const CLASS = 'citizen-pref';

/**
 * Clientprefs names theme differently from Citizen, we will need to translate it
 * TODO: Migrate to clientprefs fully on MW 1.43
 */
const CLIENTPREFS_THEME_MAP = {
	auto: 'os',
	light: 'day',
	dark: 'night'
};

const clientPrefs = require( './clientPrefs.polyfill.js' )();

/**
 * Dismiss the prefernce panel when clicked outside
 *
 * @param {Event} event
 */
function dismissOnClickOutside( event ) {
	const pref = document.getElementById( CLASS );

	if ( event.target instanceof Node && !pref.contains( event.target ) ) {
		const panel = document.getElementById( CLASS + '-panel' );

		if ( panel.classList.contains( CLASS + '-panel--active' ) ) {
			togglePanel();
		}
	}
}

/**
 * Dismiss the prefernce panel when ESCAPE is pressed
 *
 * @param {Event} event
 */
function dismissOnEscape( event ) {
	if ( event.key !== 'Escape' ) {
		return;
	}

	togglePanel();
}

/**
 * Add/remove toggle class and form input eventlistener
 *
 * @return {void}
 */
function togglePanel() {
	// .citizen-pref-panel--active
	const CLASS_PANEL_ACTIVE = CLASS + '-panel--active';
	const
		toggle = document.getElementById( CLASS + '-toggle' ),
		panel = document.getElementById( CLASS + '-panel' );

	if ( !panel.classList.contains( CLASS_PANEL_ACTIVE ) ) {
		panel.classList.add( CLASS_PANEL_ACTIVE );
		toggle.setAttribute( 'aria-expanded', true );
		window.addEventListener( 'click', dismissOnClickOutside );
		window.addEventListener( 'keydown', dismissOnEscape );
	} else {
		panel.classList.remove( CLASS_PANEL_ACTIVE );
		toggle.setAttribute( 'aria-expanded', false );
		window.removeEventListener( 'click', dismissOnClickOutside );
		window.removeEventListener( 'keydown', dismissOnEscape );
	}
}

/**
 * Get MW message and return as object to be used in Mustache
 *
 * @return {Object}
 */
function getMessages() {
	const keys = [
			'preferences'
		],
		data = {};

	keys.forEach( ( key ) => {
		const templateKey = 'msg-' + key;

		// Message keys already defined above
		// eslint-disable-next-line mediawiki/msg-doc
		data[ templateKey ] = mw.message( key ).text();
	} );

	return data;
}

/**
 * Set up the DOM and initial input states for the panel
 * It only loads when user first clicked the toggle
 *
 * @param {Event} event
 * @return {void}
 */
function initPanel( event ) {
	const template = mw.template.get(
			'skins.citizen.preferences',
			'resources/skins.citizen.preferences/templates/preferences.mustache'
		),
		data = getMessages();

	// To Mustache is to jQuery sigh
	// TODO: Use ES6 template literals when RL does not screw up multiline
	const panel = template.render( data ).get()[ 1 ];

	// Attach panel after button
	event.currentTarget.parentNode.insertBefore( panel, event.currentTarget.nextSibling );

	togglePanel();
	event.currentTarget.addEventListener( 'click', togglePanel );
	event.currentTarget.removeEventListener( 'click', initPanel );

	const clientPreferenceSelector = '#citizen-client-prefs';
	const clientPreferenceExists = document.querySelectorAll( clientPreferenceSelector ).length > 0;
	if ( clientPreferenceExists ) {
		const clientPreferences = require( /** @type {string} */ ( './clientPreferences.js' ) );
		const clientPreferenceConfig = ( require( './clientPreferences.json' ) );

		// Support legacy skin-citizen-* class
		// TODO: Remove it in the future version after sufficient time
		clientPreferenceConfig[ 'skin-theme' ].callback = () => {
			const LEGACY_THEME_CLASSES = [
				'skin-citizen-auto',
				'skin-citizen-light',
				'skin-citizen-dark'
			];
			const legacyThemeKey = Object.keys( CLIENTPREFS_THEME_MAP ).find( ( key ) => {
				return CLIENTPREFS_THEME_MAP[ key ] === clientPrefs.get( 'skin-theme' );
			} );
			document.documentElement.classList.remove( ...LEGACY_THEME_CLASSES );
			document.documentElement.classList.add( `skin-citizen-${ legacyThemeKey }` );
		};

		clientPreferences.render( clientPreferenceSelector, clientPreferenceConfig );
	}
}

/**
 * Test if storage is avaliable
 * Taken from https://developer.mozilla.org/en-US/docs/Web/API/Web_Storage_API/Using_the_Web_Storage_API
 *
 * @param {string} type
 * @return {boolean|Error}
 */
function storageAvailable( type ) {
	let storage;

	try {
		storage = window[ type ];
		const x = '__storage_test__';
		storage.setItem( x, x );
		storage.removeItem( x );
		return true;
	} catch ( /** @type {Error} */ e ) {
		return e instanceof DOMException && (
			// everything except Firefox
			e.code === 22 ||
			// Firefox
			e.code === 1014 ||
			// test name field too, because code might not be present
			// everything except Firefox
			e.name === 'QuotaExceededError' ||
			// Firefox
			e.name === 'NS_ERROR_DOM_QUOTA_REACHED' ) &&
			// acknowledge QuotaExceededError only if there's something already stored
			( storage && storage.length !== 0 );
	}
}

/**
 * Set up the container and toggle
 *
 * @param {Window} window
 * @return {void}
 */
function initPref( window ) {
	// Object.fromEntries() polyfill https://github.com/feross/fromentries
	// MIT. Copyright (c) Feross Aboukhadijeh.
	if ( typeof Object.fromEntries !== 'function' ) {
		Object.defineProperty( Object, 'fromEntries', {
			value( iterable ) {
				return Array.from( iterable ).reduce( ( obj, [ key, val ] ) => {
					obj[ key ] = val;
					return obj;
				}, {} );
			}
		} );
	}

	if ( storageAvailable( 'localStorage' ) ) {
		if ( typeof window.mw !== 'undefined' ) {
			const headerTools = document.querySelector( '.citizen-header__end' ),
				container = document.createElement( 'div' ),
				button = document.createElement( 'button' ),
				icon = document.createElement( 'span' );

			// citizen-pref
			container.id = CLASS;

			container.classList.add( CLASS, 'citizen-header__item' );
			button.id = CLASS + '-toggle';

			button.classList.add( CLASS + '__button', 'citizen-header__button', 'citizen-button' );
			button.setAttribute( 'title', mw.message( 'preferences' ).text() );
			button.setAttribute( 'aria-label', mw.message( 'preferences' ).text() );
			button.setAttribute( 'aria-controls', CLASS + '-panel' );
			button.setAttribute( 'aria-expanded', false );
			icon.classList.add( 'citizen-ui-icon', 'mw-ui-icon-wikimedia-settings' );
			button.prepend( icon );
			container.prepend( button );
			headerTools.prepend( container );

			button.addEventListener( 'click', initPanel, { once: true } );
		}
	} else {
		// eslint-disable-next-line no-console
		console.log( 'Preference module is disabled due to localStoarge being not avaliable.' );
	}
}

initPref( window );