[AAE-6623] Search and select multiple dropdown options (#7391)

* [AAE-6623] Search and select multiple dropdown options

* [ci:force] fix comment

lib/core/card-view/components/card-view-selectitem/select-filter-input/select-filter-input.component.spec.ts

@@ -20,12 +20,55 @@ import { setupTestBed } from '../../../../testing/setup-test-bed';
 import { CoreTestingModule } from '../../../../testing/core.testing.module';
 import { TranslateModule } from '@ngx-translate/core';
 import { SelectFilterInputComponent } from './select-filter-input.component';
-import { MatSelect } from '@angular/material/select';
 import { NoopAnimationsModule } from '@angular/platform-browser/animations';
+import { Component, ViewChild } from '@angular/core';
+import { By } from '@angular/platform-browser';
 import { ESCAPE } from '@angular/cdk/keycodes';
+import { MatSelect } from '@angular/material/select';
+
+@Component({
+    selector: 'adf-test-filter',
+    template: `
+        <mat-select [(ngModel)]="field.value" [compareWith]="compare" [multiple]="multiple">
+            <adf-select-filter-input *ngIf="showInputFilter" (change)="onChange($event)"></adf-select-filter-input>
+            <mat-option *ngFor="let opt of options"
+                        [value]="opt"
+                        [id]="opt.id">{{opt.name}}
+            </mat-option>
+        </mat-select>
+    `
+})
+export class TestComponent {
+    @ViewChild(SelectFilterInputComponent) filterInputComponent: SelectFilterInputComponent;
+    field: any = { value : '' };
+    showInputFilter = true;
+    multiple = false;
+    standardOptions = [
+        { 'id': '1', 'name': 'one' },
+        { 'id': '2', 'name': 'two' },
+        { 'id': '3', 'name': 'three' }
+    ];
+    options = this.standardOptions;
+
+    compare(obj1, obj2) {
+        if (!obj1 || !obj2) {
+            return false;
+        }
+        return obj1.id === obj2.id;
+    }
+
+    onChange(search: string) {
+        if (!search) {
+            this.options = this.standardOptions;
+        } else {
+            this.options = this.standardOptions.filter(({ name }) => name.includes(search));
+        }
+    }
+}
 
 describe('SelectFilterInputComponent', () => {
-
+    let testFixture: ComponentFixture<TestComponent>;
+    let testComponent: TestComponent;
     let fixture: ComponentFixture<SelectFilterInputComponent>;
     let component: SelectFilterInputComponent;
     let matSelect: MatSelect;
@@ -36,9 +79,16 @@ describe('SelectFilterInputComponent', () => {
             CoreTestingModule,
             NoopAnimationsModule
         ],
-        providers: [ MatSelect ]
+        declarations: [
+            TestComponent
+        ],
+        providers: [
+            MatSelect
+        ]
     });
 
+    describe('component', () => {
+
         beforeEach(() => {
             fixture = TestBed.createComponent(SelectFilterInputComponent);
             component = fixture.componentInstance;
@@ -90,4 +140,41 @@ describe('SelectFilterInputComponent', () => {
             fixture.detectChanges();
             expect(component.term).toBe('');
         });
+
+    });
+
+    describe('testComponent', () => {
+        beforeEach(() => {
+            testFixture = TestBed.createComponent(TestComponent);
+            testComponent = testFixture.componentInstance;
+        });
+
+        afterEach(() => testFixture.destroy());
+
+        it('should preserve the values for multiple search', async () => {
+            const userSelection = [{ 'id': '3', 'name': 'three' }];
+            const preSelected = [
+                { 'id': '1', 'name': 'one' },
+                { 'id': '2', 'name': 'two' }
+            ];
+            testComponent.field.value = preSelected;
+            testComponent.multiple = true;
+            testFixture.detectChanges();
+
+            const dropdown: HTMLElement = testFixture.nativeElement.querySelector('.mat-select-trigger');
+            dropdown.click();
+            await testFixture.whenStable();
+            testFixture.detectChanges();
+
+            const filter = testFixture.debugElement.query(By.css('input'));
+            filter.triggerEventHandler('input', { target: { value: 'three' } });
+            testFixture.detectChanges();
+
+            const option = testFixture.debugElement.query(By.css('mat-option'));
+            option.triggerEventHandler('click', null);
+            testFixture.detectChanges();
+
+            expect(testComponent.field.value).toEqual([...preSelected, ...userSelection]);
+        });
+    });
 });

lib/core/card-view/components/card-view-selectitem/select-filter-input/select-filter-input.component.ts

@@ -33,6 +33,7 @@ export class SelectFilterInputComponent implements OnDestroy {
     @Output() change = new EventEmitter<string>();
 
     term = '';
+    previousSelected: any[];
     private onDestroy$ = new Subject<void>();
 
     constructor(@Inject(MatSelect) private matSelect: MatSelect) {}
@@ -55,6 +56,33 @@ export class SelectFilterInputComponent implements OnDestroy {
                     this.change.next('');
                 }
             });
+
+        if (this.matSelect.ngControl) {
+            this.previousSelected = this.matSelect.ngControl.value;
+            this.matSelect.ngControl.valueChanges
+                .pipe(takeUntil(this.onDestroy$))
+                .subscribe((values) => {
+                    let restoreSelection = false;
+                    if (this.matSelect.multiple && Array.isArray(this.previousSelected)) {
+                        if (!Array.isArray(values)) {
+                            values = [];
+                        }
+                        const options = this.matSelect.options.map(option => option.value);
+                        this.previousSelected.forEach((previous) => {
+                            const isSelected = [...values, ...options].some(current => this.matSelect.compareWith(current, previous));
+                            if (!isSelected) {
+                                values.push(previous);
+                                restoreSelection = true;
+                            }
+                        });
+                    }
+
+                    this.previousSelected = values;
+                    if (restoreSelection) {
+                        this.matSelect._onChange(values);
+                    }
+                });
+        }
     }
 
     reset(event?: Event) {