/* global screenReaderText */

/**

 * Theme functions file.

 *

 * Contains handlers for navigation and widget area.

 */

( function( $ ) {

	var $body, $window, $sidebar, adminbarOffset, top = false,

	    bottom = false, windowWidth, windowHeight, lastWindowPos = 0,

	    topOffset = 0, bodyHeight, sidebarHeight, resizeTimer,

		secondary, button;

	// Add dropdown toggle that display child menu items.

	$( '.main-navigation .menu-item-has-children > a' ).after( '<button class="dropdown-toggle" aria-expanded="false">' + screenReaderText.expand + '</button>' );

	// Toggle buttons and submenu items with active children menu items.

	$( '.main-navigation .current-menu-ancestor > button' ).addClass( 'toggle-on' );

	$( '.main-navigation .current-menu-ancestor > .sub-menu' ).addClass( 'toggled-on' );

	$( '.dropdown-toggle' ).click( function( e ) {

		var _this = $( this );

		e.preventDefault();

		_this.toggleClass( 'toggle-on' );

		_this.next( '.children, .sub-menu' ).toggleClass( 'toggled-on' );

		_this.attr( 'aria-expanded', _this.attr( 'aria-expanded' ) === 'false' ? 'true' : 'false' );

		_this.html( _this.html() === screenReaderText.expand ? screenReaderText.collapse : screenReaderText.expand );

	} );

	secondary = $( '#secondary' );

	button = $( '.site-branding' ).find( '.secondary-toggle' );

	// Enable menu toggle for small screens.

	( function() {

		var menu, widgets, social;

		if ( ! secondary || ! button ) {

			return;

		}

		// Hide button if there are no widgets and the menus are missing or empty.

		menu    = secondary.find( '.nav-menu' );

		widgets = secondary.find( '#widget-area' );

		social  = secondary.find( '#social-navigation' );

		if ( ! widgets.length && ! social.length && ( ! menu || ! menu.children().length ) ) {

			button.hide();

			return;

		}

		button.on( 'click.twentyfifteen', function() {

			secondary.toggleClass( 'toggled-on' );

			secondary.trigger( 'resize' );

			$( this ).toggleClass( 'toggled-on' );

			if ( $( this, secondary ).hasClass( 'toggled-on' ) ) {

				$( this ).attr( 'aria-expanded', 'true' );

				secondary.attr( 'aria-expanded', 'true' );

			} else {

				$( this ).attr( 'aria-expanded', 'false' );

				secondary.attr( 'aria-expanded', 'false' );

			}

		} );

	} )();

	/**

	 * @summary Add or remove ARIA attributes.

	 * Uses jQuery's width() function to determine the size of the window and add

	 * the default ARIA attributes for the menu toggle if it's visible.

	 * @since Twenty Fifteen 1.1

	 */

	function onResizeARIA() {

		if ( 955 > $window.width() ) {

			button.attr( 'aria-expanded', 'false' );

			secondary.attr( 'aria-expanded', 'false' );

			button.attr( 'aria-controls', 'secondary' );

		} else {

			button.removeAttr( 'aria-expanded' );

			secondary.removeAttr( 'aria-expanded' );

			button.removeAttr( 'aria-controls' );

		}

	}

	// Sidebar scrolling.

	function resize() {

		windowWidth = $window.width();

		if ( 955 > windowWidth ) {

			top = bottom = false;

			$sidebar.removeAttr( 'style' );

		}

	}

	function scroll() {

		var windowPos = $window.scrollTop();

		if ( 955 > windowWidth ) {

			return;

		}

		sidebarHeight = $sidebar.height();

		windowHeight  = $window.height();

		bodyHeight    = $body.height();

		if ( sidebarHeight + adminbarOffset > windowHeight ) {

			if ( windowPos > lastWindowPos ) {

				if ( top ) {

					top = false;

					topOffset = ( $sidebar.offset().top > 0 ) ? $sidebar.offset().top - adminbarOffset : 0;

					$sidebar.attr( 'style', 'top: ' + topOffset + 'px;' );

				} else if ( ! bottom && windowPos + windowHeight > sidebarHeight + $sidebar.offset().top && sidebarHeight + adminbarOffset < bodyHeight ) {

					bottom = true;

					$sidebar.attr( 'style', 'position: fixed; bottom: 0;' );

				}

			} else if ( windowPos < lastWindowPos ) {

				if ( bottom ) {

					bottom = false;

					topOffset = ( $sidebar.offset().top > 0 ) ? $sidebar.offset().top - adminbarOffset : 0;

					$sidebar.attr( 'style', 'top: ' + topOffset + 'px;' );

				} else if ( ! top && windowPos + adminbarOffset < $sidebar.offset().top ) {

					top = true;

					$sidebar.attr( 'style', 'position: fixed;' );

				}

			} else {

				top = bottom = false;

				topOffset = ( $sidebar.offset().top > 0 ) ? $sidebar.offset().top - adminbarOffset : 0;

				$sidebar.attr( 'style', 'top: ' + topOffset + 'px;' );

			}

		} else if ( ! top ) {

			top = true;

			$sidebar.attr( 'style', 'position: fixed;' );

		}

		lastWindowPos = windowPos;

	}

	function resizeAndScroll() {

		resize();

		scroll();

	}

	$( document ).ready( function() {

		$body          = $( document.body );

		$window        = $( window );

		$sidebar       = $( '#sidebar' ).first();

		adminbarOffset = $body.is( '.admin-bar' ) ? $( '#wpadminbar' ).height() : 0;

		$window

			.on( 'scroll.twentyfifteen', scroll )

			.on( 'load.twentyfifteen', onResizeARIA )

			.on( 'resize.twentyfifteen', function() {

				clearTimeout( resizeTimer );

				resizeTimer = setTimeout( resizeAndScroll, 500 );

				onResizeARIA();

			} );

		$sidebar.on( 'click.twentyfifteen keydown.twentyfifteen', 'button', resizeAndScroll );

		resizeAndScroll();

		for ( var i = 1; i < 6; i++ ) {

			setTimeout( resizeAndScroll, 100 * i );

		}

	} );

} )( jQuery );