element-web/src/components/structures/ContextMenu.tsx

/*
Copyright 2015, 2016 OpenMarket Ltd
Copyright 2018 New Vector Ltd
Copyright 2019 The Matrix.org Foundation C.I.C.

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 React, {CSSProperties, useRef, useState} from "react";
import ReactDOM from "react-dom";
import classNames from "classnames";

import {Key} from "../../Keyboard";
import {Writeable} from "../../@types/common";

// Shamelessly ripped off Modal.js.  There's probably a better way
// of doing reusable widgets like dialog boxes & menus where we go and
// pass in a custom control as the actual body.

const ContextualMenuContainerId = "mx_ContextualMenu_Container";

function getOrCreateContainer(): HTMLDivElement {
    let container = document.getElementById(ContextualMenuContainerId) as HTMLDivElement;

    if (!container) {
        container = document.createElement("div");
        container.id = ContextualMenuContainerId;
        document.body.appendChild(container);
    }

    return container;
}

const ARIA_MENU_ITEM_ROLES = new Set(["menuitem", "menuitemcheckbox", "menuitemradio"]);

interface IPosition {
    top?: number;
    bottom?: number;
    left?: number;
    right?: number;
}

export enum ChevronFace {
    Top = "top",
    Bottom = "bottom",
    Left = "left",
    Right = "right",
    None = "none",
}

interface IProps extends IPosition {
    menuWidth?: number;
    menuHeight?: number;

    chevronOffset?: number;
    chevronFace?: ChevronFace;

    menuPaddingTop?: number;
    menuPaddingBottom?: number;
    menuPaddingLeft?: number;
    menuPaddingRight?: number;

    zIndex?: number;

    // If true, insert an invisible screen-sized element behind the menu that when clicked will close it.
    hasBackground?: boolean;
    // whether this context menu should be focus managed. If false it must handle itself
    managed?: boolean;

    // Function to be called on menu close
    onFinished();
    // on resize callback
    windowResize?();
}

interface IState {
    contextMenuElem: HTMLDivElement;
}

// Generic ContextMenu Portal wrapper
// all options inside the menu should be of role=menuitem/menuitemcheckbox/menuitemradiobutton and have tabIndex={-1}
// this will allow the ContextMenu to manage its own focus using arrow keys as per the ARIA guidelines.
export class ContextMenu extends React.PureComponent<IProps, IState> {
    private initialFocus: HTMLElement;

    static defaultProps = {
        hasBackground: true,
        managed: true,
    };

    constructor(props, context) {
        super(props, context);
        this.state = {
            contextMenuElem: null,
        };

        // persist what had focus when we got initialized so we can return it after
        this.initialFocus = document.activeElement as HTMLElement;
    }

    componentWillUnmount() {
        // return focus to the thing which had it before us
        this.initialFocus.focus();
    }

    private collectContextMenuRect = (element) => {
        // We don't need to clean up when unmounting, so ignore
        if (!element) return;

        let first = element.querySelector('[role^="menuitem"]');
        if (!first) {
            first = element.querySelector('[tab-index]');
        }
        if (first) {
            first.focus();
        }

        this.setState({
            contextMenuElem: element,
        });
    };

    private onContextMenu = (e) => {
        if (this.props.onFinished) {
            this.props.onFinished();

            e.preventDefault();
            e.stopPropagation();
            const x = e.clientX;
            const y = e.clientY;

            // XXX: This isn't pretty but the only way to allow opening a different context menu on right click whilst
            // a context menu and its click-guard are up without completely rewriting how the context menus work.
            setImmediate(() => {
                const clickEvent = document.createEvent('MouseEvents');
                clickEvent.initMouseEvent(
                    'contextmenu', true, true, window, 0,
                    0, 0, x, y, false, false,
                    false, false, 0, null,
                );
                document.elementFromPoint(x, y).dispatchEvent(clickEvent);
            });
        }
    };

    private onContextMenuPreventBubbling = (e) => {
        // stop propagation so that any context menu handlers don't leak out of this context menu
        // but do not inhibit the default browser menu
        e.stopPropagation();
    };

    // Prevent clicks on the background from going through to the component which opened the menu.
    private onFinished = (ev: React.MouseEvent) => {
        ev.stopPropagation();
        ev.preventDefault();
        if (this.props.onFinished) this.props.onFinished();
    };

    private onMoveFocus = (element: Element, up: boolean) => {
        let descending = false; // are we currently descending or ascending through the DOM tree?

        do {
            const child = up ? element.lastElementChild : element.firstElementChild;
            const sibling = up ? element.previousElementSibling : element.nextElementSibling;

            if (descending) {
                if (child) {
                    element = child;
                } else if (sibling) {
                    element = sibling;
                } else {
                    descending = false;
                    element = element.parentElement;
                }
            } else {
                if (sibling) {
                    element = sibling;
                    descending = true;
                } else {
                    element = element.parentElement;
                }
            }

            if (element) {
                if (element.classList.contains("mx_ContextualMenu")) { // we hit the top
                    element = up ? element.lastElementChild : element.firstElementChild;
                    descending = true;
                }
            }
        } while (element && !ARIA_MENU_ITEM_ROLES.has(element.getAttribute("role")));

        if (element) {
            (element as HTMLElement).focus();
        }
    };

    private onMoveFocusHomeEnd = (element: Element, up: boolean) => {
        let results = element.querySelectorAll('[role^="menuitem"]');
        if (!results) {
            results = element.querySelectorAll('[tab-index]');
        }
        if (results && results.length) {
            if (up) {
                (results[0] as HTMLElement).focus();
            } else {
                (results[results.length - 1] as HTMLElement).focus();
            }
        }
    };

    private onKeyDown = (ev: React.KeyboardEvent) => {
        if (!this.props.managed) {
            if (ev.key === Key.ESCAPE) {
                this.props.onFinished();
                ev.stopPropagation();
                ev.preventDefault();
            }
            return;
        }

        let handled = true;

        switch (ev.key) {
            case Key.TAB:
            case Key.ESCAPE:
            // close on left and right arrows too for when it is a context menu on a <Toolbar />
            case Key.ARROW_LEFT:
            case Key.ARROW_RIGHT:
                this.props.onFinished();
                break;
            case Key.ARROW_UP:
                this.onMoveFocus(ev.target as Element, true);
                break;
            case Key.ARROW_DOWN:
                this.onMoveFocus(ev.target as Element, false);
                break;
            case Key.HOME:
                this.onMoveFocusHomeEnd(this.state.contextMenuElem, true);
                break;
            case Key.END:
                this.onMoveFocusHomeEnd(this.state.contextMenuElem, false);
                break;
            default:
                handled = false;
        }

        if (handled) {
            // consume all other keys in context menu
            ev.stopPropagation();
            ev.preventDefault();
        }
    };

    protected renderMenu(hasBackground = this.props.hasBackground) {
        const position: Partial<Writeable<DOMRect>> = {};
        const props = this.props;

        if (props.top) {
            position.top = props.top;
        } else {
            position.bottom = props.bottom;
        }

        let chevronFace: ChevronFace;
        if (props.left) {
            position.left = props.left;
            chevronFace = ChevronFace.Left;
        } else {
            position.right = props.right;
            chevronFace = ChevronFace.Right;
        }

        const contextMenuRect = this.state.contextMenuElem ? this.state.contextMenuElem.getBoundingClientRect() : null;

        const chevronOffset: CSSProperties = {};
        if (props.chevronFace) {
            chevronFace = props.chevronFace;
        }
        const hasChevron = chevronFace && chevronFace !== ChevronFace.None;

        if (chevronFace === ChevronFace.Top || chevronFace === ChevronFace.Bottom) {
            chevronOffset.left = props.chevronOffset;
        } else if (position.top !== undefined) {
            const target = position.top;

            // By default, no adjustment is made
            let adjusted = target;

            // If we know the dimensions of the context menu, adjust its position
            // such that it does not leave the (padded) window.
            if (contextMenuRect) {
                const padding = 10;
                adjusted = Math.min(position.top, document.body.clientHeight - contextMenuRect.height + padding);
            }

            position.top = adjusted;
            chevronOffset.top = Math.max(props.chevronOffset, props.chevronOffset + target - adjusted);
        }

        let chevron;
        if (hasChevron) {
            chevron = <div style={chevronOffset} className={"mx_ContextualMenu_chevron_" + chevronFace} />;
        }

        const menuClasses = classNames({
            'mx_ContextualMenu': true,
            'mx_ContextualMenu_left': !hasChevron && position.left,
            'mx_ContextualMenu_right': !hasChevron && position.right,
            'mx_ContextualMenu_top': !hasChevron && position.top,
            'mx_ContextualMenu_bottom': !hasChevron && position.bottom,
            'mx_ContextualMenu_withChevron_left': chevronFace === ChevronFace.Left,
            'mx_ContextualMenu_withChevron_right': chevronFace === ChevronFace.Right,
            'mx_ContextualMenu_withChevron_top': chevronFace === ChevronFace.Top,
            'mx_ContextualMenu_withChevron_bottom': chevronFace === ChevronFace.Bottom,
        });

        const menuStyle: CSSProperties = {};
        if (props.menuWidth) {
            menuStyle.width = props.menuWidth;
        }

        if (props.menuHeight) {
            menuStyle.height = props.menuHeight;
        }

        if (!isNaN(Number(props.menuPaddingTop))) {
            menuStyle["paddingTop"] = props.menuPaddingTop;
        }
        if (!isNaN(Number(props.menuPaddingLeft))) {
            menuStyle["paddingLeft"] = props.menuPaddingLeft;
        }
        if (!isNaN(Number(props.menuPaddingBottom))) {
            menuStyle["paddingBottom"] = props.menuPaddingBottom;
        }
        if (!isNaN(Number(props.menuPaddingRight))) {
            menuStyle["paddingRight"] = props.menuPaddingRight;
        }

        const wrapperStyle = {};
        if (!isNaN(Number(props.zIndex))) {
            menuStyle["zIndex"] = props.zIndex + 1;
            wrapperStyle["zIndex"] = props.zIndex;
        }

        let background;
        if (hasBackground) {
            background = (
                <div
                    className="mx_ContextualMenu_background"
                    style={wrapperStyle}
                    onClick={this.onFinished}
                    onContextMenu={this.onContextMenu}
                />
            );
        }

        return (
            <div
                className="mx_ContextualMenu_wrapper"
                style={{...position, ...wrapperStyle}}
                onKeyDown={this.onKeyDown}
                onContextMenu={this.onContextMenuPreventBubbling}
            >
                <div
                    className={menuClasses}
                    style={menuStyle}
                    ref={this.collectContextMenuRect}
                    role={this.props.managed ? "menu" : undefined}
                >
                    { chevron }
                    { props.children }
                </div>
                { background }
            </div>
        );
    }

    render(): React.ReactChild {
        return ReactDOM.createPortal(this.renderMenu(), getOrCreateContainer());
    }
}

// Placement method for <ContextMenu /> to position context menu to right of elementRect with chevronOffset
export const toRightOf = (elementRect: DOMRect, chevronOffset = 12) => {
    const left = elementRect.right + window.pageXOffset + 3;
    let top = elementRect.top + (elementRect.height / 2) + window.pageYOffset;
    top -= chevronOffset + 8; // where 8 is half the height of the chevron
    return {left, top, chevronOffset};
};

// Placement method for <ContextMenu /> to position context menu right-aligned and flowing to the left of elementRect
export const aboveLeftOf = (elementRect: DOMRect, chevronFace = ChevronFace.None) => {
    const menuOptions: IPosition & { chevronFace: ChevronFace } = { chevronFace };

    const buttonRight = elementRect.right + window.pageXOffset;
    const buttonBottom = elementRect.bottom + window.pageYOffset;
    const buttonTop = elementRect.top + window.pageYOffset;
    // Align the right edge of the menu to the right edge of the button
    menuOptions.right = window.innerWidth - buttonRight;
    // Align the menu vertically on whichever side of the button has more space available.
    if (buttonBottom < window.innerHeight / 2) {
        menuOptions.top = buttonBottom;
    } else {
        menuOptions.bottom = window.innerHeight - buttonTop;
    }

    return menuOptions;
};

export const useContextMenu = () => {
    const button = useRef(null);
    const [isOpen, setIsOpen] = useState(false);
    const open = () => {
        setIsOpen(true);
    };
    const close = () => {
        setIsOpen(false);
    };

    return [isOpen, button, open, close, setIsOpen];
};

export default class LegacyContextMenu extends ContextMenu {
    render() {
        return this.renderMenu(false);
    }
}

// XXX: Deprecated, used only for dynamic Tooltips. Avoid using at all costs.
export function createMenu(ElementClass, props) {
    const onFinished = function(...args) {
        ReactDOM.unmountComponentAtNode(getOrCreateContainer());

        if (props && props.onFinished) {
            props.onFinished.apply(null, args);
        }
    };

    const menu = <LegacyContextMenu
        {...props}
        onFinished={onFinished} // eslint-disable-line react/jsx-no-bind
        windowResize={onFinished} // eslint-disable-line react/jsx-no-bind
    >
        <ElementClass {...props} onFinished={onFinished} />
    </LegacyContextMenu>;

    ReactDOM.render(menu, getOrCreateContainer());

    return {close: onFinished};
}

// re-export the semantic helper components for simplicity
export {ContextMenuButton} from "../../accessibility/context_menu/ContextMenuButton";
export {ContextMenuTooltipButton} from "../../accessibility/context_menu/ContextMenuTooltipButton";
export {MenuGroup} from "../../accessibility/context_menu/MenuGroup";
export {MenuItem} from "../../accessibility/context_menu/MenuItem";
export {MenuItemCheckbox} from "../../accessibility/context_menu/MenuItemCheckbox";
export {MenuItemRadio} from "../../accessibility/context_menu/MenuItemRadio";
export {StyledMenuItemCheckbox} from "../../accessibility/context_menu/StyledMenuItemCheckbox";
export {StyledMenuItemRadio} from "../../accessibility/context_menu/StyledMenuItemRadio";