/* Code adapted from Yair Rand's NavPopupsRestyled.js
 * https://en.wikipedia.org/wiki/User:Yair_rand/NavPopupsRestyled.js
 */

( function ( $, mw ) {
	var closeTimer, // The timer use to delay `closeBox`
		openTimer, // The timer used to delay sending the API request/opening the popup form cache
		scrolled = false, // true if user scrolled the page but haven't moved mouse cursor
		elTime, // EL: UNIX timestamp of when the popup was rendered
		elDuration, // EL: How long was the popup open in milliseconds
		elAction, // EL: Was the popup clicked or middle clicked or dismissed
		elSessionId, // EL: Get defined after the getSessionId method is created
		currentLink, // DOM element of the current anchor tag
		cache = {},
		curRequest, // Current API request
		supportsSVG = document.implementation.hasFeature( 'http://www.w3.org/TR/SVG11/feature#Image', '1.1' ),
		api = new mw.Api(),
		SIZES = {
			portraitImage: {
				h: 250, // Exact height
				w: 203 // Max width
			},
			landscapeImage: {
				h: 200, // Max height
				w: 300 // Exact Width
			},
			landscapePopupWidth: 450, // Exact width of a landscape popup
			portraitPopupWidth: 300 // Exact width of a portrait popup
		},
		POPUP_DELAY = 150, // Time to wait in ms before showing a popup on hover
		POPUP_CLOSE_DELAY = 100, // Time to wait in ms before closing a popup on de-hover
		API_DELAY = 50, // Time to wait in ms before starting the API queries on hover, must be <= POPUP_DELAY
		$svg, $box; // defined at the end of the file

	/**
	 * Return a promise corresponding to a `setTimeout()` call. Call `.abort()` on the return value
	 * to perform the equivalent of `clearTimeout()`.
	 *
	 * @param {number} ms Milliseconds to wait
	 * @return {jQuery.Promise}
	 */
	function timeoutPromise( ms ) {
		var deferred, promise, timeout;

		deferred = $.Deferred();

		timeout = setTimeout( function () {
			deferred.resolve();
		}, ms );

		promise = deferred.promise( { abort: function () {
			clearTimeout( timeout );
			deferred.reject();
		} } );

		return promise;
	}

	/**
	 * @method sendRequest
	 * Send an API request, create DOM elements and
	 * put them in the cache. Returns a promise.
	 * @param {String} href
	 * @param {String} title
	 * @return {jQuery.Promise}
	 */
	function sendRequest( href, title ) {
		var deferred = $.Deferred();

		curRequest = api.get( {
			action: 'query',
			prop: 'extracts|pageimages|revisions|info',
			redirects: 'true',
			exintro: 'true',
			exsentences: 2,
			// there is an added geometric limit on .mwe-popups-extract
			// so that text does not overflow from the card
			explaintext: 'true',
			piprop: 'thumbnail',
			pithumbsize: 300,
			rvprop: 'timestamp',
			inprop: 'watched',
			indexpageids: true,
			titles: title
		} );

		curRequest.done( function ( re ) {
			curRequest = undefined;

			if ( re.query.pages[ re.query.pageids[ 0 ] ].extract === '' ){
				return false;
			}

			var $a,
				page = re.query.pages[ re.query.pageids[ 0 ] ],
				$contentbox = $( '<div>' )
					.addClass( 'mwe-popups-extract' )
					.text( page.extract ),
				thumbnail = page.thumbnail,
				tall = thumbnail && thumbnail.height > thumbnail.width,
				$thumbnail = createThumbnail( thumbnail, tall ),
				timestamp = new Date( page.revisions[ 0 ].timestamp ),
				timediff = new Date() - timestamp,
				oneDay = 1000 * 60 * 60 * 24,
				timestampclass = ( timediff < oneDay ) ?
					'mwe-popups-timestamp-recent' :
					'mwe-popups-timestamp-older',
				$timestamp = $( '<div>' )
					.addClass( timestampclass )
					.append(
						$( '<span>' ).text( mw.message( 'popups-last-edited',
							moment( timestamp ).fromNow() ).text() )
				);

			$a = $( '<a>' )
				.append( $thumbnail, $contentbox, $timestamp )
				.attr( 'href', href )
				.on( 'click', logClick );

			cache[ href ] = {
				box: $a,
				thumbnail: thumbnail,
				tall: tall
			};

			deferred.resolve();
		} );

		return deferred.promise();
	}

	/**
	 * @method createSVGTag
	 * Use createElementNS to create the svg:image tag as jQuery
	 * uses createElement instead. Some browsers map the `image` tag
	 * to `img` tag, thus an `svg:image` is required.
	 * @param {String} tag
	 * @return {Object}
	 */
	function createSVGTag( tag ) {
		return document.createElementNS( 'http://www.w3.org/2000/svg', tag );
	}

	/**
	 * @method createThumbnail
	 * Returns a thumbnail object based on the ratio of the image
	 * Uses an SVG image where available to add the triangle/pokey
	 * mask on the image. Crops and resizes the SVG image so that
	 * is fits inside a rectangle of a particular size.
	 * @param {Object} thumbnail
	 * @param {boolean} tall
	 * @return {Object} jQuery DOM element of the thumbnail
	 */
	function createThumbnail( thumbnail, tall ) {
		if ( !thumbnail ) {
			return $( '<span>' );
		}

		var $thumbnailSVGImage, $thumbnail;

		if ( tall ) {
			if ( supportsSVG ) {
				$thumbnailSVGImage = $( createSVGTag( 'image' ) );
				$thumbnailSVGImage
					.addClass( 'mwe-popups-is-not-tall' )
					.attr( {
						'xlink:href': thumbnail.source,
						x: ( thumbnail.width > SIZES.portraitImage.w ) ?
							( ( thumbnail.width - SIZES.portraitImage.w ) / -2 ) :
							( SIZES.portraitImage.w - thumbnail.width ),
						y: ( thumbnail.height > SIZES.portraitImage.h ) ?
							( ( thumbnail.height - SIZES.portraitImage.h ) / -2 ) :
							0,
						width: thumbnail.width,
						height: thumbnail.height
					} );

				$thumbnail = $( '<svg>' )
					.attr( {
						xmlns: 'http://www.w3.org/2000/svg',
						width: SIZES.portraitImage.w,
						height: SIZES.portraitImage.h
					} )
					.append( $thumbnailSVGImage );
			} else {
				$thumbnail = $( '<div>' )
					.addClass( 'mwe-popups-is-tall' )
					.css( 'background-image', 'url(' + thumbnail.source + ')' );
			}
		} else {
			if ( supportsSVG ) {
				$thumbnailSVGImage = $( createSVGTag( 'image' ) );
				$thumbnailSVGImage
					.addClass( 'mwe-popups-is-not-tall' )
					.attr( {
						'xlink:href': thumbnail.source,
						'clip-path': 'url(#mwe-popups-mask)',
						x: 0,
						y: ( thumbnail.height > SIZES.landscapeImage.h ) ?
							( ( thumbnail.height - SIZES.landscapeImage.h ) / -2 ) :
							0,
						width: thumbnail.width,
						height: thumbnail.height
					} );

				$thumbnail = $( '<svg>' )
					.attr( {
						xmlns: 'http://www.w3.org/2000/svg',
						width: SIZES.landscapeImage.w + 3,
						height: ( thumbnail.height > SIZES.landscapeImage.h ) ?
							SIZES.landscapeImage.h :
							thumbnail.height
					} )
					.append( $thumbnailSVGImage );
			} else {
				$thumbnail = $( '<div>' )
					.addClass( 'mwe-popups-is-not-tall' )
					.css( 'background-image', 'url(' + thumbnail.source + ')' );
			}
		}

		return $thumbnail;
	}

	/**
	 * @method createBox
	 * Looks into the `cache` and uses the href to render the popup
	 * and offsets it to the link. Rebinds the `mouseleave` event
	 * for the anchor element to `leaveActive`.
	 * @param {String} href
	 * @param {Object} $el
	 * @param {Object} event
	 */
	function createBox( href, $el, event ) {
		var
			bar = cache[ href ],
			offsetTop = ( event.pageY ) ?
				event.pageY + 20 :
				$el.offset().top + $el.height() + 9,
			offsetLeft = ( event.pageX ) ?
				event.pageX :
				$el.offset().left,
			flipped = false;

		elTime = mw.now();
		elAction = 'dismissed';

		if ( bar.thumbnail === undefined ) {
			bar.thumbnail = false;
		}

		if ( bar.tall === undefined ) {
			bar.tall = false;
		}

		if ( offsetLeft > ( $( window ).width() / 2 ) ) {
			offsetLeft += ( !event.pageX ) ? $el.width() : 0;
			offsetLeft -= ( !bar.tall ) ? SIZES.portraitPopupWidth : SIZES.landscapePopupWidth;
			flipped = true;
		}

		if ( event.pageX ) {
			offsetLeft += ( flipped ) ? 20 : -20; // compensating the position of the triangle
		}

		$box
			.children()
			.detach()
			// avoid .empty() to keep event handlers
			.end()
			.removeClass( 'mwe-popups-is-tall mwe-popups-is-not-tall mwe-popups-no-image-tri mwe-popups-image-tri flipped' )
			.toggleClass( 'flipped', flipped )
			// Add border triangle if there is no image or its landscape
			.toggleClass( 'mwe-popups-no-image-tri', ( !bar.thumbnail || bar.tall ) )
			// If theres an image and the popup is portrait do the SVG stuff
			.toggleClass( 'mwe-popups-image-tri', ( bar.thumbnail && !bar.tall ) )
			.addClass( bar.tall ? 'mwe-popups-is-tall' : 'mwe-popups-is-not-tall' )
			.css( {
				top: offsetTop,
				left: offsetLeft
			} )
			.append( bar.box )
			.attr( 'aria-hidden', 'false' )
			.show()
			.removeClass( 'mwe-popups-fade-out mwe-popups-fade-in' )
			.addClass( 'mwe-popups-fade-in' )
			// Hack to 'refresh' the SVG and thus display it
			// Elements get added to the DOM and not to the screen because of different namespaces of HTML and SVG
			// More information and workarounds here - http://stackoverflow.com/a/13654655/366138
			.html( $box.html() );

		if ( flipped && bar.thumbnail ) {
			if ( !bar.tall ) {
				$box.find( 'image' )[ 0 ].setAttribute( 'clip-path', 'url(#mwe-popups-mask-flip)' );
			} else {
				$box
					.removeClass( 'mwe-popups-no-image-tri' )
					.find( 'image' )[ 0 ].setAttribute( 'clip-path', 'url(#mwe-popups-landscape-mask)' );
			}
		}

		$el
			.off( 'mouseleave blur', leaveInactive )
			.on( 'mouseleave blur', leaveActive );

		$( document ).on( 'keydown', closeOnEsc );
	}

	/**
	 * @method closeOnEsc
	 * Use escape to close popup
	 */
	function closeOnEsc( e ) {
		if ( e.keyCode === 27 ) {
			closeBox();
		}
	}

	/**
	 * @method leaveActive
	 * Closes the box after a delay
	 * Delay to give enough time for the user to move the pointer from
	 * the link to the popup box. Also avoids closing the popup by accident.
	 */
	function leaveActive() {
		closeTimer = setTimeout( closeBox, POPUP_CLOSE_DELAY );
	}

	/**
	 * @method leaveInactive
	 * Unbinds events on the anchor tag and aborts AJAX request.
	 */
	function leaveInactive() {
		$( currentLink ).off( 'mouseleave', leaveInactive );
		if ( openTimer ) {
			openTimer.abort();
		}
		if ( curRequest ) {
			curRequest.abort();
		}
		currentLink = openTimer = curRequest = undefined;
	}

	/**
	 * @method closeBox
	 * Removes the hover class from the link and unbinds events
	 * Hides the popup, clears timers and sets it and the
	 * `currentLink` to undefined.
	 */
	function closeBox() {
		elDuration = mw.now() - elTime;

		$( currentLink ).removeClass( 'mwe-popups-anchor-hover' ).off( 'mouseleave', leaveActive );

		$box
			.removeClass( 'mwe-popups-fade-out mwe-popups-fade-in' )
			.addClass( 'mwe-popups-fade-out' ); // Removed and added to trigger animation

		setTimeout( function () {
			if ( $box.hasClass( 'mwe-popups-fade-out' ) ) {
				$box
					.attr( 'aria-hidden', 'true' )
					.hide()
					.removeClass( 'mwe-popups-fade-out' );
			}
		}, 150 ); // Matches 0.15s in the .mwe-popups-fade-out class

		if ( closeTimer ) {
			clearTimeout( closeTimer );
		}

		$( document ).off( 'keydown', closeOnEsc );

		logEvent();
		currentLink = closeTimer = undefined;
	}

	/**
	 * @method logClick
	 * Logs different actions such as meta and shift click on the popup.
	 * Is bound to the `click` event.
	 * @param {Object} e
	 */
	function logClick( e ) {
		if ( e.which === 2 ) { // middle click
			elAction = 'opened in new tab';
		} else if ( e.which === 1 ) {
			if ( e.ctrlKey || e.metaKey ) {
				elAction = 'opened in new tab';
			} else if ( e.shiftKey ) {
				elAction = 'opened in new window';
			} else {
				elAction = 'opened in same tab';
				elDuration = mw.now() - elTime;
				logEvent( this.href );
				e.preventDefault();
			}
		}
	}

	/**
	 * @method logEvent
	 * Logs the Popup event as defined in the following schema -
	 * https://meta.wikimedia.org/wiki/Schema:Popups
	 * If `href` is passed it redirects to that location after the event is logged.
	 * @param {string} href
	 */
	function logEvent( href ) {
		if ( typeof mw.eventLog !== 'function' ) {
			return false;
		}

		var dfd = $.Deferred(),
			event = {
				duration: Math.round( elDuration ),
				action: elAction
			};

		if ( elSessionId !== null ) {
			event.sessionId = elSessionId;
		}

		if ( href ) {
			dfd.always( function () {
				location.href = href;
			} );
		}

		mw.eventLog.logEvent( 'Popups', event ).then( dfd.resolve, dfd.reject );
		setTimeout( dfd.reject, 1000 );
		elTime = elDuration = elAction = undefined;
	}

	/**
	 * @method getSessionId
	 * Generates a unique sessionId or pulls an existing one from localStorage
	 * @return {string} sessionId
	 */
	function getSessionId() {
		var sessionId = null;
		try {
			sessionId = localStorage.getItem( 'popupsSessionId' );
			if ( sessionId === null ) {
				sessionId = mw.user.generateRandomSessionId();
				localStorage.setItem( 'popupsSessionId', sessionId );
			}
		} catch ( e ) {}
		return sessionId;
	}
	elSessionId = getSessionId();

	// Prevent popups from showing up when the mouse cursor accidentally
	// ends up hovering a link after scrolling
	$( window ).on( 'scroll', function () {
		scrolled = true;
	} );
	$( window ).on( 'mousemove', function () {
		scrolled = false;
	} );

	$( function () {
		// Container for the popup
		$box = $( '<div>' )
			.attr( 'role', 'tooltip' )
			.addClass( 'mwe-popups' )
			.on( {
				mouseleave: leaveActive,
				mouseenter: function () {
					if ( closeTimer ) {
						clearTimeout( closeTimer );
					}
				}
			} )
			.appendTo( document.body );

		// SVG for masking and creating the triangle/pokey
		if ( supportsSVG ) {
			$svg = $( '<div>' )
				.attr( 'id', 'mwe-popups-svg' )
				.appendTo( document.body )
				.html(
					'<svg width="0" height="0">' +
						'<defs>' +
							'<clippath id="mwe-popups-mask">' +
								'<polygon points="0 8, 10 8, 18 0, 26 8, 1000 8, 1000 1000, 0 1000"/>' +
							'</clippath>' +
							'<clippath id="mwe-popups-mask-flip">' +
								'<polygon points="0 8, 274 8, 282 0, 290 8, 1000 8, 1000 1000, 0 1000"/>' +
							'</clippath>' +
							'<clippath id="mwe-popups-landscape-mask">' +
								'<polygon points="0 8, 174 8, 182 0, 190 8, 1000 8, 1000 1000, 0 1000"/>' +
							'</clippath>' +
						'</defs>' +
					'</svg>'
				);
		}
	} );

	mw.hook( 'wikipage.content' ).add( function ( $content ) {
		// Remove title attribute to remove the default yellow tooltip
		// Put the title back after the hover
		$content.find( 'a:not(.extiw):not(.image):not(.new):not(.internal):not([title=""])' )
			.on( 'mouseenter focus', function () {
				$( this )
					.attr( 'data-original-title', $( this ).attr( 'title' ) )
					.attr( 'title', '' );
			} )
			.on( 'mouseleave blur', function () {
				$( this )
					.attr( 'title', $( this ).attr( 'data-original-title' ) )
					.attr( 'data-original-title', '' );
			} );

		$content.find( 'a' ).on( 'mouseenter focus', function ( event ) {
			var $this = $( this ),
				href = $this.attr( 'href' ),
				title = $this.attr( 'data-original-title' );

			// If a popup for the following link can't be shown
			if (
				scrolled ||
				!title ||
				$this.hasClass( 'extiw' ) ||
				$this.hasClass( 'image' ) ||
				$this.hasClass( 'new' ) ||
				$this.hasClass( 'internal' ) ||
				href.indexOf( '?' ) !== -1 ||
				href.indexOf( location.origin + location.pathname + '#' ) === 0
			) {
				return;
			}

			// This will happen when the mouse goes from the popup box back to the
			// anchor tag. In such a case, the timer to close the box is cleared.
			if ( currentLink === this ) {
				clearTimeout( closeTimer );
				return;
			}

			// If the mouse moves to another link (we already check if its the same
			// link in the previous condition), then close the popup.
			if ( currentLink ) {
				closeBox();
			}

			currentLink = this;
			$this.on( 'mouseleave blur', leaveInactive );

			// Delay to avoid triggering the popup and AJAX requests on accidental
			// hovers (likes ones during srcolling or moving the pointer elsewhere).
			if ( cache[ href ] ) {
				// If we have this popup cached, just wait normally
				openTimer = timeoutPromise( POPUP_DELAY ).done( function () {
					createBox( href, $this, event );
				} );
			} else {
				// Otherwise wait a little before we start loading the data (to avoid unnecessary requests),
				// then wait normally before actually displaying the output
				openTimer = timeoutPromise( API_DELAY ).done( function () {
					openTimer = timeoutPromise( POPUP_DELAY - API_DELAY );
					$.when(
						sendRequest( href, title ),
						openTimer
					).done( function () {
						// Data is cached now
						createBox( href, $this, event );
					} );
				} );
			}
		} );
	} );

}( jQuery, mediaWiki ) );