User:Nardog/dark-mode-toggle.js

/**
 * Enables or disables the dark-mode gadget.
 *
 * Authors: ], ]
 */

// 'Dark mode' and 'Light mode' messages must match the ::before content in
// ] and ], respectively.
// Don't overwrite existing messages, if already set on a foreign wiki prior to loading this file
if (!mw.messages.get('darkmode-turn-on-label')) {
	mw.messages.set({
		'darkmode-turn-on-label': 'Dark mode',
		'darkmode-turn-on-tooltip': 'Turn dark mode on',
		'darkmode-turn-off-label': 'Light mode',
		'darkmode-turn-off-tooltip': 'Turn dark mode off',
	});
}

var isOn = mw.loader.getState('ext.gadget.dark-mode') === 'ready';

var broadcastChannel = new BroadcastChannel('gadget-dark-mode');

function setThemeColor() {
	// Update the theme-color used by some browsers for coloration of the tab headers and surrounding UI
	$('meta').attr('content', isOn ? '#000000' : '#eaecf0');
}

function setHtmlClass() {
	// CSS class for externally styling elements in dark mode via TemplateStyles (or CSS from other gadgets or common.css)
	// A brief flash of the original styles will occur, so this is only suitable for style changes for which flashes are tolerable.
	// For others, update Gadget-dark-mode.css directly which is loaded without FOUCs
	$(document.documentElement).toggleClass('client-dark-mode', isOn);
}

function vectorStickyCallback() {
	mw.hook('vector.page_title_scroll').remove(vectorStickyCallback);
	if (document.getElementById('pt-darkmode-sticky-header')) return;
	makePortletLink('p-personal-sticky-header', 'pt-darkmode-sticky-header', '#pt-watchlist-sticky-header');
}

function addPortlets() {
	makePortletLink('p-personal', 'pt-darkmode', '#pt-watchlist');

	if (mw.config.get('skin') === 'vector-2022') {
		mw.hook('vector.page_title_scroll').add(vectorStickyCallback);
	}
}

function getMsg(suffix) {
	var key = 'darkmode-turn-' + (isOn ? 'off' : 'on') + '-' + suffix;
	return mw.msg(key);
}

function makePortletLink(portletId, portletLinkId, nextnode) {
	var label = getMsg('label');
	var tooltip = getMsg('tooltip');
	$(mw.util.addPortletLink(portletId, '#', label, portletLinkId, tooltip, '', nextnode))
		.children().on('click', function (e) {
			e.preventDefault();
			toggleMode();
		});
}

function togglePortlets() {
	var labelSelector;
	switch (mw.config.get('skin')) {
		case 'vector':
		case 'vector-2022':
		case 'minerva':
			labelSelector = '#pt-darkmode span:not(:empty), #pt-darkmode-sticky-header span:not(:empty)';
			break;
		default:
			labelSelector = '#pt-darkmode a';
	}
	$(labelSelector).text(getMsg('label'));
	$('#pt-darkmode a, #pt-darkmode-sticky-header a')
		.attr('title', getMsg('tooltip'));
}

function actuallyToggleDarkMode() {
	// Modify the <link> element on the page to include/exclude dark-mode styles
	// We can't use mw.loader as it doesn't work both ways (see talk page)
	var scriptPath = mw.util.wikiScript('load');
	var $gadgetsLink = $('link');
	if ($gadgetsLink.length) {
		var uri = new mw.Uri($gadgetsLink.prop('href'));
		if (isOn) {
			uri.query.modules += ',dark-mode';
		} else {
			if (uri.query.modules === 'ext.gadget.dark-mode') {
				// dark-mode is the only module in this link
				$gadgetsLink.remove();
				return;
			}
			uri.query.modules = uri.query.modules
				.replace('ext.gadget.dark-mode,', 'ext.gadget.') // dark-mode is first in the gadget list
				.replace(/,dark-mode(,|$)/, '$1'); // dark-mode is in middle or end of the list
		}
		$gadgetsLink.prop('href', uri.getRelativePath());
	} else {
		// No gadget-containing styles are enabled
		$('<link>').attr({
			rel: 'stylesheet',
			href: scriptPath + '?lang=' + mw.config.get('wgUserLanguage') +
				'&modules=ext.gadget.dark-mode&only=styles&skin=' + mw.config.get('skin')
		}).appendTo(document.head);
	}
}

function savePreference() {
	new mw.Api().saveOption('gadget-dark-mode', isOn ? '1' : '0');
}

function savePreferenceLocally() {
	mw.user.options.set('gadget-dark-mode', Number(isOn));

	// In case the user navigates to another page too quickly
	mw.storage.session.set('dark-mode-toggled', isOn ? '1' : '0');
}

function notifyOtherTabs() {
	// Broadcast state change to other tabs
	broadcastChannel.postMessage(isOn);
}

function toggleMode(offline) {
	isOn = !isOn;
	if (!offline) {
		savePreference();
		notifyOtherTabs();
	}
	setHtmlClass();
	setThemeColor();
	savePreferenceLocally();
	togglePortlets();
	actuallyToggleDarkMode();
}

function toggleBasedOnSystemColourScheme() {
	var systemSchemeNow = matchMedia('(prefers-color-scheme: dark)').matches;
	var systemSchemeLast = mw.storage.get('dark-mode-system-scheme') === '1';

	if (systemSchemeNow !== systemSchemeLast) {
		if (systemSchemeNow !== isOn) {
			toggleMode();
		}
		mw.requestIdleCallback(function () {
			mw.storage.set('dark-mode-system-scheme', systemSchemeNow ? '1' : '0');
		});
	}
}


$.when($.ready, mw.loader.using()).then(function () {
	setHtmlClass();
	setThemeColor();
	addPortlets();

	// Recover state if the navigation was too quick
	var storageState = mw.storage.session.get('dark-mode-toggled');
	if (storageState && Number(storageState) !== Number(isOn)) {
		toggleMode(true);
	}

	// Listen to dark mode state change made on other tabs
	broadcastChannel.onmessage = function (msg) {
		if (msg.data !== isOn) {
			toggleMode(true);
		}
	};

	if (window.wpDarkModeAutoToggle) {
		toggleBasedOnSystemColourScheme();

		// If system colour scheme changes while user is viewing, toggle immediately
		var mediaQuery = matchMedia('(prefers-color-scheme: dark)');
		if (mediaQuery.addEventListener) {
			mediaQuery.addEventListener('change', toggleBasedOnSystemColourScheme);
		} else if (mediaQuery.addListener) { // Safari 13 and older
			mediaQuery.addListener(toggleBasedOnSystemColourScheme);
		}
	}
});