(function(){

  let RECAPTCHA_TOKEN_NAME = "recaptcha";
  let RECAPTCHA_TOKEN_TTL = 90000;
  let RECAPTCHA_API_CLIENT_KEY = "6LddVcoUAAAAAFlmmt09ROXX7ofVMgBJSPg3U1c1";
  let RECAPTCHA_API_CLIENT_URL = "https://www.google.com/recaptcha/api.js?render=6LddVcoUAAAAAFlmmt09ROXX7ofVMgBJSPg3U1c1";

  
  if (typeof jQuery === 'undefined') {
  
      alert(['Ошибка подключения reCAPTCHA.', 'Не подключена библиотека jQuery.'].join('\n'));
  
  } else {
  
      let tokenCache = '', tokenTime = 0;

      $.getScript(RECAPTCHA_API_CLIENT_URL, function() {
  
          $(function() {

              if (!RECAPTCHA_API_CLIENT_KEY) {
                alert(['Ошибка подключения reCAPTCHA.', 'Не задан ключ для текущего домена.'].join('\n'));
              }

              let forms = $('form.recaptcha3');
              forms
                  .append('<input type="hidden" name="' + RECAPTCHA_TOKEN_NAME + '" value="' + tokenCache + '">')
                  .submit(function(event) {
                      let form = $(this);
                      submitForm(form, event);
                  });
  
              function getValidToken() {
                  let lifetime = Date.now() - tokenTime;
                  let outdated = lifetime > RECAPTCHA_TOKEN_TTL;
                  return !outdated ? tokenCache : '';
              }
           
              function requestToken(callback) {
                  let token = getValidToken();
                  if (token) {
                      if (callback) {
                          callback(token);
                      }
                      return;
                  }
                  try {
                      grecaptcha.ready(function() {
                          grecaptcha.execute(RECAPTCHA_API_CLIENT_KEY, {action: 'common'})
                              .then(function(token) {
                                  tokenCache = token;
                                  tokenTime = Date.now();
                                  if (callback) {
                                      callback(tokenCache);
                                  }
                              });
                      });
                  } catch (error) {
                      error = 'Ошибка подключения к серверу reCAPTCHA.\n' + error;
                      alert(error);
                  }
              }
           
              function submitForm(form, event) {
                  let tokenInput = form.find('input[name="' + RECAPTCHA_TOKEN_NAME + '"]');
                  let submitButton = form.find('[type="submit"]').eq(0);
                  let token = getValidToken();
                  let assigned = (token === tokenInput.val());
                  let ready = (token && assigned);
                  if (!ready) {
                      event.preventDefault();
                      formSetProcessing(forms, true);
                      requestToken(function(token) {
                          formSetProcessing(forms, false);
                          tokenInput.val(token);
                          setTimeout(function() {
                              submitButton.click();
                          }, 100);
                      });
                  }
              }
  
              function elementsSetPropertiesStyles(elements, properties, styles) {
                  properties = properties || {};
                  styles = styles || {};
                  $(elements).each(function() {
                      let element = this;
                      for (let key in properties) {
                          let backupKey = 'backup_property_' + key;
                          if (!element.dataset[backupKey]) {
                              element.dataset[backupKey] = JSON.stringify(element[key]);
                          }
                          element[key] = properties[key];
                      }
                      for (let key in styles) {
                          let styleKey = 'backup_style_' + key;
                          if (!element.dataset[styleKey]) {
                              element.dataset[styleKey] = JSON.stringify(element.style[key]);
                          }
                          element.style[key] = styles[key];
                      }
                  });
              }
           
              function elementsRestorePropertiesStyles(elements) {
                  $(elements).each(function() {
                      let element = this;
                      for (let key in element.dataset) {
                          let value = undefined;
                          try { 
                              value = JSON.parse(element.dataset[key]); 
                          } catch(e) {
                          }
                          let propertyKey = (key.match(/^backup_property_(.*)/) || [])[1];
                          if (propertyKey) {
                              element[propertyKey] = value;
                              delete element.dataset[key];
                          }
                          let styleKey = (key.match(/^backup_style_(.*)/) || [])[1];
                          if (styleKey) {
                              element.style[styleKey] = value;
                              delete element.dataset[key];
                          }
                      }
                  });
              }
           
              function formSetProcessing(form, processing) {
                  let cursor = 'wait';
                  let opacity = '0.5';
                  let body = $('document.body');
                  let submit = form.find('[type="submit"]');
                  let controls = form.find('input, textarea, select, button');
                  if (processing) {
                      elementsSetPropertiesStyles(body, {}, {cursor: cursor});
                      elementsSetPropertiesStyles(form, {disabled: true}, {opacity: opacity});
                      elementsSetPropertiesStyles(submit, {disabled: true}, {cursor: cursor});
                      elementsSetPropertiesStyles(controls, {readonly: true}, {cursor: cursor});
                  } else {
                      elementsRestorePropertiesStyles(body);
                      elementsRestorePropertiesStyles(form);
                      elementsRestorePropertiesStyles(submit);
                      elementsRestorePropertiesStyles(controls);
                  }
              }
  
              requestToken(function(token) {
                  forms.find('input[name="' + RECAPTCHA_TOKEN_NAME + '"]').val(token);
              });
  
          });
  
      });
  
  }

})();