/*

 * Script run inside a Customizer preview frame.

 */

(function( exports, $ ){

	var api = wp.customize,

		debounce,

		currentHistoryState = {};

	/*

	 * Capture the state that is passed into history.replaceState() and history.pushState()

	 * and also which is returned in the popstate event so that when the changeset_uuid

	 * gets updated when transitioning to a new changeset there the current state will

	 * be supplied in the call to history.replaceState().

	 */

	( function( history ) {

		var injectUrlWithState;

		if ( ! history.replaceState ) {

			return;

		}

		/**

		 * Amend the supplied URL with the customized state.

		 *

		 * @since 4.7.0

		 * @access private

		 *

		 * @param {string} url URL.

		 * @returns {string} URL with customized state.

		 */

		injectUrlWithState = function( url ) {

			var urlParser, oldQueryParams, newQueryParams;

			urlParser = document.createElement( 'a' );

			urlParser.href = url;

			oldQueryParams = api.utils.parseQueryString( location.search.substr( 1 ) );

			newQueryParams = api.utils.parseQueryString( urlParser.search.substr( 1 ) );

			newQueryParams.customize_changeset_uuid = oldQueryParams.customize_changeset_uuid;

			if ( oldQueryParams.customize_autosaved ) {

				newQueryParams.customize_autosaved = 'on';

			}

			if ( oldQueryParams.customize_theme ) {

				newQueryParams.customize_theme = oldQueryParams.customize_theme;

			}

			if ( oldQueryParams.customize_messenger_channel ) {

				newQueryParams.customize_messenger_channel = oldQueryParams.customize_messenger_channel;

			}

			urlParser.search = $.param( newQueryParams );

			return urlParser.href;

		};

		history.replaceState = ( function( nativeReplaceState ) {

			return function historyReplaceState( data, title, url ) {

				currentHistoryState = data;

				return nativeReplaceState.call( history, data, title, 'string' === typeof url && url.length > 0 ? injectUrlWithState( url ) : url );

			};

		} )( history.replaceState );

		history.pushState = ( function( nativePushState ) {

			return function historyPushState( data, title, url ) {

				currentHistoryState = data;

				return nativePushState.call( history, data, title, 'string' === typeof url && url.length > 0 ? injectUrlWithState( url ) : url );

			};

		} )( history.pushState );

		window.addEventListener( 'popstate', function( event ) {

			currentHistoryState = event.state;

		} );

	}( history ) );

	/**

	 * Returns a debounced version of the function.

	 *

	 * @todo Require Underscore.js for this file and retire this.

	 */

	debounce = function( fn, delay, context ) {

		var timeout;

		return function() {

			var args = arguments;

			context = context || this;

			clearTimeout( timeout );

			timeout = setTimeout( function() {

				timeout = null;

				fn.apply( context, args );

			}, delay );

		};

	};

	/**

	 * @memberOf wp.customize

	 * @alias wp.customize.Preview

	 *

	 * @constructor

	 * @augments wp.customize.Messenger

	 * @augments wp.customize.Class

	 * @mixes wp.customize.Events

	 */

	api.Preview = api.Messenger.extend(/** @lends wp.customize.Preview.prototype */{

		/**

		 * @param {object} params  - Parameters to configure the messenger.

		 * @param {object} options - Extend any instance parameter or method with this object.

		 */

		initialize: function( params, options ) {

			var preview = this, urlParser = document.createElement( 'a' );

			api.Messenger.prototype.initialize.call( preview, params, options );

			urlParser.href = preview.origin();

			preview.add( 'scheme', urlParser.protocol.replace( /:$/, '' ) );

			preview.body = $( document.body );

			preview.window = $( window );

			if ( api.settings.channel ) {

				// If in an iframe, then intercept the link clicks and form submissions.

				preview.body.on( 'click.preview', 'a', function( event ) {

					preview.handleLinkClick( event );

				} );

				preview.body.on( 'submit.preview', 'form', function( event ) {

					preview.handleFormSubmit( event );

				} );

				preview.window.on( 'scroll.preview', debounce( function() {

					preview.send( 'scroll', preview.window.scrollTop() );

				}, 200 ) );

				preview.bind( 'scroll', function( distance ) {

					preview.window.scrollTop( distance );

				});

			}

		},

		/**

		 * Handle link clicks in preview.

		 *

		 * @since 4.7.0

		 * @access public

		 *

		 * @param {jQuery.Event} event Event.

		 */

		handleLinkClick: function( event ) {

			var preview = this, link, isInternalJumpLink;

			link = $( event.target ).closest( 'a' );

			// No-op if the anchor is not a link.

			if ( _.isUndefined( link.attr( 'href' ) ) ) {

				return;

			}

			// Allow internal jump links and JS links to behave normally without preventing default.

			isInternalJumpLink = ( '#' === link.attr( 'href' ).substr( 0, 1 ) );

			if ( isInternalJumpLink || ! /^https?:$/.test( link.prop( 'protocol' ) ) ) {

				return;

			}

			// If the link is not previewable, prevent the browser from navigating to it.

			if ( ! api.isLinkPreviewable( link[0] ) ) {

				wp.a11y.speak( api.settings.l10n.linkUnpreviewable );

				event.preventDefault();

				return;

			}

			// Prevent initiating navigating from click and instead rely on sending url message to pane.

			event.preventDefault();

			/*

			 * Note the shift key is checked so shift+click on widgets or

			 * nav menu items can just result on focusing on the corresponding

			 * control instead of also navigating to the URL linked to.

			 */

			if ( event.shiftKey ) {

				return;

			}

			// Note: It's not relevant to send scroll because sending url message will have the same effect.

			preview.send( 'url', link.prop( 'href' ) );

		},

		/**

		 * Handle form submit.

		 *

		 * @since 4.7.0

		 * @access public

		 *

		 * @param {jQuery.Event} event Event.

		 */

		handleFormSubmit: function( event ) {

			var preview = this, urlParser, form;

			urlParser = document.createElement( 'a' );

			form = $( event.target );

			urlParser.href = form.prop( 'action' );

			// If the link is not previewable, prevent the browser from navigating to it.

			if ( 'GET' !== form.prop( 'method' ).toUpperCase() || ! api.isLinkPreviewable( urlParser ) ) {

				wp.a11y.speak( api.settings.l10n.formUnpreviewable );

				event.preventDefault();

				return;

			}

			/*

			 * If the default wasn't prevented already (in which case the form

			 * submission is already being handled by JS), and if it has a GET

			 * request method, then take the serialized form data and add it as

			 * a query string to the action URL and send this in a url message

			 * to the customizer pane so that it will be loaded. If the form's

			 * action points to a non-previewable URL, the customizer pane's

			 * previewUrl setter will reject it so that the form submission is

			 * a no-op, which is the same behavior as when clicking a link to an

			 * external site in the preview.

			 */

			if ( ! event.isDefaultPrevented() ) {

				if ( urlParser.search.length > 1 ) {

					urlParser.search += '&';

				}

				urlParser.search += form.serialize();

				preview.send( 'url', urlParser.href );

			}

			// Prevent default since navigation should be done via sending url message or via JS submit handler.

			event.preventDefault();

		}

	});

	/**

	 * Inject the changeset UUID into links in the document.

	 *

	 * @since 4.7.0

	 * @access protected

	 *

	 * @access private

	 * @returns {void}

	 */

	api.addLinkPreviewing = function addLinkPreviewing() {

		// Inject links into initial document.

		$( document.body ).find( linkSelectors ).each( function() {

			api.prepareLinkPreview( this );

		} );

		// Inject links for new elements added to the page.

		if ( 'undefined' !== typeof MutationObserver ) {

			api.mutationObserver = new MutationObserver( function( mutations ) {

				_.each( mutations, function( mutation ) {

					$( mutation.target ).find( linkSelectors ).each( function() {

						api.prepareLinkPreview( this );

					} );

				} );

			} );

			api.mutationObserver.observe( document.documentElement, {

				childList: true,

				subtree: true

			} );

		} else {

			// If mutation observers aren't available, fallback to just-in-time injection.

			$( document.documentElement ).on( 'click focus mouseover', linkSelectors, function() {

				api.prepareLinkPreview( this );

			} );

		}

	};

	/**

	 * Should the supplied link is previewable.

	 *

	 * @since 4.7.0

	 * @access public

	 *

	 * @param {HTMLAnchorElement|HTMLAreaElement} element Link element.

	 * @param {string} element.search Query string.

	 * @param {string} element.pathname Path.

	 * @param {string} element.host Host.

	 * @param {object} [options]

	 * @param {object} [options.allowAdminAjax=false] Allow admin-ajax.php requests.

	 * @returns {boolean} Is appropriate for changeset link.

	 */

	api.isLinkPreviewable = function isLinkPreviewable( element, options ) {

		var matchesAllowedUrl, parsedAllowedUrl, args, elementHost;

		args = _.extend( {}, { allowAdminAjax: false }, options || {} );

		if ( 'javascript:' === element.protocol ) { // jshint ignore:line

			return true;

		}

		// Only web URLs can be previewed.

		if ( 'https:' !== element.protocol && 'http:' !== element.protocol ) {

			return false;

		}

		elementHost = element.host.replace( /:(80|443)$/, '' );

		parsedAllowedUrl = document.createElement( 'a' );

		matchesAllowedUrl = ! _.isUndefined( _.find( api.settings.url.allowed, function( allowedUrl ) {

			parsedAllowedUrl.href = allowedUrl;

			return parsedAllowedUrl.protocol === element.protocol && parsedAllowedUrl.host.replace( /:(80|443)$/, '' ) === elementHost && 0 === element.pathname.indexOf( parsedAllowedUrl.pathname.replace( /\/$/, '' ) );

		} ) );

		if ( ! matchesAllowedUrl ) {

			return false;

		}

		// Skip wp login and signup pages.

		if ( /\/wp-(login|signup)\.php$/.test( element.pathname ) ) {

			return false;

		}

		// Allow links to admin ajax as faux frontend URLs.

		if ( /\/wp-admin\/admin-ajax\.php$/.test( element.pathname ) ) {

			return args.allowAdminAjax;

		}

		// Disallow links to admin, includes, and content.

		if ( /\/wp-(admin|includes|content)(\/|$)/.test( element.pathname ) ) {

			return false;

		}

		return true;

	};

	/**

	 * Inject the customize_changeset_uuid query param into links on the frontend.

	 *

	 * @since 4.7.0

	 * @access protected

	 *

	 * @param {HTMLAnchorElement|HTMLAreaElement} element Link element.

	 * @param {string} element.search Query string.

	 * @param {string} element.host Host.

	 * @param {string} element.protocol Protocol.

	 * @returns {void}

	 */

	api.prepareLinkPreview = function prepareLinkPreview( element ) {

		var queryParams, $element = $( element );

		// Skip links in admin bar.

		if ( $element.closest( '#wpadminbar' ).length ) {

			return;

		}

		// Ignore links with href="#", href="#id", or non-HTTP protocols (e.g. javascript: and mailto:).

		if ( '#' === $element.attr( 'href' ).substr( 0, 1 ) || ! /^https?:$/.test( element.protocol ) ) {

			return;

		}

		// Make sure links in preview use HTTPS if parent frame uses HTTPS.

		if ( api.settings.channel && 'https' === api.preview.scheme.get() && 'http:' === element.protocol && -1 !== api.settings.url.allowedHosts.indexOf( element.host ) ) {