From 557bad60bc0cef220ea7a20b3bde5e98a341f24a Mon Sep 17 00:00:00 2001
From: schroda <50052685+schroda@users.noreply.github.com>
Date: Sat, 12 Aug 2023 17:14:58 +0200
Subject: [PATCH] Prevent last page read to be greater than max page count
 (#655)

There were cases where the last page read was greater than the max page count of a chapter.
This is not possible and is just invalid data, that is saved in the database, possible leading to other errors down the line.

This could happen in case the chapter was loaded at some point with e.g. 18 pages and after some time got fetched again from the source, now with fewer pages than before e.g. 15.
If the chapters last page was already read by that time, the last read page would have been 18, while the chapter now has only 15 pages.
---
 .../suwayomi/tachidesk/graphql/mutations/ChapterMutation.kt   | 4 +++-
 .../tachidesk/manga/impl/chapter/ChapterForDownload.kt        | 3 +++
 2 files changed, 6 insertions(+), 1 deletion(-)

diff --git a/server/src/main/kotlin/suwayomi/tachidesk/graphql/mutations/ChapterMutation.kt b/server/src/main/kotlin/suwayomi/tachidesk/graphql/mutations/ChapterMutation.kt
index b42cab68..40dda6b0 100644
--- a/server/src/main/kotlin/suwayomi/tachidesk/graphql/mutations/ChapterMutation.kt
+++ b/server/src/main/kotlin/suwayomi/tachidesk/graphql/mutations/ChapterMutation.kt
@@ -228,7 +228,9 @@ class ChapterMutation {
                     this[PageTable.chapter] = chapterId
                 }
                 ChapterTable.update({ ChapterTable.id eq chapterId }) {
-                    it[ChapterTable.pageCount] = pageList.size
+                    val pageCount = pageList.size
+                    it[ChapterTable.pageCount] = pageCount
+                    it[ChapterTable.lastPageRead] = chapter[ChapterTable.lastPageRead].coerceAtMost(pageCount - 1)
                 }
             }
 
diff --git a/server/src/main/kotlin/suwayomi/tachidesk/manga/impl/chapter/ChapterForDownload.kt b/server/src/main/kotlin/suwayomi/tachidesk/manga/impl/chapter/ChapterForDownload.kt
index 622e4d91..b184dea1 100644
--- a/server/src/main/kotlin/suwayomi/tachidesk/manga/impl/chapter/ChapterForDownload.kt
+++ b/server/src/main/kotlin/suwayomi/tachidesk/manga/impl/chapter/ChapterForDownload.kt
@@ -118,8 +118,11 @@ private class ChapterForDownload(
         val pageCount = pageList.count()
 
         transaction {
+            val lastPageRead = ChapterTable.select { ChapterTable.id eq chapterId }.firstOrNull()?.get(ChapterTable.lastPageRead) ?: 0
+
             ChapterTable.update({ ChapterTable.id eq chapterId }) {
                 it[ChapterTable.pageCount] = pageCount
+                it[ChapterTable.lastPageRead] = lastPageRead.coerceAtMost(pageCount - 1)
             }
         }
     }