Add more supporting functions for ToC component

src/lib/components/TableOfContents.svelte

@@ -6,11 +6,75 @@
 
   let { rootAddress } = $props<{ rootAddress: string }>();
 
+  let publicationTree = getContext('publicationTree') as PublicationTree;
+
+  let tocAddresses = $state<Map<string, TocEntry>>(new Map());
+  let tocRoot = $state<TocEntry | null>(null);
+
   // Determine the event kind.
   // If index, use the publication tree to build the table of contents.
   // If single event, build the table of contents from the rendered HTML.
   // Each rendered `<h>` should receive an entry in the ToC.
 
+  function normalizeHashPath(title: string): string {
+    // TODO: Confirm this uses good normalization logic to produce unique hrefs within the page.
+    return title.toLowerCase().replace(/ /g, '-');
+  }
+
+  async function insertIntoTocFromPublicationTree(address: string): Promise<void> {
+    const targetEvent = await publicationTree.getEvent(address);
+    if (!targetEvent) {
+      console.warn(`[ToC] Event ${address} not found.`);
+      // TODO: Determine how to handle this case in the UI.
+      return;
+    }
+
+    const hierarchyEvents = await publicationTree.getHierarchy(address);
+    if (hierarchyEvents.length === 0) {
+      // This means we are at root.
+      return;
+    }
+
+    // Michael J 05 May 2025 - In this loop, we assume that the parent of the current event has
+    // already been populated into the ToC.  As long as the root is set when the component is
+    // initialized, this code will work fine.
+    let currentParentTocNode: TocEntry | null = tocRoot;
+    for (let i = 0; i < hierarchyEvents.length; i++) {
+      const currentEvent = hierarchyEvents[i];
+      const currentAddress = currentEvent.tagAddress();
+
+      if (tocAddresses.has(currentAddress)) {
+        continue;
+      }
+
+      const currentEventChildAddresses = await publicationTree.getChildAddresses(currentAddress);
+      for (let address of currentEventChildAddresses) {
+        if (address === null) {
+          continue;
+        }
+
+        const childEvent = await publicationTree.getEvent(address);
+        if (!childEvent) {
+          console.warn(`[ToC] Event ${address} not found.`);
+          continue;
+        }
+
+        currentParentTocNode!.children ??= [];
+
+        const childTocEntry: TocEntry = {
+          title: childEvent.getMatchingTags('title')[0][1],
+          href: `${page.url.pathname}#${normalizeHashPath(childEvent.getMatchingTags('title')[0][1])}`,
+          expanded: false,
+          children: null,
+        };
+        currentParentTocNode!.children.push(childTocEntry);
+        tocAddresses.set(address, childTocEntry);
+      }
+
+      currentParentTocNode = tocAddresses.get(currentAddress)!;
+    }
+  }
+
   function buildTocFromDocument(parentElement: HTMLElement): void {
     const entries: TocEntry[] = [];
     const currentPathname = page.url.pathname;
@@ -30,8 +94,8 @@
           const tocEntry: TocEntry = {
             title,
             href,
-            expanded: false, // Default to not expanded; can be changed as needed.
-            children: null,  // These are leaf entries from a flat scan of headers.
+            expanded: false,
+            children: null,
           };
           entries.push(tocEntry);
         }
@@ -39,10 +103,6 @@
 
     // TODO: Update ToC state within the component.
   }
-
-  let toc = $state<TocEntry[]>([]);
-
-	const publicationTree = getContext('publicationTree') as PublicationTree;
 </script>
 
 <!-- TODO: Add contents. -->