MediaWiki:Gadget-ReferenceTooltips.js

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// See [[mw:Reference Tooltips]]
// Source https://en.wikipedia.org/wiki/MediaWiki:Gadget-ReferenceTooltips.js

/*eslint space-in-parens: ["error", "always"], array-bracket-spacing: ["error", "always"]*/

( function () {

// If you're loading the script from another wiki and want to set your settings, do that in `window`
// properties with `rt_` prefix, e.g.
//   window.rt_REF_LINK_SELECTOR = '...';
// They will be used instead of enwiki detaults.
var REF_LINK_SELECTOR = window.rt_REF_LINK_SELECTOR || '.reference, a[href^="#CITEREF"]',
	COMMENTED_TEXT_CLASS = window.rt_COMMENTED_TEXT_CLASS || 'rt-commentedText',
	COMMENTED_TEXT_SELECTOR = (
		window.rt_COMMENTED_TEXT_SELECTOR ||
		( COMMENTED_TEXT_CLASS ? '.' + COMMENTED_TEXT_CLASS + ', ' : '' ) +
		'abbr[title]'
	);

if ( mw.messages.get( 'rt-settings' ) === null ) {
	mw.messages.set( {
		'rt-settings': 'Reference Tooltips settings',
		'rt-enable-footer': 'Enable Reference Tooltips',
		'rt-settings-title': 'Reference Tooltips',
		'rt-save': 'Save',
		'rt-enable': 'Enable Reference Tooltips',
		'rt-activationMethod': 'Show a tooltip when I\'m',
		'rt-hovering': 'hovering a reference',
		'rt-clicking': 'clicking a reference',
		'rt-delay': 'Delay before the tooltip appears (in milliseconds)',
		'rt-tooltipsForComments': 'Show the tooltip over <span title="Tooltip example" class="' + ( COMMENTED_TEXT_CLASS || 'rt-commentedText' ) + '" style="border-bottom: 1px dotted; cursor: help;">text with a dotted underline</span> in Reference Tooltips style (allows to see such tooltips on devices with no mouse support)',
		'rt-disabledNote': 'You can re-enable Reference Tooltips using a link in the footer of the page.',
		'rt-done': 'Done',
		'rt-enabled': 'Reference Tooltips are enabled'
	} );
}

// "Global" variables
var SECONDS_IN_A_DAY = 60 * 60 * 24,
	CLASSES = {
		FADE_IN_DOWN: 'rt-fade-in-down',
		FADE_IN_UP: 'rt-fade-in-up',
		FADE_OUT_DOWN: 'rt-fade-out-down',
		FADE_OUT_UP: 'rt-fade-out-up'
	},
	IS_TOUCHSCREEN = 'ontouchstart' in document.documentElement,
	// Quite a rough check for mobile browsers, a mix of what is advised at
	// https://stackoverflow.com/a/24600597 (sends to
	// https://developer.mozilla.org/en-US/docs/Browser_detection_using_the_user_agent)
	// and https://stackoverflow.com/a/14301832
	IS_MOBILE = /Mobi|Android/i.test( navigator.userAgent ) ||
		typeof window.orientation !== 'undefined',
	CLIENT_NAME = $.client.profile().name,
	settingsString, settings, enabled, delay, activatedByClick, tooltipsForComments, cursorWaitCss,
	windowManager, $teleportTarget,
	$body = $( document.body ),
	$window = $( window ),
	$overlay = $( '<div>' )
		.addClass( 'rt-overlay' )
		.appendTo( $body );

// Can't use before https://phabricator.wikimedia.org/T369880 is resolved
// mw.loader.using( 'mediawiki.page.ready' ).then( function ( require ) {
// 	$teleportTarget = $( require( 'mediawiki.page.ready' ).teleportTarget );
// 	$overlay.appendTo( $teleportTarget );
// } );

function rt( $content ) {
	// Popups gadget
	if ( window.pg ) {
		return;
	}

	var teSelector,
		settingsDialogOpening = false;

	function setSettingsCookie() {
		mw.cookie.set(
			'RTsettings',
			(
				Number( enabled ) +
				'|' +
				delay +
				'|' +
				Number( activatedByClick ) +
				'|' +
				Number( tooltipsForComments )
			),
			{ path: '/', expires: 90 * SECONDS_IN_A_DAY, prefix: '' }
		);
	}

	function enableRt() {
		enabled = true;
		setSettingsCookie();
		$( '.rt-enableItem' ).remove();
		rt( $content );
		mw.notify( mw.msg( 'rt-enabled' ) );
	}

	function disableRt() {
		$content.find( teSelector ).removeClass( 'rt-commentedText' ).off( '.rt' );
		$body.off( '.rt' );
		$window.off( '.rt' );
	}

	function addEnableLink() {
		// #footer-places – Vector
		// #f-list – Timeless, Monobook, Modern
		// parent of #footer li – Cologne Blue
		var $footer = $( '#footer-places, #f-list' );
		if ( !$footer.length ) {
			$footer = $( '#footer li' ).parent();
		}
		if ( !$footer.find( '.rt-enableItem' ).length ) {
			$footer.append(
				$( '<li>' )
					.addClass( 'rt-enableItem' )
					.append(
						$( '<a>' )
							.text( mw.msg( 'rt-enable-footer' ) )
							.attr( 'href', '#' )
							.click( function ( e ) {
								e.preventDefault();
								enableRt();
							} )
					)
			);
		}
	}

	function TooltippedElement( $element ) {
		var events,
			te = this;

		function onStartEvent( e ) {
			var showRefArgs;

			if ( activatedByClick && te.type !== 'commentedText' && e.type !== 'contextmenu' ) {
				e.preventDefault();
			}
			if ( !te.noRef ) {
				showRefArgs = [ $( this ) ];
				if ( te.type !== 'supRef' ) {
					showRefArgs.push( e.pageX, e.pageY );
				}
				te.showRef.apply( te, showRefArgs );
			}
		}

		function onEndEvent() {
			if ( !te.noRef ) {
				te.hideRef();
			}
		}

		if ( !$element ) {
			return;
		}

		// TooltippedElement.$element and TooltippedElement.$originalElement will be different when
		// the first is changed after its cloned version is hovered in a tooltip
		this.$element = $element;
		this.$originalElement = $element;
		if ( this.$element.is( REF_LINK_SELECTOR ) ) {
			if ( this.$element.prop( 'tagName' ) === 'SUP' ) {
				this.type = 'supRef';
			} else {
				this.type = 'harvardRef';
			}
		} else {
			this.type = 'commentedText';
			this.comment = this.$element.attr( 'title' );
			if ( !this.comment ) {
				return;
			}
			this.$element.addClass( 'rt-commentedText' );
		}

		if ( activatedByClick ) {
			events = {
				'click.rt': onStartEvent
			};
			// Adds an ability to see tooltips for links
			if (
				this.type === 'commentedText' &&
				( this.$element.closest( 'a' ).length || this.$element.has( 'a' ).length )
			) {
				events[ 'contextmenu.rt' ] = onStartEvent;
			}
		} else {
			events = {
				'mouseenter.rt': onStartEvent,
				'mouseleave.rt': onEndEvent
			};
		}

		this.$element.on( events );

		this.hideRef = function ( immediately ) {
			clearTimeout( te.showTimer );

			if ( this.type === 'commentedText' ) {
				this.$element.attr( 'title', this.comment );
			}

			if ( this.tooltip && this.tooltip.isPresent ) {
				if ( activatedByClick || immediately ) {
					this.tooltip.hide();
				} else {
					this.hideTimer = setTimeout( function () {
						te.tooltip.hide();
					}, 200 );
				}
			} else if ( this.$ref && this.$ref.hasClass( 'rt-target' ) ) {
				this.$ref.removeClass( 'rt-target' );
				if ( activatedByClick ) {
					$body.off( 'click.rt touchstart.rt', this.onBodyClick );
				}
			}
		};

		this.showRef = function ( $element, ePageX, ePageY ) {
			// Popups gadget
			if ( window.pg ) {
				disableRt();
				return;
			}

			if ( this.tooltip && !this.tooltip.$content.length ) {
				return;
			}

			var tooltipInitiallyPresent = this.tooltip && this.tooltip.isPresent;

			function reallyShow() {
				var viewportTop, refOffsetTop, teHref;

				if ( !te.$ref && !te.comment ) {
					teHref = te.type === 'supRef' ?
						te.$element.find( 'a' ).attr( 'href' ) :
						te.$element.attr( 'href' ); // harvardRef
					te.$ref = teHref &&
						$( '#' + $.escapeSelector( teHref.slice( 1 ) ) );
					if ( !te.$ref || !te.$ref.length || !te.$ref.text() ) {
						te.noRef = true;
						return;
					}
				}

				if ( !tooltipInitiallyPresent && !te.comment ) {
					viewportTop = $window.scrollTop();
					refOffsetTop = te.$ref.offset().top;
					if (
						!activatedByClick &&
						viewportTop < refOffsetTop &&
						viewportTop + $window.height() > refOffsetTop + te.$ref.height() &&
						// There can be gadgets/scripts that make references horizontally scrollable.
						$window.width() > te.$ref.offset().left + te.$ref.width()
					) {
						// Highlight the reference itself
						te.$ref.addClass( 'rt-target' );
						return;
					}
				}

				if ( !te.tooltip ) {
					te.tooltip = new Tooltip( te );
					if ( !te.tooltip.$content.length ) {
						return;
					}
				}

				// If this tooltip is called from inside another tooltip. We can't define it
				// in the constructor since a ref can be cloned but have the same Tooltip object;
				// so, Tooltip.parent is a floating value.
				te.tooltip.parent = te.$element.closest( '.rt-tooltip' ).data( 'tooltip' );
				if ( te.tooltip.parent && te.tooltip.parent.disappearing ) {
					return;
				}

				te.tooltip.show();

				if ( tooltipInitiallyPresent ) {
					if ( te.tooltip.$element.hasClass( 'rt-tooltip-above' ) ) {
						te.tooltip.$element.addClass( CLASSES.FADE_IN_DOWN );
					} else {
						te.tooltip.$element.addClass( CLASSES.FADE_IN_UP );
					}
					return;
				}

				te.tooltip.calculatePosition( ePageX, ePageY );

				$window.on( 'resize.rt', te.onWindowResize );
			}

			// We redefine this.$element here because e.target can be a reference link inside
			// a reference tooltip, not a link that was initially assigned to this.$element
			this.$element = $element;

			if ( this.type === 'commentedText' ) {
				this.$element.attr( 'title', '' );
			}

			if ( activatedByClick ) {
				if (
					tooltipInitiallyPresent ||
					( this.$ref && this.$ref.hasClass( 'rt-target' ) )
				) {
					return;
				} else {
					setTimeout( function () {
						$body.on( 'click.rt touchstart.rt', te.onBodyClick );
					}, 0 );
				}
			}

			if ( activatedByClick || tooltipInitiallyPresent ) {
				reallyShow();
			} else {
				this.showTimer = setTimeout( reallyShow, delay );
			}
		};

		this.onBodyClick = function ( e ) {
			if ( !te.tooltip && !( te.$ref && te.$ref.hasClass( 'rt-target' ) ) ) {
				return;
			}

			var $current = $( e.target );

			function contextMatchesParameter( parameter ) {
				return this === parameter;
			}

			// The last condition is used to determine cases when a clicked tooltip is the current
			// element's tooltip or one of its descendants
			while (
				$current.length &&
				(
					!$current.hasClass( 'rt-tooltip' ) ||
					!$current.data( 'tooltip' ) ||
					!$current.data( 'tooltip' ).upToTopParent(
						contextMatchesParameter, [ te.tooltip ],
						true
					)
				)
			) {
				$current = $current.parent();
			}
			if ( !$current.length ) {
				te.hideRef();
			}
		};

		this.onWindowResize = function () {
			te.tooltip.calculatePosition();
		};
	}

	function Tooltip( te ) {
		function openSettingsDialog() {
			var settingsDialog, settingsWindow;

			if ( cursorWaitCss ) {
				cursorWaitCss.disabled = true;
			}

			function SettingsDialog() {
				SettingsDialog.parent.call( this );
			}
			OO.inheritClass( SettingsDialog, OO.ui.ProcessDialog );

			SettingsDialog.static.name = 'settingsDialog';
			SettingsDialog.static.title = mw.msg( 'rt-settings-title' );
			SettingsDialog.static.actions = [
				{
					modes: 'main',
					action: 'save',
					label: mw.msg( 'rt-save' ),
					flags: [ 'primary', 'progressive' ]
				},
				{
					modes: 'main',
					flags: [ 'safe', 'close' ]
				},
				{
					modes: 'disabled',
					action: 'deactivated',
					label: mw.msg( 'rt-done' ),
					flags: [ 'primary', 'progressive' ]
				}
			];

			SettingsDialog.prototype.initialize = function () {
				var dialog = this;

				SettingsDialog.parent.prototype.initialize.apply( this, arguments );

				this.enableCheckbox = new OO.ui.CheckboxInputWidget( {
					selected: true
				} );
				this.enableCheckbox.on( 'change', function ( selected ) {
					dialog.activationMethodSelect.setDisabled( !selected );
					dialog.delayInput.setDisabled( !selected || dialog.clickOption.isSelected() );
					dialog.tooltipsForCommentsCheckbox.setDisabled( !selected );
				} );
				this.enableField = new OO.ui.FieldLayout( this.enableCheckbox, {
					label: mw.msg( 'rt-enable' ),
					align: 'inline',
					classes: [ 'rt-enableField' ]
				} );

				this.hoverOption = new OO.ui.RadioOptionWidget( {
					label: mw.msg( 'rt-hovering' )
				} );
				this.clickOption = new OO.ui.RadioOptionWidget( {
					label: mw.msg( 'rt-clicking' )
				} );
				this.activationMethodSelect = new OO.ui.RadioSelectWidget( {
					items: [ this.hoverOption, this.clickOption ]
				} );
				this.activationMethodSelect.selectItem(
					activatedByClick ? this.clickOption : this.hoverOption
				);
				this.activationMethodSelect.on( 'choose', function ( item ) {
					dialog.delayInput.setDisabled( item === dialog.clickOption );
				} );
				this.activationMethodField = new OO.ui.FieldLayout( this.activationMethodSelect, {
					label: mw.msg( 'rt-activationMethod' ),
					align: 'top'
				} );

				this.delayInput = new OO.ui.NumberInputWidget( {
					input: { value: delay },
					step: 50,
					min: 0,
					max: 5000,
					disabled: activatedByClick,
					classes: [ 'rt-numberInput' ]
				} );
				this.delayField = new OO.ui.FieldLayout( this.delayInput, {
					label: mw.msg( 'rt-delay' ),
					align: 'top'
				} );

				this.tooltipsForCommentsCheckbox = new OO.ui.CheckboxInputWidget( {
					selected: tooltipsForComments
				} );
				this.tooltipsForCommentsField = new OO.ui.FieldLayout(
					this.tooltipsForCommentsCheckbox,
					{
						label: new OO.ui.HtmlSnippet( mw.msg( 'rt-tooltipsForComments' ) ),
						align: 'inline',
						classes: [ 'rt-tooltipsForCommentsField' ]
					}
				);
				new TooltippedElement(
					this.tooltipsForCommentsField.$element.find(
						'.' + ( COMMENTED_TEXT_CLASS || 'rt-commentedText' )
					)
				);

				this.fieldset = new OO.ui.FieldsetLayout();
				this.fieldset.addItems( [
					this.enableField,
					this.activationMethodField,
					this.delayField,
					this.tooltipsForCommentsField
				] );

				this.panelSettings = new OO.ui.PanelLayout( {
					padded: true,
					expanded: false
				} );
				this.panelSettings.$element.append( this.fieldset.$element );

				this.panelDisabled = new OO.ui.PanelLayout( {
					padded: true,
					expanded: false
				} );
				this.panelDisabled.$element.append(
					$( '<table>' )
						.addClass( 'rt-disabledHelp' )
						.append(
							$( '<tr>' ).append(
								$( '<td>' ).append(
									$( '<img>' ).attr( 'src', '/media/wikipedia/commons/c/c0/MediaWiki_footer_link_ltr.svg' )
								),
								$( '<td>' )
									.addClass( 'rt-disabledNote' )
									.text( mw.msg( 'rt-disabledNote' ) )
							)
						)
				);

				this.stackLayout = new OO.ui.StackLayout( {
					items: [ this.panelSettings, this.panelDisabled ]
				} );

				this.$body.append( this.stackLayout.$element );
			};

			SettingsDialog.prototype.getSetupProcess = function ( data ) {
				return SettingsDialog.parent.prototype.getSetupProcess.call( this, data )
					.next( function () {
						this.stackLayout.setItem( this.panelSettings );
						this.actions.setMode( 'main' );
					}, this );
			};

			SettingsDialog.prototype.getActionProcess = function ( action ) {
				var dialog = this;

				if ( action === 'save' ) {
					return new OO.ui.Process( function () {
						var newDelay = Number( dialog.delayInput.getValue() );

						enabled = dialog.enableCheckbox.isSelected();
						if ( newDelay >= 0 && newDelay <= 5000 ) {
							delay = newDelay;
						}
						activatedByClick = dialog.clickOption.isSelected();
						tooltipsForComments = dialog.tooltipsForCommentsCheckbox.isSelected();

						setSettingsCookie();

						if ( enabled ) {
							dialog.close();
							disableRt();
							rt( $content );
						} else {
							dialog.actions.setMode( 'disabled' );
							dialog.stackLayout.setItem( dialog.panelDisabled );
							disableRt();
							addEnableLink();
						}
					} );
				} else if ( action === 'deactivated' ) {
					dialog.close();
				}
				return SettingsDialog.parent.prototype.getActionProcess.call( this, action );
			};

			SettingsDialog.prototype.getBodyHeight = function () {
				return this.stackLayout.getCurrentItem().$element.outerHeight( true );
			};

			tooltip.upToTopParent( function adjustRightAndHide() {
				if ( this.isPresent ) {
					if ( this.$element[ 0 ].style.right ) {
						this.$element.css(
							'right',
							'+=' + ( window.innerWidth - $window.width() )
						);
					}
					this.te.hideRef( true );
				}
			} );

			if ( !windowManager ) {
				windowManager = new OO.ui.WindowManager();
				$body.append( windowManager.$element );
			}

			settingsDialog = new SettingsDialog();
			windowManager.addWindows( [ settingsDialog ] );
			settingsWindow = windowManager.openWindow( settingsDialog );
			settingsWindow.opened.then( function () {
				settingsDialogOpening = false;
			} );
			settingsWindow.closed.then( function () {
				windowManager.clearWindows();
			} );
		}

		var tooltip = this;

		// This variable can change: one tooltip can be called from a harvard-style reference link
		// that is put into different tooltips
		this.te = te;

		switch ( this.te.type ) {
			case 'supRef':
				this.id = 'rt-' + this.te.$originalElement.attr( 'id' );
				this.$content = this.te.$ref
					.contents()
					.filter( function ( i ) {
						var $this = $( this );
						return (
							this.nodeType === Node.TEXT_NODE ||
							!(
								$this.is( '.mw-cite-backlink' ) ||
								(
									i === 0 &&
									// Template:Cnote, Template:Note
									( $this.is( 'b' ) ||
										// Template:Note_label
										$this.is( 'a' ) &&
										$this.attr( 'href' ).indexOf( '#ref' ) === 0
									)
								)
							)
						);
					} )
					.clone( true );
				break;
			case 'harvardRef':
				this.id = 'rt-' + this.te.$originalElement.closest( 'li' ).attr( 'id' );
				this.$content = this.te.$ref
					.clone( true )
					.removeAttr( 'id' );
				break;
			case 'commentedText':
				this.id = 'rt-' + String( Math.random() ).slice( 2 );
				this.$content = $( document.createTextNode( this.te.comment ) );
				break;
		}
		if ( !this.$content.length ) {
			return;
		}

		this.isInsideWindow = Boolean( this.te.$element.closest( '.oo-ui-window' ).length );

		this.$element = $( '<div>' )
			.addClass( 'rt-tooltip' )
			.attr( 'id', this.id )
			.attr( 'role', 'tooltip' )
			.data( 'tooltip', this );

		var $hoverArea = $( '<div>' )
			.addClass( 'rt-hoverArea' )
			.appendTo( this.$element );
		
		var $scroll = $( '<div>' )
			.addClass( 'rt-scroll' )
			.appendTo( $hoverArea );

		this.$content = this.$content
			.wrapAll( '<div>' )
			.parent()
			.addClass( 'rt-content' )
			.addClass( 'mw-parser-output' )
			.appendTo( $scroll );

		if ( !activatedByClick ) {
			this.$element
				.mouseenter( function () {
					if ( !tooltip.disappearing ) {
						tooltip.upToTopParent( function () {
							this.show();
						} );
					}
				} )
				.mouseleave( function ( e ) {
					// https://stackoverflow.com/q/47649442 workaround. Relying on relatedTarget
					// alone has pitfalls: when alt-tabbing, relatedTarget is empty too
					if (
						CLIENT_NAME !== 'chrome' ||
						(
							!e.originalEvent ||
							e.originalEvent.relatedTarget !== null ||
							!tooltip.clickedTime ||
							$.now() - tooltip.clickedTime > 50
						)
					) {
						tooltip.upToTopParent( function () {
							this.te.hideRef();
						} );
					}
				} )
				.click( function () {
					tooltip.clickedTime = $.now();
				} );
		}

		if ( !this.isInsideWindow ) {
			$( '<a>' )
				.addClass( 'rt-settingsLink' )
				.attr( 'role', 'button' )
				.attr( 'href', '#' )
				.attr( 'title', mw.msg( 'rt-settings' ) )
				.click( function ( e ) {
					e.preventDefault();
					if ( settingsDialogOpening ) {
						return;
					}
					settingsDialogOpening = true;

					if ( mw.loader.getState( 'oojs-ui' ) !== 'ready' ) {
						if ( cursorWaitCss ) {
							cursorWaitCss.disabled = false;
						} else {
							cursorWaitCss = mw.util.addCSS( 'body { cursor: wait; }' );
						}
					}
					mw.loader.using( [ 'oojs', 'oojs-ui' ], openSettingsDialog );
				} )
				.prependTo( this.$content );
		}

		// Tooltip tail element is inside tooltip content element in order for the tooltip
		// not to disappear when the mouse is above the tail
		this.$tail = $( '<div>' )
			.addClass( 'rt-tail' )
			.prependTo( this.$element );

		this.disappearing = false;

		this.show = function () {
			this.disappearing = false;
			clearTimeout( this.te.hideTimer );
			clearTimeout( this.te.removeTimer );

			this.$element
				.removeClass( CLASSES.FADE_OUT_DOWN )
				.removeClass( CLASSES.FADE_OUT_UP );

			if ( !this.isPresent ) {
				$overlay.append( this.$element );
			}

			this.isPresent = true;
		};

		this.hide = function () {
			var tooltip = this;

			tooltip.disappearing = true;

			if ( tooltip.$element.hasClass( 'rt-tooltip-above' ) ) {
				tooltip.$element
					.removeClass( CLASSES.FADE_IN_DOWN )
					.addClass( CLASSES.FADE_OUT_UP );
			} else {
				tooltip.$element
					.removeClass( CLASSES.FADE_IN_UP )
					.addClass( CLASSES.FADE_OUT_DOWN );
			}

			tooltip.te.removeTimer = setTimeout( function () {
				if ( tooltip.isPresent ) {
					tooltip.$element.detach();

					tooltip.$tail.css( 'left', '' );

					if ( activatedByClick ) {
						$body.off( 'click.rt touchstart.rt', tooltip.te.onBodyClick );
					}
					$window.off( 'resize.rt', tooltip.te.onWindowResize );

					tooltip.isPresent = false;
				}
			}, 200 );
		};

		this.calculatePosition = function ( ePageX, ePageY ) {
			var teElement, teOffsets, teOffset, targetTailOffsetX, tailLeft;

			this.$tail.css( 'left', '' );

			teElement = this.te.$element.get( 0 );
			if ( ePageX !== undefined ) {
				targetTailOffsetX = ePageX;
				teOffsets = ( teElement.getClientRects && teElement.getClientRects() ) ||
					teElement.getBoundingClientRect();
				if ( teOffsets.length > 1 ) {
					for ( var i = teOffsets.length - 1; i >= 0; i-- ) {
						if (
							ePageY >= Math.round( $window.scrollTop() + teOffsets[ i ].top ) &&
							ePageY <= Math.round(
								$window.scrollTop() + teOffsets[i].top + teOffsets[ i ].height
							)
						) {
							teOffset = teOffsets[ i ];
						}
					}
				}
			}

			if ( !teOffset ) {
				teOffset = ( teElement.getClientRects && teElement.getClientRects()[ 0 ] ) ||
					teElement.getBoundingClientRect();
			}
			teOffset = {
				top: $window.scrollTop() + teOffset.top,
				left: $window.scrollLeft() + teOffset.left,
				width: teOffset.width,
				height: teOffset.height
			};
			if ( !targetTailOffsetX ) {
				targetTailOffsetX = teOffset.left + ( teOffset.width / 2 );
			}

			// Value of `left` in `.rt-tooltip-above .rt-tail`
			var defaultTailLeft = 19;

			// Value of `width` in `.rt-tail`
			var tailSideWidth = 13;

			// We tilt the square 45 degrees, so we need square root to calculate the distance.
			var tailWidth = tailSideWidth * Math.SQRT2;
			var tailHeight = tailWidth / 2;
			var tailCenterDelta = tailSideWidth + 1 - ( tailWidth / 2 );

			var tooltip = this;
			var getTop = function ( isBelow ) {
				var delta = isBelow ?
					teOffset.height + tailHeight :
					-tooltip.$element.outerHeight() - tailHeight + 1;
				return teOffset.top + delta;
			};

			this.$element.css( {
				top: getTop(),
				left: targetTailOffsetX - defaultTailLeft - tailCenterDelta,
				right: ''
			} );

			// Is it squished against the right side of the page?
			if ( this.$element.offset().left + this.$element.outerWidth() > $window.width() - 1 ) {
				this.$element.css( {
					left: '',
					right: 0
				} );
				tailLeft = targetTailOffsetX - this.$element.offset().left - tailCenterDelta;
			}

			// Is a part of it above the top of the screen?
			if ( teOffset.top < this.$element.outerHeight() + $window.scrollTop() + tailHeight ) {
				this.$element
					.removeClass( 'rt-tooltip-above' )
					.addClass( 'rt-tooltip-below' )
					.addClass( CLASSES.FADE_IN_UP )
					.css( {
						top: getTop( true )
					} );
				if ( tailLeft ) {
					this.$tail.css( 'left', ( tailLeft + tailSideWidth ) + 'px' );
				}
			} else {
				this.$element
					.removeClass( 'rt-tooltip-below' )
					.addClass( 'rt-tooltip-above' )
					.addClass( CLASSES.FADE_IN_DOWN )
					// A fix for cases when a tooltip shown once is then wrongly positioned when it
					// is shown again after a window resize.
					.css( {
						top: getTop()
					} );
				if ( tailLeft ) {
					this.$tail.css( 'left', tailLeft + 'px' );
				}
			}
		};

		// Run some function for all the tooltips up to the top one in a tree. Its context will be
		// the tooltip, while its parameters may be passed to Tooltip.upToTopParent as an array
		// in the second parameter. If the third parameter passed to ToolTip.upToTopParent is true,
		// the execution stops when the function in question returns true for the first time,
		// and ToolTip.upToTopParent returns true as well.
		this.upToTopParent = function ( func, parameters, stopAtTrue ) {
			var returnValue,
				currentTooltip = this;

			do {
				returnValue = func.apply( currentTooltip, parameters );
				if ( stopAtTrue && returnValue ) {
					break;
				}
			} while ( ( currentTooltip = currentTooltip.parent ) );

			if ( stopAtTrue ) {
				return returnValue;
			}
		};
	}

	if ( !enabled ) {
		addEnableLink();
		return;
	}

	teSelector = REF_LINK_SELECTOR;
	if ( tooltipsForComments ) {
		teSelector += ', ' + COMMENTED_TEXT_SELECTOR;
	}
	$content.find( teSelector ).each( function () {
		new TooltippedElement( $( this ) );
	} );
}

settingsString = mw.cookie.get( 'RTsettings', '' );
if ( settingsString ) {
	settings = settingsString.split( '|' );
	enabled = Boolean( Number( settings[ 0 ] ) );
	delay = Number( settings[ 1 ] );
	activatedByClick = Boolean( Number( settings[ 2 ] ) );
	// The forth value was added later, so we provide for a default value. See comments below
	// for why we use "IS_TOUCHSCREEN && IS_MOBILE".
	tooltipsForComments = settings[ 3 ] === undefined ?
		IS_TOUCHSCREEN && IS_MOBILE :
		Boolean( Number( settings[ 3 ] ) );
} else {
	enabled = true;
	delay = 200;
	// Since the mobile browser check is error-prone, adding IS_MOBILE condition here would probably
	// leave cases where a user interacting with the browser using touches doesn't know how to call
	// a tooltip in order to switch to activation by click. Some touch-supporting laptop users
	// interacting by touch (though probably not the most popular use case) would not be happy too.
	activatedByClick = IS_TOUCHSCREEN;
	// Arguably we shouldn't convert native tooltips into gadget tooltips for devices that have
	// mouse support, even if they have touchscreens (there are laptops with touchscreens).
	// IS_TOUCHSCREEN check here is for reliability, since the mobile check is prone to false
	// positives.
	tooltipsForComments = IS_TOUCHSCREEN && IS_MOBILE;
}

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

}() );