Tranga/Connector.cs

@@ -78,16 +78,6 @@ public abstract class Connector
         return comicInfo.ToString();
     }
     
-    public bool ChapterIsDownloaded(Publication publication, Chapter chapter)
-    {
-        return File.Exists(CreateFullFilepath(publication, chapter));
-    }
-
-    protected string CreateFullFilepath(Publication publication, Chapter chapter)
-    {
-        return Path.Join(downloadLocation, publication.folderName, chapter.fileName);
-    }
-    
     /// <summary>
     /// Downloads Image from URL and saves it to the given path(incl. fileName)
     /// </summary>

Tranga/Connectors/MangaDex.cs

@@ -201,7 +201,7 @@ public class MangaDex : Connector
         File.WriteAllText(comicInfoPath, CreateComicInfo(publication, chapter));
         
         //Download Chapter-Images
-        DownloadChapterImages(imageUrls.ToArray(), CreateFullFilepath(publication, chapter), downloadClient, comicInfoPath);
+        DownloadChapterImages(imageUrls.ToArray(), Path.Join(downloadLocation, publication.folderName, chapter.fileName), this.downloadClient, comicInfoPath);
     }
 
     public override void DownloadCover(Publication publication)

Tranga/Publication.cs

@@ -33,7 +33,7 @@ public readonly struct Publication
         this.originalLanguage = originalLanguage;
         this.status = status;
         this.downloadUrl = downloadUrl;
-        this.folderName = string.Concat(sortName.Split(Path.GetInvalidPathChars().Concat(Path.GetInvalidFileNameChars()).ToArray()));
+        this.folderName = string.Concat(sortName.Split(Path.GetInvalidPathChars()));
     }
 
     /// <summary>

Tranga/TaskExecutor.cs

@@ -93,11 +93,14 @@ public static class TaskExecutor
     private static List<Chapter> UpdateChapters(Connector connector, Publication publication, string language, Dictionary<Publication, List<Chapter>> chapterCollection)
     {
         List<Chapter> newChaptersList = new();
-        chapterCollection.TryAdd(publication, newChaptersList); //To ensure publication is actually in collection
+        if (!chapterCollection.ContainsKey(publication))
+            return newChaptersList;
         
+        List<Chapter> currentChapters = chapterCollection[publication];
         Chapter[] newChapters = connector.GetChapters(publication, language);
-        newChaptersList = newChapters.Where(nChapter => !connector.ChapterIsDownloaded(publication, nChapter)).ToList();
         
+        newChaptersList = newChapters.ToList()
+            .ExceptBy(currentChapters.Select(cChapter => cChapter.url), nChapter => nChapter.url).ToList();
         return newChaptersList;
     }
 }