Allow reordering of the space panel via Drag and Drop

package.json

@@ -89,6 +89,7 @@
     "qrcode": "^1.4.4",
     "re-resizable": "^6.9.0",
     "react": "^17.0.2",
+    "react-beautiful-dnd": "^13.1.0",
     "react-dom": "^17.0.2",
     "react-focus-lock": "^2.5.0",
     "react-transition-group": "^4.4.1",
@@ -132,6 +133,7 @@
     "@types/parse5": "^6.0.0",
     "@types/qrcode": "^1.3.5",
     "@types/react": "^17.0.2",
+    "@types/react-beautiful-dnd": "^13.0.0",
     "@types/react-dom": "^17.0.2",
     "@types/react-transition-group": "^4.4.0",
     "@types/sanitize-html": "^2.3.1",

res/css/structures/_SpacePanel.scss

@@ -31,7 +31,6 @@ $activeBorderColor: $secondary-fg-color;
     // Create another flexbox so the Panel fills the container
     display: flex;
     flex-direction: column;
-    overflow-y: auto;
 
     .mx_SpacePanel_spaceTreeWrapper {
         flex: 1;
@@ -69,6 +68,12 @@ $activeBorderColor: $secondary-fg-color;
         cursor: pointer;
     }
 
+    .mx_SpaceItem_dragging {
+        .mx_SpaceButton_toggleCollapse {
+            visibility: hidden;
+        }
+    }
+
     .mx_SpaceTreeLevel {
         display: flex;
         flex-direction: column;

src/components/structures/AutoHideScrollbar.tsx

@@ -15,9 +15,9 @@ See the License for the specific language governing permissions and
 limitations under the License.
 */
 
-import React from "react";
+import React, { HTMLAttributes } from "react";
 
-interface IProps {
+interface IProps extends HTMLAttributes<HTMLDivElement> {
     className?: string;
     onScroll?: () => void;
     onWheel?: () => void;
@@ -52,14 +52,18 @@ export default class AutoHideScrollbar extends React.Component<IProps> {
     }
 
     public render() {
+        // eslint-disable-next-line @typescript-eslint/no-unused-vars
+        const { className, onScroll, onWheel, style, tabIndex, wrappedRef, children, ...otherProps } = this.props;
+
         return (<div
+            {...otherProps}
             ref={this.containerRef}
-            style={this.props.style}
-            className={["mx_AutoHideScrollbar", this.props.className].join(" ")}
-            onWheel={this.props.onWheel}
-            tabIndex={this.props.tabIndex}
+            style={style}
+            className={["mx_AutoHideScrollbar", className].join(" ")}
+            onWheel={onWheel}
+            tabIndex={tabIndex}
         >
-            { this.props.children }
+            { children }
         </div>);
     }
 }

src/components/structures/IndicatorScrollbar.js

@@ -185,21 +185,24 @@ export default class IndicatorScrollbar extends React.Component {
     };
 
     render() {
+        // eslint-disable-next-line no-unused-vars
+        const { children, trackHorizontalOverflow, verticalScrollsHorizontally, ...otherProps } = this.props;
+
         const leftIndicatorStyle = {left: this.state.leftIndicatorOffset};
         const rightIndicatorStyle = {right: this.state.rightIndicatorOffset};
-        const leftOverflowIndicator = this.props.trackHorizontalOverflow
+        const leftOverflowIndicator = trackHorizontalOverflow
             ? <div className="mx_IndicatorScrollbar_leftOverflowIndicator" style={leftIndicatorStyle} /> : null;
-        const rightOverflowIndicator = this.props.trackHorizontalOverflow
+        const rightOverflowIndicator = trackHorizontalOverflow
             ? <div className="mx_IndicatorScrollbar_rightOverflowIndicator" style={rightIndicatorStyle} /> : null;
 
         return (<AutoHideScrollbar
             ref={this._collectScrollerComponent}
             wrappedRef={this._collectScroller}
             onWheel={this.onMouseWheel}
-            {...this.props}
+            {...otherProps}
         >
             { leftOverflowIndicator }
-            { this.props.children }
+            { children }
             { rightOverflowIndicator }
         </AutoHideScrollbar>);
     }

src/components/structures/SpaceRoomDirectory.tsx

@@ -14,34 +14,34 @@ See the License for the specific language governing permissions and
 limitations under the License.
 */
 
-import React, {ReactNode, useMemo, useState} from "react";
-import {Room} from "matrix-js-sdk/src/models/room";
-import {MatrixClient} from "matrix-js-sdk/src/client";
-import {EventType, RoomType} from "matrix-js-sdk/src/@types/event";
+import React, { ReactNode, useMemo, useState } from "react";
+import { Room } from "matrix-js-sdk/src/models/room";
+import { MatrixClient } from "matrix-js-sdk/src/client";
+import { EventType, RoomType } from "matrix-js-sdk/src/@types/event";
 import classNames from "classnames";
-import {sortBy} from "lodash";
+import { sortBy } from "lodash";
 
-import {MatrixClientPeg} from "../../MatrixClientPeg";
+import { MatrixClientPeg } from "../../MatrixClientPeg";
 import dis from "../../dispatcher/dispatcher";
-import {_t} from "../../languageHandler";
-import AccessibleButton, {ButtonEvent} from "../views/elements/AccessibleButton";
+import { _t } from "../../languageHandler";
+import AccessibleButton, { ButtonEvent } from "../views/elements/AccessibleButton";
 import BaseDialog from "../views/dialogs/BaseDialog";
 import Spinner from "../views/elements/Spinner";
 import SearchBox from "./SearchBox";
 import RoomAvatar from "../views/avatars/RoomAvatar";
 import RoomName from "../views/elements/RoomName";
-import {useAsyncMemo} from "../../hooks/useAsyncMemo";
-import {EnhancedMap} from "../../utils/maps";
+import { useAsyncMemo } from "../../hooks/useAsyncMemo";
+import { EnhancedMap } from "../../utils/maps";
 import StyledCheckbox from "../views/elements/StyledCheckbox";
 import AutoHideScrollbar from "./AutoHideScrollbar";
 import BaseAvatar from "../views/avatars/BaseAvatar";
-import {mediaFromMxc} from "../../customisations/Media";
+import { mediaFromMxc } from "../../customisations/Media";
 import InfoTooltip from "../views/elements/InfoTooltip";
 import TextWithTooltip from "../views/elements/TextWithTooltip";
-import {useStateToggle} from "../../hooks/useStateToggle";
-import {getOrder} from "../../stores/SpaceStore";
+import { useStateToggle } from "../../hooks/useStateToggle";
+import { getChildOrder } from "../../stores/SpaceStore";
 import AccessibleTooltipButton from "../views/elements/AccessibleTooltipButton";
-import {linkifyElement} from "../../HtmlUtils";
+import { linkifyElement } from "../../HtmlUtils";
 
 interface IHierarchyProps {
     space: Room;
@@ -286,7 +286,7 @@ export const HierarchyLevel = ({
     const children = Array.from(relations.get(spaceId)?.values() || []);
     const sortedChildren = sortBy(children, ev => {
         // XXX: Space Summary API doesn't give the child origin_server_ts but once it does we should use it for sorting
-        return getOrder(ev.content.order, null, ev.state_key);
+        return getChildOrder(ev.content.order, null, ev.state_key);
     });
     const [subspaces, childRooms] = sortedChildren.reduce((result, ev: ISpaceSummaryEvent) => {
         const roomId = ev.state_key;

src/components/views/spaces/SpacePanel.tsx

@@ -14,17 +14,18 @@ See the License for the specific language governing permissions and
 limitations under the License.
 */
 
-import React, { useEffect, useState } from "react";
+import React, { Dispatch, ReactNode, SetStateAction, useEffect, useState } from "react";
+import { DragDropContext, Droppable, Draggable } from "react-beautiful-dnd";
 import classNames from "classnames";
-import {Room} from "matrix-js-sdk/src/models/room";
+import { Room } from "matrix-js-sdk/src/models/room";
 
-import {_t} from "../../../languageHandler";
+import { _t } from "../../../languageHandler";
 import RoomAvatar from "../avatars/RoomAvatar";
-import {useContextMenu} from "../../structures/ContextMenu";
+import { useContextMenu } from "../../structures/ContextMenu";
 import SpaceCreateMenu from "./SpaceCreateMenu";
-import {SpaceItem} from "./SpaceTreeLevel";
+import { SpaceItem } from "./SpaceTreeLevel";
 import AccessibleTooltipButton from "../elements/AccessibleTooltipButton";
-import {useEventEmitter} from "../../../hooks/useEventEmitter";
+import { useEventEmitter } from "../../../hooks/useEventEmitter";
 import SpaceStore, {
     HOME_SPACE,
     UPDATE_INVITED_SPACES,
@@ -38,9 +39,9 @@ import {
     RovingAccessibleTooltipButton,
     RovingTabIndexProvider,
 } from "../../../accessibility/RovingTabIndex";
-import {Key} from "../../../Keyboard";
-import {RoomNotificationStateStore} from "../../../stores/notifications/RoomNotificationStateStore";
-import {NotificationState} from "../../../stores/notifications/NotificationState";
+import { Key } from "../../../Keyboard";
+import { RoomNotificationStateStore } from "../../../stores/notifications/RoomNotificationStateStore";
+import { NotificationState } from "../../../stores/notifications/NotificationState";
 import SettingsStore from "../../../settings/SettingsStore";
 
 interface IButtonProps {
@@ -122,11 +123,65 @@ const useSpaces = (): [Room[], Room[], Room | null] => {
     return [invites, spaces, activeSpace];
 };
 
+interface IInnerSpacePanelProps {
+    children?: ReactNode;
+    isPanelCollapsed: boolean;
+    setPanelCollapsed: Dispatch<SetStateAction<boolean>>;
+}
+
+// Optimisation based on https://github.com/atlassian/react-beautiful-dnd/blob/master/docs/api/droppable.md#recommended-droppable--performance-optimisation
+const InnerSpacePanel = React.memo<IInnerSpacePanelProps>(({ children, isPanelCollapsed, setPanelCollapsed }) => {
+    const [invites, spaces, activeSpace] = useSpaces();
+    const activeSpaces = activeSpace ? [activeSpace] : [];
+
+    const homeNotificationState = SettingsStore.getValue("feature_spaces.all_rooms")
+        ? RoomNotificationStateStore.instance.globalState : SpaceStore.instance.getNotificationState(HOME_SPACE);
+
+    return <div className="mx_SpaceTreeLevel">
+        <SpaceButton
+            className="mx_SpaceButton_home"
+            onClick={() => SpaceStore.instance.setActiveSpace(null)}
+            selected={!activeSpace}
+            tooltip={SettingsStore.getValue("feature_spaces.all_rooms") ? _t("All rooms") : _t("Home")}
+            notificationState={homeNotificationState}
+            isNarrow={isPanelCollapsed}
+        />
+        { invites.map(s => (
+            <SpaceItem
+                key={s.roomId}
+                space={s}
+                activeSpaces={activeSpaces}
+                isPanelCollapsed={isPanelCollapsed}
+                onExpand={() => setPanelCollapsed(false)}
+            />
+        )) }
+        { spaces.map((s, i) => (
+            <Draggable key={s.roomId} draggableId={s.roomId} index={i}>
+                {(provided, snapshot) => (
+                    <SpaceItem
+                        {...provided.draggableProps}
+                        {...provided.dragHandleProps}
+                        key={s.roomId}
+                        innerRef={provided.innerRef}
+                        className={snapshot.isDragging
+                            ? "mx_SpaceItem_dragging"
+                            : undefined}
+                        space={s}
+                        activeSpaces={activeSpaces}
+                        isPanelCollapsed={isPanelCollapsed}
+                        onExpand={() => setPanelCollapsed(false)}
+                    />
+                )}
+            </Draggable>
+        )) }
+        { children }
+    </div>;
+});
+
 const SpacePanel = () => {
     // We don't need the handle as we position the menu in a constant location
     // eslint-disable-next-line @typescript-eslint/no-unused-vars
     const [menuDisplayed, handle, openMenu, closeMenu] = useContextMenu<void>();
-    const [invites, spaces, activeSpace] = useSpaces();
     const [isPanelCollapsed, setPanelCollapsed] = useState(true);
 
     useEffect(() => {
@@ -135,10 +190,6 @@ const SpacePanel = () => {
         }
     }, [isPanelCollapsed]); // eslint-disable-line react-hooks/exhaustive-deps
 
-    const newClasses = classNames("mx_SpaceButton_new", {
-        mx_SpaceButton_newCancel: menuDisplayed,
-    });
-
     let contextMenu = null;
     if (menuDisplayed) {
         contextMenu = <SpaceCreateMenu onFinished={closeMenu} />;
@@ -205,63 +256,61 @@ const SpacePanel = () => {
         }
     };
 
-    const activeSpaces = activeSpace ? [activeSpace] : [];
-    const expandCollapseButtonTitle = isPanelCollapsed ? _t("Expand space panel") : _t("Collapse space panel");
+    const onNewClick = menuDisplayed ? closeMenu : () => {
+        if (!isPanelCollapsed) setPanelCollapsed(true);
+        openMenu();
+    };
 
-    const homeNotificationState = SettingsStore.getValue("feature_spaces.all_rooms")
-        ? RoomNotificationStateStore.instance.globalState : SpaceStore.instance.getNotificationState(HOME_SPACE);
+    return (
+        <DragDropContext onDragEnd={result => {
+            if (!result.destination) return; // dropped outside the list
+            SpaceStore.instance.moveRootSpace(result.source.index, result.destination.index);
+        }}>
+            <RovingTabIndexProvider handleHomeEnd={true} onKeyDown={onKeyDown}>
+                {({onKeyDownHandler}) => (
+                    <ul
+                        className={classNames("mx_SpacePanel", { collapsed: isPanelCollapsed })}
+                        onKeyDown={onKeyDownHandler}
+                    >
+                        <Droppable droppableId="top-level-spaces">
+                            {(provided, snapshot) => (
+                                <AutoHideScrollbar
+                                    {...provided.droppableProps}
+                                    wrappedRef={provided.innerRef}
+                                    className="mx_SpacePanel_spaceTreeWrapper"
+                                    style={snapshot.isDraggingOver ? {
+                                        pointerEvents: "none",
+                                    } : undefined}
+                                >
+                                    <InnerSpacePanel
+                                        isPanelCollapsed={isPanelCollapsed}
+                                        setPanelCollapsed={setPanelCollapsed}
+                                    >
+                                        { provided.placeholder }
+                                    </InnerSpacePanel>
 
-    // TODO drag and drop for re-arranging order
-    return <RovingTabIndexProvider handleHomeEnd={true} onKeyDown={onKeyDown}>
-        {({onKeyDownHandler}) => (
-            <ul
-                className={classNames("mx_SpacePanel", { collapsed: isPanelCollapsed })}
-                onKeyDown={onKeyDownHandler}
-            >
-                <AutoHideScrollbar className="mx_SpacePanel_spaceTreeWrapper">
-                    <div className="mx_SpaceTreeLevel">
-                        <SpaceButton
-                            className="mx_SpaceButton_home"
-                            onClick={() => SpaceStore.instance.setActiveSpace(null)}
-                            selected={!activeSpace}
-                            tooltip={SettingsStore.getValue("feature_spaces.all_rooms") ? _t("All rooms") : _t("Home")}
-                            notificationState={homeNotificationState}
-                            isNarrow={isPanelCollapsed}
+                                    <SpaceButton
+                                        className={classNames("mx_SpaceButton_new", {
+                                            mx_SpaceButton_newCancel: menuDisplayed,
+                                        })}
+                                        tooltip={menuDisplayed ? _t("Cancel") : _t("Create a space")}
+                                        onClick={onNewClick}
+                                        isNarrow={isPanelCollapsed}
+                                    />
+                                </AutoHideScrollbar>
+                            )}
+                        </Droppable>
+                        <AccessibleTooltipButton
+                            className={classNames("mx_SpacePanel_toggleCollapse", { expanded: !isPanelCollapsed })}
+                            onClick={() => setPanelCollapsed(!isPanelCollapsed)}
+                            title={isPanelCollapsed ? _t("Expand space panel") : _t("Collapse space panel")}
                         />
-                        { invites.map(s => <SpaceItem
-                            key={s.roomId}
-                            space={s}
-                            activeSpaces={activeSpaces}
-                            isPanelCollapsed={isPanelCollapsed}
-                            onExpand={() => setPanelCollapsed(false)}
-                        />) }
-                        { spaces.map(s => <SpaceItem
-                            key={s.roomId}
-                            space={s}
-                            activeSpaces={activeSpaces}
-                            isPanelCollapsed={isPanelCollapsed}
-                            onExpand={() => setPanelCollapsed(false)}
-                        />) }
-                    </div>
-                    <SpaceButton
-                        className={newClasses}
-                        tooltip={menuDisplayed ? _t("Cancel") : _t("Create a space")}
-                        onClick={menuDisplayed ? closeMenu : () => {
-                            if (!isPanelCollapsed) setPanelCollapsed(true);
-                            openMenu();
-                        }}
-                        isNarrow={isPanelCollapsed}
-                    />
-                </AutoHideScrollbar>
-                <AccessibleTooltipButton
-                    className={classNames("mx_SpacePanel_toggleCollapse", {expanded: !isPanelCollapsed})}
-                    onClick={() => setPanelCollapsed(!isPanelCollapsed)}
-                    title={expandCollapseButtonTitle}
-                />
-                { contextMenu }
-            </ul>
-        )}
-    </RovingTabIndexProvider>
+                        { contextMenu }
+                    </ul>
+                )}
+            </RovingTabIndexProvider>
+        </DragDropContext>
+    );
 };
 
 export default SpacePanel;