chore(backport release-1.0): feat: versioned docs dropdown

docs/docusaurus.config.js

@@ -80,6 +80,10 @@ const config = {
             label: 'Akuity.io',
             position: 'left',
           },
+          {
+            type: 'custom-version-dropdown',
+            position: 'right',
+          },
           {
             href: 'https://kargo.io/',
             label: 'Kargo.io',

docs/src/components/VersionDropdown.css

@@ -0,0 +1,18 @@
+.version_dropdown {
+    appearance: none;
+    -webkit-appearance: none; /* For Safari */
+    -moz-appearance: none; /* For Firefox */
+    position: relative;
+    background-color: transparent;
+    border: 1px solid #ccc;
+    border-radius: 5px;
+    cursor: pointer;
+    padding: 5px 10px;
+    font-size: 1rem;
+    font-family: 'Monospace', 'Roboto', 'Open Sans', 'Lato', 'Courier New', monospace;
+    font-weight: bold;
+}
+
+.version_dropdown option {
+    font-weight: normal; /* Keeps options normal weight */
+}

docs/src/components/VersionDropdown.js

@@ -0,0 +1,122 @@
+import React, { useState, useEffect } from 'react';
+import './VersionDropdown.css';
+
+function VersionDropdown() {
+  console.log("Navbar Version dropdown initialized");
+
+  const githubApiUrl = 'https://api.github.com/repos/akuity/kargo/branches?protected=true';
+  const protocol = 'https://';
+  const domain = 'docs.kargo.io';
+  const latestVersionLabel = 'Latest Version';
+  const latestVersionUrl = `${protocol}${domain}`;
+  const edgeVersionLabel = 'Edge Version (main)';
+  const edgeVersionUrl = `${protocol}main.${domain}`;
+  const unrecognizedVersionLabel = 'Unrecognized Version';
+
+  const [versions, setVersions] = useState([]);
+  const [loading, setLoading] = useState(true);
+  const [currentVersion, setCurrentVersion] = useState('');
+
+  // Change the implementation of the currentUrl function to aid in testing
+  const currentUrl = () => new URL(window.location.href);
+
+  const versionLabel = (major, minor) => `v${major}.${minor}`;
+
+  const fetchVersions = async () => {
+    try {
+      console.log("Before fetching versions");
+      const response = await fetch(githubApiUrl);
+      const branches = await response.json();
+      console.log("Fetched branches are: ", branches);
+
+      const releaseBranches = branches
+        .map(branch => branch.name)
+        .filter(name => /^release-([1-9]\d*\.\d+)$/.test(name))
+        .map(name => {
+          const [major, minor] = name.replace('release-', '').split('.');
+          return {
+            version: versionLabel(major, minor),
+            url: `${protocol}${name.replace('.', '-')}.${domain}`
+          };
+        });
+
+      console.log("These are release branches before sorting and updating 0 element: ", releaseBranches);
+      releaseBranches.sort((a, b) => {
+        if (a.version > b.version) {
+          return -1;
+        }
+        if (a.version < b.version) {
+          return 1;
+        }
+        return 0;
+      });
+      // Overwrite the first element with the latest version
+      releaseBranches[0] = {
+        version: latestVersionLabel,
+        url: latestVersionUrl
+      };
+      // Put the "edge" version at the end of the list
+      releaseBranches.push({
+        version: edgeVersionLabel,
+        url: edgeVersionUrl,
+      })
+      const currentVersion = getCurrentVersion();
+      // If the current version is not recognized, add it to the end of the list
+      if (currentVersion === unrecognizedVersionLabel) {
+        const url = currentUrl();
+        releaseBranches.push({
+          version: unrecognizedVersionLabel,
+          url: `${url.protocol}//${url.hostname}${url.port ? `:${url.port}` : ''}`
+        });
+      }
+      console.log("These are release branches: ", releaseBranches);
+      setVersions(releaseBranches);
+      setLoading(false);
+    } catch (error) {
+      console.error('Error fetching versions:', error);
+      setLoading(false);
+    }
+  };
+
+  const getCurrentVersion = () => {
+    const url = currentUrl();
+    if (url.hostname === new URL(latestVersionUrl).hostname && !url.port) {
+      return 'Latest Version';
+    }
+    if (url.hostname === new URL(edgeVersionUrl).hostname && !url.port) {
+      return 'Edge Version (main)';
+    }
+    const match = url.hostname.match(/^release-(\d+)-(\d+)\.docs\.kargo\.io$/);
+    return match && !url.port ? versionLabel(match[1], match[2]) : unrecognizedVersionLabel;
+  };
+
+  useEffect(() => {
+    setCurrentVersion(getCurrentVersion());
+    fetchVersions();
+  }, []);
+
+  const handleVersionChange = (event) => {
+    const selectedVersion = versions.find(v => v.version === event.target.value);
+    if (selectedVersion) {
+      window.location.href = selectedVersion.url;
+    }
+  };
+
+  if (loading) return null;
+
+  return (
+    <select
+      className="version_dropdown"
+      onChange={handleVersionChange}
+      value={currentVersion}
+    >
+      {versions.map(version => (
+        <option key={version.version} value={version.version}>
+          {version.version}
+        </option>
+      ))}
+  </select>
+  );
+}
+
+export default VersionDropdown;

docs/src/theme/NavbarItem/ComponentTypes.js

@@ -0,0 +1,7 @@
+import VersionDropdown from '@site/src/components/VersionDropdown';
+import DefaultComponentTypes from '@theme-original/NavbarItem/ComponentTypes';
+
+export default {
+    ...DefaultComponentTypes,
+    'custom-version-dropdown': VersionDropdown,
+};