/* global APP */
import { jitsiLocalStorage } from '@jitsi/js-utils';
import Logger from '@jitsi/logger';

import {
    ACTION_SHORTCUT_PRESSED as PRESSED,
    ACTION_SHORTCUT_RELEASED as RELEASED,
    createShortcutEvent,
    sendAnalytics
} from '../../react/features/analytics';
import { clickOnVideo } from '../../react/features/filmstrip/actions';
import { openSettingsDialog } from '../../react/features/settings/actions';
import { SETTINGS_TABS } from '../../react/features/settings/constants';

const logger = Logger.getLogger(__filename);

/**
 * Map of shortcuts. When a shortcut is registered it enters the mapping.
 * @type {Map}
 */
const _shortcuts = new Map();

/**
 * Map of registered keyboard keys and translation keys describing the
 * action performed by the key.
 * @type {Map}
 */
const _shortcutsHelp = new Map();

/**
 * The key used to save in local storage if keyboard shortcuts are enabled.
 */
const _enableShortcutsKey = 'enableShortcuts';

/**
 * Prefer keyboard handling of these elements over global shortcuts.
 * If a button is triggered using the Spacebar it should not trigger PTT.
 * If an input element is focused and M is pressed it should not mute audio.
 */
const _elementsBlacklist = [
    'input',
    'textarea',
    'button',
    '[role=button]',
    '[role=menuitem]',
    '[role=radio]',
    '[role=tab]',
    '[role=option]',
    '[role=switch]',
    '[role=range]',
    '[role=log]'
];

/**
 * An element selector for elements that have their own keyboard handling.
 */
const _focusedElementsSelector = `:focus:is(${_elementsBlacklist.join(',')})`;

/**
 * Maps keycode to character, id of popover for given function and function.
 */
const KeyboardShortcut = {

    init() {
        this._initGlobalShortcuts();

        window.onkeyup = e => {
            if (!this.getEnabled()) {
                return;
            }
            const key = this._getKeyboardKey(e).toUpperCase();
            const num = parseInt(key, 10);

            if (!document.querySelector(_focusedElementsSelector)) {
                if (_shortcuts.has(key)) {
                    _shortcuts.get(key).function(e);
                } else if (!isNaN(num) && num >= 0 && num <= 9) {
                    APP.store.dispatch(clickOnVideo(num));
                }
            }
        };

        window.onkeydown = e => {
            if (!this.getEnabled()) {
                return;
            }
            const focusedElement = document.querySelector(_focusedElementsSelector);

            if (!focusedElement) {
                if (this._getKeyboardKey(e).toUpperCase() === ' ') {
                    if (APP.conference.isLocalAudioMuted()) {
                        sendAnalytics(createShortcutEvent(
                            'push.to.talk',
                            PRESSED));
                        logger.log('Talk shortcut pressed');
                        APP.conference.muteAudio(false);
                    }
                }
            } else if (this._getKeyboardKey(e).toUpperCase() === 'ESCAPE') {
                // Allow to remove focus from selected elements using ESC key.
                if (focusedElement && focusedElement.blur) {
                    focusedElement.blur();
                }
            }
        };
    },

    /**
     * Enables/Disables the keyboard shortcuts.
     * @param {boolean} value - the new value.
     */
    enable(value) {
        jitsiLocalStorage.setItem(_enableShortcutsKey, value);
    },

    getEnabled() {
        // Should be enabled if not explicitly set to false
        // eslint-disable-next-line no-unneeded-ternary
        return jitsiLocalStorage.getItem(_enableShortcutsKey) === 'false' ? false : true;
    },

    getShortcutsDescriptions() {
        return _shortcutsHelp;
    },

    /**
     * Opens the {@SettingsDialog} dialog on the  Shortcuts page.
     *
     * @returns {void}
     */
    openDialog() {
        APP.store.dispatch(openSettingsDialog(SETTINGS_TABS.SHORTCUTS, false));
    },

    /**
     * Registers a new shortcut.
     *
     * @param shortcutChar the shortcut character triggering the action
     * @param shortcutAttr the "shortcut" html element attribute mapping an
     * element to this shortcut and used to show the shortcut character on the
     * element tooltip
     * @param exec the function to be executed when the shortcut is pressed
     * @param helpDescription the description of the shortcut that would appear
     * in the help menu
     * @param altKey whether or not the alt key must be pressed.
     */
    registerShortcut(// eslint-disable-line max-params
            shortcutChar,
            shortcutAttr,
            exec,
            helpDescription,
            altKey = false) {
        _shortcuts.set(altKey ? `:${shortcutChar}` : shortcutChar, {
            character: shortcutChar,
            function: exec,
            shortcutAttr,
            altKey
        });

        if (helpDescription) {
            this._addShortcutToHelp(altKey ? `:${shortcutChar}` : shortcutChar, helpDescription);
        }
    },

    /**
     * Unregisters a shortcut.
     *
     * @param shortcutChar unregisters the given shortcut, which means it will
     * no longer be usable
     * @param altKey whether or not shortcut is combo with alt key
     */
    unregisterShortcut(shortcutChar, altKey = false) {
        _shortcuts.delete(altKey ? `:${shortcutChar}` : shortcutChar);
        _shortcutsHelp.delete(shortcutChar);
    },

    /**
     * @param e a KeyboardEvent
     * @returns {string} e.key or something close if not supported
     */
    _getKeyboardKey(e) {
        // If alt is pressed a different char can be returned so this takes
        // the char from the code. It also prefixes with a colon to differentiate
        // alt combo from simple keypress.
        if (e.altKey) {
            const key = e.code.replace('Key', '');

            return `:${key}`;
        }

        // If e.key is a string, then it is assumed it already plainly states
        // the key pressed. This may not be true in all cases, such as with Edge
        // and "?", when the browser cannot properly map a key press event to a
        // keyboard key. To be safe, when a key is "Unidentified" it must be
        // further analyzed by jitsi to a key using e.which.
        if (typeof e.key === 'string' && e.key !== 'Unidentified') {
            return e.key;
        }
        if (e.type === 'keypress'
                && ((e.which >= 32 && e.which <= 126)
                    || (e.which >= 160 && e.which <= 255))) {
            return String.fromCharCode(e.which);
        }

        // try to fallback (0-9A-Za-z and QWERTY keyboard)
        switch (e.which) {
        case 27:
            return 'Escape';
        case 191:
            return e.shiftKey ? '?' : '/';
        }
        if (e.shiftKey || e.type === 'keypress') {
            return String.fromCharCode(e.which);
        }

        return String.fromCharCode(e.which).toLowerCase();

    },

    /**
     * Adds the given shortcut to the help dialog.
     *
     * @param shortcutChar the shortcut character
     * @param shortcutDescriptionKey the description of the shortcut
     * @private
     */
    _addShortcutToHelp(shortcutChar, shortcutDescriptionKey) {
        _shortcutsHelp.set(shortcutChar, shortcutDescriptionKey);
    },

    /**
     * Initialise global shortcuts.
     * Global shortcuts are shortcuts for features that don't have a button or
     * link associated with the action. In other words they represent actions
     * triggered _only_ with a shortcut.
     */
    _initGlobalShortcuts() {
        this.registerShortcut('?', null, () => {
            sendAnalytics(createShortcutEvent('help'));
            this.openDialog();
        }, 'keyboardShortcuts.toggleShortcuts');

        // register SPACE shortcut in two steps to insure visibility of help
        // message
        this.registerShortcut(' ', null, () => {
            sendAnalytics(createShortcutEvent('push.to.talk', RELEASED));
            logger.log('Talk shortcut released');
            APP.conference.muteAudio(true);
        });
        this._addShortcutToHelp('SPACE', 'keyboardShortcuts.pushToTalk');

        /**
         * FIXME: Currently focus keys are directly implemented below in
         * onkeyup. They should be moved to the SmallVideo instead.
         */
        this._addShortcutToHelp('0', 'keyboardShortcuts.focusLocal');
        this._addShortcutToHelp('1-9', 'keyboardShortcuts.focusRemote');
    }
};

export default KeyboardShortcut;