revert changes to DownloadDecryptBook. This is not the correct fix

Source/FileLiberator/DownloadDecryptBook.cs

@@ -6,10 +6,8 @@ using System.Threading.Tasks;
 using AaxDecrypter;
 using ApplicationServices;
 using AudibleApi;
-using AudibleApi.Common;
 using DataLayer;
 using Dinah.Core;
-using Dinah.Core.Collections.Generic;
 using Dinah.Core.ErrorHandling;
 using FileManager;
 using LibationFileManager;
@@ -100,61 +98,18 @@ namespace FileLiberator
 
         private async Task<bool> downloadAudiobookAsync(LibraryBook libraryBook)
         {
+            var config = Configuration.Instance;
+
             downloadValidation(libraryBook);
 
             var api = await libraryBook.GetApiAsync();
-
-			var catalogProduct = await api.GetCatalogProductAsync(libraryBook.Book.AudibleProductId, CatalogOptions.ResponseGroupOptions.ALL_OPTIONS);
-
-            // normal non-MultiPart
-            if (!catalogProduct.ContentDeliveryType.In(ContentDeliveryType.MultiPartIssue, ContentDeliveryType.MultiPartBook))
-            {
             var contentLic = await api.GetDownloadLicenseAsync(libraryBook.Book.AudibleProductId);
-                return await downloadAudiobookPartAsync(contentLic, libraryBook);
-            }
-
-            #region // notes on multi-part
-            // Frankly, decoupling asin and LibraryBook can be potentially dicey depending on how LibraryBook is used down the line.
-            // I checked and it passes cursory inspection. **No promises though.** If you find something that looks wrong, it probably is.
-
-            // the only multi-part title we've found in the wild so far is B002V1PM18
-            // run this un-authenticated call to see its Relationship values
-            //   GetCatalogProductAsync("B002V1PM18", ALL_OPTIONS)
-
-            // there's a bit of guess-work in the code below. In B002V1PM18:
-            // there's some single part we don't need
-            //   RelationshipToProduct: "child"
-            //   RelationshipType: "merchant_title_authority"
-            // and the multiple Relationship parts we do want to download
-            //   RelationshipToProduct: "child"
-            //   RelationshipType:      "component"
-            #endregion
-            // multi-part: handle each part separately
-            var asins = catalogProduct.Relationships
-				.Where(r => r.RelationshipType.In(RelationshipType.Component, RelationshipType.Episode))
-				.OrderBy(r => r.Sort)
-				.Select(r => r.Asin)
-				.ToList();
-			var result = true;
-            foreach (var asin in asins)
-            {
-                var contentLic = await api.GetDownloadLicenseAsync(asin);
-                var success = await downloadAudiobookPartAsync(contentLic, libraryBook);
-				result &= success;
-            }
-			return result;
-        }
-
-        private async Task<bool> downloadAudiobookPartAsync(ContentLicense contentLic, LibraryBook libraryBook)
-		{
-			var config = Configuration.Instance;
-
             var dlOptions = BuildDownloadOptions(libraryBook, config, contentLic);
 
             var outFileName = AudibleFileStorage.Audio.GetInProgressFilename(libraryBook, dlOptions.OutputFormat.ToString().ToLower());
             var cacheDir = AudibleFileStorage.DownloadsInProgressDirectory;
 
-			if (contentLic.DrmType != DrmType.Adrm)
+            if (contentLic.DrmType != AudibleApi.Common.DrmType.Adrm)
                 abDownloader = new UnencryptedAudiobookDownloader(outFileName, cacheDir, dlOptions);
             else
             {
@@ -183,15 +138,15 @@ namespace FileLiberator
             return success;
         }
 
-		private DownloadOptions BuildDownloadOptions(LibraryBook libraryBook, Configuration config, ContentLicense contentLic)
+        private DownloadOptions BuildDownloadOptions(LibraryBook libraryBook, Configuration config, AudibleApi.Common.ContentLicense contentLic)
         {
             //I assume if ContentFormat == "MPEG" that the delivered file is an unencrypted mp3.
             //I also assume that if DrmType != Adrm, the file will be an mp3.
             //These assumptions may be wrong, and only time and bug reports will tell.
 
-			var isEncrypted = contentLic.DrmType == DrmType.Adrm;
+            bool encrypted = contentLic.DrmType == AudibleApi.Common.DrmType.Adrm;
 
-			var outputFormat = !isEncrypted || (config.AllowLibationFixup && config.DecryptToLossy) ?
+            var outputFormat = !encrypted || (config.AllowLibationFixup && config.DecryptToLossy) ?
                      OutputFormat.Mp3 : OutputFormat.M4b;
 
             long chapterStartMs = config.StripAudibleBrandAudio ?
@@ -208,7 +163,7 @@ namespace FileLiberator
                 AudibleIV = contentLic?.Voucher?.Iv,
                 OutputFormat = outputFormat,
                 TrimOutputToChapterLength = config.AllowLibationFixup && config.StripAudibleBrandAudio,
-				RetainEncryptedFile = config.RetainAaxFile && isEncrypted,
+                RetainEncryptedFile = config.RetainAaxFile && encrypted,
                 StripUnabridged = config.AllowLibationFixup && config.StripUnabridged,
                 Downsample = config.AllowLibationFixup && config.LameDownsampleMono,
                 MatchSourceBitrate = config.AllowLibationFixup && config.LameMatchSourceBR && config.LameTargetBitrate,
@@ -315,9 +270,9 @@ namespace FileLiberator
 
 		*/
 
-		public static List<Chapter> flattenChapters(IList<Chapter> chapters, string titleConcat = ": ")
+        public static List<AudibleApi.Common.Chapter> flattenChapters(IList<AudibleApi.Common.Chapter> chapters, string titleConcat = ": ")
         {
-			List<Chapter> chaps = new();
+            List<AudibleApi.Common.Chapter> chaps = new();
 
             foreach (var c in chapters)
             {
@@ -346,7 +301,7 @@ namespace FileLiberator
             return chaps;
         }
 
-		public static void combineCredits(IList<Chapter> chapters)
+        public static void combineCredits(IList<AudibleApi.Common.Chapter> chapters)
         {
             if (chapters.Count > 1 && chapters[0].Title == "Opening Credits")
             {