Add nested groups support in side nav

src/main/kotlin/nl/avisi/structurizr/site/generatr/site/SiteGenerator.kt

@@ -19,6 +19,8 @@ fun copySiteWideAssets(exportDir: File) {
     copySiteWideAsset(exportDir, "/css/admonition.css")
     copySiteWideAsset(exportDir, "/js/admonition.js")
     copySiteWideAsset(exportDir, "/js/reformat-mermaid.js")
+    copySiteWideAsset(exportDir, "/css/treeview.css")
+    copySiteWideAsset(exportDir, "/js/treeview.js")
 }
 
 private fun copySiteWideAsset(exportDir: File, asset: String) {

src/main/kotlin/nl/avisi/structurizr/site/generatr/site/model/MenuViewModel.kt

@@ -27,4 +27,30 @@ class MenuViewModel(generatorContext: GeneratorContext, private val pageViewMode
 
     private fun createMenuItem(title: String, href: String, exact: Boolean = true) =
         LinkViewModel(pageViewModel, title, href, exact)
+
+    data class Node(val name: String, val children: MutableList<Node>)
+
+    val nestedSoftwareSystems = generatorContext.workspace.model.includedSoftwareSystems
+        .map {it.group + "/" + it.name}
+        .sortedBy {it.lowercase()}
+
+    fun buildTree(data: List<String>, delimiter: Char):MutableList<Node> {
+        val rootNode = Node("", mutableListOf())
+        for (path in data) {
+            val parts = path.split(delimiter)
+            var currentNode = rootNode
+
+            for (part in parts) {
+                val existingNode = currentNode.children.find { it.name == part }
+                currentNode = if (existingNode == null) {
+                    val newNode = Node(part, mutableListOf())
+                    currentNode.children.add(newNode)
+                    newNode
+                } else {
+                    existingNode
+                }
+            }
+        }
+        return rootNode.children
+    }
 }

src/main/kotlin/nl/avisi/structurizr/site/generatr/site/model/PageViewModel.kt

@@ -15,14 +15,15 @@ abstract class PageViewModel(protected val generatorContext: GeneratorContext) {
     val headerBar by lazy { HeaderBarViewModel(this, generatorContext) }
     val menu by lazy { MenuViewModel(generatorContext, this) }
     val includeAutoReloading = generatorContext.serving
-    
-    val flexmarkConfig by lazy { 
-        buildFlexmarkConfig(generatorContext) 
+
+    val flexmarkConfig by lazy {
+        buildFlexmarkConfig(generatorContext)
     }
     val includeAdmonition = flexmarkConfig.selectedExtensionMap.containsKey("Admonition")
     val includeKatex = flexmarkConfig.selectedExtensionMap.containsKey("GitLab")
 
     val configuration = generatorContext.workspace.views.configuration.properties
+    val includeTreeview = configuration.getOrDefault("generatr.nav.nestGroups", "false").toBoolean()
 
     abstract val url: String
     abstract val pageSubTitle: String

src/main/kotlin/nl/avisi/structurizr/site/generatr/site/views/Menu.kt

@@ -1,13 +1,14 @@
 package nl.avisi.structurizr.site.generatr.site.views
 
 import kotlinx.html.*
+import nl.avisi.structurizr.site.generatr.site.GeneratorContext
 import nl.avisi.structurizr.site.generatr.site.model.LinkViewModel
 import nl.avisi.structurizr.site.generatr.site.model.MenuViewModel
 
-fun DIV.menu(viewModel: MenuViewModel) {
+fun DIV.menu(viewModel: MenuViewModel, nestGroups:Boolean) {
     aside(classes = "menu p-3") {
         generalSection(viewModel.generalItems)
-        softwareSystemsSection(viewModel.softwareSystemItems)
+        softwareSystemsSection(viewModel, nestGroups)
     }
 }
 
@@ -16,9 +17,18 @@ private fun ASIDE.generalSection(items: List<LinkViewModel>) {
     menuItemLinks(items)
 }
 
-private fun ASIDE.softwareSystemsSection(items: List<LinkViewModel>) {
+private fun ASIDE.softwareSystemsSection(viewModel: MenuViewModel, nestGroups:Boolean) {
     p(classes = "menu-label") { +"Software systems" }
-    menuItemLinks(items)
+    if(nestGroups){
+        // Display SoftwareSystems as a nested lists
+        val rootNode = MenuViewModel.Node("", viewModel.buildTree(viewModel.nestedSoftwareSystems, "/".toCharArray()[0]))
+        ul(classes = "listree menu-list has-site-branding"){
+            buildHtmlTree(rootNode, viewModel).invoke(this)
+        }
+    } else {
+        // Display SoftwareSystems as a flat list
+        menuItemLinks(viewModel.softwareSystemItems)
+    }
 }
 
 private fun ASIDE.menuItemLinks(items: List<LinkViewModel>) {
@@ -30,3 +40,43 @@ private fun ASIDE.menuItemLinks(items: List<LinkViewModel>) {
         }
     }
 }
+
+private fun buildHtmlTree(node: MenuViewModel.Node, viewModel: MenuViewModel): UL.() -> Unit = {
+
+    if (node.name.isNotEmpty() && node.children.isEmpty()) {
+        val itemLink = viewModel.softwareSystemItems.find { it.title == node.name }
+        li {
+            if (itemLink != null) {
+                link(itemLink)
+            }
+        }
+    }
+
+    if (node.name.isNotEmpty()  && node.children.isNotEmpty()) {
+        li {
+            if(node.name == "null"){
+                div(classes = "listree-submenu-heading") {
+                    +"No Group"
+                }
+            } else {
+                div(classes = "listree-submenu-heading") {
+                    +node.name
+                }
+            }
+
+            ul(classes = "listree-submenu-items") {
+                for (child in node.children) {
+                    buildHtmlTree(child,viewModel).invoke(this)
+                }
+            }
+        }
+    }
+    if (node.name.isEmpty() && node.children.isNotEmpty()) {
+        ul(classes = "listree-submenu-items") {
+            for (child in node.children) {
+                buildHtmlTree(child, viewModel).invoke(this)
+            }
+        }
+    }
+
+}

src/main/kotlin/nl/avisi/structurizr/site/generatr/site/views/Page.kt

@@ -27,7 +27,14 @@ private fun HTML.headFragment(viewModel: PageViewModel) {
             href = "./" + "/style-branding.css".asUrlToFile(viewModel.url)
         )
 
-        if (viewModel.includeAdmonition) 
+        if(viewModel.includeTreeview){
+            link(
+                rel = "stylesheet",
+                href = "../" + "/treeview.css".asUrlToFile(viewModel.url)
+            )
+        }
+
+        if (viewModel.includeAdmonition)
             markdownAdmonitionStylesheet(viewModel)
 
         if (viewModel.includeKatex)
@@ -54,7 +61,7 @@ private fun HTML.bodyFragment(viewModel: PageViewModel, block: DIV.() -> Unit) {
 
         div(classes = "site-layout") {
             id = "site"
-            menu(viewModel.menu)
+            menu(viewModel.menu, viewModel.includeTreeview)
             div(classes = "container is-fluid has-background-white") {
                 block()
             }
@@ -64,6 +71,19 @@ private fun HTML.bodyFragment(viewModel: PageViewModel, block: DIV.() -> Unit) {
             updateSiteErrorHero()
         if (viewModel.includeAdmonition)
             markdownAdmonitionScript(viewModel)
+        if (viewModel.includeTreeview)
+
         mermaidScript(viewModel)
+
+        if (viewModel.includeTreeview){
+            script(
+                type = ScriptType.textJavaScript,
+                src = "../" + "/treeview.js".asUrlToFile(viewModel.url)
+            ) { }
+
+            script(
+                type = ScriptType.textJavaScript
+            ) { unsafe { +"listree();" } }
+        }
     }
 }

src/main/resources/assets/css/treeview.css

@@ -0,0 +1,35 @@
+.listree-submenu-heading {
+    cursor: pointer
+}
+
+ul.listree {
+    list-style: none
+}
+
+ul.listree-submenu-items {
+    list-style: none;
+    white-space: nowrap;
+    padding-left: 10px
+}
+
+div.listree-submenu-heading.collapsed:before {
+    content: "\25B6";
+    margin-right: 4px
+}
+
+div.listree-submenu-heading.expanded:before {
+    content: "\25BC";
+    margin-right: 4px
+}
+
+.scrollable-menu {
+    height: auto;
+    max-width: 800px;
+    overflow-y: hidden
+}
+
+.menu-list li ul {
+    border-left: 0;
+    margin: .25em;
+    padding-left: .75em;
+}

src/main/resources/assets/js/treeview.js

@@ -0,0 +1,65 @@
+function listree() {
+
+  const subMenuHeadingClass = "listree-submenu-heading";
+  const expandedClass = "expanded";
+  const collapsedClass = "collapsed";
+  const activeClass = "is-active";
+  const subMenuHeadings = document.getElementsByClassName(subMenuHeadingClass);
+
+  Array
+    .from(subMenuHeadings)
+    .forEach(function(subMenuHeading) {
+      // Collapse all the subMenuHeadings while searching for is-active class
+      let foundActive = false;
+      subMenuHeading.classList.add(collapsedClass);
+      subMenuHeading.nextElementSibling.style.display = "none";
+
+      // Check if this sub-menu heading is active
+      const liElements = subMenuHeading.nextElementSibling.children;
+      for (let i = 0; i < liElements.length; i++) {
+        if (liElements[i].hasChildNodes()) {
+          if (liElements[i].children[0].tagName === "A") {
+            if (liElements[i].children[0].classList.contains(activeClass)) {
+              foundActive = true;
+              break;
+            }
+          }
+        }
+      }
+
+      // Expand all parent sub-menus until root menu is reached
+      if (foundActive) {
+        subMenuHeading.classList.remove(collapsedClass);
+        subMenuHeading.classList.add(expandedClass);
+        subMenuHeading.nextElementSibling.style.display = "block";
+
+        let currentSubMenu = subMenuHeading.parentElement;
+        while (currentSubMenu !== null && !currentSubMenu.classList.contains("listree")) {
+          if(currentSubMenu.tagName === "UL"){
+            if(currentSubMenu.previousElementSibling != null) {
+              currentSubMenu.previousElementSibling.classList.remove(collapsedClass);
+              currentSubMenu.previousElementSibling.classList.add(expandedClass);
+              currentSubMenu.style.display = "block";
+            }
+          }
+          currentSubMenu = currentSubMenu.parentElement
+        }
+      }
+
+      // Add the eventlistener to all subMenuHeadings
+      subMenuHeading.addEventListener("click", function(event) {
+        event.preventDefault();
+        const subMenuList = event.target.nextElementSibling;
+        if (subMenuList.style.display === "none") {
+          subMenuHeading.classList.remove(collapsedClass);
+          subMenuHeading.classList.add(expandedClass);
+          subMenuHeading.nextElementSibling.style.display = "block";
+        } else {
+          subMenuHeading.classList.remove(expandedClass);
+          subMenuHeading.classList.add(collapsedClass);
+          subMenuHeading.nextElementSibling.style.display = "none";
+        }
+        event.stopPropagation();
+      });
+    });
+}