var isBrowser = typeof document !== 'undefined';
function getRegisteredStyles(registered, registeredStyles, classNames) {
  var rawClassName = '';
  classNames.split(' ').forEach(function (className) {
    if (registered[className] !== undefined) {
      registeredStyles.push(registered[className]);
    } else {
      rawClassName += className + " ";
    }
  });
  return rawClassName;
}
var insertStyles = function insertStyles(context, insertable, isStringTag) {
  if ( // we only need to add the styles to the registered cache if the
  // class name could be used further down
  // the tree but if it's a string tag, we know it won't
  // so we don't have to add it to registered cache.
  // this improves memory usage since we can avoid storing the whole style string
  (isStringTag === false || // we need to always store it if we're in compat mode and
  // in node since emotion-server relies on whether a style is in
  // the registered cache to know whether a style is global or not
  // also, note that this check will be dead code eliminated in the browser
  isBrowser === false && context.compat !== undefined) && context.registered[context.key + "-" + insertable.name] === undefined) {
    context.registered[context.key + "-" + insertable.name] = insertable.styles;
  }

  if (context.inserted[insertable.name] === undefined) {
    var rules = context.stylis("." + context.key + "-" + insertable.name, insertable.styles);
    context.inserted[insertable.name] = true;

    if (isBrowser) {
      rules.forEach(context.sheet.insert, context.sheet);
    } else {
      var joinedRules = rules.join('');

      if (context.compat === undefined) {
        // in regular mode, we don't set the styles on the inserted cache
        // since we don't need to and that would be wasting memory
        // we return them so that they are rendered in a style tag
        return joinedRules;
      } else {
        // in compat mode, we put the styles on the inserted cache so
        // that emotion-server can pull out the styles
        context.inserted[insertable.name] = joinedRules;
      }
    }
  }
};

export { isBrowser, getRegisteredStyles, insertStyles };