kmz-favorite-posts.php

<?php

/**
 * Plugin Name: KMZ Favorite Posts
 * Description: Display and manage favorite posts
 * Version: 1.0.0
 * Author: Vladimir Kamuz
 * License: GPL-2.0+
 * License URI: http://www.gnu.org/licenses/gpl-2.0.txt
 * Author URI: https://wpdev.pp.ua/
 * Plugin URI: https://github.com/kamuz/wp-favorite-posts
 * Text Domain: kmz-favorite-posts
 * Domain Path: /languages
*/

require_once __DIR__ . '/inc/KMZ_Favorite_Widget.php';

/**
 * Add button before content single post for logged users
 */
function kmz_favorites_content( $content ) {
	global $post;
	$img_loader_src = plugins_url( '/img/ajax-loader.gif', __FILE__ );
	if ( !is_single() || !is_user_logged_in() ) {
		return $content;
	}
	elseif (kmz_is_favorites($post->ID)){
		return '<p class="favorite-links remove-favorite"><a href="#" data-action="del">Remove from favorites</a> <img src="' . $img_loader_src . '" alt="loader" class="loader-gif hidden" data-action="del"> </p>' . $content;
	}
	else {
		return '<p class="favorite-links add-to-favorite"><a href="#" data-action="add">Add to Favorite</a> <img src="' . $img_loader_src . '" alt="loader" class="hidden"> </p>' . $content;
	}
}
add_filter( 'the_content', 'kmz_favorites_content' );

/**
 * Add CSS and JavaScript
 */
function kmz_favorite_css_js() {
	global $post;
	if( is_user_logged_in() ){
		wp_enqueue_style( 'dashicons' );
		wp_enqueue_style( 'kmz-favorite-style', plugins_url('/css/style.css', __FILE__), null, '1.0.0', 'screen' );
		wp_enqueue_script( 'kmz-favorite-script', plugins_url('/js/script.js', __FILE__), array( 'jquery' ), '1.0.0', true);
		wp_localize_script( 'kmz-favorite-script', 'kmzFavorites', [ 'url' => admin_url( 'admin-ajax.php' ), 'nonce' => wp_create_nonce( 'kmz-favorites' ), 'postId' => $post->ID, 'postTitle' => $post->post_title, 'postUrl' => get_permalink($post->ID)] );
	}
}
add_action( 'wp_enqueue_scripts', 'kmz_favorite_css_js' );

/**
 * Function for AJAX request for add post to favorite
 */
function kmz_add_favorite(){
	if(!wp_verify_nonce( $_POST['security'], 'kmz-favorites' )){
		wp_die("Security error!");
	}
	$post_id = (int)$_POST['postId'];
	$user = wp_get_current_user();
	if(kmz_is_favorites($post_id)){
		wp_die('Current post is already added');
	}
	if(add_user_meta( $user->ID, 'kmz_favorites', $post_id )){
		wp_die('You post successfully added');
	}
	wp_die('AJAX request completed!');
}
add_action( 'wp_ajax_kmz_add_favorite', 'kmz_add_favorite' );

/**
 * Function for AJAX request for delete post from favorite
 */
function kmz_del_favorite(){
	if(!wp_verify_nonce( $_POST['security'], 'kmz-favorites' )){
		wp_die("Security error!");
	}
	$post_id = (int)$_POST['postId'];
	$user = wp_get_current_user();
	if(!kmz_is_favorites($post_id)){
		wp_die();
	}
	if(delete_user_meta( $user->ID, 'kmz_favorites', $post_id )){
		wp_die('Removed');
	}
	wp_die('Error of removing post meta data from the database!');
}
add_action( 'wp_ajax_kmz_del_favorite', 'kmz_del_favorite' );

/**
 * Check in current post is added
 */
function kmz_is_favorites($post_id){
	$user = wp_get_current_user();
	$favorites = get_user_meta( $user->ID, 'kmz_favorites' );
	foreach($favorites as $favorite){
		if($favorite == $post_id){
			return true;
		}
	}
	return false;
}

/**
 * Add dashboard widget
 */
function kmz_favorites_dashboard_widget(){
	wp_add_dashboard_widget( 'kmz_favorites_dashboard', 'Your list of favorite posts', 'kmz_show_dashboard_widget' );
}
add_action('wp_dashboard_setup', 'kmz_favorites_dashboard_widget' );

function kmz_show_dashboard_widget(){
	$user = wp_get_current_user();
	$favorites = get_user_meta( $user->ID, 'kmz_favorites' );
	$favorites = array_reverse($favorites);
	if(!$favorites){
		echo "You don't have favorite posts yet!";
	}
	else{
		$img_loader_src = plugins_url( '/img/ajax-loader.gif', __FILE__ );
		echo '<ul class="kmz-widget-favorite-posts">';
		foreach($favorites as $favorite){
			echo '<li class="favorite-post-' . $favorite . '"><a href="' . get_the_permalink( $favorite ) . '" target="_blank">' . get_the_title($favorite) . '</a><span><a href="#" data-post="' . $favorite . '" class="dashicons dashicons-no"></a></span><img src="' . $img_loader_src . '" alt="loader" class="loader-gif hidden"> </li>';
		}
		echo '</ul>';
		echo '<div class="kmz-favorites-del-all"><button class="button button-primary btn btn-danger mt-3">Delete All</button><img src="' . $img_loader_src . '" alt="loader" class="loader-gif hidden"></div>';
	}
}

function kmz_widget_content(){
	$user = wp_get_current_user();
	$favorites = get_user_meta( $user->ID, 'kmz_favorites' );
	$favorites = array_reverse($favorites);
	if(!$favorites){
		echo "You don't have favorite posts yet!";
	}
	else{
		echo '<ul class="kmz-widget-favorite-posts">';
		foreach($favorites as $favorite){
			echo '<li class="favorite-post-' . $favorite . '"><a href="' . get_the_permalink( $favorite ) . '" target="_blank">' . get_the_title($favorite) . '</a></li>';
		}
		echo '</ul>';
	}
}

/**
 * Add files of JS scripts and CSS styles to admin section
 */
function kmz_favorite_admin_scripts( $hook) {
	if($hook != 'index.php'){
		return;
	}
	else{
		wp_enqueue_script( 'kmz-favorite-admin-script', plugins_url('/js/admin-script.js', __FILE__), array( 'jquery' ), '1.0.0', true);
		wp_enqueue_style( 'kmz-favorite-admin-style', plugins_url('/css/admin-style.css', __FILE__), null, '1.0.0', 'screen' );
		wp_localize_script( 'kmz-favorite-admin-script', 'kmzFavorites', [ 'nonce' => wp_create_nonce( 'kmz-favorites' ) ] );
	}
}
add_action( 'admin_enqueue_scripts', 'kmz_favorite_admin_scripts' );

/**
 * Delete all favorite posts from admin widget
 */
function kmz_del_all(){
	if(!wp_verify_nonce( $_POST['security'], 'kmz-favorites' )){
		wp_die("Security error!");
	}

	$user = wp_get_current_user();

	if(delete_metadata('user', $user->ID, 'kmz_favorites')){
		wp_die('List empty');
	}
	else{
		wp_die('Error of deleting');
	}
}
add_action( 'wp_ajax_kmz_del_all', 'kmz_del_all' );

/**
 * Create new widget for Front End
 */
function kmz_favorite_widget(){
	register_widget('KMZ_Favorite_Widget');
}
add_action('widgets_init', 'kmz_favorite_widget');