( function ( mw, $ ) {
	/**
	 * Module containing the RevisionSlider tutorial
	 *
	 * @param {Object} config
	 * @constructor
	 */
	var HelpDialog = function ( config ) {
		HelpDialog.super.call( this, config );
	};

	OO.inheritClass( HelpDialog, OO.ui.ProcessDialog );

	HelpDialog.static.title = mw.msg( 'revisionslider-tutorial' );
	HelpDialog.static.name = 'revisionslider-tutorial';
	HelpDialog.static.actions = [
		{
			action: 'next',
			label: mw.msg( 'revisionslider-next-dialog' ),
			flags: [ 'primary', 'progressive' ],
			modes: [ 'initial', 'middle' ],
			classes: [ 'mw-revslider-help-next' ]
		},
		{ action: 'previous', flags: 'safe', label: mw.msg( 'revisionslider-previous-dialog' ), modes: [ 'middle', 'last' ], classes: [ 'mw-revslider-help-previous' ] },
		{ label: mw.msg( 'revisionslider-close-dialog' ), flags: 'safe', modes: 'initial', classes: [ 'mw-revslider-help-close-start' ] },
		{ label: mw.msg( 'revisionslider-close-dialog' ), flags: 'primary', modes: 'last', classes: [ 'mw-revslider-help-close-end' ] }
	];

	$.extend( HelpDialog.prototype, {
		/**
		 * @type {OO.ui.PanelLayout[]}
		 */
		slides: [],

		/**
		 * @type {number}
		 */
		slidePointer: 0,

		initialize: function () {
			HelpDialog.super.prototype.initialize.call( this );

			this.slides = [ this.getSlide1(), this.getSlide2(), this.getSlide3(), this.getSlide4() ];

			this.stackLayout = new OO.ui.StackLayout( {
				items: this.slides
			} );

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

		/**
		 * @return {OO.ui.PanelLayout}
		 */
		getSlide1: function () {
			var slide = new OO.ui.PanelLayout( { $: this.$, padded: true, expanded: false } );

			slide.$element
				.append(
					$( '<div>' ).addClass( 'mw-revslider-help-dialog-image-landscape mw-revslider-help-dialog-slide-1' )
				)
				.append(
					$( '<p>' ).addClass( 'mw-revslider-help-dialog-text' )
						.html( mw.message( 'revisionslider-help-dialog-slide1' ).parse() )
				);

			slide.$element.find( 'a' ).attr( 'target', '_blank' );

			return slide;
		},

		/**
		 * @return {OO.ui.PanelLayout}
		 */
		getSlide2: function () {
			var slide = new OO.ui.PanelLayout( { $: this.$, padded: true, expanded: false } );

			slide.$element
				.append( $( '<div>' ).addClass( 'mw-revslider-help-dialog-image-landscape mw-revslider-help-dialog-slide-2' ) )
				.append(
					$( '<p>' ).addClass( 'mw-revslider-help-dialog-text' )
						.text( mw.msg( 'revisionslider-help-dialog-slide2' ) )
				);

			return slide;
		},

		/**
		 * @return {OO.ui.PanelLayout}
		 */
		getSlide3: function () {
			var slide = new OO.ui.PanelLayout( { $: this.$, padded: true, expanded: false } ),
				msgKey = 'revisionslider-help-dialog-slide3',
				className = 'mw-revslider-help-dialog-slide-3';

			if ( mw.config.get( 'extRevisionSliderAlternateSlider' ) ) {
				msgKey = 'revisionslider-help-dialog-slide3a';
				className = 'mw-revslider-help-dialog-slide-3a';
			}

			slide.$element
				.append( $( '<div>' ).addClass( 'mw-revslider-help-dialog-image-portrait ' + className + ' mw-revslider-column-image' ) )
				.append(
					$( '<div>' ).addClass( 'mw-revslider-column-text mw-revslider-help-dialog-text' )
						.html( mw.message( msgKey ).parse() )
				)
				.append( $( '<div>' ).css( 'clear', 'both' ) );

			return slide;
		},

		/**
		 * @return {OO.ui.PanelLayout}
		 */
		getSlide4: function () {
			var slide = new OO.ui.PanelLayout( { $: this.$, padded: true, expanded: false } ),
				className = 'mw-revslider-help-dialog-slide-4';

			if ( mw.config.get( 'extRevisionSliderAlternateSlider' ) ) {
				className = 'mw-revslider-help-dialog-slide-4a';
			}

			slide.$element
				.append( $( '<div>' ).addClass( 'mw-revslider-help-dialog-image-landscape ' + className ) )
				.append(
					$( '<p>' ).addClass( 'mw-revslider-help-dialog-text' )
						.text( mw.msg( 'revisionslider-help-dialog-slide4' ) )
				);

			return slide;
		},

		/**
		 * @param {string} action
		 * @return {OO.ui.Process}
		 */
		getActionProcess: function ( action ) {
			if ( action === 'next' ) {
				this.stackLayout.setItem( this.slides[ ++this.slidePointer ] );
			} else if ( action === 'previous' ) {
				this.stackLayout.setItem( this.slides[ --this.slidePointer ] );
			}

			if ( this.slidePointer === 0 ) {
				this.actions.setMode( 'initial' );
			} else if ( this.slidePointer === this.slides.length - 1 ) {
				this.actions.setMode( 'last' );
			} else {
				this.actions.setMode( 'middle' );
			}

			this.stackLayout.$element.closest( '.oo-ui-window-frame' ).css( 'height', this.getContentHeight() + 'px' );
			return HelpDialog.super.prototype.getActionProcess.call( this, action );
		},

		getSetupProcess: function ( data ) {
			return HelpDialog.super.prototype.getSetupProcess.call( this, data )
				.next( function () {
					this.actions.setMode( 'initial' );
				}, this );
		},

		/**
		 * Needed to set the initial height of the dialog
		 *
		 * @return {number}
		 */
		getBodyHeight: function () {
			return this.slides[ this.slidePointer ].$element.outerHeight( true );
		}
	} );

	/**
	 * Initializes the help dialog
	 */
	HelpDialog.init = function () {
		var windowManager = new OO.ui.WindowManager(),
			dialogue;

		$( 'body' )
			.append( windowManager.$element )
			.click( function ( event ) {
				if ( $( event.target ).hasClass( 'mw-revslider-help-dialog' ) ) {
					HelpDialog.hide();
				}
			} );

		HelpDialog.show = function () {
			dialogue = new HelpDialog( { size: 'medium', classes: [ 'mw-revslider-help-dialog' ] } );
			windowManager.addWindows( [ dialogue ] );
			windowManager.openWindow( dialogue );
		};

		HelpDialog.hide = function () {
			if ( windowManager.hasWindow( dialogue ) ) {
				windowManager.closeWindow( dialogue );
			}
		};
	};

	mw.libs.revisionSlider = mw.libs.revisionSlider || {};
	mw.libs.revisionSlider.HelpDialog = HelpDialog;
}( mediaWiki, jQuery ) );