@use "sass:math";
@use "../../core/objects" as *;
@use "../../core/settings" as *;
@use "../../core/tools" as *;
@use "../../core/helpers" as *;
@forward "../../core/styles/icons";
@forward "../input";

////
/// Header component
///
/// This component has 4 colour variations:
///
/// 1. Blue background
/// 2. Blue background with white background for navigation
/// 3. White background with blue background for navigation
/// 4. White background
///
/// The behaviour with regards to navigation is as follows:
///
/// Menu toggle button is hidden until there is no space for navigation items
/// to display horizontally. Once there are overflowing navigation items to
/// display, the menu toggle button is shown, which toggles the overflow menu.
///
/// @group components/header
////

$nhsuk-header-item-colour: $nhsuk-brand-colour;
$nhsuk-header-item-button-colour: nhsuk-tint($nhsuk-brand-colour, 93%);
$nhsuk-header-item-hover-colour: nhsuk-shade($nhsuk-brand-colour, 20%);
$nhsuk-header-item-active-colour: nhsuk-shade($nhsuk-brand-colour, 35%);

$nhsuk-header-reverse-item-colour: $nhsuk-reverse-text-colour;
$nhsuk-header-reverse-item-hover-colour: $nhsuk-reverse-text-colour;
$nhsuk-header-reverse-item-active-colour: $nhsuk-reverse-text-colour;

/// Header link styling
///
/// @param {Colour} $link-colour [$nhsuk-header-item-colour] - Link colour
/// @param {Colour} $link-hover-colour [$nhsuk-header-item-hover-colour] - Link hover colour
/// @param {Colour} $link-active-colour [$nhsuk-header-item-active-colour] - Link active colour
///
/// @access private

@mixin _header-link-style(
  $link-colour: $nhsuk-header-item-colour,
  $link-hover-colour: $nhsuk-header-item-hover-colour,
  $link-active-colour: $nhsuk-header-item-active-colour
) {
  & {
    color: $link-colour;
  }

  @include nhsuk-link-style-visited($link-colour);
  @include nhsuk-link-style-hover($link-hover-colour);
  @include nhsuk-link-style-active($link-active-colour);
  @include nhsuk-link-style-focus;

  &:focus {
    color: $nhsuk-focus-text-colour;
    box-shadow: inset 0 ($nhsuk-focus-width * -1) $nhsuk-focus-text-colour;
  }

  @include nhsuk-print-colour($print-colour: inherit) {
    &::after {
      content: "";
    }
  }
}

@include nhsuk-exports("nhsuk/components/header") {
  $_header-item-padding: 12px;
  $_header-link-padding: 2px;
  $_header-item-active-size: $nhsuk-focus-width;

  .nhsuk-header {
    outline: 1px solid transparent;
    color: $nhsuk-reverse-text-colour;
    background-color: $nhsuk-brand-colour;

    // Add shadow to bottom of header when open
    &:has(.nhsuk-header__menu-list:not([hidden])) {
      border-bottom: nhsuk-spacing(1) solid $nhsuk-border-colour;
    }

    @include nhsuk-print-colour;
  }

  .nhsuk-header__container {
    padding: nhsuk-spacing(3) 0;

    .nhsuk-header--inline & {
      display: flex;
      flex-flow: row wrap;
      gap: nhsuk-spacing(3);

      @include nhsuk-media-query($from: tablet) {
        gap: nhsuk-spacing(3) nhsuk-spacing(4);
      }
    }

    @include nhsuk-media-query($from: tablet) {
      display: flex;
      flex-flow: row wrap;
      gap: nhsuk-spacing(3);
    }
  }

  // Service logo (and optional name)

  .nhsuk-header__logo {
    min-width: nhsuk-px-to-rem(100px);
    height: intrinsic;
  }

  .nhsuk-header__service,
  .nhsuk-header__service-logo {
    margin-right: auto;
    gap: nhsuk-spacing(2) nhsuk-spacing(3);
  }

  .nhsuk-header__service {
    display: flex;

    // Always reserve space for service name when inline
    .nhsuk-header--inline & {
      flex-basis: nhsuk-px-to-rem(220px);
      flex-grow: 999;
    }

    // Unless we know there's no service name
    .nhsuk-header--inline &:not(:has(.nhsuk-header__service-name)) {
      flex-basis: auto;
    }

    @include nhsuk-media-query($from: tablet) {
      flex-grow: 999;
    }
  }

  .nhsuk-header__service-name {
    display: inline-flex;

    flex-direction: column;
    flex-grow: 0;
    justify-content: center;

    max-width: 54ch;
    margin-right: auto;

    text-wrap: balance;
    @include nhsuk-font(19, $line-height: 1.1);

    &:only-child {
      display: block;
    }
  }

  .nhsuk-header__service-logo {
    display: inline-flex;

    position: relative;

    flex-grow: 0;

    margin-right: 0;

    line-height: 0;
    text-decoration: none;

    &:only-child {
      display: flex;
    }

    // Add SVG logo underline on hover
    //
    // It should be possible to add a box shadow directly to .nhsuk-header_logo
    // however Safari doesn’t render anything beyond the bounding box of the SVG.
    // By adding a pseudo element with the same dimensions, we style this instead.
    &:has(svg):not(:focus):hover::before {
      content: "";

      box-sizing: border-box;

      display: inline;

      position: absolute;
      top: 0.2rem;

      width: nhsuk-px-to-rem(100px);
      height: nhsuk-px-to-rem(40px);

      border-bottom: 0.1rem solid currentcolor;
    }
  }

  .nhsuk-header__service-logo,
  .nhsuk-header__service-name[href],
  .nhsuk-header__account-button,
  .nhsuk-header__account-link {
    @include _header-link-style(
      $link-colour: $nhsuk-header-reverse-item-colour,
      $link-hover-colour: $nhsuk-header-reverse-item-hover-colour,
      $link-active-colour: $nhsuk-header-reverse-item-active-colour
    );
  }

  // Account

  .nhsuk-header__account {
    flex-grow: 1;

    margin-top: nhsuk-spacing(3);

    overflow: hidden;

    border: 1px solid nhsuk-shade($nhsuk-brand-colour, 20%);
    border-radius: nhsuk-px-to-rem($nhsuk-border-radius);

    background-color: nhsuk-shade($nhsuk-brand-colour, 20%);

    .nhsuk-icon--user {
      flex-shrink: 0;
      width: nhsuk-px-to-rem(24px);
      height: nhsuk-px-to-rem(24px);
    }

    .nhsuk-header--inline & {
      align-self: start;

      // Expand header account by 1px to ensure the search
      // input does not appear to be taller when inline
      margin: -1px;
    }

    @include nhsuk-print-hide;

    @include nhsuk-media-query($from: tablet) {
      align-self: start;

      // Expand header account by 1px to ensure the search
      // input does not appear to be taller when inline
      margin: -1px;
    }
  }

  .nhsuk-header__account-list {
    display: flex;

    position: relative;

    flex-wrap: wrap;

    margin: 0;
    padding: 0;

    overflow: hidden;

    list-style: none;

    gap: 1px;
  }

  .nhsuk-header__account-item {
    display: flex;

    flex-grow: 1;

    margin: 0;
    padding: nhsuk-spacing(2) $_header-item-padding;

    outline: 1px solid $nhsuk-brand-colour;

    overflow-wrap: anywhere;

    gap: nhsuk-spacing(2);
    @include nhsuk-font(16);

    &:nth-last-child(2) {
      margin-right: auto;
    }

    &:last-child {
      flex-grow: 0;
    }
  }

  .nhsuk-header__account-button,
  .nhsuk-header__account-link {
    display: flex;
    margin: nhsuk-spacing(-2) ($_header-item-padding * -1);
    padding: nhsuk-spacing(2) $_header-item-padding;
    overflow-wrap: anywhere;
    gap: nhsuk-spacing(2);
  }

  .nhsuk-header__account-button {
    border: 0;
    background: none;
    text-decoration: underline;
    cursor: pointer;
    @include nhsuk-font(16);
  }

  // Search

  .nhsuk-header__search {
    display: block;
    position: relative;
    z-index: 10;
    flex-grow: 1;
    margin-top: nhsuk-spacing(3);

    .nhsuk-header--inline & {
      margin-top: 0;
    }

    @include nhsuk-print-hide;

    @include nhsuk-media-query($from: tablet) {
      margin: 0;
    }

    .nhsuk-icon--search {
      width: nhsuk-px-to-rem(28px);
      height: nhsuk-px-to-rem(28px);
    }
  }

  .nhsuk-header__search-form {
    display: flex;
    height: 100%;
    overflow: visible;

    .nhsuk-form-group {
      width: 100%;
      margin: 0;
    }

    .nhsuk-input-wrapper {
      display: flex;
      flex-direction: row;
    }
  }

  // Disable default search input appearance
  .nhsuk-header__search-form .nhsuk-input,
  // Deprecated, to be removed in v11.0
  .nhsuk-header__search-input {
    width: 100%;
    height: nhsuk-px-to-rem(40px);
    padding-right: $_header-item-padding - $nhsuk-border-width-form-element;
    padding-left: $_header-item-padding - $nhsuk-border-width-form-element;

    border-radius: nhsuk-px-to-rem($nhsuk-border-radius) 0 0 nhsuk-px-to-rem($nhsuk-border-radius);
    border-color: transparent;

    background-color: $nhsuk-input-background-colour;

    @include nhsuk-font-size(16);

    &:focus {
      z-index: 10;
      border-color: $nhsuk-focus-text-colour;
    }

    // Hide search input clear button (IE)
    &::-ms-clear {
      display: none;
    }

    // Hide search input icon and cancel button (WebKit, Blink)
    &::-webkit-search-decoration,
    &::-webkit-search-cancel-button {
      appearance: none;
    }

    @include nhsuk-media-query($until: tablet) {
      font-size: inherit;
    }
  }

  .nhsuk-header__search-form .nhsuk-button,
  // Deprecated, to be removed in v11.0
  .nhsuk-header__search-submit {
    flex-shrink: 0;

    width: nhsuk-px-to-rem(44px);
    height: nhsuk-px-to-rem(40px);

    // stylelint-disable-next-line declaration-no-important
    margin: 0 !important;

    // Reduce padding to better fit icon
    padding: 0 nhsuk-spacing(2) - 1px;

    border: 1px solid transparent;
    border-radius: 0 nhsuk-px-to-rem($nhsuk-border-radius) nhsuk-px-to-rem($nhsuk-border-radius) 0;

    color: $nhsuk-brand-colour;
    background-color: $nhsuk-header-item-button-colour;
    box-shadow: none;

    line-height: 1;

    cursor: pointer;

    &:hover,
    &:active {
      border-color: nhsuk-colour("white");
      color: nhsuk-colour("white");
      background-color: $nhsuk-header-item-hover-colour;
    }

    &:active {
      background-color: $nhsuk-header-item-active-colour;
    }

    // Prevent height change when pressed
    &:active,
    &:active:focus {
      top: 0;
    }

    &:focus {
      outline: none;
    }

    &:focus:not(:active),
    &:focus:not(:active):hover {
      border-color: transparent;

      @include nhsuk-focused-button;
    }
  }

  // Navigation

  .nhsuk-header__navigation {
    border: 0 solid nhsuk-colour("white");
    color: nhsuk-colour("white");
    background-color: $nhsuk-brand-colour;

    @media screen and (forced-colors: active), (-ms-high-contrast: active) {
      border: 0;
    }

    @include nhsuk-print-hide;
  }

  .nhsuk-header__navigation-list {
    display: flex;

    position: relative;

    flex-wrap: wrap;

    width: calc(100% + $nhsuk-gutter-half);
    margin: 0 math.div($nhsuk-gutter-half, 2) * -1;
    padding: 0;

    list-style: none;

    @include nhsuk-media-query($from: tablet) {
      width: calc(100% + $nhsuk-gutter);
      margin: 0 math.div($nhsuk-gutter, 2) * -1;
    }

    .nhsuk-header__navigation--justified & {
      @include nhsuk-media-query($from: desktop) {
        justify-content: space-between;
      }
    }

    .nhsuk-frontend-supported & {
      flex-wrap: nowrap;
    }
  }

  .nhsuk-header__navigation-item {
    margin-bottom: 0;
    padding: 0 math.div($nhsuk-gutter-half, 2);

    @include nhsuk-media-query($from: tablet) {
      padding: 0 $nhsuk-gutter-half;
    }
  }

  // This is a <strong> element used as a fallback mechanism for visually
  // indicating current page in scenarios where CSS isn’t available.
  // We don’t actually want it to be bold normally, so inherit parent font-weight.
  .nhsuk-header__navigation-item-current-fallback {
    font-weight: inherit;
  }

  .nhsuk-header__navigation-link,
  .nhsuk-header__navigation-text {
    display: block;

    position: relative;

    margin: 0;
    padding: nhsuk-spacing(3) $_header-link-padding;

    border: 0;
    border-radius: 0;

    color: $nhsuk-header-reverse-item-colour;

    background: transparent;

    text-decoration: underline;
    white-space: nowrap;

    cursor: pointer;
    @include nhsuk-font(16);

    // Visual indicator for navigation item uses a border on bottom edge
    &::before {
      content: "";

      display: block;

      position: absolute;
      right: 0;
      bottom: 0;
      left: 0;

      border: 0 solid currentcolor;
    }

    // Visual indicator for current navigation
    &[aria-current="page"]::before,
    &[aria-current="true"]::before {
      border-bottom-width: $_header-item-active-size;
    }

    @include nhsuk-media-query($until: tablet) {
      font-size: inherit;
    }
  }

  .nhsuk-header__navigation-link {
    @include _header-link-style(
      $link-colour: $nhsuk-header-reverse-item-colour,
      $link-hover-colour: $nhsuk-header-reverse-item-hover-colour,
      $link-active-colour: $nhsuk-header-reverse-item-active-colour
    );
  }

  // Menu (shown when screen can’t fit all navigation items)

  .nhsuk-header__menu {
    align-self: center;
    padding: 0 math.div($nhsuk-gutter-half, 2);

    &[hidden] {
      display: none;
    }

    @include nhsuk-media-query($from: tablet) {
      padding: 0 $nhsuk-gutter-half;
    }
  }

  .nhsuk-header__menu-toggle {
    $_chevron-font-size: 19;

    display: flex;
    align-items: center;
    padding-right: nhsuk-em($_chevron-font-size, 16);
    text-align: center;

    &,
    &:hover {
      text-decoration: none;
    }

    &[hidden] {
      display: none;
    }

    &::after {
      content: "";

      position: absolute;
      top: 2px;
      right: $_header-link-padding;
      bottom: 0;

      margin: auto;

      @include nhsuk-shape-chevron(down, currentcolor, $font-size: $_chevron-font-size);
    }

    &[aria-expanded="true"]::after {
      @include nhsuk-shape-chevron(up, currentcolor, $font-size: $_chevron-font-size);
    }
  }

  .nhsuk-header__menu-list {
    position: absolute;
    top: 100%;
    right: 0;
    left: 0;

    margin: 0 math.div($nhsuk-gutter-half, 2);
    padding: 0;

    list-style: none;

    @include nhsuk-print-hide;

    @include nhsuk-media-query($from: tablet) {
      margin: 0 $nhsuk-gutter-half;
    }

    &[hidden] {
      display: none;
    }

    .nhsuk-header__navigation-link,
    .nhsuk-header__navigation-text {
      color: $nhsuk-header-item-colour;

      // Visual indicator for navigation item uses a border on left edge
      &[aria-current="page"]::before,
      &[aria-current="true"]::before {
        top: 0;
        right: auto;
        bottom: 0;
        left: -$nhsuk-gutter-half;

        width: 0;

        border-left-width: $_header-item-active-size;

        // stylelint-disable-next-line max-nesting-depth
        @include nhsuk-media-query($from: desktop) {
          left: -$nhsuk-gutter;
        }
      }
    }

    .nhsuk-header__navigation-link {
      @include _header-link-style;
    }

    .nhsuk-header__navigation-item {
      padding: 0;
      border-bottom: 1px solid nhsuk-colour("grey-5");

      &:last-child {
        border-color: transparent;
      }
    }
  }

  // White header navigation variant

  .nhsuk-header__navigation--white {
    color: $nhsuk-brand-colour;
    background-color: nhsuk-colour("white");

    .nhsuk-header__navigation-link,
    .nhsuk-header__navigation-text {
      color: $nhsuk-header-item-colour;
    }

    .nhsuk-header__navigation-link {
      @include _header-link-style;
    }

    .nhsuk-header__menu-list {
      border-top: 1px solid nhsuk-colour("grey-5");
    }
  }

  // When header and navigation have the same background colour:
  // - Until tablet breakpoint, add negative top margin
  // - From tablet breakpoint, add a top border
  .nhsuk-header__navigation-container {
    box-shadow: 0 -1px 0 0 $nhsuk-reverse-border-colour;

    .nhsuk-header--white .nhsuk-header__navigation--white & {
      box-shadow: 0 -1px 0 0 $nhsuk-border-colour;
    }

    .nhsuk-header--white :not(.nhsuk-header__navigation--white) &,
    .nhsuk-header__navigation--white & {
      margin-top: 0;
      box-shadow: none;
    }

    &,
    .nhsuk-header--white .nhsuk-header__navigation--white & {
      @include nhsuk-media-query($until: tablet) {
        margin-top: math.div($nhsuk-gutter, 2) * -1;
        box-shadow: none;
      }
    }
  }

  // White header variant

  .nhsuk-header--white {
    color: $nhsuk-brand-colour;
    background-color: nhsuk-colour("white");

    .nhsuk-header__service-logo,
    .nhsuk-header__service-name[href],
    .nhsuk-header__account-button,
    .nhsuk-header__account-link {
      @include _header-link-style;
    }

    .nhsuk-header__service-logo:not(:focus):not(:hover) .nhsuk-header__organisation-name {
      color: $nhsuk-text-colour;
    }

    .nhsuk-header__account {
      border-color: $nhsuk-border-colour;
      background-color: nhsuk-colour("grey-5");
    }

    .nhsuk-header__account-item {
      outline-color: $nhsuk-border-colour;
    }

    .nhsuk-header__search-form .nhsuk-input:not(:focus),
    // Deprecated, to be removed in v11.0
    .nhsuk-header__search-input:not(:focus) {
      margin-right: -1px;
      padding-right: $_header-item-padding;
      padding-left: $_header-item-padding - 1px;
      border-width: 1px;
      border-color: nhsuk-colour("grey-3");
    }

    .nhsuk-header__search-form .nhsuk-button,
    // Deprecated, to be removed in v11.0
    .nhsuk-header__search-submit {
      color: $nhsuk-reverse-text-colour;
      background-color: $nhsuk-header-item-colour;

      &:hover,
      &:active {
        border-color: $nhsuk-header-item-hover-colour;
        background-color: $nhsuk-header-item-hover-colour;
      }

      &:active {
        background-color: $nhsuk-header-item-active-colour;
      }
    }
  }

  // Organisation header variant

  .nhsuk-header--organisation {
    .nhsuk-header__logo {
      width: nhsuk-px-to-rem(60px);
      min-width: auto;
      height: nhsuk-px-to-rem(24px);
      margin-bottom: nhsuk-px-to-rem(6px);

      @include nhsuk-media-query($from: tablet) {
        width: nhsuk-px-to-rem(80px);
        height: nhsuk-px-to-rem(32px);
      }
    }

    .nhsuk-header__service-logo {
      display: block;

      // Adjust SVG logo underline position
      &:has(svg):not(:focus):hover::before {
        width: nhsuk-px-to-rem(60px);
        height: nhsuk-px-to-rem(24px);

        @include nhsuk-media-query($from: tablet) {
          width: nhsuk-px-to-rem(80px);
          height: nhsuk-px-to-rem(32px);
        }
      }
    }
  }

  .nhsuk-header__organisation-name {
    display: block;
    @include nhsuk-font(22, $weight: bold, $line-height: 1.1);
  }

  .nhsuk-header__organisation-name-split {
    display: block;
  }

  .nhsuk-header__organisation-name-descriptor {
    display: block;
    @include nhsuk-font(14, $weight: bold);
  }

  .nhsuk-header__organisation-logo {
    width: nhsuk-px-to-rem(280px);
    height: auto;
    border: 0;

    @include nhsuk-media-query($until: 450px) {
      max-width: nhsuk-px-to-rem(150px);
    }

    &[src$=".svg"] {
      width: nhsuk-px-to-rem(220px);
      max-width: nhsuk-px-to-rem(220px);
    }
  }

  // Remove service name underline
  .nhsuk-header .nhsuk-header__service-name[href] {
    text-decoration: none;
  }

  // Add service logo underline on hover
  .nhsuk-header .nhsuk-header__service-logo:not(:focus):hover,
  .nhsuk-header .nhsuk-header__service-logo:not(:focus):hover .nhsuk-header__service-name,
  .nhsuk-header .nhsuk-header__service-name[href]:not(:focus):hover {
    text-decoration: underline;
  }

  // Add service logo box shadow on focus
  .nhsuk-header .nhsuk-header__service-logo:focus {
    @include nhsuk-focused-box;
  }
}