[CoursePress] - Completion Date Column. Adds a new column for completion date in Assessments page

cp-completion-date-col.php

<?php
/**
* Plugin Name: [CoursePress] - Completion Date Column
* Plugin URI: https://premium.wpmudev.org/
* Description: Adds a new column for completion date in Assessments page
* Author: Panos Lyrakis @ WPMUDEV
* Author URI: https://premium.wpmudev.org/
* License: GPLv2 or later
*/


if ( ! defined( 'ABSPATH' ) ) {
	exit;
}


if ( ! class_exists( 'WPMUDEV_CP_Completion_Date_Col' ) ) {
    
    class WPMUDEV_CP_Completion_Date_Col {

        private static $_instance = null;

        public static function get_instance() {

            if( is_null( self::$_instance ) ){
                self::$_instance = new WPMUDEV_CP_Completion_Date_Col();
            }
            return self::$_instance;
            
        }

        private function __construct() {

            add_action( 'admin_footer', array( $this, 'js' ) );
            add_action( 'wp_ajax_wpmudev_cp_course_completion_date', array( $this, 'course_completion_date_ajax' ) );
        }

        public function course_completion_date_ajax() {

        	check_ajax_referer( 'wpmudev_cp_course_completion_date', 'security' );
			
        	$course_id 		= isset( $_POST['course_id'] ) ? (int) $_POST['course_id'] : false;
        	$student_id 	= isset( $_POST['student_id'] ) ? (int) $_POST['student_id'] : false;

        	if ( ! $course_id || ! $student_id ) {
        		$return = array(
	                'success'       =>  false,
	                'content'       =>  'Something is missing'
	            );
	            wp_send_json($return);
        	}

        	$completion_date = $this->get_course_completion_date( $course_id, $student_id );        	

        	if ( ! $completion_date ) {
        		$return = array(
	                'success'       =>  true,
	                'content'       =>  '-'
	            );
	            wp_send_json($return);
        	}

        	$completion_date = date(
					        		get_option( 'date_format' ) . ' ' . get_option( 'time_format' ),
					        		strtotime( $completion_date )
					        	);

        	$return = array(
                'success'       =>  true,
                'content'       =>  $completion_date
            );
            wp_send_json($return);

        }

        public function get_course_completion_date( $course_id, $student_id ) {

        	$completed = CoursePress_Data_Student::is_course_complete( $student_id, $course_id );

        	if ( ! $completed ) {
        		return false;
        	}

        	$certificate_id = CoursePress_Data_Certificate::get_certificate_id( $student_id, $course_id );
        	return get_post_field( 'post_date', $certificate_id );
        }

        public function js() {

        	if ( ! is_callable( 'get_current_screen' ) || 'course_page_coursepress_assessments' != get_current_screen()->id ) {
        		return;
        	}

        	?>
        	<script type="text/javascript">
        		($ => {

        			var WPMUDEV_CP_Comp_Date_Col = {

        				load : function() {

        					$( document ).ajaxComplete(function( event, xhr, settings ) {
                                var action = WPMUDEV_CP_Comp_Date_Col.get_action( 'action', settings.data );
                                var response = JSON.parse(xhr.responseText);

                                if ( 
                                	typeof response != "undefined" && 
                                	typeof response.data != "undefined" && 
                                	typeof response.data.action != "undefined" && 
                                	'table' == response.data.action ) {

                                	const 	table = $( '#assessment-table-container table.users' )
                                			course_id = $( '#course-list' ).val();

									table.find('tr').each(function(){

										$(this).find('th').eq(2).after('<th>Completion date</th>');

										let row_id = $(this).attr('id');

										if ( typeof row_id != "undefined" ) {

											let _row_id = row_id.split( '-' ),
												student = _row_id[1]
												el_class = 'course-completion-date-' + course_id + '-' + student;

											$(this).find( '.row-actions .id' ).hide();

											$(this).find('td').eq(2).after('<td class="' + el_class + '"></td>' );
											WPMUDEV_CP_Comp_Date_Col.get_completion_date( course_id, student, el_class );
											
										}

									});

                                }

                            });
       					

        				},

        				get_completion_date( course_id, student, el_class ) {

        					var data = {
	                                action 		: 'wpmudev_cp_course_completion_date',                                
	                                security 	: '<?php echo wp_create_nonce( "wpmudev_cp_course_completion_date" ); ?>',
	                                student_id 	: student,
	                                course_id	: course_id
	                            };
	                        var completion_date = '';

        					$.post(ajaxurl, data, function(response) {

                                if( response.success ){
                                    $( '.' + el_class ).html( response.content );
                                }
                                else{
                                	console.log( 'Something went wrong' );
                                }
                                
                            });        				
        					
        				},

        				get_action: function(name, url){
                            if (!url){
                                return '';
                            }
                            name = name.replace(/[\[\]]/g, "\\$&");
                            var regex = new RegExp(name + "(=([^&#]*)|&|#|$)"),
                                results = regex.exec(url);
                            if (!results) return null;
                            if (!results[2]) return '';
                            return decodeURIComponent(results[2].replace(/\+/g, " "));
                        }

        			}

        			$( window ).load( () => {
        				WPMUDEV_CP_Comp_Date_Col.load();
        			});
        		})(jQuery);

    		</script>
    		<?php

        }

    }

	if ( ! function_exists( 'wpmudev_cp_completion_date_col' ) ) {

        function wpmudev_cp_completion_date_col(){            
            return WPMUDEV_CP_Completion_Date_Col::get_instance();
        };

        add_action( 'plugins_loaded', 'wpmudev_cp_completion_date_col', 10 );
    }

}