From 13d23d9c6c35e13a5608c1d9ed7ca20edec7a71a Mon Sep 17 00:00:00 2001
From: jasongao97 <jasongao97@gmail.com>
Date: Wed, 24 Jan 2024 14:28:44 +0800
Subject: [PATCH] add `Example` endpoint

---
 gatsby/create-resolvers.js   | 20 +++++++++++++++
 gatsby/lib/parse-content.mjs | 47 +++++++++++++++++++++++++++++-------
 gatsby/on-create-node.js     | 27 ++++++++++++++++++---
 3 files changed, 82 insertions(+), 12 deletions(-)

diff --git a/gatsby/create-resolvers.js b/gatsby/create-resolvers.js
index 2ef50ac4..d702a68f 100644
--- a/gatsby/create-resolvers.js
+++ b/gatsby/create-resolvers.js
@@ -20,6 +20,26 @@ module.exports = ({ createResolvers }) => {
         },
       },
     },
+
+    Example: {
+      screenshot: {
+        type: 'File',
+        resolve: async (source, args, context, info) => {
+          const screenshot = await context.nodeModel.findOne({
+            type: 'File',
+            query: {
+              filter: {
+                relativeDirectory: {
+                  eq: source.relativeDirectory,
+                },
+                internal: { mediaType: { regex: '/^(image)/' } },
+              },
+            },
+          });
+          return screenshot;
+        },
+      },
+    },
   };
   createResolvers(resolvers);
 };
diff --git a/gatsby/lib/parse-content.mjs b/gatsby/lib/parse-content.mjs
index 5d14737b..9903a07d 100644
--- a/gatsby/lib/parse-content.mjs
+++ b/gatsby/lib/parse-content.mjs
@@ -67,15 +67,6 @@ export function parseContent(html) {
 
   const ast = unified().use(rehypeParse, { fragment: true }).parse(html);
 
-  const transformedAst = unified()
-    .use(replaceMedia)
-    .use(externalLinkInNewTab)
-    .use(rehypeCodesplit)
-    .use(rehypeHighlight)
-    .use(rehypeSlug)
-    .use(rehypeKatex)
-    .runSync(ast);
-
   /**
    * Generate Table of Content
    */
@@ -88,8 +79,46 @@ export function parseContent(html) {
     });
   });
 
+  /**
+   * List all examples
+   */
+  const examples = [];
+  visit(ast, { tagName: 'div' }, (node) => {
+    if (node.properties.dataType !== 'example') {
+      return;
+    }
+
+    // Locate the h3 element within the current node's children
+    const titleNode = node.children.find((child) => child.tagName === 'h3');
+    const slug = titleNode && titleNode.properties.id;
+    const title =
+      titleNode && titleNode.children.length > 0
+        ? titleNode.children[0].value
+        : '';
+
+    visit(node, { tagName: 'div' }, (embedDivNode) => {
+      if (embedDivNode.properties.dataType !== 'embed') return;
+      examples.push({
+        title,
+        slug,
+        relativeDirectory: embedDivNode.properties.dataExamplePath,
+        webEditorURL: embedDivNode.properties.dataP5Editor,
+      });
+    });
+  });
+
+  const transformedAst = unified()
+    .use(replaceMedia)
+    .use(externalLinkInNewTab)
+    .use(rehypeCodesplit)
+    .use(rehypeHighlight)
+    .use(rehypeSlug)
+    .use(rehypeKatex)
+    .runSync(ast);
+
   return {
     ast: transformedAst,
     toc,
+    examples,
   };
 }
diff --git a/gatsby/on-create-node.js b/gatsby/on-create-node.js
index c9a79961..0212ad07 100644
--- a/gatsby/on-create-node.js
+++ b/gatsby/on-create-node.js
@@ -1,5 +1,11 @@
-module.exports = async ({ node, actions, loadNodeContent }) => {
-  const { createNodeField } = actions;
+module.exports = async ({
+  node,
+  actions,
+  loadNodeContent,
+  createContentDigest,
+  createNodeId,
+}) => {
+  const { createNodeField, createNode, createParentChildLink } = actions;
 
   if (node.internal.mediaType !== `text/html`) {
     return;
@@ -9,7 +15,7 @@ module.exports = async ({ node, actions, loadNodeContent }) => {
 
   // load the html source to every HTML file node
   const content = await loadNodeContent(node);
-  const { ast, toc } = parseContent(content);
+  const { ast, toc, examples } = parseContent(content);
 
   createNodeField({
     node,
@@ -22,4 +28,19 @@ module.exports = async ({ node, actions, loadNodeContent }) => {
     name: 'toc',
     value: JSON.stringify(toc),
   });
+
+  for (let example of examples) {
+    const exampleNode = {
+      id: createNodeId(example.relativeDirectory),
+      parent: node.id,
+      internal: {
+        type: 'Example',
+        contentDigest: createContentDigest(example),
+      },
+      ...example,
+    };
+
+    createNode(exampleNode);
+    createParentChildLink({ parent: node, child: exampleNode });
+  }
 };