Files
rio/frontend/code/components/dropdown.ts
2024-06-23 01:54:05 +02:00

475 lines
15 KiB
TypeScript

import { ComponentBase, ComponentState } from './componentBase';
import { applyIcon } from '../designApplication';
import { pixelsPerRem } from '../app';
import { InputBox } from '../inputBox';
import { markEventAsHandled } from '../eventHandling';
export type DropdownState = ComponentState & {
_type_: 'Dropdown-builtin';
optionNames?: string[];
label?: string;
selectedName?: string;
is_sensitive?: boolean;
is_valid?: boolean;
};
export class DropdownComponent extends ComponentBase {
state: Required<DropdownState>;
private inputBox: InputBox;
private popupElement: HTMLElement;
private optionsElement: HTMLElement;
private isOpen: boolean = false;
// The currently highlighted option, if any
private highlightedOptionElement: HTMLElement | null = null;
createElement(): HTMLElement {
// Create the elements
let element = document.createElement('div');
element.classList.add('rio-dropdown');
this.inputBox = new InputBox(element);
// Add an arrow icon
let arrowElement = document.createElement('div');
arrowElement.classList.add('rio-dropdown-arrow');
applyIcon(
arrowElement,
'material/expand-more',
'var(--rio-local-text-color)'
);
this.inputBox.suffixElement = arrowElement;
// Create the popup
this.popupElement = document.createElement('div');
this.popupElement.tabIndex = -999; // Required for Chrome, sets `FocusEvent.relatedTarget`
this.popupElement.classList.add('rio-dropdown-popup');
this.optionsElement = document.createElement('div');
this.optionsElement.classList.add('rio-dropdown-options');
this.popupElement.appendChild(this.optionsElement);
document.body.appendChild(this.popupElement);
// Connect events
element.addEventListener(
'mousedown',
this._onMouseDown.bind(this),
true
);
this.inputBox.inputElement.addEventListener(
'keydown',
this._onKeyDown.bind(this)
);
this.inputBox.inputElement.addEventListener(
'input',
this._onInputValueChange.bind(this)
);
this.inputBox.inputElement.addEventListener(
'focusin',
this._onFocusIn.bind(this)
);
this.inputBox.inputElement.addEventListener(
'focusout',
this._onFocusOut.bind(this)
);
return element;
}
private _onFocusIn(): void {
// Clear the input text so that all options are shown in the dropdown
this.inputBox.value = '';
this.showPopup();
}
private _onFocusOut(event: FocusEvent): void {
// When the input element loses focus, that means the user is done
// entering input. Depending on whether they inputted a valid option,
// either save it or reset.
//
// Careful: Clicking on a dropdown option with the mouse also causes us
// to lose focus. If we close the popup too early, the click won't hit
// anything.
//
// In Firefox the click is triggered before the focusout, so
// that's no problem. But in Chrome, we have to check whether the focus
// went to our popup element.
if (
event.relatedTarget instanceof HTMLElement &&
event.relatedTarget.classList.contains('rio-dropdown-popup')
) {
return;
}
this.trySubmitInput();
}
private trySubmitInput(): void {
this.inputBox.unfocus();
this.hidePopup();
// Check if the inputted text corresponds to a valid option
let inputText = this.inputBox.value;
if (inputText === this.state.selectedName) {
return;
}
if (this.state.optionNames.includes(inputText)) {
this.state.selectedName = inputText;
this.sendMessageToBackend({
name: inputText,
});
} else {
this.inputBox.value = this.state.selectedName;
}
}
private cancelInput(): void {
this.inputBox.value = this.state.selectedName;
this.trySubmitInput();
}
private submitInput(optionName: string): void {
this.inputBox.value = optionName;
this.trySubmitInput();
}
private _onMouseDown(event: MouseEvent): void {
if (!this.state.is_sensitive) {
return;
}
// Not left click?
if (event.button !== 0) {
return;
}
// Eat the event
markEventAsHandled(event);
// Already open?
if (this.isOpen) {
this.cancelInput();
return;
}
// Make the text input appear as active
this.inputBox.focus();
}
_onKeyDown(event: KeyboardEvent): void {
// Close the dropdown on escape
if (event.key === 'Escape') {
this.cancelInput();
}
// Enter -> select the highlighted option
else if (event.key === 'Enter') {
if (this.highlightedOptionElement !== null) {
this.highlightedOptionElement.click();
}
}
// Move highlight up
else if (event.key === 'ArrowDown') {
let nextOption;
if (this.highlightedOptionElement === null) {
nextOption = this.optionsElement.firstElementChild;
} else {
nextOption = this.highlightedOptionElement.nextElementSibling;
if (nextOption === null) {
nextOption = this.optionsElement.firstElementChild;
}
}
this._highlightOption(nextOption as HTMLElement);
}
// Move highlight down
else if (event.key === 'ArrowUp') {
let nextOption: Element | null;
if (this.highlightedOptionElement === null) {
nextOption = this.optionsElement.lastElementChild;
} else {
nextOption =
this.highlightedOptionElement.previousElementSibling;
if (nextOption === null) {
nextOption = this.optionsElement.lastElementChild;
}
}
this._highlightOption(nextOption as HTMLElement);
}
// Any other key -> let the event propagate
else {
return;
}
markEventAsHandled(event);
}
private _onInputValueChange(): void {
this._updateOptionEntries();
}
private _highlightOption(optionElement: HTMLElement | null): void {
// Remove the highlight from the previous option
if (this.highlightedOptionElement !== null) {
this.highlightedOptionElement.classList.remove(
'rio-dropdown-option-highlighted'
);
}
// Remember the new option and highlight it
this.highlightedOptionElement = optionElement;
if (optionElement !== null) {
optionElement.classList.add('rio-dropdown-option-highlighted');
}
}
private showPopup(): void {
if (this.isOpen) {
return;
}
this.isOpen = true;
this._updateOptionEntries();
// Position & Animate
let dropdownRect = this.element.getBoundingClientRect();
let popupHeight = this.popupElement.scrollHeight;
let windowHeight = window.innerHeight - 1; // innerHeight is rounded
this.popupElement.style.removeProperty('top');
this.popupElement.style.removeProperty('bottom');
this.popupElement.style.width = `${dropdownRect.width}px`;
const MARGIN_IF_ENTIRELY_ABOVE = 0.5 * pixelsPerRem;
// Popup is larger than the window. Give it all the space that's
// available.
if (popupHeight >= windowHeight) {
this.popupElement.style.overflowY = 'scroll';
this.popupElement.style.top = '0';
this.popupElement.classList.add('rio-dropdown-popup-above');
}
// Popup fits below the dropdown
else if (dropdownRect.bottom + popupHeight <= windowHeight) {
this.popupElement.style.overflowY = 'hidden';
this.popupElement.style.top = `${dropdownRect.bottom}px`;
this.popupElement.classList.remove('rio-dropdown-popup-above');
}
// Popup fits above the dropdown
else if (dropdownRect.top - popupHeight >= MARGIN_IF_ENTIRELY_ABOVE) {
this.popupElement.style.overflowY = 'hidden';
this.popupElement.style.bottom = `${
windowHeight - dropdownRect.top + MARGIN_IF_ENTIRELY_ABOVE
}px`;
this.popupElement.classList.add('rio-dropdown-popup-above');
}
// Popup doesn't fit above or below the dropdown. Center it as much
// as possible
else {
this.popupElement.style.overflowY = 'hidden';
let top =
dropdownRect.top + dropdownRect.height / 2 - popupHeight / 2;
if (top < 0) {
top = 0;
} else if (top + popupHeight > windowHeight) {
top = windowHeight - popupHeight;
}
this.popupElement.style.top = `${top}px`;
this.popupElement.classList.add('rio-dropdown-popup-above');
}
this.popupElement.style.left = dropdownRect.left + 'px';
}
private hidePopup(): void {
if (!this.isOpen) {
return;
}
this.isOpen = false;
// Animate the disappearance
this.popupElement.style.height = '0';
}
onDestruction(): void {
super.onDestruction();
this.popupElement.remove();
}
/// Find needle in haystack, returning a HTMLElement with the matched
/// sections highlighted. If no match is found, return null. Needle must be
/// lowercase.
_highlightMatches(
haystack: string,
needleLower: string
): HTMLElement | null {
// Special case: Empty needle matches everything, and would cause a hang
// in the while loop below
if (needleLower.length === 0) {
const container = document.createElement('div');
container.textContent = haystack;
return container;
}
// Create a div element to hold the highlighted content
const container = document.createElement('div');
// Start searching
let startIndex = 0;
let haystackLower = haystack.toLowerCase();
let index = haystackLower.indexOf(needleLower, startIndex);
while (index !== -1) {
// Add the text before the match as a text node
container.appendChild(
document.createTextNode(haystack.substring(startIndex, index))
);
// Add the matched portion as a highlighted span
const span = document.createElement('span');
span.className = 'rio-dropdown-option-highlight';
span.textContent = haystack.substring(
index,
index + needleLower.length
);
container.appendChild(span);
// Update the start index for the next search
startIndex = index + needleLower.length;
// Find the next occurrence of needle in haystack
index = haystackLower.indexOf(needleLower, startIndex);
}
// Add any remaining text after the last match
container.appendChild(
document.createTextNode(haystack.substring(startIndex))
);
// Was anything found?
return container.children.length === 0 ? null : container;
}
/// Update the visible options based on everything matching the search
/// filter
_updateOptionEntries(): void {
this.optionsElement.innerHTML = '';
let needleLower = this.inputBox.value.toLowerCase();
// Find matching options
for (let optionName of this.state.optionNames) {
let match = this._highlightMatches(optionName, needleLower);
if (match === null) {
continue;
}
match.classList.add('rio-dropdown-option');
this.optionsElement.appendChild(match);
match.addEventListener('mouseenter', () => {
this._highlightOption(match);
});
// With a `click` handler, the <input> element loses focus for a
// little while, which is noticeable because the floating label will
// quickly move down and then back up. To avoid this, we use
// `mousedown` instead.
match.addEventListener('mousedown', (event) => {
this.submitInput(optionName);
markEventAsHandled(event);
});
}
// If only one option was found, highlight it
if (this.optionsElement.children.length === 1) {
this._highlightOption(
this.optionsElement.firstElementChild as HTMLElement
);
}
// Was anything found?
if (this.optionsElement.children.length === 0) {
applyIcon(
this.optionsElement,
'material/error',
'var(--rio-local-text-color)'
);
// The icon is loaded asynchronously, so make sure to give the
// element some space
this.popupElement.style.height = '7rem';
} else {
// Resize the popup to fit the new content
this.popupElement.style.height = `${this.optionsElement.scrollHeight}px`;
}
}
updateElement(
deltaState: DropdownState,
latentComponents: Set<ComponentBase>
): void {
super.updateElement(deltaState, latentComponents);
let element = this.element;
if (deltaState.optionNames !== undefined) {
this.state.optionNames = deltaState.optionNames;
if (this.isOpen) {
this._updateOptionEntries();
}
}
if (deltaState.label !== undefined) {
this.inputBox.label = deltaState.label;
}
if (deltaState.selectedName !== undefined) {
this.inputBox.value = deltaState.selectedName;
}
if (deltaState.is_sensitive === true) {
this.inputBox.isSensitive = true;
element.classList.remove(
'rio-disabled-input',
'rio-switcheroo-disabled'
);
} else if (deltaState.is_sensitive === false) {
this.inputBox.isSensitive = false;
element.classList.add(
'rio-disabled-input',
'rio-switcheroo-disabled'
);
this.hidePopup();
}
if (deltaState.is_valid === false) {
this.element.style.setProperty(
'--rio-local-text-color',
'var(--rio-global-danger-bg)'
);
} else if (deltaState.is_valid === true) {
this.element.style.removeProperty('--rio-local-text-color');
}
}
}