fix: skip duplicate books during reading list import

closes #622

ERRORCODES.md

@@ -26,3 +26,4 @@ ERR_1019 | Cannot import file that is part of an existing library
 ERR_1020 | Book to upgrade does not belong to provided series
 ERR_1021 | Destination file already exists
 ERR_1022 | Newly imported book could not be scanned
+ERR_1023 | Book already present in ReadingList

komga-webui/src/locales/en.json

@@ -535,7 +535,8 @@
     "ERR_1019": "Cannot import file that is part of an existing library",
     "ERR_1020": "Book to upgrade does not belong to provided series",
     "ERR_1021": "Destination file already exists",
-    "ERR_1022": "Newly imported book could not be scanned"
+    "ERR_1022": "Newly imported book could not be scanned",
+    "ERR_1023": "Book already present in ReadingList"
   },
   "filter": {
     "age_rating": "age rating",

komga/src/main/kotlin/org/gotson/komga/domain/service/ReadListMatcher.kt

@@ -45,6 +45,7 @@ class ReadListMatcher(
           when {
             bookMatches.size > 1 -> unmatchedBooks += ReadListRequestResultBook(book, "ERR_1013")
             bookMatches.isEmpty() -> unmatchedBooks += ReadListRequestResultBook(book, "ERR_1014")
+            bookIds.contains(bookMatches.first()) -> unmatchedBooks += ReadListRequestResultBook(book, "ERR_1023")
             else -> bookIds.add(bookMatches.first())
           }
         }

komga/src/test/kotlin/org/gotson/komga/domain/service/ReadListMatcherTest.kt

@@ -220,4 +220,52 @@ class ReadListMatcherTest(
       assertThat(unmatchedBooks[3].errorCode).isEqualTo("ERR_1013")
     }
   }
+
+  @Test
+  fun `given request with duplicate books when matching then returns result with appropriate error codes`() {
+    // given
+    val booksSeries1 = listOf(
+      makeBook("book1", libraryId = library.id),
+      makeBook("book2", libraryId = library.id),
+    )
+    makeSeries(name = "batman", libraryId = library.id).let { s ->
+      seriesLifecycle.createSeries(s)
+      seriesLifecycle.addBooks(s, booksSeries1)
+      seriesLifecycle.sortBooks(s)
+    }
+
+    val request = ReadListRequest(
+      name = "readlist",
+      books = listOf(
+        ReadListRequestBook(series = "batman", number = "1"),
+        ReadListRequestBook(series = "batman", number = "2"),
+        ReadListRequestBook(series = "batman", number = "2"),
+      )
+    )
+
+    // when
+    val result = readListMatcher.matchReadListRequest(request)
+
+    // then
+    with(result) {
+      assertThat(readList).isNotNull
+      with(readList!!) {
+        assertThat(name).isEqualTo(request.name)
+        assertThat(bookIds).hasSize(2)
+        assertThat(bookIds).containsExactlyEntriesOf(
+          mapOf(
+            0 to booksSeries1[0].id,
+            1 to booksSeries1[1].id,
+          )
+        )
+      }
+
+      assertThat(errorCode).isBlank
+
+      assertThat(unmatchedBooks).hasSize(1)
+
+      assertThat(unmatchedBooks[0].book).isEqualTo(request.books[2])
+      assertThat(unmatchedBooks[0].errorCode).isEqualTo("ERR_1023")
+    }
+  }
 }