Files
rio/frontend/code/components/dropdown.ts
2025-01-09 18:27:57 +01:00

515 lines
18 KiB
TypeScript

import { ComponentBase, ComponentState } from "./componentBase";
import { applyIcon } from "../designApplication";
import { pixelsPerRem } from "../app";
import { InputBox, InputBoxStyle } from "../inputBox";
import { markEventAsHandled } from "../eventHandling";
import { PopupManager, positionDropdown } from "../popupManager";
export type DropdownState = ComponentState & {
_type_: "Dropdown-builtin";
optionNames?: string[];
label?: string;
accessibility_label?: string;
style?: InputBoxStyle;
selectedName?: string;
is_sensitive?: boolean;
is_valid?: boolean;
};
export class DropdownComponent extends ComponentBase {
declare state: Required<DropdownState>;
private inputBox: InputBox;
private hiddenOptionsElement: HTMLElement;
private popupElement: HTMLElement;
private popupOptionsElement: HTMLElement;
private popupManager: PopupManager;
// The currently highlighted option, if any
private highlightedOptionElement: HTMLElement | null = null;
createElement(): HTMLElement {
// Create root element
let element = document.createElement("div");
element.classList.add("rio-dropdown");
// The dropdown is styled as an input box, so use the InputBox
// abstraction.
this.inputBox = new InputBox({
labelIsAlwaysSmall: true,
// Don't make any elements clickable because they steal away the
// focus from the <input> for a short while, which causes the
// dropdown to close and immediately reopen
connectClickHandlers: false,
});
element.appendChild(this.inputBox.outerElement);
// In order to ensure the dropdown can actually fit its options, add a
// hidden element that will contain a copy of all options. This element
// will have no height, but but its width will push the dropdown to be
// wide enough to fit all texts.
this.hiddenOptionsElement = document.createElement("div");
this.hiddenOptionsElement.classList.add("rio-dropdown-options");
element.appendChild(this.hiddenOptionsElement);
// Add an arrow icon
let arrowElement = document.createElement("div");
arrowElement.classList.add("rio-dropdown-arrow");
applyIcon(arrowElement, "material/expand_more");
this.inputBox.suffixElement = arrowElement;
// Create the popup content
this.popupElement = document.createElement("div");
this.popupElement.tabIndex = -999; // Required for Chrome, sets `FocusEvent.relatedTarget`
this.popupElement.classList.add(
"rio-dropdown-popup",
"rio-popup-manager-animation-dropdown"
);
this.popupOptionsElement = document.createElement("div");
this.popupOptionsElement.classList.add("rio-dropdown-options");
this.popupElement.appendChild(this.popupOptionsElement);
// Connect events
element.addEventListener(
"pointerdown",
this._onPointerDown.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)
);
// Initialize a popup manager
this.popupManager = new PopupManager({
anchor: element,
content: this.popupElement,
positioner: positionDropdown,
modal: false,
userClosable: true,
onUserClose: this.hidePopupDontCommit.bind(this),
});
return element;
}
/// Open the dropdown and show all options
private _onPointerDown(event: PointerEvent): void {
// Do we care?
if (!this.state.is_sensitive || event.button !== 0) {
return;
}
// Eat the event
markEventAsHandled(event);
// If the popup was already open, close it
if (this.popupManager.isOpen) {
this.hidePopupDontCommit();
return;
}
// Otherwise focus it. The focus handler will do the remaining work.
this.inputBox.focus();
}
private _onFocusIn(): void {
// Clear the input text so that all options are shown in the dropdown
this.inputBox.value = "";
// Show the popup
this.showPopup();
}
private _onFocusOut(event: FocusEvent): void {
// Careful: Clicking on a dropdown option 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;
}
// When the input element loses focus, that means the user is done
// entering input. Depending on whether they have put in a valid option,
// either save it or reset.
this.hidePopupAndCommit(this.inputBox.value);
}
_onKeyDown(event: KeyboardEvent): void {
// Escape: close the popup without committing
if (event.key === "Escape") {
this.hidePopupDontCommit();
}
// Enter: select the highlighted option
else if (event.key === "Enter") {
if (this.highlightedOptionElement !== null) {
let pointerDownEvent = new PointerEvent("pointerdown", {
bubbles: true,
cancelable: true,
view: window,
});
this.highlightedOptionElement.dispatchEvent(pointerDownEvent);
}
}
// Move highlight down
else if (event.key === "ArrowDown") {
let nextOption;
if (this.highlightedOptionElement === null) {
nextOption = this.popupOptionsElement.firstElementChild;
} else {
nextOption = this.highlightedOptionElement.nextElementSibling;
if (nextOption === null) {
nextOption = this.popupOptionsElement.firstElementChild;
}
}
this._highlightOption(nextOption as HTMLElement);
}
// Move highlight up
else if (event.key === "ArrowUp") {
let nextOption: Element | null;
if (this.highlightedOptionElement === null) {
nextOption = this.popupOptionsElement.lastElementChild;
} else {
nextOption =
this.highlightedOptionElement.previousElementSibling;
if (nextOption === null) {
nextOption = this.popupOptionsElement.lastElementChild;
}
}
this._highlightOption(nextOption as HTMLElement);
}
// Any other key: let the event propagate
else {
return;
}
markEventAsHandled(event);
}
private _onInputValueChange(): void {
this._updatePopupOptionsElement();
}
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");
}
}
/// Opens the popup if it isn't open already. Does nothing otherwise.
private showPopup(): void {
// Already open?
if (this.popupManager.isOpen) {
return;
}
// Reset the highlighted option
this._updatePopupOptionsElement();
// Tell the popup manager to show the popup
//
// This must happen before the options are updated, because the popup
// manager needs knowledge about the size of the options.
this.popupManager.isOpen = true;
// Make sure mobile browsers don't display a keyboard.
//
// The popup positioner communicates the layout it has decided on via
// CSS classes.
this.inputBox.inputElement.readOnly =
this.popupElement.classList.contains(
"rio-dropdown-popup-mobile-fullscreen"
);
}
/// Close the popup and apply the selected option. Does nothing if the popup
/// isn't open, or the given option is invalid.
private hidePopupAndCommit(newOptionName: string): void {
// Already closed?
if (!this.popupManager.isOpen) {
return;
}
// Close the popup
this.popupManager.isOpen = false;
// No longer focus the input box
this.inputBox.unfocus();
// If the chosen text hasn't changed there is nothing more to be done
if (newOptionName === this.state.selectedName) {
return;
}
// If the given option is valid, tell the almighty snake
if (this.state.optionNames.includes(newOptionName)) {
this.inputBox.value = newOptionName;
this.state.selectedName = newOptionName;
this.sendMessageToBackend({
name: newOptionName,
});
}
// Nope, revert
else {
this.inputBox.value = this.state.selectedName;
}
}
/// Closes the popup without applying the selected option. Does nothing if
/// the popup isn't open.
private hidePopupDontCommit(): void {
// Note that there is no check here for whether the dropdown is already
// closed. That's because this function is called by the popup manager
// when closed by the user (e.g. clicking outside the popup), at which
// point the manager may already consider itself closed. That's fine,
// because this function doesn't do anything fancy and can be called
// as often as you like.
// Make sure the popup isn't visible
this.popupManager.isOpen = false;
// Revert the text input to what was already selected
this.inputBox.value = this.state.selectedName;
// Make sure to defocus the input box, so that clicking on it again
// re-opens the popup.
this.inputBox.unfocus();
// There is no need to tell Python, since nothing has changed.
}
onDestruction(): void {
super.onDestruction();
this.popupManager.destroy();
}
/// Find `needleLower` in `haystack`, returning a HTMLElement with the
/// matched sections highlighted. If no match is found, return null. The
/// needle must be lowercase.
_highlightMatches(
haystack: string,
needleLower: string
): HTMLElement | null {
// Special case: Empty needles 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-highlighted";
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;
}
_updateHiddenOptionsElement(): void {
this.hiddenOptionsElement.innerHTML = "";
for (let optionName of this.state.optionNames) {
let child = document.createElement("div");
child.classList.add("rio-dropdown-option");
child.textContent = optionName;
this.hiddenOptionsElement.appendChild(child);
}
}
/// Rebuilds the popup options element, filtering the visible options to
/// those matching the input text. This also updates the matches visually
/// where appropriate.
_updatePopupOptionsElement(): void {
// Prepare
let needleLower = this.inputBox.value.toLowerCase();
// Clean up
this.popupOptionsElement.innerHTML = "";
// 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.popupOptionsElement.appendChild(match);
match.addEventListener("pointerenter", () => {
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
// `pointerdown` instead.
match.addEventListener("pointerdown", (event) => {
this.hidePopupAndCommit(optionName);
markEventAsHandled(event);
});
}
// If only one option was found, highlight it
if (this.popupOptionsElement.children.length === 1) {
this._highlightOption(
this.popupOptionsElement.firstElementChild as HTMLElement
);
}
// Display an icon and resize the element
//
// For some reason the SVG has an explicit opacity set. Because of that,
// using CSS isn't possible. Overwrite the opacity here.
if (this.popupOptionsElement.children.length === 0) {
applyIcon(this.popupOptionsElement, "material/error").then(() => {
(
this.popupOptionsElement.firstElementChild as SVGElement
).style.opacity = "0.2";
});
this.popupElement.style.height = "7rem";
} else {
this.popupElement.style.height = `${this.popupOptionsElement.scrollHeight}px`;
}
}
updateElement(
deltaState: DropdownState,
latentComponents: Set<ComponentBase>
): void {
super.updateElement(deltaState, latentComponents);
// If the options have changed update the options element, and also
// store its width
if (deltaState.optionNames !== undefined) {
// Store the new value, because it is about to be accessed
this.state.optionNames = deltaState.optionNames;
// Update the hidden options element
this._updateHiddenOptionsElement();
// Update the visible options element
if (this.popupManager.isOpen) {
this._updatePopupOptionsElement();
}
}
if (deltaState.label !== undefined) {
this.inputBox.label = deltaState.label;
}
if (deltaState.accessibility_label !== undefined) {
this.inputBox.accessibilityLabel = deltaState.accessibility_label;
}
if (deltaState.style !== undefined) {
this.inputBox.style = deltaState.style;
}
if (deltaState.selectedName !== undefined) {
this.inputBox.value = deltaState.selectedName;
}
if (deltaState.is_sensitive === true) {
this.inputBox.isSensitive = true;
this.element.classList.remove(
"rio-disabled-input",
"rio-switcheroo-disabled"
);
} else if (deltaState.is_sensitive === false) {
this.inputBox.isSensitive = false;
this.element.classList.add(
"rio-disabled-input",
"rio-switcheroo-disabled"
);
this.hidePopupDontCommit();
}
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");
}
}
}