( function ( $ ) {
	var jmpressOpts = {
		fullscreen: false,
		hash: { use: false },
		mouse: { clickSelects: false },
		keyboard: { use: true },
		animation: { transitionDuration: '1s' },
		presentationMode: false,
		stepSelector: '.step',
		duration: {
			defaultValue: 0,
		},
	};

	/**
	 * Presentation constructor
	 */
	function Presentation( wrapper ) {
		var _self, duration, new_css, ie_regex, matches;

		_self = this;

		_self.wrapper = $( wrapper ); // The wrapper for toggling fullscreen
		_self.slideshow = $( '.presentation', wrapper ); // Holds the slides for jmpress
		_self.navLeft = $( '.nav-arrow-left', wrapper );
		_self.navRight = $( '.nav-arrow-right', wrapper );
		_self.expandButton = $( '.nav-fullscreen-button', wrapper );
		_self.overlay = $( '.autoplay-overlay', wrapper );
		_self.fullscreen = false;
		_self.autoPlaying = false;
		_self.autoplayTime = parseFloat( _self.slideshow.attr( 'data-autoplay' ), 10 ) || 0;

		// The wrapper is scaled to the contents' size so that its border wraps tightly
		_self.wrapper.css( {
			width: _self.slideshow.width(),
			height: _self.slideshow.height(),
		} );

		duration = _self.slideshow.attr( 'duration' ) || '1s';
		jmpressOpts.animation.transitionDuration = duration;

		// Compensate for transition times
		if ( _self.autoplayTime ) {
			_self.autoplayTime += parseFloat( duration, 10 ) * 1000;
		}

		// Set the opacity transition duration
		// as it is delegated by css and not jmpress
		duration = 'opacity ' + duration;
		new_css = {
			width: _self.slideshow.width(),
			height: _self.slideshow.height(),
			'-webkit-transition': duration,
			'-moz-transition': duration,
			'-ms-transition': duration,
			'-o-transition': duration,
			transition: duration,
		};

		$( '.step', _self.slideshow ).each( function ( i, step ) {
			$( step ).css( new_css );
		} );

		// Apply attribute to allow fading individual bullets here,
		// otherwise wp_kses will strip the attribute out
		$( '.step.fadebullets li', _self.slideshow ).each( function ( i, step ) {
			$( step ).attr( 'data-jmpress', 'fade' );
		} );

		// Register resizing to window when fullscreen
		$( window ).resize( function () {
			if ( _self.fullscreen ) {
				_self.resizePresentation();
			}
		} );

		// Register the nav bars to move the slides
		_self.navLeft.on( 'click', function () {
			_self.slideshow.jmpress( 'prev' );
			_self.overlay.css( 'opacity', 0 );
			return false;
		} );

		_self.navRight.on( 'click', function () {
			_self.slideshow.jmpress( 'next' );
			_self.overlay.css( 'opacity', 0 );
			return false;
		} );

		_self.slideshow.on( 'click', function () {
			_self.setAutoplay( true );
			return false;
		} );

		_self.slideshow.on( 'focusout', function () {
			_self.setAutoplay( false );
		} );

		// Register toggling fullscreen except for IE 9 or lower
		ie_regex = /MSIE\s(\d+)\.\d+/;
		matches = ie_regex.exec( navigator.userAgent );

		if ( matches && parseInt( matches[ 1 ], 10 ) < 10 ) {
			_self.expandButton.remove();
			_self.expandButton = null;
		} else {
			_self.expandButton.on( 'click', function () {
				_self.setFullscreen( ! _self.fullscreen );
				return false;
			} );
		}

		// Register ESC key to exit fullscreen
		$( window ).on( 'keydown', function ( event ) {
			if ( event.which === 27 ) {
				_self.setFullscreen( false );
			}
		} );

		// Start the presentation
		_self.slideshow.jmpress( jmpressOpts );

		// Make content visible and remove error message on jmpress success
		if ( _self.slideshow.jmpress( 'initialized' ) ) {
			_self.slideshow.css( 'display', '' );
			_self.overlay.css( 'display', '' );
			$( '.not-supported-msg', _self.wrapper ).remove();
		}

		// A bug in Firefox causes issues with the nav arrows appearing
		// on hover in presentation mode. Explicitly disabling fullscreen
		// on init seems to fix the issue
		_self.setFullscreen( false );
	}

	$.extend( Presentation.prototype, {
		resizePresentation: function () {
			var scale, duration, settings, new_css, widthScale, heightScale;

			// Set the animation duration to 0 during resizing
			// so that there isn't an animation delay when scaling
			// up the slide contents
			settings = this.slideshow.jmpress( 'settings' );
			duration = settings.animation.transitionDuration;

			settings.animation.transitionDuration = '0s';
			this.slideshow.jmpress( 'reselect' );

			scale = 1;
			new_css = {
				top: 0,
				left: 0,
				zoom: 1,
			};

			// Expand the presentation to fill the lesser of the max width or height
			// This avoids content moving past the window for certain window sizes
			if ( this.fullscreen ) {
				widthScale = $( window ).width() / this.slideshow.width();
				heightScale = $( window ).height() / this.slideshow.height();

				scale = Math.min( widthScale, heightScale );

				new_css.top = ( $( window ).height() - scale * this.slideshow.height() ) / 2;
				new_css.left = ( $( window ).width() - scale * this.slideshow.width() ) / 2;
			}

			// Firefox does not support the zoom property; IE does, but it does not work
			// well like in webkit, so we manually transform and position the slideshow
			if ( this.slideshow.css( '-moz-transform' ) || this.slideshow.css( '-ms-transform' ) ) {
				// Firefox keeps the center of the element in place and expands outward
				// so we must shift everything to compensate
				new_css.top += ( ( scale - 1 ) * this.slideshow.height() ) / 2;
				new_css.left += ( ( scale - 1 ) * this.slideshow.width() ) / 2;

				scale = 'scale(' + scale + ')';

				$.extend( new_css, {
					'-moz-transform': scale,
					'-ms-transform': scale,
					transform: scale,
				} );
			} else {
				// webkit scales everything with zoom so we need to offset the right amount
				// so that the content is vertically centered after scaling effects
				new_css.top /= scale;
				new_css.left /= scale;
				new_css.zoom = scale;
			}

			this.slideshow.css( new_css );

			settings.animation.transitionDuration = duration;
			this.slideshow.jmpress( 'reselect' );
		},

		setFullscreen: function ( on ) {
			this.fullscreen = on;
			this.setAutoplay( false );

			// Save the scroll positions before going into fullscreen mode
			if ( on ) {
				this.scrollVert = $( window ).scrollTop();
				this.scrollHoriz = $( window ).scrollLeft();

				// Chrome Bug: Force scroll to be at top
				// otherwise the presentation can end up offscreen
				$( window ).scrollTop( 0 );
				$( window ).scrollLeft( 0 );
			}

			$( 'html' ).toggleClass( 'presentation-global-fullscreen', on );
			$( 'body' ).toggleClass( 'presentation-global-fullscreen', on );

			this.wrapper.toggleClass( 'presentation-wrapper-fullscreen', on );

			this.wrapper.parents().each( function ( i, e ) {
				$( e ).toggleClass( 'presentation-wrapper-fullscreen-parent', on );
			} );

			this.resizePresentation();

			// Reset the scroll positions after exiting fullscreen mode
			if ( ! on ) {
				$( window ).scrollTop( this.scrollVert );
				$( window ).scrollLeft( this.scrollHoriz );
			}
		},

		setAutoplay: function ( on ) {
			var _self = this,
				newAutoplayTime;

			if ( _self.autoPlaying === on ) {
				return;
			}

			newAutoplayTime = on && _self.autoplayTime > 0 ? _self.autoplayTime : 0;
			_self.slideshow.jmpress( 'settings' ).duration.defaultValue = newAutoplayTime;

			// Move to the next slide when activating autoplay
			if ( newAutoplayTime ) {
				_self.slideshow.jmpress( 'next' );
				_self.overlay.css( 'opacity', 0 );
			} else {
				_self.slideshow.jmpress( 'reselect' );
			}

			_self.autoPlaying = on;
		},
	} );

	addEventListener( 'DOMContentLoaded', () => {
		document.querySelectorAll( '.presentation-wrapper' ).forEach( el => {
			new Presentation( el );
		} );
	} );
} )( jQuery );
