From b9b1d3fd8dc20684de0e0dbd3e2f7bfd82db900f Mon Sep 17 00:00:00 2001
From: Alexandre Vryghem <alexandre@atmire.com>
Date: Fri, 5 Jul 2024 13:30:01 +0200
Subject: [PATCH] 116404: Added navigation with arrow keys in navbar &
 collapsed the expandable menu when hovering outside of it

(cherry picked from commit 05232cdf2b068223c8147ed61afe364fc92986d1)
---
 .../expandable-navbar-section.component.html  |  59 +++++-----
 .../expandable-navbar-section.component.ts    | 104 ++++++++++++++++--
 .../shared/utils/hover-outside.directive.ts   |  51 +++++++++
 .../expandable-navbar-section.component.ts    |  14 ++-
 4 files changed, 185 insertions(+), 43 deletions(-)
 create mode 100644 src/app/shared/utils/hover-outside.directive.ts

diff --git a/src/app/navbar/expandable-navbar-section/expandable-navbar-section.component.html b/src/app/navbar/expandable-navbar-section/expandable-navbar-section.component.html
index f37fc222d5..f8facaa82a 100644
--- a/src/app/navbar/expandable-navbar-section/expandable-navbar-section.component.html
+++ b/src/app/navbar/expandable-navbar-section/expandable-navbar-section.component.html
@@ -1,36 +1,37 @@
-<div class="ds-menu-item-wrapper text-md-center"
-    [id]="'expandable-navbar-section-' + section.id"
-    (mouseenter)="onMouseEnter($event)"
-    (mouseleave)="onMouseLeave($event)"
-    data-test="navbar-section-wrapper">
-    <a href="javascript:void(0);" routerLinkActive="active"
-       role="menuitem"
-       (keyup.enter)="toggleSection($event)"
-       (keyup.space)="toggleSection($event)"
-       (click)="toggleSection($event)"
-       (keydown.space)="$event.preventDefault()"
-       (keydown.tab)="deactivateSection($event, false)"
-       aria-haspopup="menu"
-       data-test="navbar-section-toggler"
-       [attr.aria-expanded]="(active$ | async).valueOf()"
-       [attr.aria-controls]="expandableNavbarSectionId(section.id)"
-       class="d-flex flex-row flex-nowrap align-items-center gapx-1 ds-menu-toggler-wrapper"
-       [class.disabled]="section.model?.disabled">
+<div #expandableNavbarSectionContainer class="ds-menu-item-wrapper text-md-center"
+     [id]="'expandable-navbar-section-' + section.id"
+     (mouseenter)="onMouseEnter($event)"
+     (mouseleave)="onMouseLeave($event)"
+     data-test="navbar-section-wrapper">
+  <a href="javascript:void(0);" routerLinkActive="active"
+     role="menuitem"
+     (keyup.enter)="toggleSection($event)"
+     (keyup.space)="toggleSection($event)"
+     (click)="toggleSection($event)"
+     (keydown)="keyDown($event)"
+     aria-haspopup="menu"
+     data-test="navbar-section-toggler"
+     [attr.aria-expanded]="(active$ | async).valueOf()"
+     [attr.aria-controls]="expandableNavbarSectionId()"
+     class="d-flex flex-row flex-nowrap align-items-center gapx-1 ds-menu-toggler-wrapper"
+     [class.disabled]="section.model?.disabled">
       <span class="flex-fill">
         <ng-container
           *ngComponentOutlet="(sectionMap$ | async).get(section.id).component; injector: (sectionMap$ | async).get(section.id).injector;"></ng-container>
       </span>
-      <i class="fas fa-caret-down fa-xs toggle-menu-icon" aria-hidden="true"></i>
-    </a>
-    <div *ngIf="(active$ | async).valueOf() === true" (click)="deactivateSection($event)"
-        [id]="expandableNavbarSectionId(section.id)"
-        role="menu"
-        class="dropdown-menu show nav-dropdown-menu m-0 shadow-none border-top-0 px-3 px-md-0 pt-0 pt-md-1">
-      <div @slide role="presentation">
-        <div *ngFor="let subSection of (subSections$ | async)" class="text-nowrap" role="presentation">
-              <ng-container
-                      *ngComponentOutlet="(sectionMap$ | async).get(subSection.id).component; injector: (sectionMap$ | async).get(subSection.id).injector;"></ng-container>
-          </div>
+    <i class="fas fa-caret-down fa-xs toggle-menu-icon" aria-hidden="true"></i>
+  </a>
+  <div *ngIf="(active$ | async).valueOf() === true" (click)="deactivateSection($event)"
+       [id]="expandableNavbarSectionId()"
+       [dsHoverOutsideOfElement]="expandableNavbarSection"
+       (dsHoverOutside)="deactivateSection($event, false)"
+       role="menu"
+       class="dropdown-menu show nav-dropdown-menu m-0 shadow-none border-top-0 px-3 px-md-0 pt-0 pt-md-1">
+    <div @slide role="presentation">
+      <div *ngFor="let subSection of (subSections$ | async)" class="text-nowrap" role="presentation">
+        <ng-container
+          *ngComponentOutlet="(sectionMap$ | async).get(subSection.id).component; injector: (sectionMap$ | async).get(subSection.id).injector;"></ng-container>
       </div>
     </div>
+  </div>
 </div>
diff --git a/src/app/navbar/expandable-navbar-section/expandable-navbar-section.component.ts b/src/app/navbar/expandable-navbar-section/expandable-navbar-section.component.ts
index 7f4405e2b6..7fb86ce323 100644
--- a/src/app/navbar/expandable-navbar-section/expandable-navbar-section.component.ts
+++ b/src/app/navbar/expandable-navbar-section/expandable-navbar-section.component.ts
@@ -5,11 +5,14 @@ import {
   NgIf,
 } from '@angular/common';
 import {
+  AfterViewChecked,
   Component,
+  ElementRef,
   HostListener,
   Inject,
   Injector,
   OnInit,
+  ViewChild,
 } from '@angular/core';
 import { RouterLinkActive } from '@angular/router';
 import { Observable } from 'rxjs';
@@ -19,6 +22,8 @@ import { slide } from '../../shared/animations/slide';
 import { HostWindowService } from '../../shared/host-window.service';
 import { MenuService } from '../../shared/menu/menu.service';
 import { MenuID } from '../../shared/menu/menu-id.model';
+import { MenuSection } from '../../shared/menu/menu-section.model';
+import { HoverOutsideDirective } from '../../shared/utils/hover-outside.directive';
 import { VarDirective } from '../../shared/utils/var.directive';
 import { NavbarSectionComponent } from '../navbar-section/navbar-section.component';
 
@@ -31,9 +36,20 @@ import { NavbarSectionComponent } from '../navbar-section/navbar-section.compone
   styleUrls: ['./expandable-navbar-section.component.scss'],
   animations: [slide],
   standalone: true,
-  imports: [VarDirective, RouterLinkActive, NgComponentOutlet, NgIf, NgFor, AsyncPipe],
+  imports: [
+    AsyncPipe,
+    HoverOutsideDirective,
+    NgComponentOutlet,
+    NgFor,
+    NgIf,
+    RouterLinkActive,
+    VarDirective,
+  ],
 })
-export class ExpandableNavbarSectionComponent extends NavbarSectionComponent implements OnInit {
+export class ExpandableNavbarSectionComponent extends NavbarSectionComponent implements AfterViewChecked, OnInit {
+
+  @ViewChild('expandableNavbarSectionContainer') expandableNavbarSection: ElementRef;
+
   /**
    * This section resides in the Public Navbar
    */
@@ -54,6 +70,13 @@ export class ExpandableNavbarSectionComponent extends NavbarSectionComponent imp
    */
   isMobile$: Observable<boolean>;
 
+  /**
+   * Boolean used to add the event listeners to the items in the expandable menu when expanded. This is done for
+   * performance reasons, there is currently an *ngIf on the menu to prevent the {@link HoverOutsideDirective} to tank
+   * performance when not expanded.
+   */
+  addArrowEventListeners = false;
+
   @HostListener('window:resize', ['$event'])
   onResize() {
     this.isMobile$.pipe(
@@ -68,17 +91,33 @@ export class ExpandableNavbarSectionComponent extends NavbarSectionComponent imp
     });
   }
 
-  constructor(@Inject('sectionDataProvider') menuSection,
-              protected menuService: MenuService,
-              protected injector: Injector,
-              private windowService: HostWindowService,
+  constructor(
+    @Inject('sectionDataProvider') public section: MenuSection,
+    protected menuService: MenuService,
+    protected injector: Injector,
+    protected windowService: HostWindowService,
   ) {
-    super(menuSection, menuService, injector);
+    super(section, menuService, injector);
     this.isMobile$ = this.windowService.isMobile();
   }
 
   ngOnInit() {
     super.ngOnInit();
+    this.subs.push(this.active$.subscribe((active: boolean) => {
+      if (active === true) {
+        this.addArrowEventListeners = true;
+      }
+    }));
+  }
+
+  ngAfterViewChecked(): void {
+    if (this.addArrowEventListeners) {
+      const dropdownItems = document.querySelectorAll(`#${this.expandableNavbarSectionId()} *[role="menuitem"]`);
+      dropdownItems.forEach(item => {
+        item.addEventListener('keydown', this.navigateDropdown.bind(this));
+      });
+      this.addArrowEventListeners = false;
+    }
   }
 
   /**
@@ -113,9 +152,54 @@ export class ExpandableNavbarSectionComponent extends NavbarSectionComponent imp
 
   /**
    * returns the ID of the DOM element representing the navbar section
-   * @param sectionId
    */
-  expandableNavbarSectionId(sectionId: string) {
-    return `expandable-navbar-section-${sectionId}-dropdown`;
+  expandableNavbarSectionId(): string {
+    return `expandable-navbar-section-${this.section.id}-dropdown`;
+  }
+
+  /**
+   * Handles the navigation between the menu items
+   *
+   * @param event
+   */
+  navigateDropdown(event: KeyboardEvent): void {
+    if (event.key === 'Tab') {
+      this.deactivateSection(event, false);
+      return;
+    }
+    event.preventDefault();
+    event.stopPropagation();
+
+    const items: NodeListOf<Element> = document.querySelectorAll(`#${this.expandableNavbarSectionId()} *[role="menuitem"]`);
+    if (items.length === 0) {
+      return;
+    }
+    const currentIndex: number = Array.from(items).findIndex((item: Element) => item === event.target);
+
+    if (event.key === 'ArrowDown') {
+      (items[(currentIndex + 1) % items.length] as HTMLElement).focus();
+    } else if (event.key === 'ArrowUp') {
+      (items[(currentIndex - 1 + items.length) % items.length] as HTMLElement).focus();
+    }
+  }
+
+  /**
+   * Handles all the keydown events on the dropdown toggle
+   *
+   * @param event
+   */
+  keyDown(event: KeyboardEvent): void {
+    switch (event.code) {
+      // Works for both Tab & Shift Tab
+      case 'Tab':
+        this.deactivateSection(event, false);
+        break;
+      case 'ArrowDown':
+        this.navigateDropdown(event);
+        break;
+      case 'Space':
+        event.preventDefault();
+        break;
+    }
   }
 }
diff --git a/src/app/shared/utils/hover-outside.directive.ts b/src/app/shared/utils/hover-outside.directive.ts
new file mode 100644
index 0000000000..a0abb8bb63
--- /dev/null
+++ b/src/app/shared/utils/hover-outside.directive.ts
@@ -0,0 +1,51 @@
+import {
+  Directive,
+  ElementRef,
+  EventEmitter,
+  HostListener,
+  Input,
+  Output,
+} from '@angular/core';
+
+/**
+ * Directive to detect when the user hovers outside of the element the directive was put on
+ *
+ * BEWARE: it's probably not good for performance to use this excessively (on {@link ExpandableNavbarSectionComponent}
+ * for example, a workaround for this problem was to add an `*ngIf` to prevent this Directive from always being active)
+ */
+@Directive({
+  selector: '[dsHoverOutside]',
+  standalone: true,
+})
+export class HoverOutsideDirective {
+
+  /**
+   * Emits null when the user hovers outside of the element
+   */
+  @Output()
+  public dsHoverOutside = new EventEmitter();
+
+  /**
+   * The {@link ElementRef} for which this directive should emit when the mouse leaves it. By default this will be the
+   * element the directive was put on.
+   */
+  @Input()
+  public dsHoverOutsideOfElement: ElementRef;
+
+  constructor(
+    private elementRef: ElementRef,
+  ) {
+    this.dsHoverOutsideOfElement = this.elementRef;
+  }
+
+  @HostListener('document:mouseover', ['$event'])
+  public onMouseOver(event: MouseEvent): void {
+    const targetElement: HTMLElement = event.target as HTMLElement;
+    const hoveredInside = this.dsHoverOutsideOfElement.nativeElement.contains(targetElement);
+
+    if (!hoveredInside) {
+      this.dsHoverOutside.emit(null);
+    }
+  }
+
+}
diff --git a/src/themes/custom/app/navbar/expandable-navbar-section/expandable-navbar-section.component.ts b/src/themes/custom/app/navbar/expandable-navbar-section/expandable-navbar-section.component.ts
index f0e2ebd502..167b805fd5 100644
--- a/src/themes/custom/app/navbar/expandable-navbar-section/expandable-navbar-section.component.ts
+++ b/src/themes/custom/app/navbar/expandable-navbar-section/expandable-navbar-section.component.ts
@@ -9,11 +9,9 @@ import { RouterLinkActive } from '@angular/router';
 
 import { ExpandableNavbarSectionComponent as BaseComponent } from '../../../../../app/navbar/expandable-navbar-section/expandable-navbar-section.component';
 import { slide } from '../../../../../app/shared/animations/slide';
+import { HoverOutsideDirective } from '../../../../../app/shared/utils/hover-outside.directive';
 import { VarDirective } from '../../../../../app/shared/utils/var.directive';
 
-/**
- * Represents an expandable section in the navbar
- */
 @Component({
   selector: 'ds-themed-expandable-navbar-section',
   // templateUrl: './expandable-navbar-section.component.html',
@@ -22,7 +20,15 @@ import { VarDirective } from '../../../../../app/shared/utils/var.directive';
   styleUrls: ['../../../../../app/navbar/expandable-navbar-section/expandable-navbar-section.component.scss'],
   animations: [slide],
   standalone: true,
-  imports: [VarDirective, RouterLinkActive, NgComponentOutlet, NgIf, NgFor, AsyncPipe],
+  imports: [
+    AsyncPipe,
+    HoverOutsideDirective,
+    NgComponentOutlet,
+    NgFor,
+    NgIf,
+    RouterLinkActive,
+    VarDirective,
+  ],
 })
 export class ExpandableNavbarSectionComponent extends BaseComponent {
 }