<script>
  import { createEventDispatcher } from "svelte";
  import Fa from "svelte-fa";
  import { faPlus } from "@fortawesome/free-solid-svg-icons";
  import tzData from "tzdata";

  export let newTimeZone;

  const dispatch = createEventDispatcher();
  const timeZoneNames = Object.keys(tzData.zones);

  autocomplete(document.getElementById("datetime-0"), timeZoneNames);

  function autocomplete(inp, arr) {
    /*the autocomplete function takes two arguments,
  the text field element and an array of possible autocompleted values:*/
    var currentFocus;
    /*execute a function when someone writes in the text field:*/
    inp.addEventListener("input", function (e) {
      var a,
        b,
        i,
        val = this.value;
      /*close any already open lists of autocompleted values*/
      closeAllLists();
      if (!val) {
        return false;
      }
      currentFocus = -1;
      /*create a DIV element that will contain the items (values):*/
      a = document.createElement("DIV");
      a.setAttribute("id", this.id + "autocomplete-list");
      a.setAttribute("class", "autocomplete-items");
      /*append the DIV element as a child of the autocomplete container:*/
      this.parentNode.appendChild(a);
      /*for each item in the array...*/
      for (i = 0; i < arr.length; i++) {
        /*check if the item starts with the same letters as the text field value:*/
        if (arr[i].substr(0, val.length).toUpperCase() == val.toUpperCase()) {
          /*create a DIV element for each matching element:*/
          b = document.createElement("DIV");
          /*make the matching letters bold:*/
          b.innerHTML = "<strong>" + arr[i].substr(0, val.length) + "</strong>";
          b.innerHTML += arr[i].substr(val.length);
          /*insert a input field that will hold the current array item's value:*/
          b.innerHTML += "<input type='hidden' value='" + arr[i] + "'>";
          /*execute a function when someone clicks on the item value (DIV element):*/
          b.addEventListener("click", function (e) {
            /*insert the value for the autocomplete text field:*/
            inp.value = this.getElementsByTagName("input")[0].value;
            /*close the list of autocompleted values,
              (or any other open lists of autocompleted values:*/
            closeAllLists();
          });
          a.appendChild(b);
        }
      }
    });
    /*execute a function presses a key on the keyboard:*/
    inp.addEventListener("keydown", function (e) {
      var x = document.getElementById(this.id + "autocomplete-list");
      if (x) x = x.getElementsByTagName("div");
      if (e.keyCode == 40) {
        /*If the arrow DOWN key is pressed,
        increase the currentFocus variable:*/
        currentFocus++;
        /*and and make the current item more visible:*/
        addActive(x);
      } else if (e.keyCode == 38) {
        //up
        /*If the arrow UP key is pressed,
        decrease the currentFocus variable:*/
        currentFocus--;
        /*and and make the current item more visible:*/
        addActive(x);
      } else if (e.keyCode == 13) {
        /*If the ENTER key is pressed, prevent the form from being submitted,*/
        e.preventDefault();
        if (currentFocus > -1) {
          /*and simulate a click on the "active" item:*/
          if (x) x[currentFocus].click();
        }
      }
    });
    function addActive(x) {
      /*a function to classify an item as "active":*/
      if (!x) return false;
      /*start by removing the "active" class on all items:*/
      removeActive(x);
      if (currentFocus >= x.length) currentFocus = 0;
      if (currentFocus < 0) currentFocus = x.length - 1;
      /*add class "autocomplete-active":*/
      x[currentFocus].classList.add("autocomplete-active");
    }
    function removeActive(x) {
      /*a function to remove the "active" class from all autocomplete items:*/
      for (var i = 0; i < x.length; i++) {
        x[i].classList.remove("autocomplete-active");
      }
    }
    function closeAllLists(elmnt) {
      /*close all autocomplete lists in the document,
    except the one passed as an argument:*/
      var x = document.getElementsByClassName("autocomplete-items");
      for (var i = 0; i < x.length; i++) {
        if (elmnt != x[i] && elmnt != inp) {
          x[i].parentNode.removeChild(x[i]);
        }
      }
    }
    /*execute a function when someone clicks in the document:*/
    document.addEventListener("click", function (e) {
      closeAllLists(e.target);
    });
  }

</script>

<style>
</style>

<form on:submit|preventDefault={dispatch('submitTimeZone', newTimeZone)}>
  <div class="autocomplete">
    <input
      type="text"
      id="datetime-0"
      autocomplete="off"
      class="input input--lg"
      placeholder="Add timezones"
      bind:value={newTimeZone} />
  </div>
  <button
    type="submit"
    disabled=""
    class="btn--lg btn--secondary"
    aria-pressed="false"
    aria-label="Add a timezone">
    <Fa icon={faPlus} id="fa-plus-icon" size="1.5x" color="--bg-main" />
  </button>
</form>