/* global anchors */

// add anchor links to headers
anchors.options.placement = 'left'
anchors.add('h3')

// Filter UI
var tocElements = document.getElementById('toc').getElementsByTagName('li')

document.getElementById('filter-input').addEventListener('keyup', function (e) {
  var i, element, children

  // enter key
  if (e.keyCode === 13) {
    // go to the first displayed item in the toc
    for (i = 0; i < tocElements.length; i++) {
      element = tocElements[i]
      if (!element.classList.contains('display-none')) {
        location.replace(element.firstChild.href)
        return e.preventDefault()
      }
    }
  }

  var match = function () {
    return true
  }

  var value = this.value.toLowerCase()

  if (!value.match(/^\s*$/)) {
    match = function (element) {
      return element.firstChild.innerHTML.toLowerCase().indexOf(value) !== -1
    }
  }

  for (i = 0; i < tocElements.length; i++) {
    element = tocElements[i]
    children = Array.from(element.getElementsByTagName('li'))
    if (match(element) || children.some(match)) {
      element.classList.remove('display-none')
    } else {
      element.classList.add('display-none')
    }
  }
})

var toggles = document.getElementsByClassName('toggle-step-sibling')
for (var i = 0; i < toggles.length; i++) {
  toggles[i].addEventListener('click', toggleStepSibling)
}

function toggleStepSibling() {
  var stepSibling = this.parentNode.parentNode.parentNode.getElementsByClassName('toggle-target')[0]
  var klass = 'display-none'
  if (stepSibling.classList.contains(klass)) {
    stepSibling.classList.remove(klass)
    stepSibling.innerHTML = '▾'
  } else {
    stepSibling.classList.add(klass)
    stepSibling.innerHTML = '▸'
  }
}

var items = document.getElementsByClassName('toggle-sibling')
for (var j = 0; j < items.length; j++) {
  items[j].addEventListener('click', toggleSibling)
}

function toggleSibling() {
  var stepSibling = this.parentNode.getElementsByClassName('toggle-target')[0]
  var icon = this.getElementsByClassName('icon')[0]
  var klass = 'display-none'
  if (stepSibling.classList.contains(klass)) {
    stepSibling.classList.remove(klass)
    icon.innerHTML = '▾'
  } else {
    stepSibling.classList.add(klass)
    icon.innerHTML = '▸'
  }
}

function showHashTarget(targetId) {
  var hashTarget = document.getElementById(targetId)
  // new target is hidden
  if (
    hashTarget &&
    hashTarget.offsetHeight === 0 &&
    hashTarget.parentNode.parentNode.classList.contains('display-none')
  ) {
    hashTarget.parentNode.parentNode.classList.remove('display-none')
  }
}

window.addEventListener('hashchange', function () {
  showHashTarget(location.hash.substring(1))
})

showHashTarget(location.hash.substring(1))

var toclinks = document.getElementsByClassName('pre-open')
for (var k = 0; k < toclinks.length; k++) {
  toclinks[k].addEventListener('mousedown', preOpen, false)
}

function preOpen() {
  showHashTarget(this.hash.substring(1))
}