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

/*
Copyright 2017 Travis Ralston
Copyright 2019 New Vector Ltd
Copyright 2019, 2020 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 * as React from "react";
import { _t } from '../../languageHandler';
import AutoHideScrollbar from './AutoHideScrollbar';
import { replaceableComponent } from "../../utils/replaceableComponent";
import AccessibleButton from "../views/elements/AccessibleButton";

/**
 * Represents a tab for the TabbedView.
 */
export class Tab {
    /**
     * Creates a new tab.
     * @param {string} id The tab's ID.
     * @param {string} label The untranslated tab label.
     * @param {string} icon The class for the tab icon. This should be a simple mask.
     * @param {React.ReactNode} body The JSX for the tab container.
     */
    constructor(public id: string, public label: string, public icon: string, public body: React.ReactNode) {
    }
}

interface IProps {
    tabs: Tab[];
    initialTabId?: string;
}

interface IState {
    activeTabIndex: number;
}

@replaceableComponent("structures.TabbedView")
export default class TabbedView extends React.Component<IProps, IState> {
    constructor(props: IProps) {
        super(props);

        let activeTabIndex = 0;
        if (props.initialTabId) {
            const tabIndex = props.tabs.findIndex(t => t.id === props.initialTabId);
            if (tabIndex >= 0) activeTabIndex = tabIndex;
        }

        this.state = {
            activeTabIndex,
        };
    }

    private _getActiveTabIndex() {
        if (!this.state || !this.state.activeTabIndex) return 0;
        return this.state.activeTabIndex;
    }

    /**
     * Shows the given tab
     * @param {Tab} tab the tab to show
     * @private
     */
    private _setActiveTab(tab: Tab) {
        const idx = this.props.tabs.indexOf(tab);
        if (idx !== -1) {
            this.setState({ activeTabIndex: idx });
        } else {
            console.error("Could not find tab " + tab.label + " in tabs");
        }
    }

    private _renderTabLabel(tab: Tab) {
        let classes = "mx_TabbedView_tabLabel ";

        const idx = this.props.tabs.indexOf(tab);
        if (idx === this._getActiveTabIndex()) classes += "mx_TabbedView_tabLabel_active";

        let tabIcon = null;
        if (tab.icon) {
            tabIcon = <span className={`mx_TabbedView_maskedIcon ${tab.icon}`} />;
        }

        const onClickHandler = () => this._setActiveTab(tab);

        const label = _t(tab.label);
        return (
            <AccessibleButton className={classes} key={"tab_label_" + tab.label} onClick={onClickHandler}>
                {tabIcon}
                <span className="mx_TabbedView_tabLabel_text">
                    { label }
                </span>
            </AccessibleButton>
        );
    }

    private _renderTabPanel(tab: Tab): React.ReactNode {
        return (
            <div className="mx_TabbedView_tabPanel" key={"mx_tabpanel_" + tab.label}>
                <AutoHideScrollbar className='mx_TabbedView_tabPanelContent'>
                    {tab.body}
                </AutoHideScrollbar>
            </div>
        );
    }

    public render(): React.ReactNode {
        const labels = this.props.tabs.map(tab => this._renderTabLabel(tab));
        const panel = this._renderTabPanel(this.props.tabs[this._getActiveTabIndex()]);

        return (
            <div className="mx_TabbedView">
                <div className="mx_TabbedView_tabLabels">
                    {labels}
                </div>
                {panel}
            </div>
        );
    }
}