Ghost/ghost/admin/lib/koenig-editor/addon/services/koenig-drag-drop-handler.js
2021-07-15 16:26:01 +01:00

714 lines
27 KiB
JavaScript

import * as constants from '../lib/dnd/constants';
import * as utils from '../lib/dnd/utils';
import Container from '../lib/dnd/container';
import ScrollHandler from '../lib/dnd/scroll-handler';
import Service from '@ember/service';
import {A} from '@ember/array';
import {alias} from '@ember/object/computed';
import {didCancel, task, waitForProperty} from 'ember-concurrency';
import {run} from '@ember/runloop';
import {inject as service} from '@ember/service';
// this service allows registration of "containers"
// containers can have both draggables and droppables
// - draggables are elements that can be dragged
// - droppables are elements that should respond if dragged over
// containers will handle the drag start/drag over/drop events triggered by this service
// this service keeps track of all containers and has centralized event handling for mouse events
export default Service.extend({
koenigUi: service(),
containers: null,
ghostInfo: null,
grabbedElement: null, // TODO: standardise on draggableInfo.element
sourceContainer: null,
isDragging: alias('koenigUi.isDragging'),
_eventHandlers: null,
// lifecycle ---------------------------------------------------------------
init() {
this._super(...arguments);
this.containers = A([]);
this.scrollHandler = new ScrollHandler();
this._eventHandlers = {};
this._transformedDroppables = A([]);
// bind any raf handler functions
this._rafUpdateGhostElementPosition = run.bind(this, this._updateGhostElementPosition);
// set up document event listeners
this._addGrabListeners();
// append body elements
this._appendGhostContainerElement();
},
willDestroy() {
this._super(...arguments);
// reset any on-going drag and remove any temporary listeners
this.cleanup();
// clean up document event listeners
this._removeGrabListeners();
// remove body elements
this._removeDropIndicator();
this._removeGhostContainerElement();
},
// interface ---------------------------------------------------------------
registerContainer(element, options) {
let container = new Container(element, options);
this.containers.pushObject(container);
// return a minimal interface to the container because this service
// should be used for management rather than the container class instance
return {
enableDrag: () => {
container.enableDrag();
},
disableDrag: () => {
container.disableDrag();
},
refresh: () => {
// re-calculate draggables/droppables
container.refresh();
},
destroy: () => {
// unregister container
this.containers.removeObject(container);
}
};
},
// remove all containers and event handlers, useful when leaving an editor route
cleanup() {
this.containers = A([]);
// cancel any tasks and remove intermittent event handlers
this._resetDrag();
},
// event handlers ----------------------------------------------------------
// we use a custom "drag" detection rather than native drag events because it
// allows better tracking across multiple containers and gives more flexibilty
// for handling touch events later if required
_onMouseDown(event) {
if (!this.isDragging && (event.button === undefined || event.button === 0)) {
this.grabbedElement = utils.getParent(event.target, constants.DRAGGABLE_SELECTOR);
if (this.grabbedElement) {
// some elements may have explicitly disabled dragging such as
// captions where we want to allow text selection instead
let dragDisabledElement = utils.getParent(event.target, constants.DRAG_DISABLED_SELECTOR);
if (dragDisabledElement && this.grabbedElement.contains(dragDisabledElement)) {
return;
}
let containerElement = utils.getParent(this.grabbedElement, constants.CONTAINER_SELECTOR);
let container = this.containers.findBy('element', containerElement);
this.sourceContainer = container;
if (container.isDragEnabled) {
this._waitForDragStart.perform(event).then(() => {
// stop the drag creating a selection
window.getSelection().removeAllRanges();
// set up the drag details
this._initiateDrag(event);
}).catch((error) => {
// ignore cancelled tasks and throw unrecognized errors
if (!didCancel(error)) {
throw error;
}
});
}
}
}
},
_onMouseMove(event) {
event.preventDefault();
if (this.draggableInfo) {
this.draggableInfo.mousePosition.x = event.clientX;
this.draggableInfo.mousePosition.y = event.clientY;
this._handleDrag(event);
}
},
_onMouseUp(/*event*/) {
if (this.draggableInfo) {
let success = false;
// TODO: accept object rather than positioned args? OR, should the
// droppable data be stored on draggableInfo?
if (this._currentOverContainer) {
success = this._currentOverContainer.onDrop(
this.draggableInfo,
this._currentOverDroppableElem,
this._currentOverDroppablePosition
);
}
this.containers.forEach((container) => {
container.onDropEnd(this.draggableInfo, success);
});
}
// remove drag info and any ghost element
this._resetDrag();
},
_onKeyDown(event) {
// cancel drag on escape
if (this.isDragging && event.key === 'Escape') {
this._resetDrag();
}
},
// private -----------------------------------------------------------------
// called when we detect a mousedown event on a draggable element. Sets
// up temporary event handlers for mousemove, mouseup, and drag. If
// sufficient movement is detected before the mouse is released and we don't
// detect a native drag event then the task will resolve. Mouseup or drag
// events will cancel the task which will result in a rejected promise if
// the task has been cast to a promise
_waitForDragStart: task(function* (startEvent) {
let moveThreshold = 1;
this.set('_dragStartConditionsMet', false);
let onMove = (event) => {
let {clientX: currentX, clientY: currentY} = event;
if (
Math.abs(startEvent.clientX - currentX) > moveThreshold ||
Math.abs(startEvent.clientY - currentY) > moveThreshold
) {
this.set('_dragStartConditionsMet', true);
}
};
let onUp = () => {
this._waitForDragStart.cancelAll();
};
// give preference to native drag/drop handlers
let onHtmlDrag = () => {
this._waitForDragStart.cancelAll();
};
// register local events
document.addEventListener('mousemove', onMove, {passive: false});
document.addEventListener('mouseup', onUp, {passive: false});
document.addEventListener('drag', onHtmlDrag, {passive: false});
try {
yield waitForProperty(this, '_dragStartConditionsMet');
} finally {
// finally is always called on task cancellation
this.set('_dragStartConditionsMet', false);
document.removeEventListener('mousemove', onMove, {passive: false});
document.removeEventListener('mouseup', onUp, {passive: false});
document.removeEventListener('drag', onHtmlDrag, {passive: false});
}
}).keepLatest(),
_initiateDrag(startEvent) {
this.set('isDragging', true);
utils.applyUserSelect(document.body, 'none');
let draggableInfo = this.sourceContainer.getDraggableInfo(this.grabbedElement);
if (!draggableInfo) {
this._resetDrag();
return;
}
// append the drop indicator if it doesn't already exist - we append to
// the editor's element rather than body so it needs to be re-appended
// each time a drag is initiated in a new editor instance
this._appendDropIndicator();
draggableInfo = Object.assign({}, draggableInfo, {
element: this.grabbedElement,
mousePosition: {
x: startEvent.clientX,
y: startEvent.clientY
}
});
this.set('draggableInfo', draggableInfo);
this.containers.forEach((container) => {
container.onDragStart(draggableInfo);
});
// style the dragged element
this.draggableInfo.element.style.opacity = 0.5;
// create the ghost element and cache it's position so avoid costly
// getBoundingClientRect calls in the mousemove handler
let ghostElement = this.sourceContainer.createGhostElement(this.draggableInfo);
if (ghostElement && ghostElement instanceof HTMLElement) {
this._ghostContainerElement.appendChild(ghostElement);
let ghostElementRect = ghostElement.getBoundingClientRect();
let ghostInfo = {
element: ghostElement,
positionX: ghostElementRect.x,
positionY: ghostElementRect.y
};
this.set('ghostInfo', ghostInfo);
} else {
// eslint-disable-next-line
console.warn('container.createGhostElement did not return an element', this.draggableInfo, {ghostElement});
this._resetDrag();
return;
}
// add watches to follow the drag/drop
this._addMoveListeners();
this._addReleaseListeners();
this._addKeyDownListeners();
// start ghost element following the mouse
requestAnimationFrame(this._rafUpdateGhostElementPosition);
// let the scroll handler select the scrollable element
this.scrollHandler.dragStart(this.draggableInfo);
// prevent the pointer showing the text caret over text content whilst dragging
document.querySelectorAll('[data-kg="editor"]').forEach((el) => {
el.style.setProperty('cursor', 'default', 'important');
});
// prevent card hover showing whilst dragging
this._elementsWithHoverRemoved = document.querySelectorAll('.kg-card-hover');
this._elementsWithHoverRemoved.forEach((el) => {
el.classList.remove('kg-card-hover');
});
this._handleDrag();
},
_handleDrag() {
// hide the ghost element so that it's not picked up by elementFromPoint
// when determining the target element under the mouse
this._ghostContainerElement.hidden = true;
let target = document.elementFromPoint(
this.draggableInfo.mousePosition.x,
this.draggableInfo.mousePosition.y
);
this.draggableInfo.target = target;
this._ghostContainerElement.hidden = false;
this.scrollHandler.dragMove(this.draggableInfo);
let overContainerElem = utils.getParent(target, constants.CONTAINER_SELECTOR);
let overDroppableElem = utils.getParent(target, constants.DROPPABLE_SELECTOR);
// it's possible for the mouse to be over a "dead" area when dragging over
// the position indicator, in this case we want to prevent a parent
// container's droppable from being picked up
if (!overContainerElem || !overContainerElem.contains(overDroppableElem)) {
overDroppableElem = null;
}
let isLeavingContainer = this._currentOverContainerElem && overContainerElem !== this._currentOverContainerElem;
let isLeavingDroppable = this._currentOverDroppableElem && overDroppableElem !== this._currentOverDroppableElem;
let isOverContainer = overContainerElem && overContainerElem !== this._currentOverContainer;
let isOverDroppable = overDroppableElem;
if (isLeavingContainer) {
this._currentOverContainer.onDragLeaveContainer();
this._currentOverContainer = null;
this._currentOverContainerElem = null;
this._hideDropIndicator();
}
if (isOverContainer) {
let container = this.containers.findBy('element', overContainerElem);
if (!this._currentOverContainer) {
container.onDragEnterContainer();
}
this._currentOverContainer = container;
this._currentOverContainerElem = overContainerElem;
}
if (isLeavingDroppable) {
if (this._currentOverContainer) {
this._currentOverContainer.onDragLeaveDroppable(overDroppableElem);
}
this._currentOverDroppableElem = null;
}
if (isOverDroppable) {
// get position within the droppable
// TODO: cache droppable rects to avoid costly queries whilst dragging
let rect = overDroppableElem.getBoundingClientRect();
let inTop = this.draggableInfo.mousePosition.y < (rect.y + rect.height / 2);
let inLeft = this.draggableInfo.mousePosition.x < (rect.x + rect.width / 2);
let position = `${inTop ? 'top' : 'bottom'}-${inLeft ? 'left' : 'right'}`;
if (!this._currentOverDroppableElem) {
this._currentOverContainer.onDragEnterDroppable(overDroppableElem, position);
}
if (overDroppableElem !== this._currentOverDroppableElem || position !== this._currentOverDroppablePosition) {
this._currentOverDroppableElem = overDroppableElem;
this._currentOverDroppablePosition = position;
this._currentOverContainer.onDragOverDroppable(overDroppableElem, position);
// container.getIndicatorPosition returns false if the drop is not allowed
let indicatorPosition = this._currentOverContainer.getIndicatorPosition(this.draggableInfo, overDroppableElem, position);
if (indicatorPosition) {
this.draggableInfo.insertIndex = indicatorPosition.insertIndex;
this._showDropIndicator(indicatorPosition);
} else {
this._hideDropIndicator();
}
}
}
},
_updateGhostElementPosition() {
if (this.isDragging) {
requestAnimationFrame(this._rafUpdateGhostElementPosition);
}
let {ghostInfo, draggableInfo} = this;
if (draggableInfo && ghostInfo) {
let left = (ghostInfo.positionX * -1) + draggableInfo.mousePosition.x;
let top = (ghostInfo.positionY * -1) + draggableInfo.mousePosition.y;
ghostInfo.element.style.transform = `translate3d(${left}px, ${top}px, 0)`;
}
},
// direction = horizontal/vertical
// horizontal = beforeElems shift left, afterElems shift right
// vertical = afterElems shift down
// position = above/below/left/right, used to place the indicator
_showDropIndicator({direction, position, beforeElems, afterElems}) {
let dropIndicator = this._dropIndicator;
// reset everything except insertIndex before re-displaying indicator
this._hideDropIndicator({clearInsertIndex: false});
if (direction === 'horizontal') {
beforeElems.forEach((elem) => {
elem.style.transform = 'translate3d(-30px, 0, 0)';
elem.style.transitionDuration = '250ms';
this._transformedDroppables.push(elem);
});
afterElems.forEach((elem) => {
elem.style.transform = 'translate3d(30px, 0, 0)';
elem.style.transitionDuration = '250ms';
this._transformedDroppables.push(elem);
});
let leftAdjustment = 0;
let droppable = this._currentOverDroppableElem;
let droppableStyles = getComputedStyle(droppable);
// calculate position based on offset parent to avoid the transform
// being accounted for
let parentRect = droppable.offsetParent.getBoundingClientRect();
let offsetLeft = parentRect.left + droppable.offsetLeft;
let offsetTop = parentRect.top + droppable.offsetTop;
if (position === 'left') {
leftAdjustment -= parseInt(droppableStyles.marginLeft);
} else {
leftAdjustment += parseInt(droppable.offsetWidth) + parseInt(droppableStyles.marginRight);
}
// account for indicator width
leftAdjustment -= 2;
let dropIndicatorParentRect = dropIndicator.parentNode.getBoundingClientRect();
let lastLeft = parseInt(dropIndicator.style.left);
let lastTop = parseInt(dropIndicator.style.top);
let newLeft = offsetLeft + leftAdjustment - dropIndicatorParentRect.left;
let newTop = offsetTop - dropIndicatorParentRect.top;
let newHeight = droppable.offsetHeight;
// if indicator hasn't moved, keep it showing, otherwise wait for
// the transform transitions to almost finish before re-positioning
// and showing
// NOTE: +- 1px is due to sub-pixel positioning of droppables
if (
newTop >= lastTop - 1 && newTop <= lastTop + 1 &&
newLeft >= lastLeft - 1 && newLeft <= lastLeft + 1
) {
dropIndicator.style.opacity = 1;
} else {
dropIndicator.style.opacity = 0;
this._dropIndicatorTimeout = run.later(this, function () {
dropIndicator.style.width = '4px';
dropIndicator.style.height = `${newHeight}px`;
dropIndicator.style.left = `${newLeft}px`;
dropIndicator.style.top = `${newTop}px`;
dropIndicator.style.opacity = 1;
}, 150);
}
}
if (direction === 'vertical') {
let transformSize = 60;
let droppable = this._currentOverDroppableElem;
let topElement, bottomElement;
if (position === 'top') {
topElement = utils.getPreviousSibling(droppable, constants.DROPPABLE_SELECTOR);
bottomElement = droppable;
} else if (position === 'bottom') {
topElement = droppable;
bottomElement = utils.getNextSibling(droppable, constants.DROPPABLE_SELECTOR);
}
// marginTop of the first element affects the offset of the
// children so it needs to be taken into account
let firstElement = (topElement || bottomElement).parentElement.children[0];
let firstElementStyles = getComputedStyle(firstElement);
let firstTopMargin = parseInt(firstElementStyles.marginTop);
let newWidth = droppable.offsetWidth;
let newLeft = droppable.offsetLeft;
let newTop;
if (topElement && bottomElement) {
let topElementStyles = getComputedStyle(topElement);
let bottomElementStyles = getComputedStyle(bottomElement);
let offsetTop = bottomElement.offsetTop;
let topMargin = parseInt(topElementStyles.marginBottom);
let bottomMargin = parseInt(bottomElementStyles.marginTop);
let marginHeight = topMargin + bottomMargin;
newTop = offsetTop - (marginHeight / 2) + firstTopMargin;
} else if (topElement) {
// at the bottom of the container
newTop = topElement.offsetTop + topElement.offsetHeight + firstTopMargin;
} else if (bottomElement) {
// at the top of the container, place the indicator 0px from the top
newTop = -26; // account for later adjustments and indicator height
transformSize = 30; // halve normal adjustment because there's no gap needed between top element
}
// account for indicator height
newTop -= 2;
// vertical always pushes elements down
newTop += 30;
// if indicator hasn't moved, keep it showing, otherwise wait for
// the transform transitions to almost finish before re-positioning
// and showing
// NOTE: +- 1px is due to sub-pixel positioning of droppables
let lastLeft = parseInt(dropIndicator.style.left);
let lastTop = parseInt(dropIndicator.style.top);
if (
newTop >= lastTop - 1 && newTop <= lastTop + 1 &&
newLeft >= lastLeft - 1 && newLeft <= lastLeft + 1
) {
dropIndicator.style.opacity = 1;
} else {
dropIndicator.style.opacity = 0;
this._dropIndicatorTimeout = run.later(this, function () {
dropIndicator.style.height = '4px';
dropIndicator.style.width = `${newWidth}px`;
dropIndicator.style.left = `${newLeft}px`;
dropIndicator.style.top = `${newTop}px`;
dropIndicator.style.opacity = 1;
}, 150);
}
// always update the droppable transforms so that re-positining in
// the same place still moves the elements. Effectively a no-op if
// the styles already exist
beforeElems.forEach((elem) => {
elem.style.transform = 'translate3d(0, 0, 0)';
elem.style.transitionDuration = '250ms';
this._transformedDroppables.push(elem);
});
afterElems.forEach((elem) => {
elem.style.transform = `translate3d(0, ${transformSize}px, 0)`;
elem.style.transitionDuration = '250ms';
this._transformedDroppables.push(elem);
});
}
},
_hideDropIndicator({clearInsertIndex = true} = {}) {
// make sure the indicator isn't shown due to a running timeout
run.cancel(this._dropIndicatorTimeout);
// clear droppable insert index unless instructed not to (eg, when
// resetting the display before re-positioning the indicator)
if (clearInsertIndex && this.draggableInfo) {
delete this.draggableInfo.insertIndex;
}
// reset all transforms
this._transformedDroppables.forEach((elem) => {
elem.style.transform = '';
});
this.transformedDroppables = A([]);
// hide drop indicator
if (this._dropIndicator) {
this._dropIndicator.style.opacity = 0;
}
},
_resetDrag() {
this._waitForDragStart.cancelAll();
this._hideDropIndicator();
this._removeMoveListeners();
this._removeReleaseListeners();
this.scrollHandler.dragStop();
if (this.grabbedElement) {
this.grabbedElement.style.opacity = '';
}
this.set('isDragging', false);
this.set('grabbedElement', null);
this.set('sourceContainer', null);
if (this.ghostInfo) {
this.ghostInfo.element.remove();
this.set('ghostInfo', null);
}
this.containers.forEach((container) => {
container.onDragEnd();
});
if (this._elementsWithHoverRemoved) {
this._elementsWithHoverRemoved.forEach((el) => {
el.classList.add('kg-card-hover');
});
}
delete this._elementsWithHoverRemoved;
utils.applyUserSelect(document.body, '');
document.querySelectorAll('[data-kg="editor"]').forEach((el) => {
el.style.cursor = '';
});
},
_appendDropIndicator() {
let dropIndicator = document.querySelector(`#${constants.DROP_INDICATOR_ID}`);
if (!dropIndicator) {
dropIndicator = document.createElement('div');
dropIndicator.id = constants.DROP_INDICATOR_ID;
dropIndicator.classList.add('bg-green', 'br-pill');
dropIndicator.style.position = 'absolute';
dropIndicator.style.opacity = 0;
dropIndicator.style.width = '4px';
dropIndicator.style.height = 0;
dropIndicator.style.zIndex = constants.DROP_INDICATOR_ZINDEX;
dropIndicator.style.pointerEvents = 'none';
// TODO: the scrollableElement should probably be configurable, it
// may need to be set on a per-container basis in case there are
// scrollable containers within a card
let scrollableElement = document.querySelector('.koenig-editor')
|| utils.getDocumentScrollingElement();
scrollableElement.appendChild(dropIndicator);
}
this._dropIndicator = dropIndicator;
},
_appendGhostContainerElement() {
if (!this._ghostContainerElement) {
let ghostContainerElement = document.createElement('div');
ghostContainerElement.id = constants.GHOST_CONTAINER_ID;
ghostContainerElement.style.position = 'fixed';
ghostContainerElement.style.width = '100%';
document.body.appendChild(ghostContainerElement);
this._ghostContainerElement = ghostContainerElement;
}
},
_removeDropIndicator() {
if (this._dropIndicator) {
this._dropIndicator.remove();
}
},
_removeGhostContainerElement() {
if (this.ghostContainerElement) {
this.ghostContainerElement.remove();
}
},
_addGrabListeners() {
this._addEventListener('mousedown', this._onMouseDown, {passive: false});
},
_removeGrabListeners() {
this._removeEventListener('mousedown');
},
_addMoveListeners() {
this._addEventListener('mousemove', this._onMouseMove, {passive: false});
},
_removeMoveListeners() {
this._removeEventListener('mousemove');
},
_addReleaseListeners() {
this._addEventListener('mouseup', this._onMouseUp, {passive: false});
},
_removeReleaseListeners() {
this._removeEventListener('mouseup');
},
_addKeyDownListeners() {
this._addEventListener('keydown', this._onKeyDown);
},
_removeKeyDownListeners() {
this._removeEventListener('keydown');
},
_addEventListener(e, method, options) {
if (!this._eventHandlers[e]) {
let handler = run.bind(this, method);
this._eventHandlers[e] = {handler, options};
document.addEventListener(e, handler, options);
}
},
_removeEventListener(e) {
let event = this._eventHandlers[e];
if (event) {
document.removeEventListener(e, event.handler, event.options);
delete this._eventHandlers[e];
}
}
});