fix(client): .app.tar.gz exam bin is macos (#64095)

client/src/templates/Challenges/exam-download/show.tsx

@@ -11,7 +11,6 @@ import {
   Row,
   Col
 } from '@freecodecamp/ui';
-import { isEmpty } from 'lodash';
 import { useTranslation, withTranslation } from 'react-i18next';
 import { createSelector } from 'reselect';
 import { connect } from 'react-redux';
@@ -108,50 +107,72 @@ function ShowExamDownload({
   const { t } = useTranslation();
 
   function handleDownloadLink(downloadLinks: string[]) {
-    const win = downloadLinks.find(link => link.match(/\.exe/));
-    const macARM = downloadLinks.find(
-      link => link.match(/aarch64/) && link.match(/\.dmg/)
-    );
-    const macX64 = downloadLinks.find(
-      link => link.match(/x64/) && link.match(/\.dmg/)
-    );
+    // Filter out signature and metadata files first
+    const filtered = downloadLinks.filter(link => !/\.(sig|json)$/i.test(link));
 
-    const linuxARM = downloadLinks.find(
-      link => link.match(/aarch64/) && link.match(/tar\.gz/)
-    );
+    function normalizeArch(token: string): string {
+      if (!token) return '';
+      const t = token.toLowerCase();
+      if (/aarch64|arm64|arm/i.test(t)) return 'arm';
+      if (/x86_64|x64|amd64/i.test(t)) return 'x64';
+      if (/x86|i386|i686/i.test(t)) return 'x86';
+      return t;
+    }
 
-    const linuxX64 = downloadLinks.find(
-      link => link.match(/amd64/) && link.match(/AppImage/)
-    );
+    const items = filtered.map(link => {
+      const urlEnd = link.split('/').pop() ?? '';
+      const name = urlEnd;
+      let ext = '';
+      if (name.endsWith('.app.tar.gz')) ext = '.app.tar.gz';
+      else if (name.endsWith('.tar.gz')) ext = '.tar.gz';
+      else if (name.endsWith('.AppImage')) ext = '.AppImage';
+      else if (name.endsWith('.dmg')) ext = '.dmg';
+      else if (name.endsWith('.exe')) ext = '.exe';
+      else {
+        const m = name.match(/(\.[^./]+)$/);
+        ext = m ? m[0] : '';
+      }
+
+      const archMatch = name.match(
+        /(aarch64|arm64|amd64|x86_64|x64|x86|i386)/i
+      );
+      const archToken = archMatch ? normalizeArch(archMatch[0]) : '';
+
+      return { link, name, ext, arch: archToken };
+    });
+
+    const detectedArch = normalizeArch(os.architecture || '');
+
+    function pickByExts(exts: string[], preferArch?: string) {
+      // prefer both ext + arch
+      let found = items.find(
+        it => exts.includes(it.ext) && it.arch === preferArch
+      );
+      if (found) return found.link;
+      // then any with ext and unspecified arch
+      found = items.find(
+        it => exts.includes(it.ext) && (!preferArch || it.arch === '')
+      );
+      if (found) return found.link;
+      // then any with ext
+      found = items.find(it => exts.includes(it.ext));
+      return found ? found.link : '';
+    }
 
     if (os.os === 'WIN') {
-      if (isEmpty(win)) return '';
-
-      return win;
+      return pickByExts(['.exe'], detectedArch) || '';
     }
 
     if (os.os === 'MAC') {
-      if (os.architecture.toLowerCase() === 'arm') {
-        if (isEmpty(macARM)) return '';
-
-        return macARM;
-      } else {
-        if (isEmpty(macX64)) return '';
-
-        return macX64;
-      }
+      // prefer .dmg files
+      return pickByExts(['.dmg'], detectedArch) || '';
     }
 
     if (os.os === 'LINUX') {
-      if (os.architecture.toLowerCase() === 'arm') {
-        if (isEmpty(linuxARM)) return '';
-
-        return linuxARM;
-      } else {
-        if (isEmpty(linuxX64)) return '';
-
-        return linuxX64;
-      }
+      // prefer AppImage, then .app.tar.gz, then .tar.gz
+      return (
+        pickByExts(['.AppImage', '.app.tar.gz', '.tar.gz'], detectedArch) || ''
+      );
     }
 
     return '';
@@ -337,31 +358,22 @@ function getRecommendedOs({
   arch: string;
   ext: string;
 }): string {
-  switch (arch) {
-    case 'x64':
-      switch (ext) {
-        case '.dmg':
-          return 'x64 MacOS';
-        case '.AppImage':
-        case '.app.tar.gz':
-          return 'x64 Linux';
-        default:
-          return 'x64 Windows';
-      }
-    case 'aarch64':
-      switch (ext) {
-        case '.dmg':
-          return 'ARM MacOS';
-        case '.app.tar.gz':
-          return 'ARM Linux';
-        default:
-          return 'ARM Windows';
-      }
-    case 'amd64':
-      return 'x64 Linux';
-    default:
-      return '';
-  }
+  const osToExt = {
+    MacOS: ['.dmg', '.app', '.app.tar.gz'],
+    Linux: ['.deb', '.rpm', '.AppImage', '.tar.gz', '.AppImage.tar.gz'],
+    Windows: ['.exe', '.msi']
+  } as const;
+  const archToHuman: Record<string, string> = {
+    x64: '64-bit',
+    aarch64: 'ARM',
+    amd64: '64-bit',
+    i386: '32-bit',
+    x86: '32-bit'
+  };
+
+  const os = Object.entries(osToExt).find(([_, exts]) => exts.includes(ext));
+
+  return `${archToHuman[arch] ?? arch} ${os ? os[0] : ''}`;
 }
 
 function getLatest(releases: GitProps[]): GitProps {