<!--
  Copyright (c) 2016-2023 Martin Donath <martin.donath@squidfunk.com>

  Permission is hereby granted, free of charge, to any person obtaining a copy
  of this software and associated documentation files (the "Software"), to
  deal in the Software without restriction, including without limitation the
  rights to use, copy, modify, merge, publish, distribute, sublicense, and/or
  sell copies of the Software, and to permit persons to whom the Software is
  furnished to do so, subject to the following conditions:

  The above copyright notice and this permission notice shall be included in
  all copies or substantial portions of the Software.

  THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
  IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
  FITNESS FOR A PARTICULAR PURPOSE AND NON-INFRINGEMENT. IN NO EVENT SHALL THE
  AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
  LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING
  FROM, OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS
  IN THE SOFTWARE.
-->

<!-- Determine analytics property -->
{% if config.extra.analytics %}
  {% set property = config.extra.analytics.property | d("", true) %}
{% endif %}

<!-- Integrate with Google Analytics 4 -->
<script id="__analytics">
  function __md_analytics() {
    window.dataLayer = window.dataLayer || []
    function gtag() { dataLayer.push(arguments) }

    /* Set up integration and send page view */
    gtag("js", new Date())
    gtag("config", "{{ property }}")

    /* Register event handlers after documented loaded */
    document.addEventListener("DOMContentLoaded", function() {

      /* Set up search tracking */
      if (document.forms.search) {
        var query = document.forms.search.query
        query.addEventListener("blur", function() {
          if (this.value)
            gtag("event", "search", { search_term: this.value })
        })
      }

      /* Set up feedback, i.e. "Was this page helpful?" */
      document$.subscribe(function() {
        var feedback = document.forms.feedback
        if (typeof feedback === "undefined")
          return

        /* Send feedback to Google Analytics */
        for (var button of feedback.querySelectorAll("[type=submit]")) {
          button.addEventListener("click", function(ev) {
            ev.preventDefault()

            /* Retrieve and send data */
            var page = document.location.pathname
            var data = this.getAttribute("data-md-value")
            gtag("event", "feedback", { page, data })

            /* Disable form and show note, if given */
            feedback.firstElementChild.disabled = true
            var note = feedback.querySelector(
              ".md-feedback__note [data-md-value='" + data + "']"
            )
            if (note)
              note.hidden = false
          })

          /* Show feedback */
          feedback.hidden = false
        }
      })

      /* Send page view on location change */
      location$.subscribe(function(url) {
        gtag("config", "{{ property }}", {
          page_path: url.pathname
        })
      })
    })

    /* Create script tag */
    var script = document.createElement("script")
    script.async = true
    script.src = "https://www.googletagmanager.com/gtag/js?id={{ property }}"

    /* Inject script tag */
    var container = document.getElementById("__analytics")
    container.insertAdjacentElement("afterEnd", script)
  }
</script>
