chore: split English and Chinese

Author: zhjwpku

book.toml

@@ -8,6 +8,8 @@ title = "Postgres Weekly, A Hacker’s Digest"
 [output.html]
 no-section-label = true
 git-repository-url = "https://github.com/pgweekly/pgweekly.github.io"
+additional-js = ["extra.js"]
+additional-css = ["extra.css"]
 
 [output.html.fold]
 enable = true     # whether or not to enable section folding

extra.css

@@ -0,0 +1,41 @@
+/* Align all right-side actions on one vertical center line */
+#menu-bar .right-buttons {
+  display: inline-flex;
+  align-items: center;
+  align-self: center;
+}
+
+/* Language switch in mdBook menu bar */
+#menu-bar .right-buttons a.pgw-menu-lang {
+  display: inline-flex;
+  align-items: center;
+  gap: 0.35em;
+  box-sizing: border-box;
+  height: var(--menu-bar-height);
+  padding: 0 10px 0 6px;
+  margin-right: 4px;
+  font-size: 1.4rem;
+  font-weight: 500;
+  line-height: 1;
+  color: var(--icons);
+  text-decoration: none;
+}
+
+#menu-bar .right-buttons a.pgw-menu-lang:hover {
+  color: var(--icons-hover);
+}
+
+/* Icon: optically nudged down to match print/github glyphs */
+#menu-bar .right-buttons a.pgw-menu-lang > .fa-language {
+  padding: 0;
+  font-size: 1.45rem;
+  line-height: 1;
+  position: relative;
+  top: 0px;
+}
+
+#menu-bar .right-buttons a.pgw-menu-lang .pgw-menu-lang-label {
+  line-height: 1;
+  position: relative;
+  top: -1px;
+}

extra.js

@@ -0,0 +1,63 @@
+/* One language in the sidebar; language switch link in the menu bar. */
+(function () {
+  var path = window.location.pathname || '';
+  var isCn = path.indexOf('/cn/') !== -1;
+
+  var sidebar = document.querySelector('#sidebar .sidebar-scrollbox ol.chapter');
+  if (sidebar) {
+    var titles = sidebar.querySelectorAll(':scope > li.part-title');
+    if (titles.length >= 2) {
+      var cnPartTitle = titles[1];
+      var el = sidebar.firstElementChild;
+      var next;
+      if (isCn) {
+        while (el && el !== cnPartTitle) {
+          next = el.nextElementSibling;
+          el.style.display = 'none';
+          el = next;
+        }
+      } else {
+        el = cnPartTitle;
+        while (el) {
+          next = el.nextElementSibling;
+          el.style.display = 'none';
+          el = next;
+        }
+      }
+    }
+  }
+
+  function otherLangPath(p) {
+    if (p.indexOf('/cn/') !== -1) return p.replace('/cn/', '/en/');
+    if (p.indexOf('/en/') !== -1) return p.replace('/en/', '/cn/');
+    return new URL('cn/2026/index.html', window.location.href).pathname;
+  }
+
+  var target = otherLangPath(path);
+  if (target === path) return;
+  if (path.indexOf('print.html') !== -1) return;
+
+  var right = document.querySelector('#menu-bar .right-buttons');
+  if (!right) return;
+
+  var a = document.createElement('a');
+  a.className = 'pgw-menu-lang';
+  a.href = target;
+  var icon = document.createElement('i');
+  icon.className = 'fa fa-language';
+  icon.setAttribute('aria-hidden', 'true');
+  var label = document.createElement('span');
+  label.className = 'pgw-menu-lang-label';
+  if (target.indexOf('/cn/') !== -1) {
+    label.textContent = '中文';
+    a.title = '切换到中文版';
+    a.setAttribute('aria-label', '切换到中文版');
+  } else {
+    label.textContent = 'English';
+    a.title = 'English version';
+    a.setAttribute('aria-label', 'English version');
+  }
+  a.appendChild(icon);
+  a.appendChild(label);
+  right.insertBefore(a, right.firstChild);
+})();