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// (C) Copyright 2015 Moodle Pty Ltd.
//
// Licensed under the Apache License, Version 2.0 (the "License");
// you may not use this file except in compliance with the License.
// You may obtain a copy of the License at
//
// http://www.apache.org/licenses/LICENSE-2.0
//
// Unless required by applicable law or agreed to in writing, software
// distributed under the License is distributed on an "AS IS" BASIS,
// WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
// See the License for the specific language governing permissions and
// limitations under the License.
import { Component, ElementRef, EventEmitter, Input, OnChanges, OnDestroy, Output, SimpleChange } from '@angular/core';
import { IonContent } from '@ionic/angular';
import { ScrollDetail } from '@ionic/core';
import { CoreUtils } from '@services/utils/utils';
import { Translate } from '@singletons';
import { CoreMath } from '@singletons/math';
/**
* Component to show a "bar" with arrows to navigate forward/backward and an slider to move around.
*
* This directive will show two arrows at the left and right of the screen to navigate to previous/next item when clicked.
* If no previous/next item is defined, that arrow won't be shown.
*
* Example usage:
* <core-navigation-bar [items]="items" (action)="goTo($event)"></core-navigation-bar>
*/
@Component({
selector: 'core-navigation-bar',
templateUrl: 'core-navigation-bar.html',
styleUrls: ['navigation-bar.scss'],
})
export class CoreNavigationBarComponent implements OnDestroy, OnChanges {
@Input() items: CoreNavigationBarItem[] = []; // List of items.
@Input() previousTranslate = 'core.previous'; // Previous translatable text, can admit $a variable.
@Input() nextTranslate = 'core.next'; // Next translatable text, can admit $a variable.
@Input() component?: string; // Component the bar belongs to.
@Input() componentId?: number; // Component ID.
@Input() contextLevel?: string; // The context level.
@Input() contextInstanceId?: number; // The instance ID related to the context.
@Input() courseId?: number; // Course ID the text belongs to. It can be used to improve performance with filters.
previousTitle?: string; // Previous item title.
nextTitle?: string; // Next item title.
previousIndex = -1; // Previous item index. If -1, the previous arrow won't be shown.
nextIndex = -1; // Next item index. If -1, the next arrow won't be shown.
currentIndex = 0;
progress = 0;
progressText = '';
protected element: HTMLElement;
protected initialHeight = 0;
protected initialPaddingBottom = 0;
protected previousTop = 0;
protected previousHeight = 0;
protected stickTimeout?: number;
protected content?: HTMLIonContentElement | null;
// Function to call when arrow is clicked. Will receive as a param the item to load.
@Output() action: EventEmitter<unknown> = new EventEmitter<unknown>();
constructor(el: ElementRef, protected ionContent: IonContent) {
this.element = el.nativeElement;
this.element.setAttribute('slot', 'fixed'); // Just in case somebody forgets to add it.
}
/**
* Setup scroll event listener.
*
* @param retries Number of retries left.
*/
protected async listenScrollEvents(retries = 3): Promise<void> {
// Already initialized.
if (this.initialHeight > 0) {
return;
}
this.initialHeight = this.element.getBoundingClientRect().height;
if (this.initialHeight == 0 && retries > 0) {
await CoreUtils.nextTicks(50);
this.listenScrollEvents(retries - 1);
return;
}
// Set a minimum height value.
this.initialHeight = this.initialHeight || 48;
this.previousHeight = this.initialHeight;
this.content = this.element.closest('ion-content');
if (!this.content) {
return;
}
this.content.classList.add('has-core-navigation');
// Move element to the nearest ion-content if it's not the parent.
if (this.element.parentElement?.nodeName != 'ION-CONTENT') {
this.content.appendChild(this.element);
}
// Set a padding to not overlap elements.
this.initialPaddingBottom = parseFloat(this.content.style.getPropertyValue('--padding-bottom') || '0');
this.content.style.setProperty('--padding-bottom', this.initialPaddingBottom + this.initialHeight + 'px');
const scroll = await this.content.getScrollElement();
this.content.scrollEvents = true;
this.setBarHeight(this.initialHeight);
this.content.addEventListener('ionScroll', (e: CustomEvent<ScrollDetail>): void => {
if (!this.content) {
return;
}
this.onScroll(e.detail, scroll);
});
}
/**
* On scroll function.
*
* @param scrollDetail Scroll detail object.
* @param scrollElement Scroll element to calculate maxScroll.
*/
protected onScroll(scrollDetail: ScrollDetail, scrollElement: HTMLElement): void {
const maxScroll = scrollElement.scrollHeight - scrollElement.offsetHeight;
if (scrollDetail.scrollTop <= 0 || scrollDetail.scrollTop >= maxScroll) {
// Reset.
this.setBarHeight(this.initialHeight);
} else {
let newHeight = this.previousHeight - (scrollDetail.scrollTop - this.previousTop);
newHeight = CoreMath.clamp(newHeight, 0, this.initialHeight);
this.setBarHeight(newHeight);
}
this.previousTop = scrollDetail.scrollTop;
}
/**
* Sets the bar height.
*
* @param height The new bar height.
*/
protected setBarHeight(height: number): void {
if (this.stickTimeout) {
clearTimeout(this.stickTimeout);
}
this.element.style.opacity = height <= 0 ? '0' : '1';
this.content?.style.setProperty('--core-navigation-height', height + 'px');
this.previousHeight = height;
if (height > 0 && height < this.initialHeight) {
// Finish opening or closing the bar.
const newHeight = height < this.initialHeight / 2 ? 0 : this.initialHeight;
this.stickTimeout = window.setTimeout(() => this.setBarHeight(newHeight), 500);
}
}
/**
* @inheritdoc
*/
ngOnChanges(changes: {[name: string]: SimpleChange}): void {
if (!changes.items || !this.items.length) {
return;
}
this.currentIndex = this.items.findIndex((item) => item.current);
if (this.currentIndex < 0) {
return;
}
this.progress = ((this.currentIndex + 1) / this.items.length) * 100;
this.progressText = `${this.currentIndex + 1} / ${this.items.length}`;
this.nextIndex = this.items[this.currentIndex + 1]?.enabled ? this.currentIndex + 1 : -1;
if (this.nextIndex >= 0) {
this.nextTitle = Translate.instant(this.nextTranslate, { $a: this.items[this.nextIndex].title || '' });
}
this.previousIndex = this.items[this.currentIndex - 1]?.enabled ? this.currentIndex - 1 : -1;
if (this.previousIndex >= 0) {
this.previousTitle = Translate.instant(this.previousTranslate, { $a: this.items[this.previousIndex].title || '' });
}
this.listenScrollEvents();
}
/**
* Navigate to an item.
*
* @param itemIndex Selected item index.
*/
navigate(itemIndex: number): void {
if (this.currentIndex == itemIndex || !this.items[itemIndex].enabled) {
return;
}
this.currentIndex = itemIndex;
this.action.emit(this.items[itemIndex].item);
}
/**
* @inheritdoc
*/
async ngOnDestroy(): Promise<void> {
this.content?.style.setProperty('--padding-bottom', this.initialPaddingBottom + 'px');
}
}
export type CoreNavigationBarItem<T = unknown> = {
item: T;
title?: string;
current: boolean;
enabled: boolean;
};