@import "../../settings/all";
@import "../../tools/all";
@import "../../helpers/all";

@import "../error-message/error-message";
@import "../fieldset/fieldset";
@import "../hint/hint";
@import "../label/label";

@include govuk-exports("govuk/component/checkboxes") {

  $govuk-touch-target-size: 44px;
  $govuk-checkboxes-size: 40px;
  $govuk-small-checkboxes-size: 24px;
  $govuk-checkboxes-label-padding-left-right: govuk-spacing(3);

  .govuk-checkboxes__item {
    @include govuk-font($size: 19);

    display: block;
    position: relative;

    min-height: $govuk-checkboxes-size;

    margin-bottom: govuk-spacing(2);
    padding-left: $govuk-checkboxes-size;

    clear: left;
  }

  .govuk-checkboxes__item:last-child,
  .govuk-checkboxes__item:last-of-type {
    margin-bottom: 0;
  }

  .govuk-checkboxes__input {
    $input-offset: ($govuk-touch-target-size - $govuk-checkboxes-size) / 2;

    cursor: pointer;

    // IE8 doesn’t support pseudo-elements, so we don’t want to hide native
    // elements there.
    @include govuk-not-ie8 {
      position: absolute;

      z-index: 1;
      top: $input-offset * -1;
      left: $input-offset * -1;

      width: $govuk-touch-target-size;
      height: $govuk-touch-target-size;
      margin: 0;

      opacity: 0;
    }

    @include govuk-if-ie8 {
      margin-top: 10px;
      margin-right: $govuk-checkboxes-size / -2;
      margin-left: $govuk-checkboxes-size / -2;
      float: left;

      // add focus outline to input
      &:focus {
        outline: $govuk-focus-width solid $govuk-focus-colour;
      }
    }
  }

  .govuk-checkboxes__label {
    display: inline-block;
    margin-bottom: 0;
    padding: 8px $govuk-checkboxes-label-padding-left-right govuk-spacing(1);
    cursor: pointer;
    // remove 300ms pause on mobile
    -ms-touch-action: manipulation;
        touch-action: manipulation;
  }

  // [ ] Check box
  .govuk-checkboxes__label::before {
    content: "";
    box-sizing: border-box;
    position: absolute;
    top: 0;
    left: 0;
    width: $govuk-checkboxes-size;
    height: $govuk-checkboxes-size;
    border: $govuk-border-width-form-element solid currentColor;
    background: transparent;
  }

  // ✔ Check mark
  //
  // The check mark is a box with a border on the left and bottom side (└──),
  // rotated 45 degrees
  .govuk-checkboxes__label::after {
    content: "";

    position: absolute;
    top: 11px;
    left: 9px;
    width: 18px;
    height: 7px;

    -webkit-transform: rotate(-45deg);

        -ms-transform: rotate(-45deg);

            transform: rotate(-45deg);
    border: solid;
    border-width: 0 0 $govuk-border-width $govuk-border-width;
    // Fix bug in IE11 caused by transform rotate (-45deg).
    // See: alphagov/govuk_elements/issues/518
    border-top-color: transparent;

    opacity: 0;

    background: transparent;
  }

  .govuk-checkboxes__hint {
    display: block;
    padding-right: $govuk-checkboxes-label-padding-left-right;
    padding-left: $govuk-checkboxes-label-padding-left-right;
  }

  // Focused state
  .govuk-checkboxes__input:focus + .govuk-checkboxes__label::before {
    // Since box-shadows are removed when users customise their colours, we set
    // a transparent outline that is shown instead.
    // https://accessibility.blog.gov.uk/2017/03/27/how-users-change-colours-on-websites/
    outline: $govuk-focus-width solid transparent;
    outline-offset: $govuk-focus-width;
    box-shadow: 0 0 0 $govuk-focus-width $govuk-focus-colour;
  }

  // Selected state
  .govuk-checkboxes__input:checked + .govuk-checkboxes__label::after {
    opacity: 1;
  }

  // Disabled state
  .govuk-checkboxes__input:disabled,
  .govuk-checkboxes__input:disabled + .govuk-checkboxes__label {
    cursor: default;
  }

  .govuk-checkboxes__input:disabled + .govuk-checkboxes__label {
    opacity: .5;
  }

  // =========================================================
  // Conditional reveals
  // =========================================================

  $conditional-border-width: $govuk-border-width-mobile;
  // Calculate the amount of padding needed to keep the border centered against the checkbox.
  $conditional-border-padding: ($govuk-checkboxes-size / 2) - ($conditional-border-width / 2);
  // Move the border centered with the checkbox
  $conditional-margin-left: $conditional-border-padding;
  // Move the contents of the conditional inline with the label
  $conditional-padding-left: $conditional-border-padding + $govuk-checkboxes-label-padding-left-right;

  .govuk-checkboxes__conditional {
    @include govuk-responsive-margin(4, "bottom");
    margin-left: $conditional-margin-left;
    padding-left: $conditional-padding-left;
    border-left: $conditional-border-width solid $govuk-border-colour;

    .js-enabled &--hidden {
      display: none;
    }

    & > :last-child {
      margin-bottom: 0;
    }
  }

  // =========================================================
  // Small checkboxes
  // =========================================================

  .govuk-checkboxes--small {

    $input-offset: ($govuk-touch-target-size - $govuk-small-checkboxes-size) / 2;
    $label-offset: $govuk-touch-target-size - $input-offset;

    .govuk-checkboxes__item {
      @include govuk-clearfix;
      min-height: 0;
      margin-bottom: 0;
      padding-left: $label-offset;
      float: left;
    }

    // Shift the touch target into the left margin so that the visible edge of
    // the control is aligned
    //
    //   ┆What colours do you like?
    //  ┌┆───┐
    //  │┆[] │ Purple
    //  └┆▲──┘
    //  ▲┆└─ Check box pseudo element, aligned with margin
    //  └─── Touch target (invisible input), shifted into the margin
    .govuk-checkboxes__input {
      @include govuk-not-ie8 {
        left: $input-offset * -1;
      }

      @include govuk-if-ie8 {
        margin-left: $govuk-small-checkboxes-size * -1;
      }
    }

    // Adjust the size and position of the label.
    //
    // Unlike larger checkboxes, we also have to float the label in order to
    // 'shrink' it, preventing the hover state from kicking in across the full
    // width of the parent element.
    .govuk-checkboxes__label {
      margin-top: -2px;
      padding: 13px govuk-spacing(3) 13px 1px;
      float: left;

      @include govuk-media-query($from: tablet) {
        padding: 11px govuk-spacing(3) 10px 1px;
      }
    }

    // [ ] Check box
    //
    // Reduce the size of the check box [1], vertically center it within the
    // touch target [2]
    .govuk-checkboxes__label::before {
      top: $input-offset - $govuk-border-width-form-element; // 2
      width: $govuk-small-checkboxes-size; // 1
      height: $govuk-small-checkboxes-size; // 1
    }

    // ✔ Check mark
    //
    // Reduce the size of the check mark and re-align within the checkbox
    .govuk-checkboxes__label::after {
      top: 15px;
      left: 6px;
      width: 9px;
      height: 3.5px;
      border-width: 0 0 3px 3px;
    }

    // Fix position of hint with small checkboxes
    //
    // Do not use hints with small checkboxes – because they're within the input
    // wrapper they trigger the hover state, but clicking them doesn't actually
    // activate the control.
    //
    // (If you do use them, they won't look completely broken... but seriously,
    // don't use them)
    .govuk-checkboxes__hint {
      padding: 0;
      clear: both;
    }

    // Align conditional reveals with small checkboxes
    .govuk-checkboxes__conditional {
      $margin-left: ($govuk-small-checkboxes-size / 2) - ($conditional-border-width / 2);
      margin-left: $margin-left;
      padding-left: $label-offset - ($margin-left + $conditional-border-width);
      clear: both;
    }

    // Hover state for small checkboxes.
    //
    // We use a hover state for small checkboxes because the touch target size
    // is so much larger than their visible size, and so we need to provide
    // feedback to the user as to which checkbox they will select when their
    // cursor is outside of the visible area.
    .govuk-checkboxes__item:hover .govuk-checkboxes__input:not(:disabled) + .govuk-checkboxes__label::before {
      box-shadow: 0 0 0 $govuk-hover-width $govuk-hover-colour;
    }

    // Because we've overridden the border-shadow provided by the focus state,
    // we need to redefine that too.
    //
    // We use two box shadows, one that restores the original focus state [1]
    // and another that then applies the hover state [2].
    .govuk-checkboxes__item:hover .govuk-checkboxes__input:focus + .govuk-checkboxes__label::before {
      // sass-lint:disable indentation
      box-shadow: 0 0 0 $govuk-focus-width $govuk-focus-colour, // 1
                  0 0 0 $govuk-hover-width $govuk-hover-colour; // 2
    }

    // For devices that explicitly don't support hover, don't provide a hover
    // state (e.g. on touch devices like iOS).
    //
    // We can't use `@media (hover: hover)` because we wouldn't get the hover
    // state in browsers that don't support `@media (hover)` (like Internet
    // Explorer) – so we have to 'undo' the hover state instead.
    @media (hover: none), (pointer: coarse) {
      .govuk-checkboxes__item:hover .govuk-checkboxes__input:not(:disabled) + .govuk-checkboxes__label::before {
        box-shadow: initial;
      }

      .govuk-checkboxes__item:hover .govuk-checkboxes__input:focus + .govuk-checkboxes__label::before {
        box-shadow: 0 0 0 $govuk-focus-width $govuk-focus-colour;
      }
    }
  }
}