From 5598e9aa09824031855d8353df55b0d7e9a671db Mon Sep 17 00:00:00 2001
From: Ludy87 <Ludy87@users.noreply.github.com>
Date: Thu, 1 Jan 2026 18:43:21 +0100
Subject: [PATCH] Refactor PDF split logic for improved clarity

Replaces getPagesToSplit with getCustomPagesToSplit and introduces shouldSplitPage to centralize split mode logic. This refactor improves code readability and maintainability by separating custom page selection from split mode handling.
---
 .../api/SplitPdfBySectionsController.java     | 95 ++++++++-----------
 1 file changed, 38 insertions(+), 57 deletions(-)

diff --git a/app/core/src/main/java/stirling/software/SPDF/controller/api/SplitPdfBySectionsController.java b/app/core/src/main/java/stirling/software/SPDF/controller/api/SplitPdfBySectionsController.java
index 174d2bd777..c578cb8141 100644
--- a/app/core/src/main/java/stirling/software/SPDF/controller/api/SplitPdfBySectionsController.java
+++ b/app/core/src/main/java/stirling/software/SPDF/controller/api/SplitPdfBySectionsController.java
@@ -63,9 +63,10 @@ public class SplitPdfBySectionsController {
                         .map(SplitTypes::valueOf)
                         .orElse(SplitTypes.SPLIT_ALL);
 
-        try (PDDocument sourceDocument = pdfDocumentFactory.load(file)) {
-            Set<Integer> pagesToSplit =
-                    getPagesToSplit(pageNumbers, splitMode, sourceDocument.getNumberOfPages());
+        try (PDDocument sourceDocument = pdfDocumentFactory.load(file, true)) {
+            int totalPages = sourceDocument.getNumberOfPages();
+            Set<Integer> customPagesToSplit =
+                    getCustomPagesToSplit(pageNumbers, splitMode, totalPages);
 
             // Process the PDF based on split parameters
             int horiz = request.getHorizontalDivisions() + 1;
@@ -79,10 +80,8 @@ public class SplitPdfBySectionsController {
                                         sourceDocument);
                         ByteArrayOutputStream baos = new ByteArrayOutputStream()) {
                     LayerUtility layerUtility = new LayerUtility(mergedDoc);
-                    for (int pageIndex = 0;
-                            pageIndex < sourceDocument.getNumberOfPages();
-                            pageIndex++) {
-                        if (pagesToSplit.contains(pageIndex)) {
+                    for (int pageIndex = 0; pageIndex < totalPages; pageIndex++) {
+                        if (shouldSplitPage(pageIndex, totalPages, splitMode, customPagesToSplit)) {
                             addSplitPageToTarget(
                                     sourceDocument,
                                     pageIndex,
@@ -101,11 +100,9 @@ public class SplitPdfBySectionsController {
                 TempFile zipTempFile = new TempFile(tempFileManager, ".zip");
                 try (ZipOutputStream zipOut =
                         new ZipOutputStream(Files.newOutputStream(zipTempFile.getPath()))) {
-                    for (int pageIndex = 0;
-                            pageIndex < sourceDocument.getNumberOfPages();
-                            pageIndex++) {
+                    for (int pageIndex = 0; pageIndex < totalPages; pageIndex++) {
                         int pageNum = pageIndex + 1;
-                        if (pagesToSplit.contains(pageIndex)) {
+                        if (shouldSplitPage(pageIndex, totalPages, splitMode, customPagesToSplit)) {
                             for (int i = 0; i < horiz; i++) {
                                 for (int j = 0; j < verti; j++) {
                                     try (PDDocument subDoc =
@@ -243,53 +240,37 @@ public class SplitPdfBySectionsController {
     }
 
     // Based on the mode, get the pages that need to be split and return the pages set
-    private Set<Integer> getPagesToSplit(String pageNumbers, SplitTypes splitMode, int totalPages) {
-        Set<Integer> pagesToSplit = new HashSet<>();
-
-        switch (splitMode) {
-            case CUSTOM:
-                if (pageNumbers == null || pageNumbers.isBlank()) {
-                    throw ExceptionUtils.createIllegalArgumentException(
-                            "error.argumentRequired",
-                            "{0} is required for {1} mode",
-                            "page numbers",
-                            "custom");
-                }
-                String[] pageOrderArr = pageNumbers.split(",");
-                List<Integer> pageListToSplit =
-                        GeneralUtils.parsePageList(pageOrderArr, totalPages, false);
-                pagesToSplit.addAll(pageListToSplit);
-                break;
-
-            case SPLIT_ALL:
-                for (int i = 0; i < totalPages; i++) {
-                    pagesToSplit.add(i);
-                }
-                break;
-
-            case SPLIT_ALL_EXCEPT_FIRST:
-                for (int i = 1; i < totalPages; i++) {
-                    pagesToSplit.add(i);
-                }
-                break;
-
-            case SPLIT_ALL_EXCEPT_LAST:
-                for (int i = 0; i < totalPages - 1; i++) {
-                    pagesToSplit.add(i);
-                }
-                break;
-
-            case SPLIT_ALL_EXCEPT_FIRST_AND_LAST:
-                for (int i = 1; i < totalPages - 1; i++) {
-                    pagesToSplit.add(i);
-                }
-                break;
-
-            default:
-                throw ExceptionUtils.createIllegalArgumentException(
-                        "error.invalidFormat", "Invalid {0} format: {1}", "split mode", splitMode);
+    private Set<Integer> getCustomPagesToSplit(
+            String pageNumbers, SplitTypes splitMode, int totalPages) {
+        if (splitMode != SplitTypes.CUSTOM) {
+            return Collections.emptySet();
         }
+        if (pageNumbers == null || pageNumbers.isBlank()) {
+            throw ExceptionUtils.createIllegalArgumentException(
+                    "error.argumentRequired",
+                    "{0} is required for {1} mode",
+                    "page numbers",
+                    "custom");
+        }
+        String[] pageOrderArr = pageNumbers.split(",");
+        List<Integer> pageListToSplit = GeneralUtils.parsePageList(pageOrderArr, totalPages, false);
+        return new HashSet<>(pageListToSplit);
+    }
 
-        return pagesToSplit;
+    private boolean shouldSplitPage(
+            int pageIndex, int totalPages, SplitTypes splitMode, Set<Integer> customPagesToSplit) {
+        return switch (splitMode) {
+            case CUSTOM -> customPagesToSplit.contains(pageIndex);
+            case SPLIT_ALL -> true;
+            case SPLIT_ALL_EXCEPT_FIRST -> pageIndex > 0;
+            case SPLIT_ALL_EXCEPT_LAST -> pageIndex < totalPages - 1;
+            case SPLIT_ALL_EXCEPT_FIRST_AND_LAST -> pageIndex > 0 && pageIndex < totalPages - 1;
+            default ->
+                    throw ExceptionUtils.createIllegalArgumentException(
+                            "error.invalidFormat",
+                            "Invalid {0} format: {1}",
+                            "split mode",
+                            splitMode);
+        };
     }
 }