(function () {
var path = window.location.pathname;
var ptr = typeof path_to_root !== 'undefined' ? path_to_root : '';
var isZh = /\/zh(\/|$)/.test(path);
var targetPath;
var dir = path.replace(/\/[^/]*$/, '/');
var a = document.createElement('a');
a.href = dir + ptr;
var bookRoot = a.pathname;
var relPath = path.startsWith(bookRoot) ? path.slice(bookRoot.length) : path;
if (isZh) {
targetPath = path.replace(/\/zh(?=\/|$)/, '').replace(/\/+$/, '') || '/';
} else {
targetPath = bookRoot + 'zh/' + relPath;
}
var label = isZh ? 'English' : 'δΈζ';
var lang = isZh ? 'en' : 'zh';
function inject() {
var toolbar = document.querySelector('.right-buttons');
if (!toolbar) return setTimeout(inject, 50);
var a = document.createElement('a');
a.href = targetPath;
a.title = label;
a.setAttribute('aria-label', label);
a.style.cssText =
'display:inline-flex;align-items:center;text-decoration:none;color:var(--icons);padding:4px;font-size:13px;font-weight:600;';
a.textContent = lang;
toolbar.insertBefore(a, toolbar.firstChild);
}
if (document.readyState === 'loading') {
document.addEventListener('DOMContentLoaded', function () {
setTimeout(inject, 100);
});
} else {
inject();
}
})();