="http://schemas.openxmlformats.org/markup-compatibility/2006"
+        xmlns:dialogs="clr-namespace:LibationAvalonia.Dialogs"
+		xmlns:vm="clr-namespace:LibationUiBase;assembly=LibationUiBase"
+        mc:Ignorable="d" d:DesignWidth="800" d:DesignHeight="450"
+		Width="800" Height="450"
+        x:Class="LibationAvalonia.Dialogs.FindBetterQualityBooksDialog"
+		x:DataType="vm:FindBetterQualityBooksViewModel"
+        Title="Scan Audible for Better Quality Audiobooks">
+
+  <Grid Margin="5" RowDefinitions="*,Auto">
+	  <DataGrid
+		Name="booksDataGrid"
+		GridLinesVisibility="All"
+		CanUserReorderColumns="True"
+		CanUserResizeColumns="True"
+		CanUserSortColumns="True"
+		AutoGenerateColumns="False"
+		IsReadOnly="True"
+		ItemsSource="{CompiledBinding Books}">
+		  <DataGrid.Styles>
+			  <Style x:DataType="vm:BookDataViewModel" Selector="DataGridRow">
+				  	<Setter Property="Background" Value="{CompiledBinding ScanStatus, Converter={x:Static dialogs:FindBetterQualityBooksDialog.RowConverter }}" />
+			  </Style>
+		  </DataGrid.Styles>
+		  <DataGrid.Columns>
+			  
+				<DataGridTextColumn
+    				Width="120"
+				    IsReadOnly="False"
+				    Binding="{CompiledBinding Asin}"
+				    Header="ASIN"/>
+
+				<DataGridTextColumn
+    				Width="120"
+				    IsReadOnly="True"
+				    Binding="{CompiledBinding Title}"
+				    Header="Title"/>
+
+				<DataGridTextColumn
+    				Width="120"
+				    IsReadOnly="True"
+				    Binding="{CompiledBinding FoundFile}"
+				    Header="Best Found File"/>
+
+				<DataGridTextColumn
+    				Width="90"
+				    IsReadOnly="True"
+				    Binding="{CompiledBinding Codec}"
+				    Header="Existing&#xa;Codec"/>
+
+				<DataGridTextColumn
+    				Width="90"
+				    IsReadOnly="True"
+					SortMemberPath="Bitrate"
+				    Binding="{CompiledBinding BitrateString}"
+				    Header="Existing&#xa;Bitrate"/>
+
+				<DataGridTextColumn
+    				Width="90"
+				    IsReadOnly="True"
+				    Binding="{CompiledBinding AvailableCodec}"
+				    Header="Available&#xa;Codec"/>
+
+				<DataGridTextColumn
+    				Width="90"
+				    IsReadOnly="True"
+					SortMemberPath="AvailableBitrate"
+				    Binding="{CompiledBinding AvailableBitrateString}"
+				    Header="Available&#xa;Bitrate"/>
+
+			  <DataGridCheckBoxColumn
+    				Width="90"
+				    IsReadOnly="True"
+					Binding="{CompiledBinding IsSignificant}"
+				    Header="Significantly&#xa;Greater?"/>
+
+          </DataGrid.Columns>
+      </DataGrid>
+	  <Grid Margin="0,5,0,0" Grid.Row="1"
+		 ColumnDefinitions="Auto,Auto,*,Auto">
+		  
+		  <CheckBox IsChecked="{Binding ScanWidevine, Mode=TwoWay}" Content="{x:Static vm:FindBetterQualityBooksViewModel.UseWidevineSboxText }" Margin="0,0,5,0" />
+
+		  <Button Name="scanBtn" IsEnabled="False" Grid.Column="1" Classes="SaveButton" Content="{Binding ScanButtonText}" Click="Scan_Click" />
+
+		  <TextBlock Grid.Column="2" VerticalAlignment="Center" Text="{Binding ScanCount}" Margin="10,0,0,0" />
+		  <Button Grid.Column="3" Classes="SaveButton" Content="{Binding MarkBooksButtonText}"
+			IsVisible="{Binding SignificantCount}" Click="MarkBooks_Click" />
+	  </Grid>
+  </Grid>
+</Window>

Source/LibationAvalonia/Dialogs/FindBetterQualityBooksDialog.axaml.cs

@@ -0,0 +1,159 @@
+using ApplicationServices;
+using Avalonia.Collections;
+using Avalonia.Controls;
+using Avalonia.Data.Converters;
+using Avalonia.Media;
+using Avalonia.Threading;
+using DataLayer;
+using LibationUiBase;
+using LibationUiBase.Forms;
+using LibationUiBase.ProcessQueue;
+using System;
+using System.Linq;
+using System.Threading.Tasks;
+
+namespace LibationAvalonia.Dialogs;
+
+public partial class FindBetterQualityBooksDialog : DialogWindow
+{
+    private FindBetterQualityBooksViewModel VM { get; }
+
+	private Task? scanTask;
+	public FindBetterQualityBooksDialog()
+	{
+		InitializeComponent();
+
+		if (Design.IsDesignMode)
+		{
+			var library = Enumerable.Repeat(MockLibraryBook.CreateBook(), 3);
+			DataContext = VM = new FindBetterQualityBooksViewModel()
+			{
+				Books = new AvaloniaList<BookDataViewModel>(library.Select(lb => new BookDataViewModel(lb)))
+			};
+			VM.Books[0].AvailableCodec = "xHE-AAC";
+			VM.Books[0].AvailableBitrate = 256;
+			VM.Books[0].ScanStatus = ProcessBookStatus.Completed;
+			VM.Books[1].ScanStatus = ProcessBookStatus.Failed;
+			VM.Books[2].ScanStatus = ProcessBookStatus.Cancelled;
+			VM.SignificantCount = 1;
+		}
+		else
+		{
+			DataContext = VM = new FindBetterQualityBooksViewModel();
+			VM.BookScanned += VM_BookScanned;
+			VM.PropertyChanged += VM_PropertyChanged;
+			Opened += Opened_LoadLibrary;
+			Opened += Opened_ShowInitialMessage;
+			Closing += FindBetterQualityBooksDialog_Closing;
+		}
+	}
+
+	private async void Opened_ShowInitialMessage(object? sender, System.EventArgs e)
+	{
+		if (!VM.ShowFindBetterQualityBooksHelp)
+			return;
+		var result = await MessageBox.Show(this, FindBetterQualityBooksViewModel.InitialMessage, Title ?? "", MessageBoxButtons.YesNo, MessageBoxIcon.Information, MessageBoxDefaultButton.Button1);
+		if (result == DialogResult.No)
+		{
+			VM.ShowFindBetterQualityBooksHelp = false;
+		}
+	}
+
+	private async void Opened_LoadLibrary(object? sender, System.EventArgs e)
+	{
+		var library = await Task.Run(() => DbContexts.GetLibrary_Flat_NoTracking());
+		VM.Books = new AvaloniaList<BookDataViewModel>(library.Where(FindBetterQualityBooksViewModel.ShouldScan).Select(lb => new BookDataViewModel(lb)));
+		Dispatcher.UIThread.Invoke(() => scanBtn.IsEnabled = true);
+	}
+
+	private void VM_BookScanned(object? sender, BookDataViewModel e)
+	{
+		Dispatcher.UIThread.Invoke(() => booksDataGrid.ScrollIntoView(e, booksDataGrid.Columns[0]));
+	}
+
+	private void VM_PropertyChanged(object? sender, System.ComponentModel.PropertyChangedEventArgs e)
+	{
+		if (e.PropertyName == nameof(FindBetterQualityBooksViewModel.IsScanning))
+		{
+			Dispatcher.UIThread.Invoke(() => scanBtn.IsEnabled = true);
+		}
+	}
+
+	private async void FindBetterQualityBooksDialog_Closing(object? sender, WindowClosingEventArgs e)
+	{
+		if (scanTask is not null)
+		{
+			await scanTask;
+			scanTask = null;
+			Dispatcher.UIThread.Invoke(Close);
+		}
+	}
+	protected override void OnClosing(WindowClosingEventArgs e)
+	{
+		if (scanTask is not null)
+		{
+			this.SaveSizeAndLocation(LibationFileManager.Configuration.Instance);
+			e.Cancel = true;
+			VM.StopScan();
+		}
+		base.OnClosing(e);
+	}
+
+	public void Scan_Click(object? sender, Avalonia.Interactivity.RoutedEventArgs e)
+	{
+		(sender as Button)?.IsEnabled = false;
+		scanTask = Task.Run(async () =>
+		{
+			try
+			{
+				if (VM.IsScanning)
+					VM.StopScan();
+				else
+					await VM.ScanAsync();
+			}
+			catch (Exception ex)
+			{
+				Serilog.Log.Error(ex, "Failed to scan for better quality books");
+				await MessageBox.Show(this, "An error occurred while scanning for better quality books. Please see the logs for more information.", "Error Scanning Books", MessageBoxButtons.OK, MessageBoxIcon.Error);
+			}
+			finally
+			{
+				Dispatcher.UIThread.Invoke(() =>
+				{
+					VM.IsScanning = false;
+					(sender as Button)?.IsEnabled = true;
+				});
+			}
+		});
+	}
+
+	public async void MarkBooks_Click(object? sender, Avalonia.Interactivity.RoutedEventArgs e)
+	{
+		(sender as Button)?.IsEnabled = false;
+		try
+		{
+			await VM.MarkBooksAsync();
+		}
+		catch (Exception ex)
+		{
+			Serilog.Log.Error(ex, "Failed to mark books as Not Liberated");
+			await MessageBox.Show(this, "An error occurred while marking books as Not Liberated. Please see the logs for more information.", "Error Marking Books", MessageBoxButtons.OK, MessageBoxIcon.Error);
+		}
+		finally
+		{
+			Dispatcher.UIThread.Invoke(() => (sender as Button)?.IsEnabled = true);
+		}
+	}
+
+	public static FuncValueConverter<ProcessBookStatus, IBrush?> RowConverter { get; } = new(status =>
+    {
+        var brush = status switch
+        {
+			ProcessBookStatus.Completed => "ProcessQueueBookCompletedBrush",
+			ProcessBookStatus.Cancelled => "ProcessQueueBookCancelledBrush",
+			ProcessBookStatus.Failed => "ProcessQueueBookFailedBrush",
+            _ => null,
+        };
+		return brush is not null && App.Current.TryGetResource(brush, App.Current.ActualThemeVariant, out var res) ? res as Brush : null;
+    });
+}

Source/LibationAvalonia/Dialogs/ImageDisplayDialog.axaml.cs

@@ -9,8 +9,8 @@ namespace LibationAvalonia.Dialogs
 {
 	public partial class ImageDisplayDialog : DialogWindow, INotifyPropertyChanged
 	{
-		public string PictureFileName { get; set; }
-		public string BookSaveDirectory { get; set; }
+		public string? PictureFileName { get; set; }
+		public string? BookSaveDirectory { get; set; }
 
 		private readonly BitmapHolder _bitmapHolder = new BitmapHolder();
 
@@ -50,7 +50,7 @@ namespace LibationAvalonia.Dialogs
 
 			try
 			{
-				_bitmapHolder.CoverImage.Save(selectedFile);
+				_bitmapHolder.CoverImage?.Save(selectedFile);
 			}
 			catch (Exception ex)
 			{
@@ -61,7 +61,7 @@ namespace LibationAvalonia.Dialogs
 
 		public class BitmapHolder : ViewModels.ViewModelBase
 		{
-			public Bitmap CoverImage { get => field; set => this.RaiseAndSetIfChanged(ref field, value); }
+			public Bitmap? CoverImage { get => field; set => this.RaiseAndSetIfChanged(ref field, value); }
 		}
 	}
 }

Source/LibationAvalonia/Dialogs/LibationFilesDialog.axaml.cs

@@ -17,11 +17,11 @@ namespace LibationAvalonia.Dialogs
 				Configuration.KnownDirectories.MyDocs
 			};
 
-			public string Directory { get; set; }
+			public string? Directory { get; set; }
 		}
 
 		private readonly DirSelectOptions dirSelectOptions;
-		public string SelectedDirectory => dirSelectOptions.Directory;
+		public string? SelectedDirectory => dirSelectOptions.Directory;
 
 		public LibationFilesDialog() : base(saveAndRestorePosition: false)
 		{
@@ -42,7 +42,7 @@ namespace LibationAvalonia.Dialogs
 		public async void Save_Click(object sender, Avalonia.Interactivity.RoutedEventArgs e)
 		{
 
-			if (!System.IO.Directory.Exists(SelectedDirectory))
+			if (SelectedDirectory is not null && !Directory.Exists(SelectedDirectory))
 			{
 				try
 				{

Source/LibationAvalonia/Dialogs/LiberatedStatusBatchManualDialog.axaml.cs

@@ -9,21 +9,21 @@ namespace LibationAvalonia.Dialogs
 		private class liberatedComboBoxItem
 		{
 			public LiberatedStatus Status { get; set; }
-			public string Text { get; set; }
-			public override string ToString() => Text;
+			public string? Text { get; set; }
+			public override string? ToString() => Text;
 		}
 
 		public LiberatedStatus BookLiberatedStatus { get; private set; }
 
-		private liberatedComboBoxItem _selectedStatus;
-		public object SelectedItem
+		private liberatedComboBoxItem? _selectedStatus;
+		public object? SelectedItem
 		{
 			get => _selectedStatus;
 			set
 			{
 				_selectedStatus = value as liberatedComboBoxItem;
 
-				BookLiberatedStatus = _selectedStatus.Status;
+				BookLiberatedStatus = _selectedStatus?.Status ?? default;
 			}
 		}
 
@@ -36,7 +36,7 @@ namespace LibationAvalonia.Dialogs
 		public LiberatedStatusBatchManualDialog(bool isPdf) : this()
 		{
 			if (isPdf)
-				this.Title = this.Title.Replace("book", "PDF");
+				Title = Title?.Replace("book", "PDF");
 		}
 
 		public LiberatedStatusBatchManualDialog()

Source/LibationAvalonia/Dialogs/LocateAudiobooksDialog.axaml.cs

@@ -11,9 +11,7 @@ using System.Collections.Generic;
 using System.IO;
 using System.Linq;
 using System.Threading;
-using System.Threading.Tasks;
 
-#nullable enable
 namespace LibationAvalonia.Dialogs
 {
 	public partial class LocateAudiobooksDialog : DialogWindow

Source/LibationAvalonia/Dialogs/Login/AvaloniaLoginChoiceEager.cs

@@ -9,7 +9,6 @@ using LibationUiBase.Forms;
 using System;
 using System.Threading.Tasks;
 
-#nullable enable
 namespace LibationAvalonia.Dialogs.Login
 {
 	public class AvaloniaLoginChoiceEager : ILoginChoiceEager

Source/LibationAvalonia/Dialogs/Login/LoginExternalDialog.axaml.cs

@@ -10,9 +10,9 @@ namespace LibationAvalonia.Dialogs.Login
 {
 	public partial class LoginExternalDialog : DialogWindow
 	{
-		public Account Account { get; }
-		public string ExternalLoginUrl { get; }
-		public string ResponseUrl { get; set; }
+		public Account? Account { get; }
+		public string? ExternalLoginUrl { get; }
+		public string? ResponseUrl { get; set; }
 
 		public LoginExternalDialog() : base(saveAndRestorePosition: false)
 		{
@@ -54,7 +54,10 @@ namespace LibationAvalonia.Dialogs.Login
 
 
 		public async void CopyUrlToClipboard_Click(object sender, Avalonia.Interactivity.RoutedEventArgs e)
-			=> await App.MainWindow.Clipboard.SetTextAsync(ExternalLoginUrl);
+		{
+			if (App.MainWindow?.Clipboard is not null)
+				await App.MainWindow.Clipboard.SetTextAsync(ExternalLoginUrl);
+		}
 
 		public void LaunchInBrowser_Click(object sender, Avalonia.Interactivity.RoutedEventArgs e)
 			=> Go.To.Url(ExternalLoginUrl);

Source/LibationAvalonia/Dialogs/MessageBoxWindow.axaml.cs

@@ -22,7 +22,7 @@ namespace LibationAvalonia.Dialogs
 		public void Button1_Click(object sender, Avalonia.Interactivity.RoutedEventArgs args)
 		{
 			var vm = DataContext as MessageBoxViewModel;
-			var dialogResult = vm.Buttons switch
+			var dialogResult = vm?.Buttons switch
 			{
 				MessageBoxButtons.OK => DialogResult.OK,
 				MessageBoxButtons.OKCancel => DialogResult.OK,
@@ -38,7 +38,7 @@ namespace LibationAvalonia.Dialogs
 		public void Button2_Click(object sender, Avalonia.Interactivity.RoutedEventArgs args)
 		{
 			var vm = DataContext as MessageBoxViewModel;
-			var dialogResult = vm.Buttons switch
+			var dialogResult = vm?.Buttons switch
 			{
 				MessageBoxButtons.OKCancel => DialogResult.Cancel,
 				MessageBoxButtons.AbortRetryIgnore => DialogResult.Retry,
@@ -53,7 +53,7 @@ namespace LibationAvalonia.Dialogs
 		public void Button3_Click(object sender, Avalonia.Interactivity.RoutedEventArgs args)
 		{
 			var vm = DataContext as MessageBoxViewModel;
-			var dialogResult = vm.Buttons switch
+			var dialogResult = vm?.Buttons switch
 			{
 				MessageBoxButtons.AbortRetryIgnore => DialogResult.Ignore,
 				MessageBoxButtons.YesNoCancel => DialogResult.Cancel,

Source/LibationAvalonia/Dialogs/SearchSyntaxDialog.axaml.cs

@@ -3,7 +3,6 @@ using LibationSearchEngine;
 using System;
 using System.Linq;
 
-#nullable enable
 namespace LibationAvalonia.Dialogs
 {
 	public partial class SearchSyntaxDialog : DialogWindow

Source/LibationAvalonia/Dialogs/SetupDialog.axaml.cs

@@ -9,7 +9,7 @@ namespace LibationAvalonia.Dialogs
 	{
 		public bool IsNewUser { get; private set; }
 		public bool IsReturningUser { get; private set; }
-		public ComboBoxItem SelectedTheme { get; set; }
+		public ComboBoxItem? SelectedTheme { get; set; }
 		public SetupDialog()
 		{
 			InitializeComponent();

Source/LibationAvalonia/Dialogs/TagsBatchDialog.axaml.cs

@@ -4,7 +4,7 @@ namespace LibationAvalonia.Dialogs
 {
 	public partial class TagsBatchDialog : DialogWindow
 	{
-		public string NewTags { get; set; }
+		public string? NewTags { get; set; }
 		public TagsBatchDialog()
 		{
 			InitializeComponent();

Source/LibationAvalonia/Dialogs/ThemePickerDialog.axaml.cs

@@ -10,7 +10,6 @@ using System.Linq;
 using Avalonia.Platform.Storage;
 using LibationUiBase.Forms;
 
-#nullable enable
 namespace LibationAvalonia.Dialogs;
 
 public partial class ThemePickerDialog : DialogWindow

Source/LibationAvalonia/Dialogs/TrashBinDialog.axaml.cs

@@ -129,7 +129,7 @@ namespace LibationAvalonia.Dialogs
 		}
 
 		private IDisposable tracker;
-		private void CheckboxPropertyChanged(Tuple<object, PropertyChangedEventArgs> e)
+		private void CheckboxPropertyChanged(Tuple<object?, PropertyChangedEventArgs> e)
 		{
 			if (e.Item2.PropertyName == nameof(CheckBoxViewModel.IsChecked))
 				CheckedBooksCount = DeletedBooks.Count(b => b.IsChecked);

Source/LibationAvalonia/Dialogs/UpgradeNotificationDialog.axaml.cs

@@ -9,11 +9,11 @@ namespace LibationAvalonia.Dialogs
 	public partial class UpgradeNotificationDialog : DialogWindow
 	{
 		private const string UpdateMessage = "There is a new version available. Would you like to update?\r\n\r\nAfter you close Libation, the upgrade will start automatically.";
-		public string TopMessage { get; }
-		public string DownloadLinkText { get; }
-		public string ReleaseNotes { get; }
-		public string OkText { get; }
-		private string PackageUrl { get; }
+		public string? TopMessage { get; }
+		public string? DownloadLinkText { get; }
+		public string? ReleaseNotes { get; }
+		public string? OkText { get; }
+		private string? PackageUrl { get; }
 		public UpgradeNotificationDialog()
 		{
 			if (Design.IsDesignMode)

Source/LibationAvalonia/FormSaveExtension.cs

@@ -7,7 +7,6 @@ using LibationFileManager;
 using System;
 using System.Linq;
 
-#nullable enable
 namespace LibationAvalonia
 {
 	public static class FormSaveExtension

Source/LibationAvalonia/LibationAvalonia.csproj

@@ -11,6 +11,7 @@
 		<PublishReadyToRun>true</PublishReadyToRun>
 		<AppendTargetFrameworkToOutputPath>false</AppendTargetFrameworkToOutputPath>
 		<AppendRuntimeIdentifierToOutputPath>false</AppendRuntimeIdentifierToOutputPath>
+		<Nullable>enable</Nullable>
 		<StartupObject />
 	</PropertyGroup>
 	

Source/LibationAvalonia/MessageBox.cs

@@ -11,9 +11,7 @@ using System;
 using System.Collections.Generic;
 using System.Linq;
 using System.Threading.Tasks;
-using Avalonia.Platform;
 
-#nullable enable
 namespace LibationAvalonia
 {
 	public class MessageBox

Source/LibationAvalonia/Program.cs

@@ -12,9 +12,7 @@ using LibationAvalonia.Dialogs;
 using Avalonia.Threading;
 using FileManager;
 using System.Linq;
-using System.Reflection;
 
-#nullable enable
 namespace LibationAvalonia
 {
 	static class Program

Source/LibationAvalonia/Themes/ChardonnayTheme.cs

@@ -11,7 +11,6 @@ using System.Linq.Expressions;
 using System.Reflection;
 using System.Collections.Frozen;
 
-#nullable enable
 namespace LibationAvalonia;
 
 public class ChardonnayTheme : IUpdatable, ICloneable

Source/LibationAvalonia/Themes/ChardonnayThemePersister.cs

@@ -5,7 +5,6 @@ using LibationFileManager;
 using Newtonsoft.Json;
 using System;
 
-#nullable enable
 namespace LibationAvalonia.Themes;
 
 public class ChardonnayThemePersister : JsonFilePersister<ChardonnayTheme>

Source/LibationAvalonia/ViewLocator.cs

@@ -1,30 +0,0 @@
-using Avalonia.Controls;
-using Avalonia.Controls.Templates;
-using LibationAvalonia.ViewModels;
-using System;
-
-namespace LibationAvalonia
-{
-	public class ViewLocator : IDataTemplate
-	{
-		public Control Build(object data)
-		{
-			var name = data.GetType().FullName!.Replace("ViewModel", "View");
-			var type = Type.GetType(name);
-
-			if (type != null)
-			{
-				return (Control)Activator.CreateInstance(type)!;
-			}
-			else
-			{
-				return new TextBlock { Text = "Not Found: " + name };
-			}
-		}
-
-		public bool Match(object data)
-		{
-			return data is ViewModelBase;
-		}
-	}
-}

Source/LibationAvalonia/ViewModels/Dialogs/MessageBoxViewModel.cs

@@ -5,7 +5,7 @@ namespace LibationAvalonia.ViewModels.Dialogs
 {
 	public class MessageBoxViewModel
 	{
-		public string Message { get => field; set => field = value; }
+		public string? Message { get => field; set => field = value; }
 		public string Caption { get; } = "Message Box";
 		private MessageBoxButtons _button;
 		private MessageBoxIcon _icon;

Source/LibationAvalonia/ViewModels/LiberateStatusButtonViewModel.cs

@@ -1,6 +1,5 @@
 using ReactiveUI;
 
-#nullable enable
 namespace LibationAvalonia.ViewModels
 {
 	public class LiberateStatusButtonViewModel : ViewModelBase

Source/LibationAvalonia/ViewModels/MainVM.BackupCounts.cs

@@ -5,7 +5,6 @@ using ReactiveUI;
 using System.Collections.Generic;
 using System.Threading.Tasks;
 
-#nullable enable
 namespace LibationAvalonia.ViewModels
 {
 	partial class MainVM

Source/LibationAvalonia/ViewModels/MainVM.Export.cs

@@ -5,7 +5,6 @@ using LibationFileManager;
 using System;
 using System.Threading.Tasks;
 
-#nullable enable
 namespace LibationAvalonia.ViewModels
 {
 	partial class MainVM

Source/LibationAvalonia/ViewModels/MainVM.Filters.cs

@@ -10,7 +10,6 @@ using System;
 using System.Linq;
 using System.Threading.Tasks;
 
-#nullable enable
 namespace LibationAvalonia.ViewModels
 {
 	partial class MainVM

Source/LibationAvalonia/ViewModels/MainVM.Import.cs

@@ -9,7 +9,6 @@ using System.Threading.Tasks;
 using Avalonia.Input;
 using LibationUiBase.Forms;
 
-#nullable enable
 namespace LibationAvalonia.ViewModels
 {
 	public partial class MainVM

Source/LibationAvalonia/ViewModels/MainVM.Liberate.cs

@@ -5,11 +5,9 @@ using System.Linq;
 using System.Threading.Tasks;
 using DataLayer;
 using LibationUiBase.Forms;
-using LibationUiBase;
 using System.Collections.Generic;
 using Avalonia.Threading;
 
-#nullable enable
 namespace LibationAvalonia.ViewModels
 {
 	partial class MainVM

Source/LibationAvalonia/ViewModels/MainVM.ProcessQueue.cs

@@ -1,13 +1,11 @@
 using DataLayer;
 using Dinah.Core;
 using LibationFileManager;
-using LibationUiBase;
 using LibationUiBase.GridView;
 using ReactiveUI;
 using System;
 using System.Linq;
 
-#nullable enable
 namespace LibationAvalonia.ViewModels
 {
 	partial class MainVM

Source/LibationAvalonia/ViewModels/MainVM.ScanAuto.cs

@@ -7,7 +7,6 @@ using System.Collections.Generic;
 using System.Linq;
 using System.Threading.Tasks;
 
-#nullable enable
 namespace LibationAvalonia.ViewModels
 {
 	partial class MainVM

Source/LibationAvalonia/ViewModels/MainVM.Settings.cs

@@ -4,11 +4,11 @@ using ReactiveUI;
 using System;
 using System.Threading.Tasks;
 
-#nullable enable
 namespace LibationAvalonia.ViewModels
 {
 	partial class MainVM
 	{
+		public string FindBetterQualityBooksTip => Configuration.GetHelpText("FindBetterQualityBooks");
 		public bool MenuBarVisible { get => field; set => this.RaiseAndSetIfChanged(ref field, value); } = !Configuration.IsMacOs;
 		private void Configure_Settings()
 		{
@@ -21,6 +21,7 @@ namespace LibationAvalonia.ViewModels
 		public Task ShowAccountsAsync() => new LibationAvalonia.Dialogs.AccountsDialog().ShowDialog(MainWindow);
 		public Task ShowSettingsAsync() => new LibationAvalonia.Dialogs.SettingsDialog().ShowDialog(MainWindow);
 		public Task ShowTrashBinAsync() => new LibationAvalonia.Dialogs.TrashBinDialog().ShowDialog(MainWindow);
+		public Task ShowFindBetterQualityBooksAsync() => new LibationAvalonia.Dialogs.FindBetterQualityBooksDialog().ShowDialog(MainWindow);
 
 		public void LaunchHangover()
 		{

Source/LibationAvalonia/ViewModels/MainVM.VisibleBooks.cs

@@ -7,9 +7,7 @@ using LibationAvalonia.Dialogs;
 using ReactiveUI;
 using LibationUiBase.Forms;
 using System.Linq;
-using LibationUiBase;
 
-#nullable enable
 namespace LibationAvalonia.ViewModels
 {
 	partial class MainVM

Source/LibationAvalonia/ViewModels/MainVM._NoUI.cs

@@ -3,7 +3,6 @@ using LibationUiBase;
 using System;
 using System.IO;
 
-#nullable enable
 namespace LibationAvalonia.ViewModels
 {
 	partial class MainVM

Source/LibationAvalonia/ViewModels/MainVM.cs

@@ -7,7 +7,6 @@ using ReactiveUI;
 using System.Collections.Generic;
 using System.Threading.Tasks;
 
-#nullable enable
 namespace LibationAvalonia.ViewModels
 {
 	public partial class MainVM : ViewModelBase

Source/LibationAvalonia/ViewModels/ProductsDisplayViewModel.cs

@@ -16,7 +16,6 @@ using System.Linq;
 using System.Runtime.CompilerServices;
 using System.Threading.Tasks;
 
-#nullable enable
 namespace LibationAvalonia.ViewModels
 {
 	public class ProductsDisplayViewModel : ViewModelBase
@@ -196,8 +195,8 @@ namespace LibationAvalonia.ViewModels
 				.ExceptBy(dbBooks.Select(lb => lb.Book.AudibleProductId), ge => ge.AudibleProductId);
 
 			//Remove books in series from their parents' Children list
-			foreach (var removed in removedBooks.Where(b => b.Liberate.IsEpisode))
-				removed.Parent.RemoveChild(removed);
+			foreach (var removed in removedBooks.Where(b => b.Liberate?.IsEpisode is true))
+				removed.Parent?.RemoveChild(removed);
 
 			//Remove series that have no children
 			var removedSeries = sourceSnapshot.EmptySeries();
@@ -265,7 +264,7 @@ namespace LibationAvalonia.ViewModels
 					seriesEntries.Add(seriesEntry);
 
 					episodeEntry = seriesEntry.Children[0];
-					seriesEntry.Liberate.Expanded = true;
+					seriesEntry.Liberate?.Expanded = true;
 					SOURCE.Insert(0, seriesEntry);
 				}
 				else
@@ -300,7 +299,7 @@ namespace LibationAvalonia.ViewModels
 
 		public async Task ToggleSeriesExpanded(SeriesEntry seriesEntry)
 		{
-			seriesEntry.Liberate.Expanded = !seriesEntry.Liberate.Expanded;
+			seriesEntry.Liberate?.Expanded = !seriesEntry.Liberate.Expanded;
 
 			await refreshGrid();
 		}
@@ -324,7 +323,7 @@ namespace LibationAvalonia.ViewModels
 		private bool CollectionFilter(object item)
 		{
 			if (item is LibraryBookEntry lbe
-				&& lbe.Liberate.IsEpisode
+				&& lbe.Liberate?.IsEpisode is true
 				&& lbe.Parent?.Liberate?.Expanded != true)
 				return false;
 

Source/LibationAvalonia/ViewModels/RowComparer.cs

@@ -3,7 +3,6 @@ using LibationUiBase.GridView;
 using System.ComponentModel;
 using System.Reflection;
 
-#nullable enable
 namespace LibationAvalonia.ViewModels
 {
 	internal class RowComparer : RowComparerBase

Source/LibationAvalonia/ViewModels/Settings/AudioSettingsVM.cs

@@ -8,7 +8,6 @@ using ReactiveUI;
 using System;
 using System.Linq;
 
-#nullable enable
 namespace LibationAvalonia.ViewModels.Settings
 {
 	public class AudioSettingsVM : ViewModelBase

Source/LibationAvalonia/ViewModels/Settings/DownloadDecryptSettingsVM.cs

@@ -3,7 +3,6 @@ using LibationFileManager;
 using ReactiveUI;
 using System.Collections.Generic;
 
-#nullable enable
 namespace LibationAvalonia.ViewModels.Settings
 {
 	public class DownloadDecryptSettingsVM : ViewModelBase

Source/LibationAvalonia/ViewModels/Settings/ImportSettingsVM.cs

@@ -1,6 +1,5 @@
 using LibationFileManager;
 
-#nullable enable
 namespace LibationAvalonia.ViewModels.Settings
 {
 	public class ImportSettingsVM

Source/LibationAvalonia/ViewModels/Settings/ImportantSettingsVM.cs

@@ -7,7 +7,6 @@ using System;
 using System.Collections.Generic;
 using System.Linq;
 
-#nullable enable
 namespace LibationAvalonia.ViewModels.Settings
 {
 	public class ImportantSettingsVM : ViewModelBase

Source/LibationAvalonia/ViewModels/Settings/SettingsVM.cs

@@ -6,7 +6,10 @@ namespace LibationAvalonia.ViewModels.Settings
 	{
 		public SettingsVM(Configuration config)
 		{
-			LoadSettings(config);
+			ImportantSettings = new ImportantSettingsVM(config);
+			ImportSettings = new ImportSettingsVM(config);
+			DownloadDecryptSettings = new DownloadDecryptSettingsVM(config);
+			AudioSettings = new AudioSettingsVM(config);
 		}
 
 		public ImportantSettingsVM ImportantSettings { get; private set; }
@@ -14,14 +17,6 @@ namespace LibationAvalonia.ViewModels.Settings
 		public DownloadDecryptSettingsVM DownloadDecryptSettings { get; private set; }
 		public AudioSettingsVM AudioSettings { get; private set; }
 
-		public void LoadSettings(Configuration config)
-		{
-			ImportantSettings = new ImportantSettingsVM(config);
-			ImportSettings = new ImportSettingsVM(config);
-			DownloadDecryptSettings = new DownloadDecryptSettingsVM(config);
-			AudioSettings = new AudioSettingsVM(config);
-		}
-
 		public void SaveSettings(Configuration config)
 		{
 			ImportantSettings.SaveSettings(config);

Source/LibationAvalonia/Views/LiberateStatusButton.axaml.cs

@@ -10,7 +10,7 @@ namespace LibationAvalonia.Views
 {
 	public partial class LiberateStatusButton : UserControl
 	{
-		public event EventHandler Click;
+		public event EventHandler? Click;
 
 		public static readonly StyledProperty<LiberatedStatus> BookStatusProperty =
 		AvaloniaProperty.Register<LiberateStatusButton, LiberatedStatus>(nameof(BookStatus));
@@ -50,12 +50,12 @@ namespace LibationAvalonia.Views
 			DataContextChanged += LiberateStatusButton_DataContextChanged;
 		}
 
-		private void LiberateStatusButton_DataContextChanged(object sender, EventArgs e)
+		private void LiberateStatusButton_DataContextChanged(object? sender, EventArgs e)
 		{
 			//Force book status recheck when an entry is scrolled into view.
 			//This will force a recheck for a partially downloaded file.
 			var status = DataContext as LibraryBookEntry;
-			status?.Liberate.Invalidate(nameof(status.Liberate.BookStatus));
+			status?.Liberate?.Invalidate(nameof(status.Liberate.BookStatus));
 		}
 
 		private void Button_Click(object sender, RoutedEventArgs e) => Click?.Invoke(this, EventArgs.Empty);