/* jshint esversion: 6 */
/* global NeveProperties */
import { httpGetAsync, isInView } from '../utils.js';

let masonryInstance = null,
		masonryContainer = null,
		page = 2;

/**
 * Initialize blog JS.
 */
export const initBlog = function() {
	if ( document.querySelector( '.blog.nv-index-posts' ) === null ) {
		return false;
	}
	masonry();
	infiniteScroll();
};

/**
 * Handles masonry
 *
 * @returns {boolean}
 */
const masonry = function() {
	if ( NeveProperties.masonry !== 'enabled' || NeveProperties.masonryColumns <
			2 ) {
		return false;
	}
	masonryContainer = document.querySelector( '.nv-index-posts .posts-wrapper' );
	imagesLoaded( masonryContainer, function() {
		masonryInstance = new Masonry( masonryContainer, {
			itemSelector: 'article.layout-grid',
			columnWidth: 'article.layout-grid',
			percentPosition: true
		} );
	} );

};

/**
 * Infinite scroll
 *
 * @returns {boolean}
 */
const infiniteScroll = function() {
	if ( NeveProperties.infiniteScroll !== 'enabled' ) {
		return false;
	}

	isInView( document.querySelector( '.infinite-scroll-trigger' ),
			function() {
				if ( typeof parent.wp.customize !== 'undefined' ) {
					parent.wp.customize.requestChangesetUpdate().then( function() {
						requestMorePosts();
					} );
					return false;
				}
				requestMorePosts();
			} );
};

/**
 * Request more posts
 * @returns {boolean}
 */
const requestMorePosts = function() {
	let trigger = document.querySelector( '.infinite-scroll-trigger' );
	if ( trigger === null ) {
		return false;
	}
	document.querySelector( '.nv-loader' ).style.display = 'block';
	if ( page > NeveProperties.infiniteScrollMaxPages ) {
		trigger.parentNode.removeChild( trigger );
		document.querySelector( '.nv-loader' ).style.display = 'none';
		return false;
	}

	let blog = document.querySelector( '.nv-index-posts .posts-wrapper' );
	let requestUrl = maybeParseUrlForCustomizer(
			NeveProperties.infiniteScrollEndpoint + page );
	page++;

	httpGetAsync( requestUrl, function(response) {
		blog.innerHTML += JSON.parse( response );
		refreshMasonry();
	}, NeveProperties.infiniteScrollQuery );
};

/**
 * Refresh masonry
 */
const refreshMasonry = function() {
	if ( masonryInstance === null ) {
		return;
	}
	imagesLoaded( masonryContainer ).on( 'progress', function(e) {
		masonryInstance.layout();
		masonryInstance.reloadItems();
	} );
};

/**
 * Parse in the customizer context.
 * @param url
 * @returns {*}
 */
const maybeParseUrlForCustomizer = function(url) {
	//Add change-set uuid.
	if ( typeof wp.customize === 'undefined' ) return url;
	url += '?customize_changeset_uuid=' + wp.customize.settings.changeset.uuid +
			'&customize_autosaved=on';

	//Add preview nonce.
	if ( typeof _wpCustomizeSettings === 'undefined' ) return url;
	url += '&customize_preview_nonce=' + _wpCustomizeSettings.nonce.preview;

	return url;
};