window.addEventListener('DOMContentLoaded', function() {
  let tabsRoot = document.querySelector('#tabs');

  let currentTab = tabsRoot.querySelector(location.hash || 'a');
  if (!currentTab) currentTab = tabsRoot.querySelector('a');

  let sections = document.querySelectorAll('#tabSections section');
  for (let i = 0; i < sections.length; i++) {
    sections[i].style.display = 'none';
  }
  selectTab(currentTab, false);
});

function selectTab(newSelection, updateUrlFragment) {
  let tabsRoot = document.querySelector('#tabs');
  let sectionRoot = document.querySelector('#tabSections');

  let previousSelection = tabsRoot.querySelector('[selected]');

  if (previousSelection) {
    previousSelection.removeAttribute('selected');
    let section = sectionRoot.querySelector(
      '#' + previousSelection.id + '-panel'
    );
    section.style.display = 'none';
  }

  newSelection.setAttribute('selected', '');
  let section = sectionRoot.querySelector('#' + newSelection.id + '-panel');
  section.style.display = 'block';

  let charts = section.querySelectorAll('.ct-chart');
  for (let i = 0; i < charts.length; i++) {
    if (charts[i].__chartist__) {
      charts[i].__chartist__.update();
    }
  }

  if (updateUrlFragment && history.replaceState) {
    history.replaceState(null, null, '#' + newSelection.id);
  }

  return false;
}