Feat: Implement combined related posts logic for main graph

Adds tag similarity fallback for post connections on main knowledge graph, ensuring preview functionality remains intact.

src/pages/blog/index.astro

@@ -63,13 +63,15 @@ const graphData = {
   edges: []
 };
 
-// Create edges between posts and their tags
+// Create edges between posts and their tags, and between related posts
+const processedPostPairs = new Set(); // Avoid duplicate A->B and B->A edges
+
 sortedPosts
   .filter(post => !post.data.draft)
   .forEach(post => {
     const postTags = post.data.tags || [];
     
-    // Add edges from post to tags
+    // 1. Add edges from post to tags
     postTags.forEach(tag => {
       graphData.edges.push({
         source: post.slug,
@@ -79,21 +81,59 @@ sortedPosts
       });
     });
 
-    // Check if post references other posts (optional)
+    // --- Find Related Posts (Explicit + Implicit) ---
-    // This requires a related_posts field in frontmatter
+    const MAX_RELATED_LINKS = 3;
-    if (post.data.related_posts && Array.isArray(post.data.related_posts)) {
+    const MIN_SHARED_TAGS_FOR_LINK = 2;
-      post.data.related_posts.forEach(relatedSlug => {
+    
-        // Make sure related post exists
+    let relatedLinks = new Map(); // Use Map to store related slug and relation type (explicit/implicit)
-        if (sortedPosts.some(p => p.slug === relatedSlug)) {
+
+    // a. Find explicitly related posts
+    const explicitSlugs = new Set(post.data.related_posts || []);
+    explicitSlugs.forEach(slug => {
+      if (sortedPosts.some(p => p.slug === slug && !p.data.draft)) {
+        relatedLinks.set(slug, 'explicit');
+      }
+    });
+
+    // b. Find implicitly related posts by tag similarity (if needed)
+    if (relatedLinks.size < MAX_RELATED_LINKS && postTags.length > 0) {
+      const potentialRelated = sortedPosts
+        .filter(otherPost =>
+          !otherPost.data.draft &&
+          otherPost.slug !== post.slug && // Not the same post
+          !relatedLinks.has(otherPost.slug) // Not already added
+        )
+        .map(otherPost => {
+          const otherTags = otherPost.data.tags || [];
+          const sharedTagsCount = postTags.filter(tag => otherTags.includes(tag)).length;
+          return { slug: otherPost.slug, score: sharedTagsCount };
+        })
+        .filter(item => item.score >= MIN_SHARED_TAGS_FOR_LINK)
+        .sort((a, b) => b.score - a.score); // Sort by most shared tags
+
+      potentialRelated.forEach(item => {
+        if (relatedLinks.size < MAX_RELATED_LINKS) {
+          relatedLinks.set(item.slug, 'implicit');
+        }
+      });
+    }
+
+    // 2. Create edges for the found related posts
+    relatedLinks.forEach((relationType, relatedSlug) => {
+      const pairKey1 = `${post.slug}-${relatedSlug}`;
+      const pairKey2 = `${relatedSlug}-${post.slug}`;
+
+      if (!processedPostPairs.has(pairKey1) && !processedPostPairs.has(pairKey2)) {
         graphData.edges.push({
           source: post.slug,
           target: relatedSlug,
           type: 'post-post',
-            strength: 2
+          strength: relationType === 'explicit' ? 3 : 1.5 // Stronger edge for explicit links
         });
+        processedPostPairs.add(pairKey1);
+        processedPostPairs.add(pairKey2); // Add both directions to set
       }
     });
-    }
   });
 
 // Terminal commands for tech effect