Exclude duplicated chapters from auto download limit (#923)

In case the new chapters include duplicates from different scanlators, they would be included in the limit causing the auto download to potentially only download duplicated chapters while there might be more non duplicated chapters to download.

Instead, the limit should only consider unique chapters and then should include all duplicates of the chapters that should get downloaded

server/src/main/kotlin/suwayomi/tachidesk/manga/impl/Chapter.kt

@@ -50,6 +50,15 @@ import java.util.TreeSet
 import java.util.concurrent.TimeUnit
 import kotlin.math.max
 
+private fun List<ChapterDataClass>.removeDuplicates(currentChapter: ChapterDataClass): List<ChapterDataClass> {
+    return groupBy { it.chapterNumber }
+        .map { (_, chapters) ->
+            chapters.find { it.id == currentChapter.id }
+                ?: chapters.find { it.scanlator == currentChapter.scanlator }
+                ?: chapters.first()
+        }
+}
+
 object Chapter {
     private val logger = KotlinLogging.logger { }
 
@@ -358,12 +367,12 @@ object Chapter {
         prevLatestChapterNumber: Float,
     ): List<Int> {
         val reUploadedChapters = newChapters.filter { it.chapterNumber < prevLatestChapterNumber }
-        val actualNewChapters = newChapters.subtract(reUploadedChapters.toSet())
+        val actualNewChapters = newChapters.subtract(reUploadedChapters.toSet()).toList()
         val chaptersToConsiderForDownloadLimit =
             if (serverConfig.autoDownloadIgnoreReUploads.value) {
-                actualNewChapters
+                actualNewChapters.removeDuplicates(actualNewChapters[0])
             } else {
-                newChapters
+                newChapters.removeDuplicates(newChapters[0])
             }.sortedBy { it.index }
 
         val latestChapterToDownloadIndex =
@@ -372,8 +381,16 @@ object Chapter {
             } else {
                 serverConfig.autoDownloadNewChaptersLimit.value.coerceAtMost(chaptersToConsiderForDownloadLimit.size)
             }
+        val limitedChaptersToDownload = chaptersToConsiderForDownloadLimit.subList(0, latestChapterToDownloadIndex)
+        val limitedChaptersToDownloadWithDuplicates =
+            (
+                limitedChaptersToDownload +
+                    newChapters.filter { newChapter ->
+                        limitedChaptersToDownload.find { it.chapterNumber == newChapter.chapterNumber } != null
+                    }
+            ).toSet()
 
-        return chaptersToConsiderForDownloadLimit.subList(0, latestChapterToDownloadIndex).map { it.id }
+        return limitedChaptersToDownloadWithDuplicates.map { it.id }
     }
 
     fun modifyChapter(