utils.jsx

// Copyright (c) 2015-present Mattermost, Inc. All Rights Reserved.
// See LICENSE.txt for license information.

import React from 'react';
import {FormattedMessage} from 'react-intl';

import {Client4} from 'mattermost-redux/client';
import {Posts} from 'mattermost-redux/constants';
import {getChannel, getRedirectChannelNameForTeam} from 'mattermost-redux/selectors/entities/channels';
import {getConfig} from 'mattermost-redux/selectors/entities/general';
import {getTeammateNameDisplaySetting, getBool} from 'mattermost-redux/selectors/entities/preferences';
import {getCurrentUserId, getUser} from 'mattermost-redux/selectors/entities/users';
import {
    blendColors,
    changeOpacity,
} from 'mattermost-redux/utils/theme_utils';
import {displayUsername} from 'mattermost-redux/utils/user_utils';
import {getCurrentTeamId, getCurrentRelativeTeamUrl, getTeam} from 'mattermost-redux/selectors/entities/teams';
import cssVars from 'css-vars-ponyfill';

import moment from 'moment';

import {browserHistory} from 'utils/browser_history';
import {searchForTerm} from 'actions/post_actions';
import Constants, {FileTypes, UserStatuses} from 'utils/constants.jsx';
import * as UserAgent from 'utils/user_agent';
import * as Utils from 'utils/utils';
import bing from 'sounds/bing.mp3';
import crackle from 'sounds/crackle.mp3';
import down from 'sounds/down.mp3';
import hello from 'sounds/hello.mp3';
import ripple from 'sounds/ripple.mp3';
import upstairs from 'sounds/upstairs.mp3';
import {t} from 'utils/i18n';
import store from 'stores/redux_store.jsx';
import {getCurrentLocale, getTranslations} from 'selectors/i18n';

export function isMac() {
    return navigator.platform.toUpperCase().indexOf('MAC') >= 0;
}

export function isLinux() {
    return navigator.platform.toUpperCase().indexOf('LINUX') >= 0;
}

export function createSafeId(prop) {
    if (prop === null) {
        return undefined;
    }

    var str = '';

    if (prop.props && prop.props.defaultMessage) {
        str = prop.props.defaultMessage;
    } else {
        str = prop.toString();
    }

    return str.replace(new RegExp(' ', 'g'), '_');
}

export function cmdOrCtrlPressed(e, allowAlt = false) {
    if (allowAlt) {
        return (isMac() && e.metaKey) || (!isMac() && e.ctrlKey);
    }
    return (isMac() && e.metaKey) || (!isMac() && e.ctrlKey && !e.altKey);
}

export function isKeyPressed(event, key) {
    // There are two types of keyboards
    // 1. English with different layouts(Ex: Dvorak)
    // 2. Different language keyboards(Ex: Russian)

    if (event.keyCode === Constants.KeyCodes.COMPOSING[1]) {
        return false;
    }

    // checks for event.key for older browsers and also for the case of different English layout keyboards.
    if (typeof event.key !== 'undefined' && event.key !== 'Unidentified' && event.key !== 'Dead') {
        const isPressedByCode = event.key === key[0] || event.key === key[0].toUpperCase();
        if (isPressedByCode) {
            return true;
        }
    }

    // used for different language keyboards to detect the position of keys
    return event.keyCode === key[1];
}

/**
 * check keydown event for line break combo. Should catch alt/option + enter not all browsers except Safari
 * @param  {object}  e - keydown event
 * @return {boolean}
 */
export function isUnhandledLineBreakKeyCombo(e) {
    return Boolean(
        isKeyPressed(e, Constants.KeyCodes.ENTER) &&
        !e.shiftKey && // shift + enter is already handled everywhere, so don't handle again
        (e.altKey && !UserAgent.isSafari() && !cmdOrCtrlPressed(e)), // alt/option + enter is already handled in Safari, so don't handle again
    );
}

/**
 * insert a new line character at keyboard cursor (or overwrites selection)
 * @param  {object}  e - keydown event
 * @return {string} message modified with new line inserted for app consumption
 * WARNING: HAS DOM SIDE EFFECTS
 */
export function insertLineBreakFromKeyEvent(e) {
    const el = e.target;
    const {selectionEnd, selectionStart, value} = el;

    // replace text selection (or insert if no selection) with new line character
    const newValue = `${value.substr(0, selectionStart)}\n${value.substr(selectionEnd, value.length)}`;

    // update value on DOM element immediately and restore key cursor to correct position
    el.value = newValue;
    setSelectionRange(el, selectionStart + 1, selectionStart + 1);

    // return the updated string so that component state can be updated
    return newValue;
}

export function isInRole(roles, inRole) {
    if (roles) {
        var parts = roles.split(' ');
        for (var i = 0; i < parts.length; i++) {
            if (parts[i] === inRole) {
                return true;
            }
        }
    }

    return false;
}

export function isChannelAdmin(isLicensed, roles, hasAdminScheme = false) {
    if (!isLicensed) {
        return false;
    }

    if (isInRole(roles, 'channel_admin') || hasAdminScheme) {
        return true;
    }

    return false;
}

export function isAdmin(roles) {
    if (isInRole(roles, 'team_admin')) {
        return true;
    }

    if (isInRole(roles, 'system_admin')) {
        return true;
    }

    return false;
}

export function isSystemAdmin(roles) {
    if (isInRole(roles, 'system_admin')) {
        return true;
    }

    return false;
}

export function isGuest(user) {
    if (user && user.roles && isInRole(user.roles, 'system_guest')) {
        return true;
    }

    return false;
}

export function getTeamRelativeUrl(team) {
    if (!team) {
        return '';
    }

    return '/' + team.name;
}

export function getChannelURL(state, channel, teamId) {
    let notificationURL;
    if (channel && (channel.type === Constants.DM_CHANNEL || channel.type === Constants.GM_CHANNEL)) {
        notificationURL = getCurrentRelativeTeamUrl(state) + '/channels/' + channel.name;
    } else if (channel) {
        const team = getTeam(state, teamId);
        notificationURL = getTeamRelativeUrl(team) + '/channels/' + channel.name;
    } else if (teamId) {
        const team = getTeam(state, teamId);
        const redirectChannel = getRedirectChannelNameForTeam(state, teamId);
        notificationURL = getTeamRelativeUrl(team) + `/channels/${redirectChannel}`;
    } else {
        const currentTeamId = getCurrentTeamId(state);
        const redirectChannel = getRedirectChannelNameForTeam(state, currentTeamId);
        notificationURL = getCurrentRelativeTeamUrl(state) + `/channels/${redirectChannel}`;
    }
    return notificationURL;
}

export const notificationSounds = new Map([
    ['Bing', bing],
    ['Crackle', crackle],
    ['Down', down],
    ['Hello', hello],
    ['Ripple', ripple],
    ['Upstairs', upstairs],
]);

var canDing = true;
export function ding(name) {
    if (hasSoundOptions() && canDing) {
        tryNotificationSound(name);
        canDing = false;
        setTimeout(() => {
            canDing = true;
        }, 3000);
    }
}

export function tryNotificationSound(name) {
    const audio = new Audio(notificationSounds.get(name) ?? notificationSounds.get('Bing'));
    audio.play();
}

export function hasSoundOptions() {
    return (!UserAgent.isEdge());
}

export function getDateForUnixTicks(ticks) {
    return new Date(ticks);
}

// returns Unix timestamp in milliseconds
export function getTimestamp() {
    return Date.now();
}

// Replaces all occurrences of a pattern
export function loopReplacePattern(text, pattern, replacement) {
    let result = text;

    let match = pattern.exec(result);
    while (match) {
        result = result.replace(pattern, replacement);
        match = pattern.exec(result);
    }

    return result;
}

// Taken from https://stackoverflow.com/questions/1068834/object-comparison-in-javascript and modified slightly
export function areObjectsEqual(x, y) {
    let p;
    const leftChain = [];
    const rightChain = [];

    // Remember that NaN === NaN returns false
    // and isNaN(undefined) returns true
    if (isNaN(x) && isNaN(y) && typeof x === 'number' && typeof y === 'number') {
        return true;
    }

    // Compare primitives and functions.
    // Check if both arguments link to the same object.
    // Especially useful on step when comparing prototypes
    if (x === y) {
        return true;
    }

    // Works in case when functions are created in constructor.
    // Comparing dates is a common scenario. Another built-ins?
    // We can even handle functions passed across iframes
    if ((typeof x === 'function' && typeof y === 'function') ||
        (x instanceof Date && y instanceof Date) ||
        (x instanceof RegExp && y instanceof RegExp) ||
        (x instanceof String && y instanceof String) ||
        (x instanceof Number && y instanceof Number)) {
        return x.toString() === y.toString();
    }

    if (x instanceof Map && y instanceof Map) {
        return areMapsEqual(x, y);
    }

    // At last checking prototypes as good a we can
    if (!(x instanceof Object && y instanceof Object)) {
        return false;
    }

    if (x.isPrototypeOf(y) || y.isPrototypeOf(x)) {
        return false;
    }

    if (x.constructor !== y.constructor) {
        return false;
    }

    if (x.prototype !== y.prototype) {
        return false;
    }

    // Check for infinitive linking loops
    if (leftChain.indexOf(x) > -1 || rightChain.indexOf(y) > -1) {
        return false;
    }

    // Quick checking of one object being a subset of another.
    for (p in y) {
        if (y.hasOwnProperty(p) !== x.hasOwnProperty(p)) {
            return false;
        } else if (typeof y[p] !== typeof x[p]) {
            return false;
        }
    }

    for (p in x) { //eslint-disable-line guard-for-in
        if (y.hasOwnProperty(p) !== x.hasOwnProperty(p)) {
            return false;
        } else if (typeof y[p] !== typeof x[p]) {
            return false;
        }

        switch (typeof (x[p])) {
        case 'object':
        case 'function':

            leftChain.push(x);
            rightChain.push(y);

            if (!areObjectsEqual(x[p], y[p])) {
                return false;
            }

            leftChain.pop();
            rightChain.pop();
            break;

        default:
            if (x[p] !== y[p]) {
                return false;
            }
            break;
        }
    }

    return true;
}

export function areMapsEqual(a, b) {
    if (a.size !== b.size) {
        return false;
    }

    for (const [key, value] of a) {
        if (!b.has(key)) {
            return false;
        }

        if (!areObjectsEqual(value, b.get(key))) {
            return false;
        }
    }

    return true;
}

export function replaceHtmlEntities(text) {
    var tagsToReplace = {
        '&amp;': '&',
        '&lt;': '<',
        '&gt;': '>',
    };
    var newtext = text;
    for (var tag in tagsToReplace) {
        if (Reflect.apply({}.hasOwnProperty, this, [tagsToReplace, tag])) {
            var regex = new RegExp(tag, 'g');
            newtext = newtext.replace(regex, tagsToReplace[tag]);
        }
    }
    return newtext;
}

export function insertHtmlEntities(text) {
    var tagsToReplace = {
        '&': '&amp;',
        '<': '&lt;',
        '>': '&gt;',
    };
    var newtext = text;
    for (var tag in tagsToReplace) {
        if (Reflect.apply({}.hasOwnProperty, this, [tagsToReplace, tag])) {
            var regex = new RegExp(tag, 'g');
            newtext = newtext.replace(regex, tagsToReplace[tag]);
        }
    }
    return newtext;
}

export function isGIFImage(extin) {
    return extin.toLowerCase() === Constants.IMAGE_TYPE_GIF;
}

const removeQuerystringOrHash = (extin) => {
    return extin.split(/[?#]/)[0];
};

export const getFileType = (extin) => {
    const ext = removeQuerystringOrHash(extin.toLowerCase());

    if (Constants.TEXT_TYPES.indexOf(ext) > -1) {
        return FileTypes.TEXT;
    }

    if (Constants.IMAGE_TYPES.indexOf(ext) > -1) {
        return FileTypes.IMAGE;
    }

    if (Constants.AUDIO_TYPES.indexOf(ext) > -1) {
        return FileTypes.AUDIO;
    }

    if (Constants.VIDEO_TYPES.indexOf(ext) > -1) {
        return FileTypes.VIDEO;
    }

    if (Constants.SPREADSHEET_TYPES.indexOf(ext) > -1) {
        return FileTypes.SPREADSHEET;
    }

    if (Constants.CODE_TYPES.indexOf(ext) > -1) {
        return FileTypes.CODE;
    }

    if (Constants.WORD_TYPES.indexOf(ext) > -1) {
        return FileTypes.WORD;
    }

    if (Constants.PRESENTATION_TYPES.indexOf(ext) > -1) {
        return FileTypes.PRESENTATION;
    }

    if (Constants.PDF_TYPES.indexOf(ext) > -1) {
        return FileTypes.PDF;
    }

    if (Constants.PATCH_TYPES.indexOf(ext) > -1) {
        return FileTypes.PATCH;
    }

    if (Constants.SVG_TYPES.indexOf(ext) > -1) {
        return FileTypes.SVG;
    }

    return FileTypes.OTHER;
};

export function getFileIconPath(fileInfo) {
    const fileType = getFileType(fileInfo.extension);

    var icon;
    if (fileType in Constants.ICON_FROM_TYPE) {
        icon = Constants.ICON_FROM_TYPE[fileType];
    } else {
        icon = Constants.ICON_FROM_TYPE.other;
    }

    return icon;
}

export function getIconClassName(fileTypeIn) {
    var fileType = fileTypeIn.toLowerCase();

    if (fileType in Constants.ICON_NAME_FROM_TYPE) {
        return Constants.ICON_NAME_FROM_TYPE[fileType];
    }

    return 'generic';
}

export function toTitleCase(str) {
    function doTitleCase(txt) {
        return txt.charAt(0).toUpperCase() + txt.substr(1).toLowerCase();
    }
    return str.replace(/\w\S*/g, doTitleCase);
}

export function isHexColor(value) {
    return value && (/^#[0-9a-f]{3}([0-9a-f]{3})?$/i).test(value);
}

// given '#fffff', returns '255, 255, 255' (no trailing comma)
export function toRgbValues(hexStr) {
    const rgbaStr = `${parseInt(hexStr.substr(1, 2), 16)}, ${parseInt(hexStr.substr(3, 2), 16)}, ${parseInt(hexStr.substr(5, 2), 16)}`;
    return rgbaStr;
}

export function applyTheme(theme) {
    if (theme.sidebarBg) {
        changeCss('.app__body .sidebar--left .sidebar__switcher, .sidebar--left, .app__body .modal .settings-modal .settings-table .settings-links, .app__body .sidebar--menu', 'background:' + theme.sidebarBg);
        changeCss('body.app__body', 'scrollbar-face-color:' + theme.sidebarBg);
        changeCss('@media(max-width: 768px){.app__body .modal .settings-modal:not(.settings-modal--tabless):not(.display--content) .modal-content', 'background:' + theme.sidebarBg);
        changeCss('.app__body .modal-tabs .nav-tabs > li.active', `border-bottom-color:${theme.sidebarBg}`);
    }

    if (theme.sidebarText) {
        changeCss('.app__body .team-sidebar .a11y--focused, .app__body .sidebar--left .a11y--focused', 'box-shadow: inset 0 0 1px 3px ' + changeOpacity(theme.sidebarText, 0.5) + ', inset 0 0 0 1px ' + theme.sidebarText);
        changeCss('.multi-select__focused > div', 'box-shadow: inset 0 0 1px 3px ' + changeOpacity(theme.sidebarText, 0.5) + ', inset 0 0 0 1px ' + theme.sidebarText);
        changeCss('.app__body .ps-container > .ps-scrollbar-y-rail > .ps-scrollbar-y', 'background:' + theme.sidebarText);
        changeCss('.app__body .ps-container:hover .ps-scrollbar-y-rail:hover, .app__body .sidebar__switcher button:hover', 'background:' + changeOpacity(theme.sidebarText, 0.15));
        changeCss('.app__body .modal .settings-modal .nav-pills>li button', 'color:' + changeOpacity(theme.sidebarText, 0.6));
        changeCss('@media(max-width: 768px){.app__body .modal .settings-modal .settings-table .nav>li>a, .app__body .sidebar--menu', 'color:' + changeOpacity(theme.sidebarText, 0.8));
        changeCss('.sidebar--left .status .offline--icon, .app__body .sidebar--menu svg, .app__body .sidebar-item .icon', 'fill:' + theme.sidebarText);
        changeCss('.sidebar--left .status.status--group', 'background:' + changeOpacity(theme.sidebarText, 0.3));
        changeCss('@media(max-width: 768px){.app__body .modal .settings-modal .settings-table .nav>li>button, .app__body #sidebarDropdownMenu .menu-divider', 'border-color:' + changeOpacity(theme.sidebarText, 0.2));
        changeCss('@media(max-width: 768px){.app__body .modal .settings-modal .settings-table .nav>li>button, .app__body .modal .settings-modal .settings-table .nav>li.active>button', 'color:' + theme.sidebarText);
        changeCss('.app__body .sidebar--left .sidebar__switcher', 'border-color:' + changeOpacity(theme.sidebarText, 0.2));
        changeCss('.app__body .team-sidebar .team-btn .badge', 'border-color:' + changeOpacity(theme.sidebarText, 0.5));
        changeCss('@media(max-width: 768px){.sidebar--left .add-channel-btn:hover, .sidebar--left .add-channel-btn:focus', 'color:' + changeOpacity(theme.sidebarText, 0.6));
        changeCss('.app__body .sidebar--left .sidebar__switcher span', 'color:' + theme.sidebarText);
        changeCss('.app__body .sidebar--left .sidebar__switcher button svg', 'fill:' + theme.sidebarText);
        changeCss('.channel-header .channel-header_plugin-dropdown a, .app__body .sidebar__switcher button', 'background:' + changeOpacity(theme.sidebarText, 0.08));
        changeCss('.app__body .icon__bot', 'fill:' + theme.sidebarText);
    }

    if (theme.sidebarTextHoverBg) {
        changeCss('.sidebar--left .nav-pills__container li .sidebar-item:hover, .sidebar--left .nav-pills__container li > .nav-more:hover, .app__body .modal .settings-modal .nav-pills>li:hover button', 'background:' + theme.sidebarTextHoverBg);
    }

    if (theme.sidebarTextActiveBorder) {
        changeCss('.multi-teams .team-sidebar .team-wrapper .team-container:before', 'background:' + theme.sidebarTextActiveBorder);
        changeCss('.multi-teams .team-sidebar .team-wrapper .team-container.active:before', 'background:' + theme.sidebarTextActiveBorder);
        changeCss('.multi-teams .team-sidebar .team-wrapper .team-container.unread:before', 'background:' + theme.sidebarTextActiveBorder);
    }

    if (theme.sidebarTextActiveColor) {
        changeCss('.sidebar--left .nav-pills__container li.active .sidebar-item, .sidebar--left .nav-pills__container li.active .sidebar-item:hover, .sidebar--left .nav-pills__container li.active .sidebar-item:focus, .app__body .modal .settings-modal .nav-pills>li.active button, .app__body .modal .settings-modal .nav-pills>li.active button:hover, .app__body .modal .settings-modal .nav-pills>li.active button:active', 'color:' + theme.sidebarTextActiveColor);
        changeCss('.sidebar--left .nav li.active .sidebar-item, .sidebar--left .nav li.active .sidebar-item:hover, .sidebar--left .nav li.active .sidebar-item:focus', 'background:' + changeOpacity(theme.sidebarTextActiveColor, 0.1));
        changeCss('@media(max-width: 768px){.app__body .modal .settings-modal .nav-pills > li.active button', 'color:' + changeOpacity(theme.sidebarText, 0.8));
    }

    if (theme.sidebarHeaderBg) {
        changeCss('.app__body .MenuWrapper .status-wrapper .status, .app__body #status-dropdown .status-wrapper .status-edit, .sidebar--left .team__header, .app__body .sidebar--menu .team__header, .app__body .post-list__timestamp > div', 'background:' + theme.sidebarHeaderBg);
        changeCss('.app__body .modal .modal-header', 'background:' + theme.sidebarHeaderBg);
        changeCss('.app__body .multi-teams .team-sidebar, .app__body #navbar_wrapper .navbar-default', 'background:' + theme.sidebarHeaderBg);
        changeCss('@media(max-width: 768px){.app__body .search-bar__container', 'background:' + theme.sidebarHeaderBg);
        changeCss('.app__body .attachment .attachment__container', 'border-left-color:' + theme.sidebarHeaderBg);
        changeCss('.emoji-picker .emoji-picker__header', 'background:' + theme.sidebarHeaderBg);
    }

    if (theme.sidebarHeaderTextColor) {
        changeCss('.app__body .MenuWrapper .status-wrapper .status, .app__body #status-dropdown .status-wrapper .status-edit, .sidebar--left .team__header .header__info, .app__body .sidebar--menu .team__header .header__info, .app__body .post-list__timestamp > div', 'color:' + theme.sidebarHeaderTextColor);
        changeCss('.app__body .icon--sidebarHeaderTextColor svg, .app__body .sidebar-header-dropdown__icon svg', 'fill:' + theme.sidebarHeaderTextColor);
        changeCss('.sidebar--left .team__header .user__name, .app__body .sidebar--menu .team__header .user__name', 'color:' + changeOpacity(theme.sidebarHeaderTextColor, 0.8));
        changeCss('.sidebar--left .team__header:hover .user__name, .app__body .sidebar--menu .team__header:hover .user__name', 'color:' + theme.sidebarHeaderTextColor);
        changeCss('.app__body .modal .modal-header .modal-title, .app__body .modal .modal-header .modal-title .name', 'color:' + theme.sidebarHeaderTextColor);
        changeCss('.app__body #navbar_wrapper .navbar-default .navbar-brand', 'color:' + theme.sidebarHeaderTextColor);
        changeCss('.app__body #navbar_wrapper .navbar-default .navbar-toggle .icon-bar', 'background:' + theme.sidebarHeaderTextColor);
        changeCss('.app__body .post-list__timestamp > div, .app__body .multi-teams .team-sidebar .team-wrapper .team-container a:hover .team-btn__content, .app__body .multi-teams .team-sidebar .team-wrapper .team-container.active .team-btn__content', 'border-color:' + changeOpacity(theme.sidebarHeaderTextColor, 0.5));
        changeCss('.app__body .team-btn', 'border-color:' + changeOpacity(theme.sidebarHeaderTextColor, 0.3));
        changeCss('@media(max-width: 768px){.app__body .search-bar__container', 'color:' + theme.sidebarHeaderTextColor);
        changeCss('.app__body .navbar-right__icon', 'background:' + changeOpacity(theme.sidebarHeaderTextColor, 0.2));
        changeCss('.app__body .navbar-right__icon:hover, .app__body .navbar-right__icon:focus', 'background:' + changeOpacity(theme.sidebarHeaderTextColor, 0.3));
        changeCss('.emoji-picker .emoji-picker__header, .emoji-picker .emoji-picker__header .emoji-picker__header-close-button', 'color:' + theme.sidebarHeaderTextColor);
    }

    if (theme.onlineIndicator) {
        changeCss('.app__body .status.status--online', 'color:' + theme.onlineIndicator);
        changeCss('.app__body .status .online--icon', 'fill:' + theme.onlineIndicator);
    }

    if (theme.awayIndicator) {
        changeCss('.app__body .status.status--away', 'color:' + theme.awayIndicator);
        changeCss('.app__body .status .away--icon', 'fill:' + theme.awayIndicator);
    }

    let dndIndicator;
    if (theme.dndIndicator) {
        dndIndicator = theme.dndIndicator;
    } else {
        switch (theme.type) {
        case 'Organization':
            dndIndicator = Constants.THEMES.organization.dndIndicator;
            break;
        case 'Mattermost Dark':
            dndIndicator = Constants.THEMES.mattermostDark.dndIndicator;
            break;
        case 'Windows Dark':
            dndIndicator = Constants.THEMES.windows10.dndIndicator;
            break;
        default:
            dndIndicator = Constants.THEMES.default.dndIndicator;
            break;
        }
    }
    changeCss('.app__body .status.status--dnd', 'color:' + dndIndicator);
    changeCss('.app__body .status .dnd--icon', 'fill:' + dndIndicator);

    // Including 'mentionBj' for backwards compatability (old typo)
    const mentionBg = theme.mentionBg || theme.mentionBj;
    if (mentionBg) {
        changeCss('.sidebar--left .nav-pills__unread-indicator', 'background:' + mentionBg);
        changeCss('.app__body .sidebar--left .badge, .app__body .list-group-item.active > .badge, .nav-pills > .active > a > .badge', 'background:' + mentionBg);
        changeCss('.multi-teams .team-sidebar .badge, .app__body .list-group-item.active > .badge, .nav-pills > .active > a > .badge', 'background:' + mentionBg);
    }

    if (theme.mentionColor) {
        changeCss('.sidebar--left .nav-pills__unread-indicator svg', 'fill:' + theme.mentionColor);
        changeCss('.app__body .sidebar--left .nav-pills__unread-indicator', 'color:' + theme.mentionColor);
        changeCss('.app__body .sidebar--left .badge, .app__body .list-group-item.active > .badge, .nav-pills > .active > a > .badge', 'color:' + theme.mentionColor);
        changeCss('.app__body .multi-teams .team-sidebar .badge, .app__body .list-group-item.active > .badge, .nav-pills > .active > a > .badge', 'color:' + theme.mentionColor);
    }

    if (theme.centerChannelBg) {
        changeCss('.app__body #channel_view.channel-view', `background: ${theme.centerChannelBg}`);
        changeCss('@media(max-width: 768px){.app__body .post .MenuWrapper .dropdown-menu button', 'background:' + theme.centerChannelBg);
        changeCss('.app__body .post-card--info, .app__body .bg--white, .app__body .system-notice, .app__body .channel-header__info .channel-header__description:before, .app__body .app__content, .app__body .markdown__table, .app__body .markdown__table tbody tr, .app__body .modal .modal-footer, .app__body .status-wrapper .status, .app__body .alert.alert-transparent', 'background:' + theme.centerChannelBg);
        changeCss('#post-list .post-list-holder-by-time, .app__body .post .dropdown-menu a, .app__body .post .Menu .MenuItem', 'background:' + theme.centerChannelBg);
        changeCss('#post-create, .app__body .emoji-picker__preview', 'background:' + theme.centerChannelBg);
        changeCss('.app__body .date-separator .separator__text, .app__body .new-separator .separator__text', 'background:' + theme.centerChannelBg);
        changeCss('.app__body .dropdown-menu, .app__body .popover, .app__body .tip-overlay', 'background:' + theme.centerChannelBg);
        changeCss('.app__body .popover.bottom>.arrow:after', 'border-bottom-color:' + theme.centerChannelBg);
        changeCss('.app__body .popover.right>.arrow:after, .app__body .tip-overlay.tip-overlay--sidebar .arrow, .app__body .tip-overlay.tip-overlay--header .arrow', 'border-right-color:' + theme.centerChannelBg);
        changeCss('.app__body .popover.left>.arrow:after', 'border-left-color:' + theme.centerChannelBg);
        changeCss('.app__body .popover.top>.arrow:after, .app__body .tip-overlay.tip-overlay--chat .arrow', 'border-top-color:' + theme.centerChannelBg);
        changeCss('@media(min-width: 768px){.app__body .form-control', 'background:' + theme.centerChannelBg);
        changeCss('.app__body .attachment__content, .app__body .attachment-actions button', 'background:' + theme.centerChannelBg);
        changeCss('body.app__body', 'scrollbar-face-color:' + theme.centerChannelBg);
        changeCss('body.app__body', 'scrollbar-track-color:' + theme.centerChannelBg);
        changeCss('.app__body .shortcut-key, .app__body .post-list__new-messages-below', 'color:' + theme.centerChannelBg);
        changeCss('.app__body .emoji-picker, .app__body .emoji-picker__search', 'background:' + theme.centerChannelBg);
        changeCss('.app__body .nav-tabs, .app__body .nav-tabs > li.active > a', 'background:' + theme.centerChannelBg);
        changeCss('.app__body .modal-tabs .nav-tabs > li', `background:${theme.centerChannelBg}`);
        changeCss('.app__body .modal-tabs .nav-tabs > li > a', `background:${theme.centerChannelBg}`);

        // Fade out effect for collapsed posts (not hovered, not from current user)
        changeCss(
            '.app__body .post-list__table .post:not(.current--user) .post-collapse__gradient, ' +
            '.app__body .post-list__table .post.post--compact .post-collapse__gradient, ' +
            '.app__body .sidebar-right__body .post.post--compact .post-collapse__gradient',
            `background:linear-gradient(${changeOpacity(theme.centerChannelBg, 0)}, ${theme.centerChannelBg})`,
        );
        changeCss(
            '.app__body .post-list__table .post-attachment-collapse__gradient, ' +
            '.app__body .sidebar-right__body .post-attachment-collapse__gradient',
            `background:linear-gradient(${changeOpacity(theme.centerChannelBg, 0)}, ${theme.centerChannelBg})`,
        );

        changeCss(
            '.app__body .post-list__table .post:not(.current--user) .post-collapse__show-more, ' +
            '.app__body .post-list__table .post.post--compact .post-collapse__show-more, ' +
            '.app__body .sidebar-right__body .post:not(.post--root) .post-collapse__show-more',
            `background-color:${theme.centerChannelBg}`,
        );
        changeCss(
            '.app__body .post-list__table .post-attachment-collapse__show-more, ' +
            '.app__body .sidebar-right__body .post-attachment-collapse__show-more',
            `background-color:${theme.centerChannelBg}`,
        );

        changeCss('.app__body .post-collapse__show-more-button:hover', `color:${theme.centerChannelBg}`);
        changeCss('.app__body .post-collapse__show-more-button', `background:${theme.centerChannelBg}`);
    }

    if (theme.centerChannelColor) {
        changeCss('.app__body .bg-text-200', 'background:' + changeOpacity(theme.centerChannelColor, 0.2));
        changeCss('.app__body .user-popover__role', 'background:' + changeOpacity(theme.centerChannelColor, 0.3));
        changeCss('.app__body .svg-text-color', 'fill:' + theme.centerChannelColor);
        changeCss('.app__body .mentions__name .status.status--group, .app__body .multi-select__note', 'background:' + changeOpacity(theme.centerChannelColor, 0.12));
        changeCss('.app__body .modal-tabs .nav-tabs > li, .app__body .system-notice, .app__body .file-view--single .file__image .image-loaded, .app__body .post .MenuWrapper .dropdown-menu button, .app__body .member-list__popover .more-modal__body, .app__body .alert.alert-transparent, .app__body .table > thead > tr > th, .app__body .table > tbody > tr > td', 'border-color:' + changeOpacity(theme.centerChannelColor, 0.12));
        changeCss('.app__body .post-list__arrows', 'fill:' + changeOpacity(theme.centerChannelColor, 0.3));
        changeCss('.app__body .post .card-icon__container', 'color:' + changeOpacity(theme.centerChannelColor, 0.3));
        changeCss('.app__body .post-image__details .post-image__download svg', 'stroke:' + changeOpacity(theme.centerChannelColor, 0.4));
        changeCss('.app__body .post-image__details .post-image__download svg', 'border-color:' + changeOpacity(theme.centerChannelColor, 0.35));
        changeCss('.app__body .modal .status .offline--icon, .app__body .channel-header__links .icon, .app__body .sidebar--right .sidebar--right__subheader .usage__icon, .app__body .more-modal__header svg, .app__body .icon--body', 'fill:' + theme.centerChannelColor);
        changeCss('@media(min-width: 768px){.app__body .post:hover .post__header .post-menu, .app__body .post.post--hovered .post__header .post-menu, .app__body .post.a11y--active .post__header .post-menu', 'border-color:' + changeOpacity(theme.centerChannelColor, 0.2));
        changeCss('.app__body .MenuWrapper .MenuItem__divider, .app__body .modal .about-modal .modal-content .modal-header, .post .attachment .attachment__image.attachment__image--opengraph, .app__body .DayPicker .DayPicker-Caption, .app__body .modal .settings-modal .team-img-preview div, .app__body .modal .settings-modal .team-img__container div, .app__body .system-notice__footer, .app__body .system-notice__footer .btn:last-child, .app__body .modal .shortcuts-modal .subsection, .app__body .channel-header, .app__body .nav-tabs > li > a:hover, .app__body .nav-tabs, .app__body .nav-tabs > li.active > a, .app__body .nav-tabs, .app__body .nav-tabs > li.active > a:focus, .app__body .nav-tabs, .app__body .nav-tabs > li.active > a:hover, .app__body .post .dropdown-menu a, .sidebar--left, .app__body .suggestion-list__content .command, .app__body .channel-archived__message, .app__body .post-card--info', 'border-color:' + changeOpacity(theme.centerChannelColor, 0.2));
        changeCss('.app__body .help-text, .app__body .post .post-waiting, .app__body .post.post--system .post__body', 'color:' + changeOpacity(theme.centerChannelColor, 0.6));
        changeCss('.app__body .nav-tabs, .app__body .nav-tabs > li.active > a, pp__body .input-group-addon, .app__body .app__content, .app__body .post-create__container .post-create-body .btn-file, .app__body .post-create__container .post-create-footer .msg-typing, .app__body .dropdown-menu, .app__body .popover, .app__body .mentions__name, .app__body .tip-overlay, .app__body .form-control[disabled], .app__body .form-control[readonly], .app__body fieldset[disabled] .form-control', 'color:' + theme.centerChannelColor);
        changeCss('.app__body .post .post__link', 'color:' + changeOpacity(theme.centerChannelColor, 0.65));
        changeCss('.app__body #archive-link-home, .video-div .video-thumbnail__error', 'background:' + changeOpacity(theme.centerChannelColor, 0.15));
        changeCss('.app__body #post-create', 'color:' + theme.centerChannelColor);
        changeCss('.app__body .mentions--top', 'box-shadow:' + changeOpacity(theme.centerChannelColor, 0.2) + ' 1px -3px 12px');
        changeCss('.app__body .mentions--top', '-webkit-box-shadow:' + changeOpacity(theme.centerChannelColor, 0.2) + ' 1px -3px 12px');
        changeCss('.app__body .mentions--top', '-moz-box-shadow:' + changeOpacity(theme.centerChannelColor, 0.2) + ' 1px -3px 12px');
        changeCss('.app__body .shadow--2', 'box-shadow: 0 20px 30px 0' + changeOpacity(theme.centerChannelColor, 0.1) + ', 0 14px 20px 0 ' + changeOpacity(theme.centerChannelColor, 0.1));
        changeCss('.app__body .shadow--2', '-moz-box-shadow: 0  20px 30px 0 ' + changeOpacity(theme.centerChannelColor, 0.1) + ', 0 14px 20px 0 ' + changeOpacity(theme.centerChannelColor, 0.1));
        changeCss('.app__body .shadow--2', '-webkit-box-shadow: 0  20px 30px 0 ' + changeOpacity(theme.centerChannelColor, 0.1) + ', 0 14px 20px 0 ' + changeOpacity(theme.centerChannelColor, 0.1));
        changeCss('.app__body .shortcut-key, .app__body .post__body hr, .app__body .loading-screen .loading__content .round, .app__body .tutorial__circles .circle', 'background:' + theme.centerChannelColor);
        changeCss('.app__body .channel-header .heading', 'color:' + theme.centerChannelColor);
        changeCss('.app__body .markdown__table tbody tr:nth-child(2n)', 'background:' + changeOpacity(theme.centerChannelColor, 0.07));
        changeCss('.app__body .channel-header__info .header-dropdown__icon', 'color:' + changeOpacity(theme.centerChannelColor, 0.8));
        changeCss('.app__body .post-create__container .post-create-body .send-button.disabled i', 'color:' + changeOpacity(theme.centerChannelColor, 0.4));
        changeCss('.app__body .channel-header .pinned-posts-button svg', 'fill:' + changeOpacity(theme.centerChannelColor, 0.6));
        changeCss('.app__body .channel-header .channel-header_plugin-dropdown svg', 'fill:' + changeOpacity(theme.centerChannelColor, 0.6));
        changeCss('.app__body .file-preview, .app__body .post-image__details, .app__body .markdown__table th, .app__body .markdown__table td, .app__body .modal .settings-modal .settings-table .settings-content .divider-light, .app__body .webhooks__container, .app__body .dropdown-menu, .app__body .modal .modal-header', 'border-color:' + changeOpacity(theme.centerChannelColor, 0.2));
        changeCss('.emoji-picker .emoji-picker__header', 'border-color:' + changeOpacity(theme.centerChannelColor, 0.2));
        changeCss('.app__body .popover.bottom>.arrow', 'border-bottom-color:' + changeOpacity(theme.centerChannelColor, 0.25));
        changeCss('.app__body .btn.btn-transparent', 'color:' + changeOpacity(theme.centerChannelColor, 0.7));
        changeCss('.app__body .popover.right>.arrow', 'border-right-color:' + changeOpacity(theme.centerChannelColor, 0.25));
        changeCss('.app__body .popover.left>.arrow', 'border-left-color:' + changeOpacity(theme.centerChannelColor, 0.25));
        changeCss('.app__body .popover.top>.arrow', 'border-top-color:' + changeOpacity(theme.centerChannelColor, 0.25));
        changeCss('.app__body .popover .popover__row', 'border-color:' + changeOpacity(theme.centerChannelColor, 0.2));
        changeCss('body.app__body, .app__body .custom-textarea', 'color:' + theme.centerChannelColor);
        changeCss('.app__body .input-group-addon', 'border-color:' + changeOpacity(theme.centerChannelColor, 0.1));
        changeCss('@media(min-width: 768px){.app__body .post-list__table .post-list__content .dropdown-menu a:hover, .dropdown-menu > li > button:hover', 'background:' + changeOpacity(theme.centerChannelColor, 0.1));
        changeCss('.app__body .MenuWrapper .MenuItem > button:hover, .app__body .Menu .MenuItem > button:hover, .app__body .MenuWrapper .MenuItem > button:focus, .app__body .MenuWrapper .MenuItem > a:hover, .app__body .dropdown-menu div > a:focus, .app__body .dropdown-menu div > a:hover, .dropdown-menu li > a:focus, .app__body .dropdown-menu li > a:hover', 'background:' + changeOpacity(theme.centerChannelColor, 0.1));
        changeCss('.app__body .attachment .attachment__content, .app__body .attachment-actions button', 'border-color:' + changeOpacity(theme.centerChannelColor, 0.3));
        changeCss('.app__body .attachment-actions button:focus, .app__body .attachment-actions button:hover', 'border-color:' + changeOpacity(theme.centerChannelColor, 0.5));
        changeCss('.app__body .attachment-actions button:focus, .app__body .attachment-actions button:hover', 'background:' + changeOpacity(theme.centerChannelColor, 0.03));
        changeCss('.app__body .input-group-addon, .app__body .channel-intro .channel-intro__content, .app__body .webhooks__container', 'background:' + changeOpacity(theme.centerChannelColor, 0.05));
        changeCss('.app__body .date-separator .separator__text', 'color:' + theme.centerChannelColor);
        changeCss('.app__body .date-separator .separator__hr, .app__body .modal-footer, .app__body .modal .custom-textarea', 'border-color:' + changeOpacity(theme.centerChannelColor, 0.2));
        changeCss('.app__body .search-item-container', 'border-color:' + changeOpacity(theme.centerChannelColor, 0.1));
        changeCss('.app__body .modal .custom-textarea:focus', 'border-color:' + changeOpacity(theme.centerChannelColor, 0.3));
        changeCss('.app__body .channel-intro, .app__body .modal .settings-modal .settings-table .settings-content .divider-dark, .app__body hr, .app__body .modal .settings-modal .settings-table .settings-links, .app__body .modal .settings-modal .settings-table .settings-content .appearance-section .theme-elements__header, .app__body .user-settings .authorized-app:not(:last-child)', 'border-color:' + changeOpacity(theme.centerChannelColor, 0.2));
        changeCss('.app__body .post.post--comment.other--root.current--user .post-comment, .app__body pre', 'background:' + changeOpacity(theme.centerChannelColor, 0.05));
        changeCss('.app__body .post.post--comment.other--root.current--user .post-comment, .app__body .more-modal__list .more-modal__row, .app__body .member-div:first-child, .app__body .member-div, .app__body .access-history__table .access__report, .app__body .activity-log__table', 'border-color:' + changeOpacity(theme.centerChannelColor, 0.1));
        changeCss('@media(max-width: 1800px){.app__body .inner-wrap.move--left .post.post--comment.same--root', 'border-color:' + changeOpacity(theme.centerChannelColor, 0.07));
        changeCss('.app__body .post.post--hovered', 'background:' + changeOpacity(theme.centerChannelColor, 0.08));
        changeCss('.app__body .attachment__body__wrap.btn-close', 'background:' + changeOpacity(theme.centerChannelColor, 0.08));
        changeCss('.app__body .attachment__body__wrap.btn-close', 'border-color:' + changeOpacity(theme.centerChannelColor, 0.2));
        changeCss('@media(min-width: 768px){.app__body .post.a11y--active, .app__body .modal .settings-modal .settings-table .settings-content .section-min:hover', 'background:' + changeOpacity(theme.centerChannelColor, 0.08));
        changeCss('@media(min-width: 768px){.app__body .post.current--user:hover .post__body ', 'background: transparent;');
        changeCss('.app__body .more-modal__row.more-modal__row--selected, .app__body .date-separator.hovered--before:after, .app__body .date-separator.hovered--after:before, .app__body .new-separator.hovered--after:before, .app__body .new-separator.hovered--before:after', 'background:' + changeOpacity(theme.centerChannelColor, 0.07));
        changeCss('@media(min-width: 768px){.app__body .dropdown-menu>li>a:focus, .app__body .dropdown-menu>li>a:hover', 'background:' + changeOpacity(theme.centerChannelColor, 0.15));
        changeCss('.app__body .form-control[disabled], .app__body .form-control[readonly], .app__body fieldset[disabled] .form-control', 'background:' + changeOpacity(theme.centerChannelColor, 0.1));
        changeCss('.app__body .sidebar--right', 'color:' + theme.centerChannelColor);
        changeCss('.app__body .modal .settings-modal .settings-table .settings-content .appearance-section .theme-elements__body', 'background:' + changeOpacity(theme.centerChannelColor, 0.05));
        if (!UserAgent.isFirefox() && !UserAgent.isInternetExplorer() && !UserAgent.isEdge()) {
            changeCss('body.app__body ::-webkit-scrollbar-thumb', 'background:' + changeOpacity(theme.centerChannelColor, 0.4));
        }
        changeCss('body', 'scrollbar-arrow-color:' + theme.centerChannelColor);
        changeCss('.app__body .post-create__container .post-create-body .btn-file svg, .app__body .post.post--compact .post-image__column .post-image__details svg, .app__body .modal .about-modal .about-modal__logo svg, .app__body .status svg, .app__body .edit-post__actions .icon svg', 'fill:' + theme.centerChannelColor);
        changeCss('.app__body .scrollbar--horizontal, .app__body .scrollbar--vertical', 'background:' + changeOpacity(theme.centerChannelColor, 0.5));
        changeCss('.app__body .post-list__new-messages-below', 'background:' + changeColor(theme.centerChannelColor, 0.5));
        changeCss('.app__body .post.post--comment .post__body', 'border-color:' + changeOpacity(theme.centerChannelColor, 0.2));
        changeCss('@media(min-width: 768px){.app__body .post.post--compact.same--root.post--comment .post__content', 'border-color:' + changeOpacity(theme.centerChannelColor, 0.2));
        changeCss('.app__body .post.post--comment.current--user .post__body', 'border-color:' + changeOpacity(theme.centerChannelColor, 0.2));
        changeCss('.app__body .channel-header__info .status .offline--icon', 'fill:' + theme.centerChannelColor);
        changeCss('.app__body .navbar .status .offline--icon', 'fill:' + theme.centerChannelColor);
        changeCss('.app__body .emoji-picker', 'color:' + theme.centerChannelColor);
        changeCss('.app__body .emoji-picker', 'border-color:' + changeOpacity(theme.centerChannelColor, 0.2));
        changeCss('.app__body .emoji-picker__search-icon', 'color:' + changeOpacity(theme.centerChannelColor, 0.4));
        changeCss('.app__body .emoji-picker__preview, .app__body .emoji-picker__items, .app__body .emoji-picker__search-container', 'border-color:' + changeOpacity(theme.centerChannelColor, 0.2));
        changeCss('.emoji-picker__category .fa:hover', 'color:' + changeOpacity(theme.centerChannelColor, 0.8));
        changeCss('.app__body .emoji-picker__category--selected, .app__body .emoji-picker__category--selected:focus, .app__body .emoji-picker__category--selected:hover', 'color:' + theme.centerChannelColor);
        changeCss('.app__body .emoji-picker__item-wrapper:hover', 'background-color:' + changeOpacity(theme.centerChannelColor, 0.8));
        changeCss('.app__body .icon__postcontent_picker:hover', 'color:' + changeOpacity(theme.centerChannelColor, 0.8));
        changeCss('.app__body .emoji-picker .nav-tabs li a', 'fill:' + theme.centerChannelColor);
        changeCss('.app__body .post .post-collapse__show-more-button', `border-color:${changeOpacity(theme.centerChannelColor, 0.1)}`);
        changeCss('.app__body .post .post-collapse__show-more-line', `background-color:${changeOpacity(theme.centerChannelColor, 0.1)}`);

        if (theme.centerChannelBg) {
            const hoveredPostBg = blendColors(theme.centerChannelBg, theme.centerChannelColor, 0.04);
            const hoveredPostBgLight = blendColors(theme.centerChannelBg, theme.centerChannelColor, 0.04);

            // Fade out effect for collapsed posts that are being hovered over
            changeCss(
                '@media(min-width: 768px){.app__body .post-list__table .post:hover .post-collapse__gradient, ' +
                '.app__body .sidebar-right__body .post:hover .post-collapse__gradient',
                `background:linear-gradient(${changeOpacity(hoveredPostBg, 0)}, ${hoveredPostBg})`,
            );
            changeCss(
                '@media(min-width: 768px){.app__body .post-list__table .post:hover .post-collapse__show-more, ' +
                '.app__body .sidebar-right__body .post:hover .post-collapse__show-more',
                `background:${hoveredPostBg}`,
            );
            changeCss(
                '@media(max-width: 768px){.app__body .post-list__table .post.current--user:hover .post-collapse__show-more',
                `background:${hoveredPostBgLight}`,
            );
            changeCss(
                '.app__body .post-list__table .post.post--hovered .post-collapse__gradient, ' +
                '.app__body .sidebar-right__body .post.post--hovered .post-collapse__gradient',
                `background:linear-gradient(${changeOpacity(hoveredPostBg, 0)}, ${hoveredPostBg})`,
            );
            changeCss(
                '.app__body .post-list__table .post.post--hovered .post-collapse__show-more, ' +
                '.app__body .sidebar-right__body .post.post--hovered .post-collapse__show-more',
                `background:${hoveredPostBg}`,
            );

            // Fade out effect for permalinked posts
            if (theme.mentionHighlightBg) {
                const highlightBg = blendColors(theme.centerChannelBg, theme.mentionHighlightBg, 0.5);
                const ownPostHighlightBg = blendColors(highlightBg, theme.centerChannelColor, 0.05);

                // For permalinked posts made by another user
                changeCss(
                    '.app__body .post-list__table .post:not(.current--user).post--highlight .post-collapse__gradient, ' +
                    '.app__body .post-list__table .post.post--compact.post--highlight .post-collapse__gradient',
                    `background:linear-gradient(${changeOpacity(highlightBg, 0)}, ${highlightBg})`,
                );

                // For permalinked posts made by the current user
                changeCss(
                    '.app__body .post-list__table .post.current--user.post--highlight:not(.post--compact) .post-collapse__gradient',
                    `background:linear-gradient(${changeOpacity(ownPostHighlightBg, 0)}, ${ownPostHighlightBg})`,
                );

                // For hovered posts
                changeCss(
                    '.app__body .post-list__table .post.current--user.post--highlight:hover .post-collapse__gradient, ' +
                    '.app__body .post-list__table .post.current--user.post--highlight.post--hovered .post-collapse__gradient',
                    `background:linear-gradient(${changeOpacity(highlightBg, 0)}, ${highlightBg})`,
                );
            }
        }
    }

    if (theme.newMessageSeparator) {
        changeCss('.app__body .new-separator .separator__text', 'color:' + theme.newMessageSeparator);
        changeCss('.app__body .new-separator .separator__hr', 'border-color:' + changeOpacity(theme.newMessageSeparator, 0.5));
    }

    if (theme.linkColor) {
        changeCss('.app__body .more-modal__list .a11y--focused, .app__body .post.a11y--focused, .app__body .channel-header.a11y--focused, .app__body .post-create.a11y--focused, .app__body .user-popover.a11y--focused, .app__body .post-message__text.a11y--focused, #archive-link-home>a.a11y--focused', 'box-shadow: inset 0 0 1px 3px ' + changeOpacity(theme.linkColor, 0.5) + ', inset 0 0 0 1px ' + theme.linkColor);
        changeCss('.multi-select__focused > div', 'box-shadow: 0 0 1px 3px ' + changeOpacity(theme.linkColor, 0.5) + ', 0 0 0 1px ' + theme.linkColor);
        changeCss('.app__body .a11y--focused', 'box-shadow: 0 0 1px 3px ' + changeOpacity(theme.linkColor, 0.5) + ', 0 0 0 1px ' + theme.linkColor);
        changeCss('.app__body .DayPicker-Day--today, .app__body .channel-header .channel-header__favorites.inactive:hover, .app__body .channel-header__links > a.active, .app__body a, .app__body a:focus, .app__body a:hover, .app__body .channel-header__links > .color--link.active, .app__body .color--link, .app__body a:focus, .app__body .color--link:hover, .app__body .btn, .app__body .btn:focus, .app__body .btn:hover', 'color:' + theme.linkColor);
        changeCss('.app__body .attachment .attachment__container', 'border-left-color:' + changeOpacity(theme.linkColor, 0.5));
        changeCss('.app__body .channel-header .channel-header_plugin-dropdown a:hover, .app__body .member-list__popover .more-modal__list .more-modal__row:hover', 'background:' + changeOpacity(theme.linkColor, 0.08));
        changeCss('.app__body .channel-header__links .icon:hover, .app__body .channel-header__links > a.active .icon, .app__body .post .post__reply', 'fill:' + theme.linkColor);
        changeCss('.app__body .channel-header__links .icon:hover, .app__body .post .card-icon__container.active svg, .app__body .post .post__reply', 'fill:' + theme.linkColor);
        changeCss('.app__body .channel-header .pinned-posts-button:hover svg', 'fill:' + changeOpacity(theme.linkColor, 0.6));
        changeCss('.app__body .member-list__popover .more-modal__actions svg', 'fill:' + theme.linkColor);
        changeCss('.app__body .modal-tabs .nav-tabs > li.active, .app__body .channel-header .channel-header_plugin-dropdown a:hover, .app__body .member-list__popover .more-modal__list .more-modal__row:hover', 'border-color:' + theme.linkColor);
        changeCss('.app__body .channel-header .channel-header_plugin-dropdown a:hover svg', 'fill:' + theme.linkColor);
        changeCss('.app__body .channel-header .dropdown-toggle:hover .heading, .app__body .channel-header .dropdown-toggle:hover .header-dropdown__icon, .app__body .channel-header__title .open .heading, .app__body .channel-header__info .channel-header__title .open .header-dropdown__icon, .app__body .channel-header__title .open .heading, .app__body .channel-header__info .channel-header__title .open .heading', 'color:' + theme.linkColor);
        changeCss('.emoji-picker__container .icon--emoji.active svg', 'fill:' + theme.linkColor);
        changeCss('.app__body .channel-header .channel-header_plugin-dropdown a:hover .fa', 'color:' + theme.linkColor);
        changeCss('.app__body .post .post-collapse__show-more', `color:${theme.linkColor}`);
        changeCss('.app__body .post .post-attachment-collapse__show-more', `color:${theme.linkColor}`);
        changeCss('.app__body .post .post-collapse__show-more-button:hover', `background-color:${theme.linkColor}`);
        changeCss('.app__body .post-message .group-mention-link', `color:${theme.linkColor}`);
    }

    if (theme.buttonBg) {
        changeCss('.app__body .modal .settings-modal .profile-img__remove:hover, .app__body .DayPicker:not(.DayPicker--interactionDisabled) .DayPicker-Day:not(.DayPicker-Day--disabled):not(.DayPicker-Day--selected):not(.DayPicker-Day--outside):hover, .app__body .modal .settings-modal .team-img__remove:hover, .app__body .btn.btn-transparent:hover, .app__body .btn.btn-transparent:active, .app__body .post-image__details .post-image__download svg:hover, .app__body .file-view--single .file__download:hover, .app__body .new-messages__button div, .app__body .btn.btn-primary, .app__body .tutorial__circles .circle.active', 'background:' + theme.buttonBg);
        changeCss('.app__body .system-notice__logo svg', 'fill:' + theme.buttonBg);
        changeCss('.app__body .post-image__details .post-image__download svg:hover', 'border-color:' + theme.buttonBg);
        changeCss('.app__body .btn.btn-primary:hover, .app__body .btn.btn-primary:active, .app__body .btn.btn-primary:focus', 'background:' + changeColor(theme.buttonBg, -0.15));
        changeCss('.app__body .emoji-picker .nav-tabs li.active a, .app__body .emoji-picker .nav-tabs li a:hover', 'fill:' + theme.buttonBg);
        changeCss('.app__body .emoji-picker .nav-tabs > li.active > a', 'border-bottom-color:' + theme.buttonBg + '!important;');
    }

    if (theme.buttonColor) {
        changeCss('.app__body .DayPicker:not(.DayPicker--interactionDisabled) .DayPicker-Day:not(.DayPicker-Day--disabled):not(.DayPicker-Day--selected):not(.DayPicker-Day--outside):hover, .app__body .modal .settings-modal .team-img__remove:hover, .app__body .btn.btn-transparent:hover, .app__body .btn.btn-transparent:active, .app__body .new-messages__button div, .app__body .btn.btn-primary', 'color:' + theme.buttonColor);
        changeCss('.app__body .new-messages__button svg', 'fill:' + theme.buttonColor);
        changeCss('.app__body .post-image__details .post-image__download svg:hover, .app__body .file-view--single .file__download svg', 'stroke:' + theme.buttonColor);
    }

    if (theme.errorTextColor) {
        changeCss('.app__body .error-text, .app__body .modal .settings-modal .settings-table .settings-content .has-error, .app__body .modal .input__help.error, .app__body .color--error, .app__body .has-error .help-block, .app__body .has-error .control-label, .app__body .has-error .radio, .app__body .has-error .checkbox, .app__body .has-error .radio-inline, .app__body .has-error .checkbox-inline, .app__body .has-error.radio label, .app__body .has-error.checkbox label, .app__body .has-error.radio-inline label, .app__body .has-error.checkbox-inline label', 'color:' + theme.errorTextColor);
    }

    if (theme.mentionHighlightBg) {
        changeCss('.app__body .mention--highlight, .app__body .search-highlight', 'background:' + theme.mentionHighlightBg);
        changeCss('.app__body .post.post--comment .post__body.mention-comment', 'border-color:' + theme.mentionHighlightBg);
        changeCss('.app__body .post.post--highlight', 'background:' + changeOpacity(theme.mentionHighlightBg, 0.5));
    }

    if (theme.mentionHighlightLink) {
        changeCss('.app__body .mention--highlight .mention-link, .app__body .mention--highlight, .app__body .search-highlight', 'color:' + theme.mentionHighlightLink);
    }

    if (!theme.codeTheme) {
        theme.codeTheme = Constants.DEFAULT_CODE_THEME;
    }
    updateCodeTheme(theme.codeTheme);
    cssVars({
        variables: {

            // RGB values derived from theme hex values i.e. '255, 255, 255'
            // (do not apply opacity mutations here)
            'away-indicator-rgb': toRgbValues(theme.awayIndicator),
            'button-bg-rgb': toRgbValues(theme.buttonBg),
            'button-color-rgb': toRgbValues(theme.buttonColor),
            'center-channel-bg-rgb': toRgbValues(theme.centerChannelBg),
            'center-channel-color-rgb': toRgbValues(theme.centerChannelColor),
            'dnd-indicator-rgb': toRgbValues(theme.dndIndicator),
            'error-text-color-rgb': toRgbValues(theme.errorTextColor),
            'link-color-rgb': toRgbValues(theme.linkColor),
            'mention-bg-rgb': toRgbValues(theme.mentionBg),
            'mention-color-rgb': toRgbValues(theme.mentionColor),
            'mention-highlight-bg-rgb': toRgbValues(theme.mentionHighlightBg),
            'mention-highlight-link-rgb': toRgbValues(theme.mentionHighlightLink),
            'new-message-separator-rgb': toRgbValues(theme.newMessageSeparator),
            'online-indicator-rgb': toRgbValues(theme.onlineIndicator),
            'sidebar-bg-rgb': toRgbValues(theme.sidebarBg),
            'sidebar-header-bg-rgb': toRgbValues(theme.sidebarHeaderBg),
            'sidebar-header-text-color-rgb': toRgbValues(theme.sidebarHeaderTextColor),
            'sidebar-text-rgb': toRgbValues(theme.sidebarText),
            'sidebar-text-active-border-rgb': toRgbValues(theme.sidebarTextActiveBorder),
            'sidebar-text-active-color-rgb': toRgbValues(theme.sidebarTextActiveColor),
            'sidebar-text-hover-bg-rgb': toRgbValues(theme.sidebarTextHoverBg),
            'sidebar-unread-text-rgb': toRgbValues(theme.sidebarUnreadText),

            // Hex CSS variables
            // TODO: phase out changeOpacity() here
            'sidebar-bg': theme.sidebarBg,
            'sidebar-text': theme.sidebarText,
            'sidebar-text-08': changeOpacity(theme.sidebarText, 0.08),
            'sidebar-text-16': changeOpacity(theme.sidebarText, 0.16),
            'sidebar-text-30': changeOpacity(theme.sidebarText, 0.3),
            'sidebar-text-40': changeOpacity(theme.sidebarText, 0.4),
            'sidebar-text-50': changeOpacity(theme.sidebarText, 0.5),
            'sidebar-text-60': changeOpacity(theme.sidebarText, 0.6),
            'sidebar-text-72': changeOpacity(theme.sidebarText, 0.72),
            'sidebar-text-80': changeOpacity(theme.sidebarText, 0.8),
            'sidebar-unread-text': theme.sidebarUnreadText,
            'sidebar-text-hover-bg': theme.sidebarTextHoverBg,
            'sidebar-text-active-border': theme.sidebarTextActiveBorder,
            'sidebar-text-active-color': theme.sidebarTextActiveColor,
            'sidebar-header-bg': theme.sidebarHeaderBg,
            'sidebar-header-text-color': theme.sidebarHeaderTextColor,
            'sidebar-header-text-color-80': changeOpacity(theme.sidebarHeaderTextColor, 0.8),
            'online-indicator': theme.onlineIndicator,
            'away-indicator': theme.awayIndicator,
            'dnd-indicator': theme.dndIndicator,
            'mention-bg': theme.mentionBg,
            'mention-color': theme.mentionColor,
            'center-channel-bg': theme.centerChannelBg,
            'center-channel-color': theme.centerChannelColor,
            'center-channel-bg-88': changeOpacity(theme.centerChannelBg, 0.88),
            'center-channel-color-88': changeOpacity(theme.centerChannelColor, 0.88),
            'center-channel-bg-80': changeOpacity(theme.centerChannelBg, 0.8),
            'center-channel-color-80': changeOpacity(theme.centerChannelColor, 0.8),
            'center-channel-color-72': changeOpacity(theme.centerChannelColor, 0.72),
            'center-channel-bg-64': changeOpacity(theme.centerChannelBg, 0.64),
            'center-channel-color-64': changeOpacity(theme.centerChannelColor, 0.64),
            'center-channel-bg-56': changeOpacity(theme.centerChannelBg, 0.56),
            'center-channel-color-56': changeOpacity(theme.centerChannelColor, 0.56),
            'center-channel-color-48': changeOpacity(theme.centerChannelColor, 0.48),
            'center-channel-bg-40': changeOpacity(theme.centerChannelBg, 0.4),
            'center-channel-color-40': changeOpacity(theme.centerChannelColor, 0.4),
            'center-channel-bg-30': changeOpacity(theme.centerChannelBg, 0.3),
            'center-channel-color-32': changeOpacity(theme.centerChannelColor, 0.32),
            'center-channel-bg-20': changeOpacity(theme.centerChannelBg, 0.2),
            'center-channel-color-20': changeOpacity(theme.centerChannelColor, 0.2),
            'center-channel-bg-16': changeOpacity(theme.centerChannelBg, 0.16),
            'center-channel-color-24': changeOpacity(theme.centerChannelColor, 0.24),
            'center-channel-color-16': changeOpacity(theme.centerChannelColor, 0.16),
            'center-channel-bg-08': changeOpacity(theme.centerChannelBg, 0.08),
            'center-channel-color-08': changeOpacity(theme.centerChannelColor, 0.08),
            'center-channel-color-04': changeOpacity(theme.centerChannelColor, 0.04),
            'new-message-separator': theme.newMessageSeparator,
            'link-color': theme.linkColor,
            'link-color-08': changeOpacity(theme.linkColor, 0.08),
            'button-bg': theme.buttonBg,
            'button-color': theme.buttonColor,
            'button-bg-88': changeOpacity(theme.buttonBg, 0.88),
            'button-color-88': changeOpacity(theme.buttonColor, 0.88),
            'button-bg-80': changeOpacity(theme.buttonBg, 0.8),
            'button-color-80': changeOpacity(theme.buttonColor, 0.8),
            'button-bg-72': changeOpacity(theme.buttonBg, 0.72),
            'button-color-72': changeOpacity(theme.buttonColor, 0.72),
            'button-bg-64': changeOpacity(theme.buttonBg, 0.64),
            'button-color-64': changeOpacity(theme.buttonColor, 0.64),
            'button-bg-56': changeOpacity(theme.buttonBg, 0.56),
            'button-color-56': changeOpacity(theme.buttonColor, 0.56),
            'button-bg-48': changeOpacity(theme.buttonBg, 0.48),
            'button-color-48': changeOpacity(theme.buttonColor, 0.48),
            'button-bg-40': changeOpacity(theme.buttonBg, 0.4),
            'button-color-40': changeOpacity(theme.buttonColor, 0.4),
            'button-bg-30': changeOpacity(theme.buttonBg, 0.32),
            'button-color-32': changeOpacity(theme.buttonColor, 0.32),
            'button-bg-24': changeOpacity(theme.buttonBg, 0.24),
            'button-color-24': changeOpacity(theme.buttonColor, 0.24),
            'button-bg-16': changeOpacity(theme.buttonBg, 0.16),
            'button-color-16': changeOpacity(theme.buttonColor, 0.16),
            'button-bg-08': changeOpacity(theme.buttonBg, 0.08),
            'button-color-08': changeOpacity(theme.buttonColor, 0.08),
            'button-bg-04': changeOpacity(theme.buttonBg, 0.04),
            'button-color-04': changeOpacity(theme.buttonColor, 0.04),
            'error-text': theme.errorTextColor,
            'error-text-08': changeOpacity(theme.errorTextColor, 0.08),
            'error-text-12': changeOpacity(theme.errorTextColor, 0.12),
            'mention-highlight-bg': theme.mentionHighlightBg,
            'mention-highlight-link': theme.mentionHighlightLink,
        },
    });
}

export function resetTheme() {
    applyTheme(Constants.THEMES.default);
}

export function changeCss(className, classValue) {
    let styleEl = document.querySelector('style[data-class="' + className + '"]');
    if (!styleEl) {
        styleEl = document.createElement('style');
        styleEl.setAttribute('data-class', className);

        // Append style element to head
        document.head.appendChild(styleEl);
    }

    // Grab style sheet
    const styleSheet = styleEl.sheet;
    const rules = styleSheet.cssRules || styleSheet.rules;
    const style = classValue.substr(0, classValue.indexOf(':'));
    const value = classValue.substr(classValue.indexOf(':') + 1).replace(/!important[;]/g, '');
    const priority = (classValue.match(/!important/) ? 'important' : null);

    for (let i = 0; i < rules.length; i++) {
        if (rules[i].selectorText === className) {
            rules[i].style.setProperty(style, value, priority);
            return;
        }
    }

    let mediaQuery = '';
    if (className.indexOf('@media') >= 0) {
        mediaQuery = '}';
    }
    try {
        styleSheet.insertRule(className + '{' + classValue + '}' + mediaQuery, styleSheet.cssRules.length);
    } catch (e) {
        console.error(e); // eslint-disable-line no-console
    }
}

export function updateCodeTheme(userTheme) {
    let cssPath = '';
    Constants.THEME_ELEMENTS.forEach((element) => {
        if (element.id === 'codeTheme') {
            element.themes.forEach((theme) => {
                if (userTheme === theme.id) {
                    cssPath = theme.cssURL;
                }
            });
        }
    });
    const link = document.querySelector('link.code_theme');
    if (link && cssPath !== link.attributes.href) {
        changeCss('code.hljs', 'visibility: hidden');
        var xmlHTTP = new XMLHttpRequest();
        xmlHTTP.open('GET', cssPath, true);
        xmlHTTP.onload = function onLoad() {
            link.attributes.href = cssPath;
            if (UserAgent.isFirefox()) {
                link.addEventListener('load', () => {
                    changeCss('code.hljs', 'visibility: visible');
                }, {once: true});
            } else {
                changeCss('code.hljs', 'visibility: visible');
            }
        };
        xmlHTTP.send();
    }
}

export function placeCaretAtEnd(el) {
    el.focus();
    el.selectionStart = el.value.length;
    el.selectionEnd = el.value.length;
}

export function getCaretPosition(el) {
    if (el.selectionStart) {
        return el.selectionStart;
    } else if (document.selection) {
        el.focus();

        var r = document.selection.createRange();
        if (r == null) {
            return 0;
        }

        var re = el.createTextRange();
        var rc = re.duplicate();
        re.moveToBookmark(r.getBookmark());
        rc.setEndPoint('EndToStart', re);

        return rc.text.length;
    }
    return 0;
}

export function setSelectionRange(input, selectionStart, selectionEnd) {
    if (input.setSelectionRange) {
        input.focus();
        input.setSelectionRange(selectionStart, selectionEnd);
    } else if (input.createTextRange) {
        var range = input.createTextRange();
        range.collapse(true);
        range.moveEnd('character', selectionEnd);
        range.moveStart('character', selectionStart);
        range.select();
    }
}

export function setCaretPosition(input, pos) {
    setSelectionRange(input, pos, pos);
}

export function scrollbarWidth(el) {
    return el.offsetWidth - el.clientWidth;
}

export function isValidUsername(name) {
    var error = '';
    if (!name) {
        error = 'This field is required';
    } else if (name.length < Constants.MIN_USERNAME_LENGTH || name.length > Constants.MAX_USERNAME_LENGTH) {
        error = 'Must be between ' + Constants.MIN_USERNAME_LENGTH + ' and ' + Constants.MAX_USERNAME_LENGTH + ' characters';
    } else if (!(/^[a-z0-9.\-_]+$/).test(name)) {
        error = "Username must contain only letters, numbers, and the symbols '.', '-', and '_'.";
    } else if (!(/[a-z]/).test(name.charAt(0))) { //eslint-disable-line no-negated-condition
        error = 'First character must be a letter.';
    } else {
        for (var i = 0; i < Constants.RESERVED_USERNAMES.length; i++) {
            if (name === Constants.RESERVED_USERNAMES[i]) {
                error = 'Cannot use a reserved word as a username.';
                break;
            }
        }
    }

    return error;
}

export function isValidBotUsername(name) {
    let error = isValidUsername(name);
    if (error) {
        return error;
    }

    if (name.endsWith('.')) {
        error = "Username must not end with '.' symbol.";
    }

    return error;
}

export function isMobile() {
    return window.innerWidth <= Constants.MOBILE_SCREEN_WIDTH;
}

export function getDirectTeammate(state, channelId) {
    let teammate = {};

    const channel = getChannel(state, channelId);
    if (!channel) {
        return teammate;
    }

    const userIds = channel.name.split('__');
    const curUserId = getCurrentUserId(state);

    if (userIds.length !== 2 || userIds.indexOf(curUserId) === -1) {
        return teammate;
    }

    if (userIds[0] === userIds[1]) {
        return getUser(state, userIds[0]);
    }

    for (var idx in userIds) {
        if (userIds[idx] !== curUserId) {
            teammate = getUser(state, userIds[idx]);
            break;
        }
    }

    return teammate;
}

export function loadImage(url, onLoad, onProgress) {
    const request = new XMLHttpRequest();

    request.open('GET', url, true);
    request.responseType = 'arraybuffer';
    request.onload = onLoad;
    request.onprogress = (e) => {
        if (onProgress) {
            let total = 0;
            if (e.lengthComputable) {
                total = e.total;
            } else {
                total = parseInt(e.target.getResponseHeader('X-Uncompressed-Content-Length'), 10);
            }

            const completedPercentage = Math.round((e.loaded / total) * 100);

            onProgress(completedPercentage);
        }
    };

    request.send();
}

export function changeColor(colourIn, amt) {
    var hex = colourIn;
    var lum = amt;

    // validate hex string
    hex = String(hex).replace(/[^0-9a-f]/gi, '');
    if (hex.length < 6) {
        hex = hex[0] + hex[0] + hex[1] + hex[1] + hex[2] + hex[2];
    }
    lum = lum || 0;

    // convert to decimal and change luminosity
    var rgb = '#';
    var c;
    var i;
    for (i = 0; i < 3; i++) {
        c = parseInt(hex.substr(i * 2, 2), 16);
        c = Math.round(Math.min(Math.max(0, c + (c * lum)), 255)).toString(16);
        rgb += ('00' + c).substr(c.length);
    }

    return rgb;
}

export function getFullName(user) {
    if (user.first_name && user.last_name) {
        return user.first_name + ' ' + user.last_name;
    } else if (user.first_name) {
        return user.first_name;
    } else if (user.last_name) {
        return user.last_name;
    }

    return '';
}

export function getDisplayName(user) {
    if (user.nickname && user.nickname.trim().length > 0) {
        return user.nickname;
    }
    var fullName = getFullName(user);

    if (fullName) {
        return fullName;
    }

    return user.username;
}

export function getLongDisplayName(user) {
    let displayName = '@' + user.username;
    var fullName = getFullName(user);
    if (fullName) {
        displayName = displayName + ' - ' + fullName;
    }
    if (user.nickname && user.nickname.trim().length > 0) {
        displayName = displayName + ' (' + user.nickname + ')';
    }

    if (user.position && user.position.trim().length > 0) {
        displayName = displayName + ' -' + user.position;
    }

    return displayName;
}

export function getLongDisplayNameParts(user) {
    return {
        displayName: '@' + user.username,
        fullName: getFullName(user),
        nickname: user.nickname && user.nickname.trim() ? user.nickname : null,
        position: user.position && user.position.trim() ? user.position : null,
    };
}

/**
 * Gets the display name of the user with the specified id, respecting the TeammateNameDisplay configuration setting
 */
export function getDisplayNameByUserId(state, userId) {
    return getDisplayNameByUser(state, getUser(state, userId));
}

/**
 * Gets the display name of the specified user, respecting the TeammateNameDisplay configuration setting
 */
export function getDisplayNameByUser(state, user) {
    const teammateNameDisplay = getTeammateNameDisplaySetting(state);
    if (user) {
        return displayUsername(user, teammateNameDisplay);
    }

    return '';
}

const UserStatusesWeight = {
    online: 0,
    away: 1,
    dnd: 2,
    offline: 3,
    ooo: 3,
    bot: 4,
};

/**
 * Sort users by status then by display name, respecting the TeammateNameDisplay configuration setting
 */
export function sortUsersByStatusAndDisplayName(users, statusesByUserId, teammateNameDisplay) {
    function compareUsers(a, b) {
        const aStatus = a.is_bot ? 'bot' : statusesByUserId[a.id] || UserStatuses.OFFLINE;
        const bStatus = b.is_bot ? 'bot' : statusesByUserId[b.id] || UserStatuses.OFFLINE;

        if (UserStatusesWeight[aStatus] !== UserStatusesWeight[bStatus]) {
            return UserStatusesWeight[aStatus] - UserStatusesWeight[bStatus];
        }

        const aName = displayUsername(a, teammateNameDisplay);
        const bName = displayUsername(b, teammateNameDisplay);

        return aName.localeCompare(bName);
    }

    return users.sort(compareUsers);
}

/**
 * Gets the entire name, including username, full name, and nickname, of the specified user
 */
export function displayEntireNameForUser(user) {
    if (!user) {
        return '';
    }

    let displayName = '';
    const fullName = getFullName(user);

    if (fullName) {
        displayName = ' - ' + fullName;
    }

    if (user.nickname) {
        displayName = displayName + ' (' + user.nickname + ')';
    }

    if (user.position) {
        displayName = displayName + ' - ' + user.position;
    }

    displayName = (
        <span id={'displayedUserName' + user.username}>
            {'@' + user.username}
            <span className='light'>{displayName}</span>
        </span>
    );

    return displayName;
}

/**
 * Gets the full name and nickname of the specified user
 */
export function displayFullAndNicknameForUser(user) {
    if (!user) {
        return '';
    }

    let displayName;
    const fullName = getFullName(user);

    if (fullName && user.nickname) {
        displayName = (
            <span className='light'>{fullName + ' (' + user.nickname + ')'}</span>
        );
    } else if (fullName) {
        displayName = (
            <span className='light'>{fullName}</span>
        );
    } else if (user.nickname) {
        displayName = (
            <span className='light'>{'(' + user.nickname + ')'}</span>
        );
    }

    return displayName;
}

export function imageURLForUser(userId, lastPictureUpdate = 0) {
    return Client4.getUsersRoute() + '/' + userId + '/image?_=' + lastPictureUpdate;
}

export function defaultImageURLForUser(userId) {
    return Client4.getUsersRoute() + '/' + userId + '/image/default';
}

// in contrast to Client4.getTeamIconUrl, for ui logic this function returns null if last_team_icon_update is unset
export function imageURLForTeam(team) {
    return team.last_team_icon_update ? Client4.getTeamIconUrl(team.id, team.last_team_icon_update) : null;
}

// Converts a file size in bytes into a human-readable string of the form '123MB'.
export function fileSizeToString(bytes) {
    // it's unlikely that we'll have files bigger than this
    if (bytes > 1024 * 1024 * 1024 * 1024) {
        return Math.floor(bytes / (1024 * 1024 * 1024 * 1024)) + 'TB';
    } else if (bytes > 1024 * 1024 * 1024) {
        return Math.floor(bytes / (1024 * 1024 * 1024)) + 'GB';
    } else if (bytes > 1024 * 1024) {
        return Math.floor(bytes / (1024 * 1024)) + 'MB';
    } else if (bytes > 1024) {
        return Math.floor(bytes / 1024) + 'KB';
    }

    return bytes + 'B';
}

// Generates a RFC-4122 version 4 compliant globally unique identifier.
export function generateId() {
    // implementation taken from https://stackoverflow.com/a/2117523
    var id = 'xxxxxxxx-xxxx-4xxx-yxxx-xxxxxxxxxxxx';

    id = id.replace(/[xy]/g, (c) => {
        var r = Math.floor(Math.random() * 16);

        var v;
        if (c === 'x') {
            v = r;
        } else {
            v = (r & 0x3) | 0x8;
        }

        return v.toString(16);
    });

    return id;
}

export function getDirectChannelName(id, otherId) {
    let handle;

    if (otherId > id) {
        handle = id + '__' + otherId;
    } else {
        handle = otherId + '__' + id;
    }

    return handle;
}

// Used to get the id of the other user from a DM channel
export function getUserIdFromChannelName(channel) {
    return getUserIdFromChannelId(channel.name);
}

// Used to get the id of the other user from a DM channel id (id1_id2)
export function getUserIdFromChannelId(channelId, currentUserId = getCurrentUserId(store.getState())) {
    var ids = channelId.split('__');
    var otherUserId = '';
    if (ids[0] === currentUserId) {
        otherUserId = ids[1];
    } else {
        otherUserId = ids[0];
    }

    return otherUserId;
}

export function importSlack(teamId, file, success, error) {
    Client4.importTeam(teamId, file, 'slack').then(success).catch(error);
}

export function windowWidth() {
    return window.innerWidth;
}

export function windowHeight() {
    return window.innerHeight;
}

// Should be refactored, seems to make most sense to wrap TextboxLinks in a connect(). To discuss
export function isFeatureEnabled(feature, state) {
    return getBool(state, Constants.Preferences.CATEGORY_ADVANCED_SETTINGS, Constants.FeatureTogglePrefix + feature.label);
}

export function fillArray(value, length) {
    const arr = [];

    for (let i = 0; i < length; i++) {
        arr.push(value);
    }

    return arr;
}

// Checks if a data transfer contains files not text, folders, etc..
// Slightly modified from https://stackoverflow.com/questions/6848043/how-do-i-detect-a-file-is-being-dragged-rather-than-a-draggable-element-on-my-pa
export function isFileTransfer(files) {
    if (UserAgent.isInternetExplorer() || UserAgent.isEdge()) {
        return files.types != null && files.types.includes('Files');
    }

    return files.types != null && (files.types.indexOf ? files.types.indexOf('Files') !== -1 : files.types.contains('application/x-moz-file'));
}

export function isUriDrop(dataTransfer) {
    if (UserAgent.isInternetExplorer() || UserAgent.isEdge() || UserAgent.isSafari()) {
        for (let i = 0; i < dataTransfer.items.length; i++) {
            if (dataTransfer.items[i].type === 'text/uri-list') {
                return true;
            }
        }
    }
    return false; // we don't care about others, they handle as we want it
}

export function clearFileInput(elm) {
    // clear file input for all modern browsers
    try {
        elm.value = '';
        if (elm.value) {
            elm.type = 'text';
            elm.type = 'file';
        }
    } catch (e) {
        // Do nothing
    }
}

export function isPostEphemeral(post) {
    return post.type === Constants.PostTypes.EPHEMERAL || post.state === Posts.POST_DELETED;
}

export function getRootId(post) {
    return post.root_id === '' ? post.id : post.root_id;
}

export function getRootPost(postList) {
    return postList.find((post) => post.root_id === '');
}

export function localizeMessage(id, defaultMessage) {
    const state = store.getState();

    const locale = getCurrentLocale(state);
    const translations = getTranslations(state, locale);

    if (!translations || !(id in translations)) {
        return defaultMessage || id;
    }

    return translations[id];
}

export function mod(a, b) {
    return ((a % b) + b) % b;
}

export const REACTION_PATTERN = /^(\+|-):([^:\s]+):\s*$/;

export function getPasswordConfig(config) {
    return {
        minimumLength: parseInt(config.PasswordMinimumLength, 10),
        requireLowercase: config.PasswordRequireLowercase === 'true',
        requireUppercase: config.PasswordRequireUppercase === 'true',
        requireNumber: config.PasswordRequireNumber === 'true',
        requireSymbol: config.PasswordRequireSymbol === 'true',
    };
}

export function isValidPassword(password, passwordConfig) {
    let errorId = t('user.settings.security.passwordError');
    let valid = true;
    const minimumLength = passwordConfig.minimumLength || Constants.MIN_PASSWORD_LENGTH;

    if (password.length < minimumLength || password.length > Constants.MAX_PASSWORD_LENGTH) {
        valid = false;
    }

    if (passwordConfig.requireLowercase) {
        if (!password.match(/[a-z]/)) {
            valid = false;
        }

        errorId += 'Lowercase';
    }

    if (passwordConfig.requireUppercase) {
        if (!password.match(/[A-Z]/)) {
            valid = false;
        }

        errorId += 'Uppercase';
    }

    if (passwordConfig.requireNumber) {
        if (!password.match(/[0-9]/)) {
            valid = false;
        }

        errorId += 'Number';
    }

    if (passwordConfig.requireSymbol) {
        if (!password.match(/[ !"\\#$%&'()*+,-./:;<=>?@[\]^_`|~]/)) {
            valid = false;
        }

        errorId += 'Symbol';
    }

    let error;
    if (!valid) {
        error = (
            <FormattedMessage
                id={errorId}
                default='Your password must contain between {min} and {max} characters.'
                values={{
                    min: minimumLength,
                    max: Constants.MAX_PASSWORD_LENGTH,
                }}
            />
        );
    }

    return {valid, error};
}

export function handleFormattedTextClick(e, currentRelativeTeamUrl) {
    const hashtagAttribute = e.target.getAttributeNode('data-hashtag');
    const linkAttribute = e.target.getAttributeNode('data-link');
    const channelMentionAttribute = e.target.getAttributeNode('data-channel-mention');

    if (hashtagAttribute) {
        e.preventDefault();

        store.dispatch(searchForTerm(hashtagAttribute.value));
    } else if (linkAttribute) {
        const MIDDLE_MOUSE_BUTTON = 1;

        if (!(e.button === MIDDLE_MOUSE_BUTTON || e.altKey || e.ctrlKey || e.metaKey || e.shiftKey)) {
            e.preventDefault();

            browserHistory.push(linkAttribute.value);
        }
    } else if (channelMentionAttribute) {
        e.preventDefault();
        browserHistory.push(currentRelativeTeamUrl + '/channels/' + channelMentionAttribute.value);
    }
}

export function isEmptyObject(object) {
    if (!object) {
        return true;
    }

    if (Object.keys(object).length === 0) {
        return true;
    }

    return false;
}

export function removePrefixFromLocalStorage(prefix) {
    const keys = [];
    for (let i = 0; i < localStorage.length; i++) {
        if (localStorage.key(i).startsWith(prefix)) {
            keys.push(localStorage.key(i));
        }
    }

    for (let i = 0; i < keys.length; i++) {
        localStorage.removeItem(keys[i]);
    }
}

export function copyToClipboard(data) {
    // Attempt to use the newer clipboard API when possible
    const clipboard = navigator.clipboard;
    if (clipboard) {
        clipboard.writeText(data);
        return;
    }

    // creates a tiny temporary text area to copy text out of
    // see https://stackoverflow.com/a/30810322/591374 for details
    const textArea = document.createElement('textarea');
    textArea.style.position = 'fixed';
    textArea.style.top = 0;
    textArea.style.left = 0;
    textArea.style.width = '2em';
    textArea.style.height = '2em';
    textArea.style.padding = 0;
    textArea.style.border = 'none';
    textArea.style.outline = 'none';
    textArea.style.boxShadow = 'none';
    textArea.style.background = 'transparent';
    textArea.value = data;
    document.body.appendChild(textArea);
    textArea.select();
    document.execCommand('copy');
    document.body.removeChild(textArea);
}

export function moveCursorToEnd(e) {
    const val = e.target.value;
    if (val.length) {
        e.target.value = '';
        e.target.value = val;
    }
}

export function compareChannels(a, b) {
    const aDisplayName = a.display_name.toUpperCase();
    const bDisplayName = b.display_name.toUpperCase();
    const result = aDisplayName.localeCompare(bDisplayName);
    if (result !== 0) {
        return result;
    }

    const aName = a.name.toUpperCase();
    const bName = b.name.toUpperCase();
    return aName.localeCompare(bName);
}

export function setCSRFFromCookie() {
    if (typeof document !== 'undefined' && typeof document.cookie !== 'undefined') {
        const cookies = document.cookie.split(';');
        for (let i = 0; i < cookies.length; i++) {
            const cookie = cookies[i].trim();
            if (cookie.startsWith('MMCSRF=')) {
                Client4.setCSRF(cookie.replace('MMCSRF=', ''));
                break;
            }
        }
    }
}

/**
 * Returns true if in dev mode, false otherwise.
 */
export function isDevMode() {
    const config = getConfig(store.getState());
    return config.EnableDeveloper === 'true';
}

/**
 * Enables dev mode features.
 */
export function enableDevModeFeatures() {
    /*eslint no-extend-native: ["error", { "exceptions": ["Set", "Map"] }]*/
    Object.defineProperty(Set.prototype, 'length', {
        configurable: true, // needed for testing
        get: () => {
            throw new Error('Set.length is not supported. Use Set.size instead.');
        },
    });
    Object.defineProperty(Map.prototype, 'length', {
        configurable: true, // needed for testing
        get: () => {
            throw new Error('Map.length is not supported. Use Map.size instead.');
        },
    });
}

/**
 * Get closest parent which match selector
 */
export function getClosestParent(elem, selector) {
    // Element.matches() polyfill
    if (!Element.prototype.matches) {
        Element.prototype.matches =
            Element.prototype.matchesSelector ||
            Element.prototype.mozMatchesSelector ||
            Element.prototype.msMatchesSelector ||
            Element.prototype.oMatchesSelector ||
            Element.prototype.webkitMatchesSelector ||
            ((s) => {
                const matches = (this.document || this.ownerDocument).querySelectorAll(s);
                let i = matches.length - 1;
                while (i >= 0 && matches.item(i) !== this) {
                    i--;
                }
                return i > -1;
            });
    }

    // Get the closest matching element
    let currentElem = elem;
    for (; currentElem && currentElem !== document; currentElem = currentElem.parentNode) {
        if (currentElem.matches(selector)) {
            return currentElem;
        }
    }
    return null;
}

export function getSortedUsers(reactions, currentUserId, profiles, teammateNameDisplay) {
    // Sort users by who reacted first with "you" being first if the current user reacted

    let currentUserReacted = false;
    const sortedReactions = reactions.sort((a, b) => a.create_at - b.create_at);
    const users = sortedReactions.reduce((accumulator, current) => {
        if (current.user_id === currentUserId) {
            currentUserReacted = true;
        } else {
            const user = profiles.find((u) => u.id === current.user_id);
            if (user) {
                accumulator.push(displayUsername(user, teammateNameDisplay));
            }
        }
        return accumulator;
    }, []);

    if (currentUserReacted) {
        users.unshift(Utils.localizeMessage('reaction.you', 'You'));
    }

    return {currentUserReacted, users};
}

const BOLD_MD = '**';
const ITALIC_MD = '*';

/**
 * Applies bold/italic markdown on textbox associated with event and returns
 * modified text alongwith modified selection positions.
 */
export function applyHotkeyMarkdown(e) {
    e.preventDefault();

    const el = e.target;
    const {selectionEnd, selectionStart, value} = el;

    // <prefix> <selection> <suffix>
    const prefix = value.substring(0, selectionStart);
    const selection = value.substring(selectionStart, selectionEnd);
    const suffix = value.substring(selectionEnd);

    // Is it italic hot key on existing bold markdown? i.e. italic on **haha**
    let isItalicFollowedByBold = false;
    let delimiter = '';
    if (e.keyCode === Constants.KeyCodes.B[1]) {
        delimiter = BOLD_MD;
    } else if (e.keyCode === Constants.KeyCodes.I[1]) {
        delimiter = ITALIC_MD;
        isItalicFollowedByBold = prefix.endsWith(BOLD_MD) && suffix.startsWith(BOLD_MD);
    }

    // Does the selection have current hotkey's markdown?
    const hasCurrentMarkdown = prefix.endsWith(delimiter) && suffix.startsWith(delimiter);

    // Does current selection have both of the markdown around it? i.e. ***haha***
    const hasItalicAndBold = prefix.endsWith(BOLD_MD + ITALIC_MD) && suffix.startsWith(BOLD_MD + ITALIC_MD);

    let newValue = '';
    let newStart = 0;
    let newEnd = 0;
    if (hasItalicAndBold || (hasCurrentMarkdown && !isItalicFollowedByBold)) {
        // message already has the markdown; remove it
        newValue = prefix.substring(0, prefix.length - delimiter.length) + selection + suffix.substring(delimiter.length);
        newStart = selectionStart - delimiter.length;
        newEnd = selectionEnd - delimiter.length;
    } else {
        newValue = prefix + delimiter + selection + delimiter + suffix;
        newStart = selectionStart + delimiter.length;
        newEnd = selectionEnd + delimiter.length;
    }

    return {
        message: newValue,
        selectionStart: newStart,
        selectionEnd: newEnd,
    };
}

/**
 * Adjust selection to correct text when there is Italic markdown (_) around selected text.
 */
export function adjustSelection(inputBox, e) {
    const el = e.target;
    const {selectionEnd, selectionStart, value} = el;

    if (selectionStart === selectionEnd) {
        // nothing selected.
        return;
    }

    e.preventDefault();

    const firstUnderscore = value.charAt(selectionStart) === '_';
    const lastUnderscore = value.charAt(selectionEnd - 1) === '_';

    const spaceBefore = value.charAt(selectionStart - 1) === ' ';
    const spaceAfter = value.charAt(selectionEnd) === ' ';

    if (firstUnderscore && lastUnderscore && (spaceBefore || spaceAfter)) {
        setSelectionRange(inputBox, selectionStart + 1, selectionEnd - 1);
    }
}

export function getNextBillingDate() {
    const nextBillingDate = moment().add(1, 'months').startOf('month');
    return nextBillingDate.format('MMM D, YYYY');
}