function hasClass(element, cls) {
  return element.classList.contains(cls)
}

function addMatch(matchedElements, node) {
  if (node.nodeType !== Node.TEXT_NODE) {
    if (matchedElements.includes(node) == false){
      matchedElements.push(node)
    }
  }
}

function addNextElements(elements, matchedElements) {
  elements.map(function(index, item){
    if (matchedElements.includes(item) == false){
      matchSubElements(item, matchedElements, null)
    }
  })
}

function checkItemIsHeader($item) {
  return $item.is(':header') //h1, h2, h3, etc
}

function matchSubElements(element, matchedElements, header, isHeader) {
  var $subElements = $(element.children)

  if (isHeader) {
    matchedElements.push($subElements[0])
  } else {
    $subElements.map(function(index, item){
      var itemIsHeader = checkItemIsHeader($(item)) ? true : false
      matchSubElements(item, matchedElements, header, itemIsHeader)
    })
  }

  matchedElements.push(element)
}

function matchHeader(header, matchedElements) {
  matchSubElements(header, matchedElements, null, true)
}

function matchElement(header, matchedElements, regexp){
  var directSibElement = $(header).nextUntil(header.tagName)[0]
  var $elements = []

  if (directSibElement){
    $elements = $(directSibElement.children)
  }

  if (header.textContent.match(regexp)){
    matchHeader(header, matchedElements)

    if (directSibElement) {addMatch(matchedElements, directSibElement) }

    addNextElements($elements, matchedElements)
  } else {
    if (!!$elements.length) {
      for (var i = 0; i < $elements.length; i++){
        if ($elements[i].textContent.match(regexp)){
          matchSubElements($elements[i], matchedElements, header)
          addMatch(matchedElements, directSibElement)
          matchHeader(header, matchedElements)
        }
      }
    }
  }
}

document.addEventListener("DOMContentLoaded", function() {

  if (!document.querySelector('#ae-search-box')) { return; }
  document.querySelector("#ae-search-box").addEventListener("input", function(event) {

    var searchTerm = this.value
    var headers = Array.prototype.slice.call(document.querySelector('.js-anchorific-content').querySelectorAll("h2"))
    var regexp = new RegExp(searchTerm, "igm")
    var allElements = document.querySelector('.js-anchorific-content').querySelectorAll('*')
    var allElementsArray = Array.prototype.slice.call(allElements)
    var matchedElements = []
    var unmatchedElements = []

    for (var i = 0; i < headers.length; i++) {
      if (matchedElements.includes(headers[i]) == false){
        matchElement(headers[i], matchedElements, regexp)
      }
    }

    unmatchedElements = allElementsArray.filter(function(element, index) {
      return matchedElements.indexOf(element) === -1
    })

    unmatchedElements.map(function(item, index) {
      item.style.display = "none"
    })

    matchedElements.map(function(item, index) {
      item.style.display = ""
    })
  })
})