( function ( M ) {
	var
		mobile = M.require( 'mobile.startup' ),
		PageGateway = mobile.PageGateway,
		toast = mobile.toast,
		time = mobile.time,
		notifications = require( './notifications.js' ),
		preInit = require( './preInit.js' ),
		initLogging = require( './initLogging.js' ),
		mobileRedirect = require( './mobileRedirect.js' ),
		search = require( './search.js' ),
		references = require( './references.js' ),
		TitleUtil = require( './TitleUtil.js' ),
		issues = require( './page-issues/index.js' ),
		Toolbar = require( './Toolbar.js' ),
		router = require( 'mediawiki.router' ),
		CtaDrawer = mobile.CtaDrawer,
		Button = mobile.Button,
		Anchor = mobile.Anchor,
		overlayManager = require( './overlayManager.js' ),
		currentPage = mobile.currentPage(),
		currentPageHTMLParser = mobile.currentPageHTMLParser(),
		$redLinks = currentPageHTMLParser.getRedLinks(),
		api = new mw.Api(),
		eventBus = mobile.eventBusSingleton,
		namespaceIDs = mw.config.get( 'wgNamespaceIds' );

	/**
	 * Event handler for clicking on an image thumbnail
	 * @param {JQuery.Event} ev
	 * @ignore
	 */
	function onClickImage( ev ) {
		// Do not interfere with non-left clicks or if modifier keys are pressed.
		if ( ( ev.button !== 0 && ev.which !== 1 ) ||
			ev.altKey || ev.ctrlKey || ev.shiftKey || ev.metaKey ) {
			return;
		}

		ev.preventDefault();
		routeThumbnail( $( this ).data( 'thumb' ) );
	}

	/**
	 * @param {JQuery.Element} thumbnail
	 * @ignore
	 */
	function routeThumbnail( thumbnail ) {
		router.navigate( '#/media/' + encodeURIComponent( thumbnail.getFileName() ) );
	}

	/**
	 * Add routes to images and handle clicks
	 * @method
	 * @ignore
	 * @param {JQuery.Object} [$container] Optional container to search within
	 */
	function initMediaViewer( $container ) {
		currentPageHTMLParser.getThumbnails( $container ).forEach( function ( thumb ) {
			thumb.$el.off().data( 'thumb', thumb ).on( 'click', onClickImage );
		} );
	}

	/**
	 * Hijack the Special:Languages link and replace it with a trigger to a languageOverlay
	 * that displays the same data
	 * @ignore
	 */
	function initButton() {
		// This catches language selectors in page actions and in secondary actions (e.g. Main Page)
		// eslint-disable-next-line no-jquery/no-global-selector
		var $primaryBtn = $( '.language-selector' );

		if ( $primaryBtn.length ) {
			// We only bind the click event to the first language switcher in page
			$primaryBtn.on( 'click', function ( ev ) {
				ev.preventDefault();

				if ( $primaryBtn.attr( 'href' ) || $primaryBtn.find( 'a' ).length ) {
					router.navigate( '/languages' );
				} else {
					toast.show( mw.msg( 'mobile-frontend-languages-not-available' ) );
				}
			} );
		}
	}

	/**
	 * Returns a rejected promise if MultimediaViewer is available. Otherwise
	 * returns the mediaViewerOverlay
	 * @method
	 * @ignore
	 * @param {string} title the title of the image
	 * @return {JQuery.Deferred|Overlay}
	 */
	function makeMediaViewerOverlayIfNeeded( title ) {
		if ( mw.loader.getState( 'mmv.bootstrap' ) === 'ready' ) {
			// This means MultimediaViewer has been installed and is loaded.
			// Avoid loading it (T169622)
			return $.Deferred().reject();
		}

		return mobile.mediaViewer.overlay( {
			api: api,
			thumbnails: currentPageHTMLParser.getThumbnails(),
			title: decodeURIComponent( title ),
			eventBus: eventBus
		} );
	}

	// Routes
	overlayManager.add( /^\/media\/(.+)$/, makeMediaViewerOverlayIfNeeded );
	overlayManager.add( /^\/languages$/, function () {
		return mobile.languageOverlay( new PageGateway( api ) );
	} );

	// Setup
	$( function () {
		initButton();
	} );

	mw.hook( 'wikipage.content' ).add( initMediaViewer );

	/**
	 * Initialisation function for last modified module.
	 *
	 * Enhances an element representing a time
	 * to show a human friendly date in seconds, minutes, hours, days
	 * months or years
	 * @ignore
	 * @param {JQuery.Object} [$lastModifiedLink]
	 */
	function initHistoryLink( $lastModifiedLink ) {
		var delta, historyUrl, msg, $bar,
			ts, username, gender;

		historyUrl = $lastModifiedLink.attr( 'href' );
		ts = $lastModifiedLink.data( 'timestamp' );
		username = $lastModifiedLink.data( 'user-name' ) || false;
		gender = $lastModifiedLink.data( 'user-gender' );

		if ( ts ) {
			delta = time.getTimeAgoDelta( parseInt( ts, 10 ) );
			if ( time.isRecent( delta ) ) {
				$bar = $lastModifiedLink.closest( '.last-modified-bar' );
				$bar.addClass( 'active' );
				$bar.find( '.mw-ui-icon-minerva-clock' ).addClass( 'mw-ui-icon-minerva-clock-invert' );
				$bar.find( '.mw-ui-icon-mf-arrow-gray' ).addClass( 'mw-ui-icon-mf-arrow-invert' );
			}
			msg = time.getLastModifiedMessage( ts, username, gender, historyUrl );
			$lastModifiedLink.replaceWith( msg );
		}
	}

	/**
	 * Initialisation function for last modified times
	 *
	 * Enhances .modified-enhancement element
	 * to show a human friendly date in seconds, minutes, hours, days
	 * months or years
	 * @ignore
	 */
	function initModifiedInfo() {
		// eslint-disable-next-line no-jquery/no-global-selector
		$( '.modified-enhancement' ).each( function () {
			initHistoryLink( $( this ) );
		} );
	}

	/**
	 * Initialisation function for user creation module.
	 *
	 * Enhances an element representing a time
	 + to show a human friendly date in seconds, minutes, hours, days
	 * months or years
	 * @ignore
	 * @param {JQuery.Object} [$tagline]
	 */
	function initRegistrationDate( $tagline ) {
		var msg, ts;

		ts = $tagline.data( 'userpage-registration-date' );

		if ( ts ) {
			msg = time.getRegistrationMessage( ts, $tagline.data( 'userpage-gender' ) );
			$tagline.text( msg );
		}
	}

	/**
	 * Initialisation function for registration date on user page
	 *
	 * Enhances .tagline-userpage element
	 * to show human friendly date in seconds, minutes, hours, days
	 * months or years
	 * @ignore
	 */
	function initRegistrationInfo() {
		// eslint-disable-next-line no-jquery/no-global-selector
		$( '#tagline-userpage' ).each( function () {
			initRegistrationDate( $( this ) );
		} );
	}

	/**
	 * Tests a URL to determine if it links to a local User namespace page or not.
	 *
	 * Assuming the current page visited is hosted on metawiki, the following examples would return
	 * true:
	 *
	 *   https://meta.wikimedia.org/wiki/User:Foo
	 *   /wiki/User:Foo
	 *   /wiki/User:Nonexistent_user_page
	 *
	 * The following examples return false:
	 *
	 *   https://en.wikipedia.org/wiki/User:Foo
	 *   /wiki/Foo
	 *   /wiki/User_talk:Foo
	 *
	 * @param {string} url
	 * @return {boolean}
	 */
	function isUserUri( url ) {
		var
			title = TitleUtil.newFromUri( url ),
			namespace = title ? title.getNamespaceId() : undefined;
		return namespace === namespaceIDs.user;
	}

	/**
	 * Strip the edit action from red links to nonexistent User namespace pages.
	 * @return {void}
	 */
	function initUserRedLinks() {
		$redLinks.filter( function ( _, element ) {
			// Filter out non-User namespace pages.
			return isUserUri( element.href );
		} ).each( function ( _, element ) {
			var uri = new mw.Uri( element.href );
			if ( uri.query.action !== 'edit' ) {
				// Nothing to strip.
				return;
			}

			// Strip the action.
			delete uri.query.action;

			// Update the element with the new link.
			element.href = uri.toString();
		} );
	}

	/**
	 * Initialize red links call-to-action
	 *
	 * Upon clicking a red link, show an interstitial CTA explaining that the page doesn't exist
	 * with a button to create it, rather than directly navigate to the edit form.
	 *
	 * Special case T201339: following a red link to a user or user talk page should not prompt for
	 * its creation. The reasoning is that user pages should be created by their owners and it's far
	 * more common that non-owners follow a user's red linked user page to consider their
	 * contributions, account age, or other activity.
	 *
	 * For example, a user adds a section to a Talk page and signs their contribution (which creates
	 * a link to their user page whether exists or not). If the user page does not exist, that link
	 * will be red. In both cases, another user follows this link, not to edit create a page for
	 * that user but to obtain information on them.
	 *
	 * @ignore
	 */
	function initRedlinksCta() {
		$redLinks.filter( function ( _, element ) {
			// Filter out local User namespace pages.
			return !isUserUri( element.href );
		} ).on( 'click', function ( ev ) {
			var drawerOptions = {
					progressiveButton: new Button( {
						progressive: true,
						label: mw.msg( 'mobile-frontend-editor-redlink-create' ),
						href: $( this ).attr( 'href' )
					} ).options,
					closeAnchor: new Anchor( {
						progressive: true,
						label: mw.msg( 'mobile-frontend-editor-redlink-leave' ),
						additionalClassNames: 'hide'
					} ).options,
					events: {
						'click .hide': 'hide' // Call CtaDrawer.hide() on closeAnchor click.
					},
					content: mw.msg( 'mobile-frontend-editor-redlink-explain' ),
					actionAnchor: false
				},
				drawer = new CtaDrawer( drawerOptions );

			// use preventDefault() and not return false to close other open
			// drawers or anything else.
			ev.preventDefault();
			drawer.show();
		} );
	}

	/**
	 * When tabs are present and one is selected, scroll the selected tab into view.
	 * @return {void}
	 */
	function initTabsScrollPosition() {
		var $tabContainer, tabPosition, containerPosition, left, right,
			// eslint-disable-next-line no-jquery/no-global-selector
			$selectedTab = $( '.minerva__tab.selected' );
		if ( $selectedTab.length !== 1 ) {
			return;
		}

		$tabContainer = $selectedTab.closest( '.minerva__tab-container' );
		tabPosition = $selectedTab.position();
		containerPosition = $tabContainer.position();
		// Position of the left edge of $selectedTab relative to the left edge of $tabContainer
		left = tabPosition.left - containerPosition.left;
		// Position of the right edge of $selectedTab relative to the left edge of $tabContainer
		right = left + $selectedTab.outerWidth();

		// If $selectedTab is (partly) scrolled out of view, scroll it into view
		// This only considers and manipulates the horizontal scroll position within $tabContainer,
		// not the vertical scroll position of the viewport
		if ( left < 0 ) {
			// Left edge of $selectedTab is to the left of the left edge of $tabContainer
			// Scroll $tabContainer to the left, by subtracting the difference from its scrollLeft
			// (we're subtracting here by adding a negative number)
			$tabContainer.scrollLeft( $tabContainer.scrollLeft() + left );
		} else if ( right > $tabContainer.innerWidth() ) {
			// Right edge of $selectedTab is to the right of the right edge of $tabContainer
			// Scroll $tabContainer to the right, by adding the difference to its scrollLeft
			$tabContainer.scrollLeft(
				$tabContainer.scrollLeft() + right - $tabContainer.innerWidth()
			);
		}
	}

	$( function () {
		var toolbarElement = document.querySelector( Toolbar.selector );
		// Init:
		// - main menu closes when you click outside of it
		// - redirects show a toast.
		preInit();
		// - logging
		initLogging();
		// - references
		references();
		// - search
		search();
		// - mobile redirect
		mobileRedirect();
		// Update anything else that needs enhancing (e.g. watchlist)
		initModifiedInfo();
		initRegistrationInfo();
		// eslint-disable-next-line no-jquery/no-global-selector
		initHistoryLink( $( '.last-modifier-tagline a' ) );
		if ( toolbarElement ) {
			Toolbar.bind( window, toolbarElement, eventBus );
			Toolbar.render( window, toolbarElement );
		}
		initRedlinksCta();
		initUserRedLinks();
		initTabsScrollPosition();
		// Setup the issues banner on the page
		// Pages which dont exist (id 0) cannot have issues
		if ( !currentPage.isMissing ) {
			issues.init( overlayManager, currentPageHTMLParser );
		}
		// If Echo is installed (using config as a proxy) and user is logged in init notifications
		if ( !mw.user.isAnon() && mw.config.get( 'wgEchoMaxNotificationCount' ) !== undefined ) {
			notifications();
		}
	} );
	module.exports = {
		overlayManager: overlayManager
	};
}( mw.mobileFrontend ) );