auto-remove duplicate chapters

[AriaMoradi]

No description provided.

[Syer10]

I took a gander at this, I think it looks much cleaner

        val dbChapterCount = transaction { ChapterTable.select { ChapterTable.manga eq mangaId }.count() }
        if (dbChapterCount > chapterCount) { // we got some clean up due
            val dbChapterList = transaction { ChapterTable.select { ChapterTable.manga eq mangaId }.toList() }
            val chapterUrls = chapterList.map { it.url }.toSet()

            dbChapterList.forEach { dbChapter ->
                if (
                    !chapterUrls.contains(dbChapter[ChapterTable.url]) || // is orphaned
                    dbChapterList.count { it[ChapterTable.url] == dbChapter[ChapterTable.url] } > 1 // is duplicate
                ) {
                    transaction {
                        PageTable.deleteWhere { PageTable.chapter eq dbChapter[ChapterTable.id] }
                        ChapterTable.deleteWhere { ChapterTable.id eq dbChapter[ChapterTable.id] }
                    }
                }
            }
        }

Though it may have issues where yours doesnt, not too sure if they are equal

[AriaMoradi]

your's is not deterministic, mine always makes sure there's a non-duplicate with bigger index exists to check with the next?

[Syer10]

I dont like non-descriptive variables like i, changed to index. Also cleaned up the code