From 8e5d4e6b71c0f50b237540c268120241e7414ec6 Mon Sep 17 00:00:00 2001
From: Emily Kho <emily.kho@bluace.nl>
Date: Fri, 12 Apr 2024 11:00:31 +0200
Subject: [PATCH] add multi-line support

---
 .../XWPF/XWPFParagraphExtensions.cs           | 48 +++++++++++++++++++
 .../XWPF/XWPFParagraphMapper.cs               |  6 +--
 2 files changed, 50 insertions(+), 4 deletions(-)
 create mode 100644 NPOI.WordTemplateMapper/Extensions/XWPF/XWPFParagraphExtensions.cs

diff --git a/NPOI.WordTemplateMapper/Extensions/XWPF/XWPFParagraphExtensions.cs b/NPOI.WordTemplateMapper/Extensions/XWPF/XWPFParagraphExtensions.cs
new file mode 100644
index 0000000..1dff17e
--- /dev/null
+++ b/NPOI.WordTemplateMapper/Extensions/XWPF/XWPFParagraphExtensions.cs
@@ -0,0 +1,48 @@
+using NPOI.XWPF.UserModel;
+using System.Text.RegularExpressions;
+
+namespace NPOI.WordTemplateMapper.Extensions.XWPF;
+
+public static class XWPFParagraphExtensions
+{
+    public static void ReplaceTextKeepLineEndings(this XWPFParagraph xwpfParagraph, string textToReplace, string replacementText)
+    {
+        string paragraphText = xwpfParagraph.Text;
+
+        if (!paragraphText.Contains(textToReplace))
+            return;
+
+        if (!replacementText.Contains('\n'))
+        {
+            string textToInsert = paragraphText.Replace(textToReplace, replacementText);
+            if (!string.IsNullOrEmpty(xwpfParagraph.Text))
+                xwpfParagraph.ReplaceText(xwpfParagraph.Text, textToInsert);
+            return;
+        }
+
+        List<int> positionsOfOldTextOccurences = new();
+        positionsOfOldTextOccurences
+            .AddRange(
+                Regex.Matches(paragraphText, Regex.Escape(textToReplace))
+                    .Select(match => match.Index)
+            );
+
+        for (int i = positionsOfOldTextOccurences.Count - 1; i >= 0; i--)
+        {
+            int currentPosition = positionsOfOldTextOccurences[i];
+            paragraphText = paragraphText
+                .Remove(currentPosition, textToReplace.Length)
+                .Insert(currentPosition, replacementText);
+        }
+
+        string[] newParagraphsToInsert = paragraphText.Split('\n');
+        xwpfParagraph.ReplaceText(xwpfParagraph.Text, string.Empty);
+
+        XWPFRun run = xwpfParagraph.CreateRun();
+        foreach (string newParagraph in newParagraphsToInsert)
+        {
+            run.AppendText(newParagraph);
+            run.AddCarriageReturn();
+        }
+    }
+}
diff --git a/NPOI.WordTemplateMapper/XWPF/XWPFParagraphMapper.cs b/NPOI.WordTemplateMapper/XWPF/XWPFParagraphMapper.cs
index e4f879e..b7b6b6b 100644
--- a/NPOI.WordTemplateMapper/XWPF/XWPFParagraphMapper.cs
+++ b/NPOI.WordTemplateMapper/XWPF/XWPFParagraphMapper.cs
@@ -3,6 +3,7 @@
 using NPOI.WordTemplateMapper.Interfaces.XWPF;
 using System.Text.RegularExpressions;
 using System.Collections;
+using NPOI.WordTemplateMapper.Extensions.XWPF;
 
 namespace NPOI.WordTemplateMapper.XWPF;
 
@@ -33,10 +34,7 @@ public XWPFParagraph MapParagraph(XWPFParagraph paragraph, IDictionary<string, o
                 KeyValuePair<string, string> mappedValue = GetMappedValue(paragraph, mapping);
                 string oldText = paragraph.Text;
 
-                // Workaround for malfunctioning ReplaceText from NPOI
-                string newText = paragraph.Text.Replace(mappedValue.Key, mappedValue.Value);
-                if (!string.IsNullOrEmpty(paragraph.Text))
-                    paragraph.ReplaceText(paragraph.Text, newText);
+                paragraph.ReplaceTextKeepLineEndings(mappedValue.Key, mappedValue.Value);
 
                 if (oldText == paragraph.Text)
                     keepMapping = false;