(function () {
  function getQueryVariable (variable) {
    const query = window.location.search.substring(1)
    const vars = query.split('&')

    for (let i = 0; i < vars.length; i++) {
      const pair = vars[i].split('=')

      if (pair[0] === variable) {
        return decodeURIComponent(pair[1].replace(/\+/g, '%20')).trim()
      }
    }
  }

  function getPreview (query, content, previewLength) {
    previewLength = previewLength || (content.length * 2)

    const parts = query.split(' ')
    let match = content.toLowerCase().indexOf(query.toLowerCase())
    let matchLength = query.length
    let preview

    // Find a relevant location in content
    for (let i = 0; i < parts.length; i++) {
      if (match >= 0) {
        break
      }

      match = content.toLowerCase().indexOf(parts[i].toLowerCase())
      matchLength = parts[i].length
    }

    // Create preview
    if (match >= 0) {
      const start = match - (previewLength / 2)
      const end = start > 0 ? match + matchLength + (previewLength / 2) : previewLength

      preview = content.substring(start, end).trim()

      if (start > 0) {
        preview = '...' + preview
      }

      if (end < content.length) {
        preview = preview + '...'
      }

      // Highlight query parts
      preview = preview.replace(new RegExp('(' + parts.join('|') + ')', 'gi'), '<strong>$1</strong>')
    } else {
      // Use start of content if no match found
      preview = content.substring(0, previewLength).trim() + (content.length > previewLength ? '...' : '')
    }

    return preview
  }

  function displaySearchResults (results, query) {
    const searchResultsEl = document.getElementById('search-results')
    const searchProcessEl = document.getElementById('search-process')

    if (results.length) {
      let resultsHTML = ''
      results.forEach(function (result) {
        const item = window.data[result.ref]
        if (item.title) {
          const contentPreview = getPreview(query, item.content, 170)
          const titlePreview = getPreview(query, item.title)
          resultsHTML += "<li><h4><a href='" + item.url.trim() + "'>" + titlePreview + '</a></h4><p><small>' + contentPreview + '</small></p></li>'
        }
      })

      searchResultsEl.innerHTML = resultsHTML
      searchProcessEl.innerText = 'Showing'
    } else {
      searchResultsEl.style.display = 'none'
      searchProcessEl.innerText = 'No'
    }
  }

  window.index = lunr(function () {
    this.field('id')
    this.field('title', { boost: 10 })
    this.field('url')
    this.field('content')
  })

  const query = decodeURIComponent((getQueryVariable('q') || '').replace(/\+/g, '%20'))
  const searchQueryContainerEl = document.getElementById('search-query-container')
  const searchQueryEl = document.getElementById('search-query')

  searchQueryEl.innerText = query
  if (query !== '') {
    searchQueryContainerEl.style.display = 'inline'
  }

  for (const key in window.data) {
    window.index.add(window.data[key])
  }

  displaySearchResults(window.index.search(query), query) // Hand the results off to be displayed
})()