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/**
* @license
* Copyright (C) 2020 The Android Open Source Project
*
* 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 '../../../styles/shared-styles';
import {flush} from '@polymer/polymer/lib/legacy/polymer.dom';
import {getRootElement} from '../../../scripts/rootElement';
import {Constructor} from '../../../utils/common-util';
import {PolymerElement} from '@polymer/polymer/polymer-element';
import {observe, property} from '@polymer/decorators';
import {
pushScrollLock,
removeScrollLock,
} from '@polymer/iron-overlay-behavior/iron-scroll-manager';
import {ShowAlertEventDetail} from '../../../types/events';
import {debounce, DelayedTask} from '../../../utils/async-util';
interface ReloadEventDetail {
clearPatchset?: boolean;
}
const HOVER_CLASS = 'hovered';
const HIDE_CLASS = 'hide';
/**
* ID for the container element.
*/
const containerId = 'gr-hovercard-container';
export function getHovercardContainer(
options: {createIfNotExists: boolean} = {createIfNotExists: false}
): HTMLElement | null {
let container = getRootElement().querySelector<HTMLElement>(
`#${containerId}`
);
if (!container && options.createIfNotExists) {
// If it does not exist, create and initialize the hovercard container.
container = document.createElement('div');
container.setAttribute('id', containerId);
getRootElement().appendChild(container);
}
return container;
}
/**
* How long should we wait before showing the hovercard when the user hovers
* over the element?
*/
const SHOW_DELAY_MS = 550;
/**
* How long should we wait before hiding the hovercard when the user moves from
* target to the hovercard.
*
* Note: this should be lower than SHOW_DELAY_MS to avoid flickering.
*/
const HIDE_DELAY_MS = 500;
/**
* The mixin for gr-hovercard-behavior.
*
* @example
*
* class YourComponent extends hovercardBehaviorMixin(
* PolymerElement
*
* @see gr-hovercard.ts
*
* // following annotations are required for polylint
* @polymer
* @mixinFunction
*/
export const HovercardBehaviorMixin = <T extends Constructor<PolymerElement>>(
superClass: T
) => {
/**
* @polymer
* @mixinClass
*/
class Mixin extends superClass {
@property({type: Object})
_target: HTMLElement | null = null;
// Determines whether or not the hovercard is visible.
@property({type: Boolean})
_isShowing = false;
// The `id` of the element that the hovercard is anchored to.
@property({type: String})
for?: string;
/**
* The spacing between the top of the hovercard and the element it is
* anchored to.
*/
@property({type: Number})
offset = 14;
/**
* Positions the hovercard to the top, right, bottom, left, bottom-left,
* bottom-right, top-left, or top-right of its content.
*/
@property({type: String})
position = 'right';
@property({type: Object})
container: HTMLElement | null = null;
private hideTask?: DelayedTask;
private showTask?: DelayedTask;
private isScheduledToShow?: boolean;
private isScheduledToHide?: boolean;
override connectedCallback() {
super.connectedCallback();
if (!this._target) {
this._target = this.target;
this.addTargetEventListeners();
}
// show the hovercard if mouse moves to hovercard
// this will cancel pending hide as well
this.addEventListener('mouseenter', this.show);
this.addEventListener('mouseenter', this.lock);
// when leave hovercard, hide it immediately
this.addEventListener('mouseleave', this.hide);
this.addEventListener('mouseleave', this.unlock);
}
override disconnectedCallback() {
this.cancelShowTask();
this.cancelHideTask();
this.unlock();
super.disconnectedCallback();
}
addTargetEventListeners() {
this._target?.addEventListener('mouseenter', this.debounceShow);
this._target?.addEventListener('focus', this.debounceShow);
this._target?.addEventListener('mouseleave', this.debounceHide);
this._target?.addEventListener('blur', this.debounceHide);
this._target?.addEventListener('click', this.hide);
}
removeTargetEventListeners() {
this._target?.removeEventListener('mouseenter', this.debounceShow);
this._target?.removeEventListener('focus', this.debounceShow);
this._target?.removeEventListener('mouseleave', this.debounceHide);
this._target?.removeEventListener('blur', this.debounceHide);
this._target?.removeEventListener('click', this.hide);
}
override ready() {
super.ready();
// First, check to see if the container has already been created.
this.container = getHovercardContainer({createIfNotExists: true});
}
readonly debounceHide = () => {
this.cancelShowTask();
if (!this._isShowing || this.isScheduledToHide) return;
this.isScheduledToHide = true;
this.hideTask = debounce(
this.hideTask,
() => {
// This happens when hide immediately through click or mouse leave
// on the hovercard
if (!this.isScheduledToHide) return;
this.hide();
},
HIDE_DELAY_MS
);
};
cancelHideTask() {
if (!this.hideTask) return;
this.hideTask.cancel();
this.isScheduledToHide = false;
this.hideTask = undefined;
}
/**
* Hovercard elements are created outside of <gr-app>, so if you want to fire
* events, then you probably want to do that through the target element.
*/
dispatchEventThroughTarget(eventName: string): void;
dispatchEventThroughTarget(
eventName: 'show-alert',
detail: ShowAlertEventDetail
): void;
dispatchEventThroughTarget(
eventName: 'reload',
detail: ReloadEventDetail
): void;
dispatchEventThroughTarget(eventName: string, detail?: unknown) {
if (!detail) detail = {};
if (this._target)
this._target.dispatchEvent(
new CustomEvent(eventName, {
detail,
bubbles: true,
composed: true,
})
);
}
/**
* Returns the target element that the hovercard is anchored to (the `id` of
* the `for` property).
*/
get target(): HTMLElement {
const parentNode = this.parentNode;
// If the parentNode is a document fragment, then we need to use the host.
const ownerRoot = this.getRootNode() as ShadowRoot;
let target;
if (this.for) {
target = ownerRoot.querySelector('#' + this.for);
} else {
target =
!parentNode || parentNode.nodeType === Node.DOCUMENT_FRAGMENT_NODE
? ownerRoot.host
: parentNode;
}
return target as HTMLElement;
}
/**
* unlock scroll, this will resume the scroll outside of the hovercard.
*/
readonly unlock = () => {
removeScrollLock(this);
};
/**
* Hides/closes the hovercard. This occurs when the user triggers the
* `mouseleave` event on the hovercard's `target` element (as long as the
* user is not hovering over the hovercard).
*
*/
readonly hide = (e?: MouseEvent) => {
this.cancelHideTask();
this.cancelShowTask();
if (!this._isShowing) {
return;
}
// If the user is now hovering over the hovercard or the user is returning
// from the hovercard but now hovering over the target (to stop an annoying
// flicker effect), just return.
if (e) {
if (
e.relatedTarget === this ||
(e.target === this && e.relatedTarget === this._target)
) {
return;
}
}
// Mark that the hovercard is not visible and do not allow focusing
this._isShowing = false;
// Clear styles in preparation for the next time we need to show the card
this.classList.remove(HOVER_CLASS);
// Reset and remove the hovercard from the DOM
this.style.cssText = '';
this.$['container'].setAttribute('tabindex', '-1');
// Remove the hovercard from the container, given that it is still a child
// of the container.
if (this.container?.contains(this)) {
this.container.removeChild(this);
}
};
/**
* Shows/opens the hovercard with a fixed delay.
*/
readonly debounceShow = () => {
this.debounceShowBy(SHOW_DELAY_MS);
};
/**
* Shows/opens the hovercard with the given delay.
*/
debounceShowBy(delayMs: number) {
this.cancelHideTask();
if (this._isShowing || this.isScheduledToShow) return;
this.isScheduledToShow = true;
this.showTask = debounce(
this.showTask,
() => {
// This happens when the mouse leaves the target before the delay is over.
if (!this.isScheduledToShow) return;
this.show();
},
delayMs
);
}
cancelShowTask() {
if (!this.showTask) return;
this.showTask.cancel();
this.isScheduledToShow = false;
this.showTask = undefined;
}
/**
* Lock background scroll but enable scroll inside of current hovercard.
*/
readonly lock = () => {
pushScrollLock(this);
};
/**
* Shows/opens the hovercard. This occurs when the user triggers the
* `mousenter` event on the hovercard's `target` element.
*/
readonly show = async () => {
this.cancelHideTask();
this.cancelShowTask();
if (this._isShowing || !this.container) {
return;
}
// Mark that the hovercard is now visible
this._isShowing = true;
this.setAttribute('tabindex', '0');
// Add it to the DOM and calculate its position
this.container.appendChild(this);
// We temporarily hide the hovercard until we have found the correct
// position for it.
this.classList.add(HIDE_CLASS);
this.classList.add(HOVER_CLASS);
// Make sure that the hovercard actually rendered and all dom-if
// statements processed, so that we can measure the (invisible)
// hovercard properly in updatePosition().
await flush();
this.updatePosition();
this.classList.remove(HIDE_CLASS);
};
updatePosition() {
const positionsToTry = new Set([
this.position,
'right',
'bottom-right',
'top-right',
'bottom',
'top',
'bottom-left',
'top-left',
'left',
]);
for (const position of positionsToTry) {
this.updatePositionTo(position);
if (this._isInsideViewport()) return;
}
console.warn('Could not find a visible position for the hovercard.');
}
_isInsideViewport() {
const thisRect = this.getBoundingClientRect();
if (thisRect.top < 0) return false;
if (thisRect.left < 0) return false;
const docuRect = document.documentElement.getBoundingClientRect();
if (thisRect.bottom > docuRect.height) return false;
if (thisRect.right > docuRect.width) return false;
return true;
}
/**
* Updates the hovercard's position based the current position of the `target`
* element.
*
* The hovercard is supposed to stay open if the user hovers over it.
* To keep it open when the user moves away from the target, the bounding
* rects of the target and hovercard must touch or overlap.
*
* NOTE: You do not need to directly call this method unless you need to
* update the position of the tooltip while it is already visible (the
* target element has moved and the tooltip is still open).
*/
updatePositionTo(position: string) {
if (!this._target) {
return;
}
// Make sure that thisRect will not get any paddings and such included
// in the width and height of the bounding client rect.
this.style.cssText = '';
const docuRect = document.documentElement.getBoundingClientRect();
const targetRect = this._target.getBoundingClientRect();
const thisRect = this.getBoundingClientRect();
const targetLeft = targetRect.left - docuRect.left;
const targetTop = targetRect.top - docuRect.top;
let hovercardLeft;
let hovercardTop;
switch (position) {
case 'top':
hovercardLeft = targetLeft + (targetRect.width - thisRect.width) / 2;
hovercardTop = targetTop - thisRect.height - this.offset;
break;
case 'bottom':
hovercardLeft = targetLeft + (targetRect.width - thisRect.width) / 2;
hovercardTop = targetTop + targetRect.height + this.offset;
break;
case 'left':
hovercardLeft = targetLeft - thisRect.width - this.offset;
hovercardTop = targetTop + (targetRect.height - thisRect.height) / 2;
break;
case 'right':
hovercardLeft = targetLeft + targetRect.width + this.offset;
hovercardTop = targetTop + (targetRect.height - thisRect.height) / 2;
break;
case 'bottom-right':
hovercardLeft = targetLeft + targetRect.width + this.offset;
hovercardTop = targetTop;
break;
case 'bottom-left':
hovercardLeft = targetLeft - thisRect.width - this.offset;
hovercardTop = targetTop;
break;
case 'top-left':
hovercardLeft = targetLeft - thisRect.width - this.offset;
hovercardTop = targetTop + targetRect.height - thisRect.height;
break;
case 'top-right':
hovercardLeft = targetLeft + targetRect.width + this.offset;
hovercardTop = targetTop + targetRect.height - thisRect.height;
break;
}
this.style.left = `${hovercardLeft}px`;
this.style.top = `${hovercardTop}px`;
}
/**
* Responds to a change in the `for` value and gets the updated `target`
* element for the hovercard.
*/
@observe('for')
_forChanged() {
this.removeTargetEventListeners();
this._target = this.target;
this.addTargetEventListeners();
}
}
return Mixin as T & Constructor<GrHovercardBehaviorInterface>;
};
export interface GrHovercardBehaviorInterface {
_target: HTMLElement | null;
_isShowing: boolean;
ready(): void;
dispatchEventThroughTarget(eventName: string, detail?: unknown): void;
hide(e?: MouseEvent): void;
debounceShow(): void;
debounceShowBy(delayMs: number): void;
cancelShowTask(): void;
show(): void;
updatePosition(): void;
}