Some work on for showing an MPA

ccm-cms-default-theme/src/main/resources/themes/librecms/templates/contentitems/org.librecms.contenttypes.MultiPartArticle.html.ftl

@@ -0,0 +1,21 @@
+<#macro details>
+    <h1>${CmsPagesCategorizedItemModel.title}</h1>
+    <p class="item-description">${CmsPagesCategorizedItemModel.description}</p>
+
+    <h2>${CmsPagesMultiPartArticleModel.currentSectionTitle}</h2>
+    <div>
+        <nav>
+            <ul class="flex-column float-end nav">
+                <#list CmsPagesMultiPartArticleModel.sectionTitles as section>
+                    <li class="nav-item">
+                        <a class="nav-link"
+                           href="${CmsPagesMultiPartArticleModel.sectionLinks[section?index]}">
+                           ${section}
+                        </a>
+                    </li>
+                </#list>
+            </ul>
+        </nav>
+        ${CmsPagesMultiPartArticleModel.currentSectionText}
+    </div>
+</#macro>

ccm-cms-default-theme/src/main/scss/_custom.scss

@@ -11,5 +11,5 @@ a.navbar-brand {
 }
 
 .item-description {
-    white-space: pre;
+    white-space: pre-wrap;
 }

ccm-cms/src/main/java/org/librecms/pages/models/MultiPartArticleModel.java

@@ -18,11 +18,6 @@
  */
 package org.librecms.pages.models;
 
-import org.libreccm.l10n.GlobalizationHelper;
-import org.librecms.contentsection.ContentItem;
-import org.librecms.contenttypes.MultiPartArticle;
-import org.librecms.contenttypes.MultiPartArticleSection;
-
 import java.util.Collections;
 import java.util.List;
 import java.util.Optional;
@@ -35,6 +30,13 @@ import javax.transaction.Transactional;
 import javax.ws.rs.WebApplicationException;
 import javax.ws.rs.core.Response;
 
+import org.libreccm.l10n.GlobalizationHelper;
+import org.librecms.contentsection.ContentItem;
+import org.librecms.contenttypes.MultiPartArticle;
+import org.librecms.contenttypes.MultiPartArticleSection;
+
+import java.util.ArrayList;
+
 /**
  *
  * @author <a href="mailto:jens.pelzetter@googlemail.com">Jens Pelzetter</a>
@@ -60,6 +62,8 @@ public class MultiPartArticleModel implements ProcessesContentItem {
 
     private List<String> sectionTitles;
 
+    private List<String> sectionLinks;
+
     private String currentSectionTitle;
 
     private String currentSectionText;
@@ -91,6 +95,13 @@ public class MultiPartArticleModel implements ProcessesContentItem {
         return Collections.unmodifiableList(sectionTitles);
     }
 
+    @Transactional(Transactional.TxType.REQUIRED)
+    public List<String> getSectionLinks() {
+        contentItemModel.init();
+
+        return Collections.unmodifiableList(sectionLinks);
+    }
+
     @Transactional(Transactional.TxType.REQUIRED)
     public String getCurrentSectionTitle() {
         contentItemModel.init();
@@ -142,8 +153,10 @@ public class MultiPartArticleModel implements ProcessesContentItem {
                 )
                 .orElse(Collections.emptyList());
 
+            sectionLinks = buildSectionLinks();
+            
             final int currentSection = readCurrentSection();
-            if (mpa.getSections().size() > currentSection) {
+            if (mpa.getSections().size() < currentSection) {
                 throw new WebApplicationException(
                     Response
                         .status(Response.Status.NOT_FOUND)
@@ -212,4 +225,45 @@ public class MultiPartArticleModel implements ProcessesContentItem {
         return model;
     }
 
+    @Transactional(Transactional.TxType.REQUIRED)
+    private List<String> buildSectionLinks() {
+        final String pathWithoutSections;
+        if (pageUrlModel.getPath().matches(".*/@sections/[0-9]*$")) {
+            final String path = pageUrlModel.getPath();
+            pathWithoutSections = path.substring(
+                0,
+                path.lastIndexOf("/@sections") + 1
+            );
+        } else {
+            pathWithoutSections = pageUrlModel.getPath();
+        }
+
+        final List<String> sectionLinksList = new ArrayList<>();
+        for (int i = 0; i < sectionTitles.size(); i++) {
+            sectionLinksList.add(
+                String.format(
+                    "%s/@sections/%d?%s",
+                    pathWithoutSections,
+                    i,
+                    pageUrlModel
+                        .getQueryParameters()
+                        .entrySet()
+                        .stream()
+                        .map(
+                            entry -> String.format(
+                                "%s=%s",
+                                entry.getKey(),
+                                entry.getValue()
+                            )
+                        )
+                        .collect(
+                            Collectors.joining("&")
+                        )
+                )
+            );
+        }
+
+        return sectionLinksList;
+    }
+
 }