feat: help centre

lang/main.json

         "connectCalendarButton": "Connect your calendar",
         "connectCalendarText": "Connect your calendar to view all your meetings in {{app}}. Plus, add {{provider}} meetings to your calendar and start them with one click.",
         "enterRoomTitle": "Start a new meeting",
+        "getHelp": "Get help",
         "roomNameAllowedChars": "Meeting name should not contain any of these characters: ?, &, :, ', \", %, #.",
         "go": "GO",
         "goSmall": "GO",
     "lonelyMeetingExperience": {
         "button": "Invite others",
         "youAreAlone": "You are the only one in the meeting"
+    },
+    "helpView": {
+        "header": "Help centre"
     }
 }

react/features/app/components/AbstractApp.js

         return (
             <Fragment>
                 <OverlayContainer />
+                { this._createExtraPlatformSpecificElement() }
             </Fragment>
         );
     }
 
+    /**
+     * Renders platform specific extra elements to be added alongside with the main element, if need be.
+     *
+     * NOTE: Overridden by child components.
+     *
+     * @returns {React$Element}
+     */
+    _createExtraPlatformSpecificElement() {
+        return null;
+    }
+
     _createMainElement: (React$Element<*>, Object) => ?React$Element<*>;
 
     /**

react/features/app/components/App.native.js

 import '../../base/responsive-ui';
 import { updateSettings } from '../../base/settings';
 import '../../google-api';
+import { HelpView } from '../../help';
 import '../../mobile/audio-mode';
 import '../../mobile/back-button';
 import '../../mobile/background';
         });
     }
 
+    /**
+     * Renders platform specific extra elements to be added alongside with the main element, if need be.
+     *
+     * @inheritdoc
+     */
+    _createExtraPlatformSpecificElement() {
+        return (
+            <HelpView />
+        );
+    }
+
     /**
      * Attempts to disable the use of React Native
      * {@link ExceptionsManager#handleException} on platforms and in

react/features/base/color-scheme/defaultScheme.js

         statusBarContent: ColorPalette.white,
         text: ColorPalette.white
     },
+    'Modal': {},
     'LargeVideo': {
         background: 'rgb(42, 58, 75)'
     },

react/features/base/modal/actionTypes.js

+// @flow
+
+/**
+ * Action type to set the ID of the active modal (or undefined if needs to be hidden).
+ */
+export const SET_ACTIVE_MODAL_ID = 'SET_ACTIVE_MODAL_ID';

react/features/base/modal/actions.js

+// @flow
+
+import { SET_ACTIVE_MODAL_ID } from './actionTypes';
+
+/**
+ * Action to set the ID of the active modal (or undefined if needs to be hidden).
+ *
+ * @param {string} activeModalId - The new modal ID or undefined.
+ * @returns {{
+ *     activeModalId: string,
+ *     type: SET_ACTIVE_MODAL_ID
+ * }}
+ */
+export function setActiveModalId(activeModalId: ?string) {
+    return {
+        activeModalId,
+        type: SET_ACTIVE_MODAL_ID
+    };
+}

react/features/base/modal/components/JitsiModal.js

+// @flow
+
+import React, { PureComponent } from 'react';
+import { SafeAreaView, View } from 'react-native';
+
+import { ColorSchemeRegistry } from '../../color-scheme';
+import { HeaderWithNavigation, SlidingView } from '../../react';
+import { connect } from '../../redux';
+import { StyleType } from '../../styles';
+
+import { setActiveModalId } from '../actions';
+
+import styles from './styles';
+
+type Props = {
+
+    /**
+     * The color schemed style of the common header component.
+     */
+    _headerStyles: StyleType,
+
+    /**
+     * True if the modal should be shown, false otherwise.
+     */
+    _show: boolean,
+
+    /**
+     * The color schemed style of the modal.
+     */
+    _styles: StyleType,
+
+    /**
+     * The children component(s) of the Modal, to be rendered.
+     */
+    children: React$Node,
+
+    /**
+     * The Redux Dispatch function.
+     */
+    dispatch: Function,
+
+    /**
+     * The i18n label key of the header title.
+     */
+    headerLabelKey: string,
+
+    /**
+     * The ID of the modal that is being rendered. This is used to show/hide the modal.
+     */
+    modalId: string,
+
+    /**
+     * Callback to be invoked when the modal closes.
+     */
+    onClose?: Function,
+
+    /**
+     * The position from where the modal should be opened. This is derived from the
+     * props of the {@code SlidingView} with the same name.
+     */
+    position?: string
+};
+
+/**
+ * Implements a custom Jitsi Modal that doesn't use the built in native
+ * Modal component of React Native.
+ */
+class JitsiModal extends PureComponent<Props> {
+    static defaultProps = {
+        position: 'bottom'
+    };
+
+    /**
+     * Instantiates a new component.
+     *
+     * @inheritdoc
+     */
+    constructor(props: Props) {
+        super(props);
+
+        this._onRequestClose = this._onRequestClose.bind(this);
+    }
+
+    /**
+     * Implements {@code PureComponent#render}.
+     *
+     * @inheritdoc
+     */
+    render() {
+        const { _headerStyles, _show, _styles, children, headerLabelKey, position } = this.props;
+
+        return (
+            <SlidingView
+                onHide = { this._onRequestClose }
+                position = { position }
+                show = { _show }>
+                <View
+                    style = { [
+                        _headerStyles.page,
+                        _styles.page
+                    ] }>
+                    <HeaderWithNavigation
+                        headerLabelKey = { headerLabelKey }
+                        onPressBack = { this._onRequestClose } />
+                    <SafeAreaView style = { styles.safeArea }>
+                        { children }
+                    </SafeAreaView>
+                </View>
+            </SlidingView>
+        );
+    }
+
+    _onRequestClose: () => boolean;
+
+    /**
+     * Callback to be invoked when the SlidingView requests closing.
+     *
+     * @returns {boolean}
+     */
+    _onRequestClose() {
+        const { _show, dispatch, onClose } = this.props;
+
+        if (_show) {
+            if (typeof onClose === 'function') {
+                onClose();
+            }
+            dispatch(setActiveModalId());
+
+            return true;
+        }
+
+        return false;
+    }
+}
+
+/**
+ * Maps part of the Redix state to the props of this component.
+ *
+ * @param {Object} state - The Redux state.
+ * @param {Props} ownProps - The own props of the component.
+ * @returns {Props}
+ */
+function _mapStateToProps(state, ownProps): $Shape<Props> {
+    return {
+        _headerStyles: ColorSchemeRegistry.get(state, 'Header'),
+        _show: state['features/base/modal'].activeModalId === ownProps.modalId,
+        _styles: ColorSchemeRegistry.get(state, 'Modal')
+    };
+}
+
+export default connect(_mapStateToProps)(JitsiModal);

react/features/base/modal/components/index.native.js

+// @flow
+
+export { default as JitsiModal } from './JitsiModal';

react/features/base/modal/components/index.web.js

+// @flow
+
+import { Component } from 'react';
+
+export const JitsiModal = Component;
+

react/features/base/modal/components/styles.js

+// @flow
+
+import { ColorSchemeRegistry, schemeColor } from '../../color-scheme';
+
+export default {
+    safeArea: {
+        flex: 1
+    }
+};
+
+ColorSchemeRegistry.register('Modal', {
+    page: {
+        backgroundColor: schemeColor('background')
+    }
+});

react/features/base/modal/index.js

+// @flow
+
+import './reducer';
+
+export * from './actions';
+export * from './actionTypes';
+export * from './components';

react/features/base/modal/reducer.js

+// @flow
+
+import { ReducerRegistry } from '../redux';
+
+import { SET_ACTIVE_MODAL_ID } from './actionTypes';
+
+ReducerRegistry.register('features/base/modal', (state = {}, action) => {
+    switch (action.type) {
+    case SET_ACTIVE_MODAL_ID:
+        return {
+            ...state,
+            activeModalId: action.activeModalId
+        };
+    }
+
+    return state;
+});

react/features/help/components/HelpView.js

+// @flow
+
+import React, { PureComponent } from 'react';
+import WebView from 'react-native-webview';
+
+import { JitsiModal } from '../../base/modal';
+import { connect } from '../../base/redux';
+
+import { HELP_VIEW_MODAL_ID } from '../constants';
+
+const DEFAULT_HELP_CENTRE_URL = 'https://web-cdn.jitsi.net/faq/meet-faq.html';
+
+type Props = {
+
+    /**
+     * The URL to display in the Help Centre.
+     */
+    _url: string
+}
+
+/**
+ * Implements a page that renders the help content for the app.
+ */
+class HelpView extends PureComponent<Props> {
+    /**
+     * Implements {@code PureComponent#render()}.
+     *
+     * @inheritdoc
+     * @returns {ReactElement}
+     */
+    render() {
+        return (
+            <JitsiModal
+                headerLabelKey = 'helpView.header'
+                modalId = { HELP_VIEW_MODAL_ID }>
+                <WebView source = {{ uri: this.props._url }} />
+            </JitsiModal>
+        );
+    }
+}
+
+/**
+ * Maps part of the Redux state to the props of this component.
+ *
+ * @param {Object} state - The Redux state.
+ * @returns {Props}
+ */
+function _mapStateToProps(state) {
+    return {
+        _url: state['features/base/config'].helpCentreURL || DEFAULT_HELP_CENTRE_URL
+    };
+}
+
+export default connect(_mapStateToProps)(HelpView);

react/features/help/components/index.js

+// @flow
+
+export { default as HelpView } from './HelpView';

react/features/help/constants.js

+// @flow
+
+export const HELP_VIEW_MODAL_ID = 'helpView';

react/features/help/index.js

+// @flow
+
+export * from './components';
+export * from './constants';

react/features/welcome/components/WelcomePageSideBar.native.js

 import { SafeAreaView, ScrollView, Text } from 'react-native';
 
 import { Avatar } from '../../base/avatar';
-import { IconInfo, IconSettings } from '../../base/icons';
+import { IconInfo, IconSettings, IconHelp } from '../../base/icons';
+import { setActiveModalId } from '../../base/modal';
 import {
     getLocalParticipant,
     getParticipantDisplayName
     SlidingView
 } from '../../base/react';
 import { connect } from '../../base/redux';
+import { HELP_VIEW_MODAL_ID } from '../../help';
 import { setSettingsViewVisible } from '../../settings';
 
 import { setSideBarVisible } from '../actions';
  */
 const PRIVACY_URL = 'https://jitsi.org/meet/privacy';
 
-/**
- * The URL at which the user may send feedback.
- */
-const SEND_FEEDBACK_URL = 'mailto:support@jitsi.org';
-
 /**
  * The URL at which the terms (of service/use) are available to the user.
  */
 
         // Bind event handlers so they are only bound once per instance.
         this._onHideSideBar = this._onHideSideBar.bind(this);
+        this._onOpenHelpPage = this._onOpenHelpPage.bind(this);
         this._onOpenSettings = this._onOpenSettings.bind(this);
     }
 
                             label = 'welcomepage.privacy'
                             url = { PRIVACY_URL } />
                         <SideBarItem
-                            icon = { IconInfo }
-                            label = 'welcomepage.sendFeedback'
-                            url = { SEND_FEEDBACK_URL } />
+                            icon = { IconHelp }
+                            label = 'welcomepage.getHelp'
+                            onPress = { this._onOpenHelpPage } />
                     </ScrollView>
                 </SafeAreaView>
             </SlidingView>
         this.props.dispatch(setSideBarVisible(false));
     }
 
+    _onOpenHelpPage: () => void;
+
+    /**
+     * Shows the {@link HelpView}.
+     *
+     * @returns {void}
+     */
+    _onOpenHelpPage() {
+        const { dispatch } = this.props;
+
+        dispatch(setSideBarVisible(false));
+        dispatch(setActiveModalId(HELP_VIEW_MODAL_ID));
+    }
+
     _onOpenSettings: () => void;
 
     /**