Add attribution footer link

src/util/yomitan/createEntryAttribution.js

@@ -4,6 +4,41 @@
  * @returns {import("yomichan-dict-builder/dist/types/yomitan/termbank").StructuredContent}
  */
 function createEntryAttribution(entry) {
+  /**
+   * @type {import('yomichan-dict-builder/dist/types/yomitan/termbank').StructuredContent[]}
+   */
+  const contentAttributionSCArray = [
+    {
+      tag: 'a',
+      href: `https://words.hk/zidin/v/${entry.id}`,
+      content: '粵典 words.hk',
+    },
+  ];
+  if (entry.tags.length > 0) {
+    // Find reference tag if exists
+    const referenceTag = entry.tags.find((tag) => tag.name === 'ref');
+    if (referenceTag) {
+      let urlDomain = '';
+      try {
+        const url = new URL(referenceTag.value);
+        urlDomain = url.hostname;
+      } catch (error) {
+        console.error(`Invalid URL: ${referenceTag.value}`);
+      }
+
+      contentAttributionSCArray.unshift(
+        {
+          tag: 'a',
+          href: referenceTag.value,
+          content: `參考: ${urlDomain}`,
+        },
+        {
+          tag: 'span',
+          content: ' | ',
+        }
+      );
+    }
+  }
   return {
     tag: 'div',
     data: {
@@ -16,13 +51,7 @@ function createEntryAttribution(entry) {
       // The examples/definitions above have marginBottom set
       marginTop: '-0.4em',
     },
-    content: [
-      {
-        tag: 'a',
-        href: `https://words.hk/zidin/v/${entry.id}`,
-        content: '粵典 words.hk',
-      },
-    ],
+    content: contentAttributionSCArray,
   };
 }