woothemes / sensei

includes/class-sensei-lesson.php

<?php

For compatibility and reusability of your code, PSR1 recommends that a file should introduce either new symbols (like classes, functions, etc.) or have side-effects (like outputting something, or including other files), but not both at the same time. The first symbol is defined on line 14 and the first side effect is on line 2.

if ( ! defined( 'ABSPATH' ) ) exit; // Exit if accessed directly

/**
 * Sensei Lessons Class
 *
 * All functionality pertaining to the lessons post type in Sensei.
 *
 * @package Content
 * @author Automattic
 *
 * @since 1.0.0
 */
class Sensei_Lesson {
	public $token;
	public $meta_fields;

	/**
	 * Constructor.
	 * @since  1.0.0
	 */
	public function __construct () {

        $this->token = 'lesson';

		// Setup meta fields for this post type
		$this->meta_fields = array( 'lesson_prerequisite', 'lesson_course', 'lesson_preview', 'lesson_length', 'lesson_complexity', 'lesson_video_embed' );

        $this->question_order = '';

		// Admin actions
		if ( is_admin() ) {

			// Metabox functions
			add_action( 'admin_menu', array( $this, 'meta_box_setup' ), 20 );
			add_action( 'save_post', array( $this, 'meta_box_save' ) );
			add_action( 'save_post', array( $this, 'quiz_update' ) );

			// Custom Write Panel Columns
			add_filter( 'manage_edit-lesson_columns', array( $this, 'add_column_headings' ), 10, 1 );
			add_action( 'manage_posts_custom_column', array( $this, 'add_column_data' ), 10, 2 );

			// Add/Update question
			add_action( 'wp_ajax_lesson_update_question', array( $this, 'lesson_update_question' ) );
			add_action( 'wp_ajax_nopriv_lesson_update_question', array( $this, 'lesson_update_question' ) );

			// Add course
			add_action( 'wp_ajax_lesson_add_course', array( $this, 'lesson_add_course' ) );
			add_action( 'wp_ajax_nopriv_lesson_add_course', array( $this, 'lesson_add_course' ) );

			// Update grade type
			add_action( 'wp_ajax_lesson_update_grade_type', array( $this, 'lesson_update_grade_type' ) );
			add_action( 'wp_ajax_nopriv_lesson_update_grade_type', array( $this, 'lesson_update_grade_type' ) );

			// Update question order
			add_action( 'wp_ajax_lesson_update_question_order', array( $this, 'lesson_update_question_order' ) );
			add_action( 'wp_ajax_nopriv_lesson_update_question_order', array( $this, 'lesson_update_question_order' ) );

			//Update question order
			add_action( 'wp_ajax_lesson_update_question_order_random', array( $this, 'lesson_update_question_order_random' ) );
			add_action( 'wp_ajax_nopriv_lesson_update_question_order_random', array( $this, 'lesson_update_question_order_random' ) );

			// Get answer ID
			add_action( 'wp_ajax_question_get_answer_id', array( $this, 'question_get_answer_id' ) );
			add_action( 'wp_ajax_nopriv_question_get_answer_id', array( $this, 'question_get_answer_id' ) );

			// Add multiple questions
			add_action( 'wp_ajax_lesson_add_multiple_questions', array( $this, 'lesson_add_multiple_questions' ) );
			add_action( 'wp_ajax_nopriv_lesson_add_multiple_questions', array( $this, 'lesson_add_multiple_questions' ) );

			// Remove multiple questions
			add_action( 'wp_ajax_lesson_remove_multiple_questions', array( $this, 'lesson_remove_multiple_questions' ) );
			add_action( 'wp_ajax_nopriv_lesson_remove_multiple_questions', array( $this, 'lesson_remove_multiple_questions' ) );

			// Get question category limit
			add_action( 'wp_ajax_get_question_category_limit', array( $this, 'get_question_category_limit' ) );
			add_action( 'wp_ajax_nopriv_get_question_category_limit', array( $this, 'get_question_category_limit' ) );

			// Add existing questions
			add_action( 'wp_ajax_lesson_add_existing_questions', array( $this, 'lesson_add_existing_questions' ) );
			add_action( 'wp_ajax_nopriv_lesson_add_existing_questions', array( $this, 'lesson_add_existing_questions' ) );

			// Filter existing questions
			add_action( 'wp_ajax_filter_existing_questions', array( $this, 'quiz_panel_filter_existing_questions' ) );
			add_action( 'wp_ajax_nopriv_filter_existing_questions', array( $this, 'quiz_panel_filter_existing_questions' ) );

            // output bulk edit fields
            add_action( 'bulk_edit_custom_box', array( $this, 'all_lessons_edit_fields' ), 10, 2 );
            add_action( 'quick_edit_custom_box', array( $this, 'all_lessons_edit_fields' ), 10, 2 );

            // load quick edit default values
            add_action('manage_lesson_posts_custom_column', array( $this, 'set_quick_edit_admin_defaults'), 11, 2);

            // save bulk edit fields
            add_action( 'wp_ajax_save_bulk_edit_book', array( $this, 'save_all_lessons_edit_fields' ) );

            // flush rewrite rules when saving a lesson
            add_action('save_post', array( __CLASS__, 'flush_rewrite_rules' ) );

		} else {

This else statement is empty and can be removed.

			// Frontend actions
		} // End If Statement
	} // End __construct()

	/**
	 * meta_box_setup function.
	 *
	 * @access public
	 * @return void
	 */
	public function meta_box_setup () {

		// Add Meta Box for Prerequisite Lesson
		add_meta_box( 'lesson-prerequisite', __( 'Lesson Prerequisite', 'woothemes-sensei' ), array( $this, 'lesson_prerequisite_meta_box_content' ), $this->token, 'side', 'default' );

		// Add Meta Box for Lesson Course
		add_meta_box( 'lesson-course', __( 'Lesson Course', 'woothemes-sensei' ), array( $this, 'lesson_course_meta_box_content' ), $this->token, 'side', 'default' );

		// Add Meta Box for Lesson Preview
		add_meta_box( 'lesson-preview', __( 'Lesson Preview', 'woothemes-sensei' ), array( $this, 'lesson_preview_meta_box_content' ), $this->token, 'side', 'default' );

		// Add Meta Box for Lesson Information
		add_meta_box( 'lesson-info', __( 'Lesson Information', 'woothemes-sensei' ), array( $this, 'lesson_info_meta_box_content' ), $this->token, 'normal', 'default' );

		// Add Meta Box for Quiz Settings
		add_meta_box( 'lesson-quiz-settings', __( 'Quiz Settings', 'woothemes-sensei' ), array( $this, 'lesson_quiz_settings_meta_box_content' ), $this->token, 'normal', 'default' );

		// Add Meta Box for Lesson Quiz Questions
		add_meta_box( 'lesson-quiz', __( 'Quiz Questions', 'woothemes-sensei' ), array( $this, 'lesson_quiz_meta_box_content' ), $this->token, 'normal', 'default' );

		// Remove "Custom Settings" meta box.
		remove_meta_box( 'woothemes-settings', $this->token, 'normal' );

		// Add JS scripts
		add_action( 'admin_enqueue_scripts', array( $this, 'enqueue_scripts' ) );

		// Add CSS
		add_action( 'admin_enqueue_scripts', array( $this, 'enqueue_styles' ) );

	} // End meta_box_setup()


	/**
	 * lesson_info_meta_box_content function.
	 *
	 * @access public
	 * @return void
	 */
	public function lesson_info_meta_box_content () {
		global $post;

		$lesson_length = get_post_meta( $post->ID, '_lesson_length', true );
		$lesson_complexity = get_post_meta( $post->ID, '_lesson_complexity', true );
		$complexity_array = $this->lesson_complexities();
		$lesson_video_embed = get_post_meta( $post->ID, '_lesson_video_embed', true );

		$html = '';
		// Lesson Length
		$html .= '<p><label for="lesson_length">' . __( 'Lesson Length in minutes', 'woothemes-sensei' ) . ': </label>';
		$html .= '<input type="number" id="lesson-length" name="lesson_length" class="small-text" value="' . esc_attr( $lesson_length ) . '" /></p>' . "\n";
		// Lesson Complexity
		$html .= '<p><label for="lesson_complexity">' . __( 'Lesson Complexity', 'woothemes-sensei' ) . ': </label>';
		$html .= '<select id="lesson-complexity-options" name="lesson_complexity" class="chosen_select lesson-complexity-select">';
			$html .= '<option value="">' . __( 'None', 'woothemes-sensei' ) . '</option>';
			foreach ($complexity_array as $key => $value){
				$html .= '<option value="' . esc_attr( $key ) . '"' . selected( $key, $lesson_complexity, false ) . '>' . esc_html( $value ) . '</option>' . "\n";
			} // End For Loop
		$html .= '</select></p>' . "\n";

		$html .= '<p><label for="lesson_video_embed">' . __( 'Video Embed Code', 'woothemes-sensei' ) . ':</label><br/>' . "\n";
		$html .= '<textarea rows="5" cols="50" name="lesson_video_embed" tabindex="6" id="course-video-embed">' . $lesson_video_embed . '</textarea></p>' . "\n";
		$html .= '<p>' .  __( 'Paste the embed code for your video (e.g. YouTube, Vimeo etc.) in the box above.', 'woothemes-sensei' ) . '</p>';

		echo $html;

	} // End lesson_info_meta_box_content()

	/**
	 * lesson_prerequisite_meta_box_content function.
	 *
	 * @access public
	 * @return void
	 */
	public function lesson_prerequisite_meta_box_content () {
		global $post;
		// Get existing post meta
		$select_lesson_prerequisite = get_post_meta( $post->ID, '_lesson_prerequisite', true );
		// Get the Lesson Posts
		$post_args = array(	'post_type' 		=> 'lesson',
							'posts_per_page' 		=> -1,
							'orderby'         	=> 'title',
    						'order'           	=> 'ASC',
    						'exclude' 			=> $post->ID,
							'suppress_filters' 	=> 0
							);
		$posts_array = get_posts( $post_args );
		// Build the HTML to Output
		$html = '';
		$html .= wp_nonce_field( 'sensei-save-post-meta','woo_' . $this->token . '_nonce', true, false  );
		if ( count( $posts_array ) > 0 ) {

This code seems to be duplicated across your project.

			$html .= '<select id="lesson-prerequisite-options" name="lesson_prerequisite" class="chosen_select widefat">' . "\n";
			$html .= '<option value="">' . __( 'None', 'woothemes-sensei' ) . '</option>';
				foreach ($posts_array as $post_item){
					$html .= '<option value="' . esc_attr( absint( $post_item->ID ) ) . '"' . selected( $post_item->ID, $select_lesson_prerequisite, false ) . '>' . esc_html( $post_item->post_title ) . '</option>' . "\n";
				} // End For Loop
			$html .= '</select>' . "\n";
		} else {
			$html .= '<p>' . esc_html( __( 'No lessons exist yet. Please add some first.', 'woothemes-sensei' ) ) . '</p>';
		} // End If Statement
		// Output the HTML
		echo $html;
	} // End lesson_prerequisite_meta_box_content()

	/**
	 * lesson_preview_meta_box_content function.
	 *
	 * @access public
	 * @return void
	 */
	public function lesson_preview_meta_box_content () {
		global $post;
		// Get existing post meta
		$lesson_preview = get_post_meta( $post->ID, '_lesson_preview', true );
		$html = '';
		$html .= wp_nonce_field( 'sensei-save-post-meta','woo_' . $this->token . '_nonce', true, false  );

		$checked = '';
		if ( isset( $lesson_preview ) && ( '' != $lesson_preview ) ) {
	 	    $checked = checked( 'preview', $lesson_preview, false );
	 	} // End If Statement

	 	$html .= '<label for="lesson_preview">';
	 	$html .= '<input type="checkbox" id="lesson_preview" name="lesson_preview" value="preview" ' . $checked . '>&nbsp;' . __( 'Allow this lesson to be viewed without purchase/login', 'woothemes-sensei' ) . '<br>';

		// Output the HTML
		echo $html;
	} // End lesson_preview_meta_box_content()

	/**
	 * meta_box_save function.
	 *
	 * @access public
	 * @param int $post_id
	 * @return integer $post_id
	 */
	public function meta_box_save ( $post_id ) {

		// Verify the nonce before proceeding.
		if ( ( get_post_type( $post_id ) != $this->token ) || !isset(   $_POST[ 'woo_' . $this->token . '_nonce'] )  || ! wp_verify_nonce( $_POST[ 'woo_' . $this->token . '_nonce' ], 'sensei-save-post-meta' ) ) {
			return $post_id;
		} // End If Statement
		// Get the post type object.
		$post_type = get_post_type_object( get_post_type( $post_id ) );
		// Check if the current user has permission to edit the post.
		if ( !current_user_can( $post_type->cap->edit_post, $post_id ) ) {
			return $post_id;
		} // End If Statement

		// Check if the current post type is a page
		if ( 'page' == $_POST[ 'post_type' ] ) {

This code seems to be duplicated across your project.

			if ( ! current_user_can( 'edit_page', $post_id ) ) {

				return $post_id;

			} // End If Statement
		} else {
			if ( ! current_user_can( 'edit_post', $post_id ) ) {
				return $post_id;
			} // End If Statement
		} // End If Statement

		// Save the post meta data fields
		if ( isset($this->meta_fields) && is_array($this->meta_fields) ) {

			foreach ( $this->meta_fields as $meta_key ) {

				remove_action( 'save_post', array( $this, 'meta_box_save') );
				$this->save_post_meta( $meta_key, $post_id );

			} // End For Loop
		} // End If Statement
	} // End meta_box_save()


	/**
     * Update the lesson quiz and all the post meta
	 *
	 * @access public
	 * @return integer|boolean $post_id or false
	 */
	public function quiz_update( $post_id ) {
		global $post;
		// Verify the nonce before proceeding.
		if ( ( 'lesson' != get_post_type( $post_id ) )|| !isset(   $_POST[ 'woo_' . $this->token . '_nonce'] )  || ! wp_verify_nonce( $_POST[ 'woo_' . $this->token . '_nonce' ], 'sensei-save-post-meta') ) {
			if ( isset($post->ID) ) {
				return $post->ID;
			} else {
				return false;
			} // End If Statement
		} // End If Statement

		if( wp_is_post_revision( $post_id ) || wp_is_post_autosave( $post_id ) ) {
			return false;
		}

		// Temporarily disable the filter
        remove_action( 'save_post', array( $this, 'quiz_update' ) );
		// Save the Quiz
		$quiz_id = $this->lesson_quizzes( $post_id, 'any');

		 // Sanitize and setup the post data
		$_POST = stripslashes_deep( $_POST );
		if ( isset( $_POST[ 'quiz_id' ] ) && ( 0 < absint( $_POST[ 'quiz_id' ] ) ) ) {
			$quiz_id = absint( $_POST[ 'quiz_id' ] );
		} // End If Statement
		$post_title = esc_html( $_POST[ 'post_title' ] );
		$post_status = esc_html( $_POST[ 'post_status' ] );
		$post_content = '';

		// Setup Query Arguments
		$post_type_args = array(	'post_content' => $post_content,
  		    						'post_status' => $post_status,
  		    						'post_title' => $post_title,
  		    						'post_type' => 'quiz',
                                    'post_parent' => $post_id,
  		    						);

		$settings = $this->get_quiz_settings();

  		// Update or Insert the Lesson Quiz
		if ( 0 < $quiz_id ) {
			// Update the Quiz
			$post_type_args[ 'ID' ] = $quiz_id;
		    wp_update_post($post_type_args);

		    // Update the post meta data
		    update_post_meta( $quiz_id, '_quiz_lesson', $post_id );

		    foreach( $settings as $field ) {
		    	if( 'random_question_order' != $field['id'] ) {
			    	$value = $this->get_submitted_setting_value( $field );
			    	if( isset( $value ) ) {
			    		update_post_meta( $quiz_id, '_' . $field['id'], $value );
			    	}
			    }
		    }

		    // Set the post terms for quiz-type
		    wp_set_post_terms( $quiz_id, array( 'multiple-choice' ), 'quiz-type' );
		} else {
			// Create the Quiz
		    $quiz_id = wp_insert_post($post_type_args);

		    // Add the post meta data WP will add it if it doesn't exist
            update_post_meta( $quiz_id, '_quiz_lesson', $post_id );

		    foreach( $settings as $field ) {
		    	if( 'random_question_order' != $field['id'] ) {

                    //ignore values not posted to avoid
                    // overwriting with empty or default values
                    // when the values are posted from bulk edit or quick edit
                    if( !isset( $_POST[ $field['id'] ] ) ){
                        continue;
                    }

			    	$value = $this->get_submitted_setting_value( $field );
			    	if( isset( $value ) ) {
			    		add_post_meta( $quiz_id, '_' . $field['id'], $value );
			    	}
			    }
		    }

		    // Set the post terms for quiz-type
		    wp_set_post_terms( $quiz_id, array( 'multiple-choice' ), 'quiz-type' );
		} // End If Statement

		// Add default lesson order meta value
		$course_id = get_post_meta( $post_id, '_lesson_course', true );
		if( $course_id ) {
			if( ! get_post_meta( $post_id, '_order_' . $course_id, true ) ) {
				update_post_meta( $post_id, '_order_' . $course_id, 0 );
			}
		}
		// Add reference back to the Quiz
		update_post_meta( $post_id, '_lesson_quiz', $quiz_id );
		// Mark if the Lesson Quiz has questions
		$quiz_questions = Sensei()->lesson->lesson_quiz_questions( $quiz_id );
		if( 0 < count( $quiz_questions ) ) {
			update_post_meta( $post_id, '_quiz_has_questions', '1' );
		}
		else {
			delete_post_meta( $post_id, '_quiz_has_questions' );
		}

		// Restore the previously disabled filter
        add_action( 'save_post', array( $this, 'quiz_update' ) );

	} // End post_updated()

	public function get_submitted_setting_value( $field = false ) {

		if( ! $field ) return;

		$value = false;

		if( 'quiz_grade_type' == $field['id'] ) {
			if( isset( $_POST[ $field['id'] ] ) && 'on' == $_POST[ $field['id'] ] ) {
				$value = 'auto';
			} else {
				$value = 'manual';
			}
			return $value;
		}

		if ( isset( $_POST[ $field['id'] ] ) ) {
			$value = $_POST[ $field['id'] ];
		} else {
			$value = $field['default'];
		}

		return $value;
	}

	/**
	 * save_post_meta function.
	 * Saves lesson meta data
	 * @access private
	 * @param string $post_key (default: '')
	 * @param int $post_id (default: 0)
	 * @return int|bool meta id or saved status
	 */
	private function save_post_meta( $post_key = '', $post_id = 0 ) {
		// Get the meta key.
		$meta_key = '_' . $post_key;

        //ignore fields are not posted

        if( !isset( $_POST[ $post_key ] ) ){

            // except for lesson preview checkbox field
            if( 'lesson_preview' == $post_key ){

                $_POST[ $post_key ] = '';

            } else {

                return false;

            }

        }

		// Get the posted data and sanitize it for use as an HTML class.
		if ( 'lesson_video_embed' == $post_key) {

This code seems to be duplicated across your project.

			$new_meta_value = esc_html( $_POST[$post_key] );
		} else {
			$new_meta_value = ( isset( $_POST[$post_key] ) ? sanitize_html_class( $_POST[$post_key] ) : '' );
		} // End If Statement

        // update field with the new value
        if( -1 != $new_meta_value  ){
            return update_post_meta( $post_id, $meta_key, $new_meta_value );
        }

	} // End save_post_meta()

	/**
	 * lesson_course_meta_box_content function.
	 *
	 * @access public
	 * @return void
	 */
	public function lesson_course_meta_box_content () {
		global $post;
		// Setup Lesson Meta Data
		$selected_lesson_course = 0;
		if ( 0 < $post->ID ) {
			$selected_lesson_course = get_post_meta( $post->ID, '_lesson_course', true );
		} // End If Statement
		// Handle preselected course
		if ( isset( $_GET[ 'course_id' ] ) && ( 0 < absint( $_GET[ 'course_id' ] ) ) ) {

This code seems to be duplicated across your project.

			$selected_lesson_course = absint( $_GET[ 'course_id' ] );
		} // End If Statement
		// Get the Lesson Posts
		$post_args = array(	'post_type' 		=> 'course',
							'posts_per_page' 		=> -1,
							'orderby'         	=> 'title',
    						'order'           	=> 'ASC',
    						'post_status'      	=> 'any',
    						'suppress_filters' 	=> 0,
							);
		$posts_array = get_posts( $post_args );
		// Buid the HTML to Output
		$html = '';
		// Nonce
		$html .= wp_nonce_field( 'sensei-save-post-meta','woo_' . $this->token . '_nonce', true, false  );

        // Select the course for the lesson
        $drop_down_args = array(
            'name'=>'lesson_course',
            'id' => 'lesson-course-options'
        );

        $courses = WooThemes_Sensei_Course::get_all_courses();
        $courses_options = array();
        foreach( $courses as $course ){
            $courses_options[ $course->ID ] = get_the_title( $course ) ;
        }
        $html .= Sensei_Utils::generate_drop_down( $selected_lesson_course, $courses_options, $drop_down_args );

        // Course Actions Panel
		if ( current_user_can( 'publish_courses' )) {
				$html .= '<div id="lesson-course-actions">';
					$html .= '<p>';
						// Add a course action link
						$html .= '<a id="lesson-course-add" href="#course-add" class="lesson-add-course">+ ' . __('Add New Course', 'woothemes-sensei' ) . '</a>';
					$html .= '</p>';
				$html .= '</div>';
				// Add a course input fields
				$html .= '<div id="lesson-course-details" class="hidden">';
					$html .= '<p>';
						// Course Title input
						$html .= '<label>' . __( 'Course Title' , 'woothemes-sensei' ) . '</label> ';
	  					$html .= '<input type="text" id="course-title" name="course_title" value="" size="25" class="widefat" />';
	  					// Course Description input
	  					$html .= '<label>' . __( 'Description' , 'woothemes-sensei' ) . '</label> ';
	  					$html .= '<textarea rows="10" cols="40" id="course-content" name="course_content" value="" size="300" class="widefat"></textarea>';
	  					// Course Prerequisite
	  					$html .= '<label>' . __( 'Course Prerequisite' , 'woothemes-sensei' ) . '</label> ';
	  					$html .= '<select id="course-prerequisite-options" name="course_prerequisite" class="chosen_select widefat">' . "\n";
							$html .= '<option value="">' . __( 'None', 'woothemes-sensei' ) . '</option>';
							foreach ($posts_array as $post_item){
								$html .= '<option value="' . esc_attr( absint( $post_item->ID ) ) . '">' . esc_html( $post_item->post_title ) . '</option>' . "\n";
							} // End For Loop
						$html .= '</select>' . "\n";
						// Course Product
                        if ( Sensei_WC::is_woocommerce_active() ) {
	  						// Get the Products
							$select_course_woocommerce_product = get_post_meta( $post_item->ID, '_course_woocommerce_product', true );

$select_course_woocommerce_product is not used, you could remove the assignment.

							$product_args = array(	'post_type' 		=> array( 'product', 'product_variation' ),
													'posts_per_page' 		=> -1,
													'orderby'         	=> 'title',
	    											'order'           	=> 'DESC',
	    											'post_status'		=> array( 'publish', 'private', 'draft' ),
	    											'tax_query'			=> array(
														array(
															'taxonomy'	=> 'product_type',
															'field'		=> 'slug',
															'terms'		=> array( 'variable', 'grouped' ),
															'operator'	=> 'NOT IN'
														)
													),
	    											'suppress_filters' 	=> 0
													);
							$products_array = get_posts( $product_args );
							$html .= '<label>' . __( 'WooCommerce Product' , 'woothemes-sensei' ) . '</label> ';
	  						$html .= '<select id="course-woocommerce-product-options" name="course_woocommerce_product" class="chosen_select widefat">' . "\n";
								$html .= '<option value="-">' . __( 'None', 'woothemes-sensei' ) . '</option>';
								$prev_parent_id = 0;
								foreach ($products_array as $products_item){

									if ( 'product_variation' == $products_item->post_type ) {
										$product_object = get_product( $products_item->ID );
										$parent_id = wp_get_post_parent_id( $products_item->ID );
										$product_name = ucwords( woocommerce_get_formatted_variation( $product_object->variation_data, true ) );
									} else {
										$parent_id = false;
										$prev_parent_id = 0;
										$product_name = $products_item->post_title;
									}

									// Show variations in groups
									if( $parent_id && $parent_id != $prev_parent_id ) {
										if( 0 != $prev_parent_id ) {
											$html .= '</optgroup>';
										}
										$html .= '<optgroup label="' . get_the_title( $parent_id ) . '">';
										$prev_parent_id = $parent_id;
									} elseif( ! $parent_id && 0 == $prev_parent_id ) {
										$html .= '</optgroup>';
									}

									$html .= '<option value="' . esc_attr( absint( $products_item->ID ) ) . '">' . esc_html( $products_item->post_title ) . '</option>' . "\n";
								} // End For Loop
							$html .= '</select>' . "\n";
						} else {
							// Default
							$html .= '<input type="hidden" name="course_woocommerce_product" id="course-woocommerce-product-options" value="-" />';
						}
						// Course Category
	  					$html .= '<label>' . __( 'Course Category' , 'woothemes-sensei' ) . '</label> ';
	  					$cat_args = array( 'echo' => false, 'hierarchical' => true, 'show_option_none' => __( 'None', 'woothemes-sensei' ), 'taxonomy' => 'course-category', 'orderby' => 'name', 'id' => 'course-category-options', 'name' => 'course_category', 'class' => 'widefat' );
						$html .= wp_dropdown_categories(apply_filters('widget_course_categories_dropdown_args', $cat_args)) . "\n";
	  					// Save the course action button
	  					$html .= '<a title="' . esc_attr( __( 'Save Course', 'woothemes-sensei' ) ) . '" href="#add-course-metadata" class="lesson_course_save button button-highlighted">' . esc_html( __( 'Add Course', 'woothemes-sensei' ) ) . '</a>';
						$html .= '&nbsp;&nbsp;&nbsp;';
						// Cancel action link
						$html .= '<a href="#course-add-cancel" class="lesson_course_cancel">' . __( 'Cancel', 'woothemes-sensei' ) . '</a>';
					$html .= '</p>';
				$html .= '</div>';
			} // End If Statement

		// Output the HTML
		echo $html;
	} // End lesson_course_meta_box_content()

	public function quiz_panel( $quiz_id = 0 ) {

		$html = wp_nonce_field( 'sensei-save-post-meta','woo_' . $this->token . '_nonce', true, false  );
		$html .= '<div id="add-quiz-main">';
			if ( 0 == $quiz_id ) {
				$html .= '<p>';
					// Default message and Add a Quiz button
					$html .= esc_html( __( 'Once you have saved your lesson you will be able to add questions.', 'woothemes-sensei' ) );
				$html .= '</p>';
			}

			// Quiz Panel CSS Class
			$quiz_class = '';
			if ( 0 == $quiz_id ) {
				$quiz_class = ' class="hidden"';
			} // End If Statement
			// Build the HTML to Output
			$message_class = '';

			// Setup Questions Query
			$questions = array();
			if ( 0 < $quiz_id ) {
				$questions = $this->lesson_quiz_questions( $quiz_id );
			} // End If Statement

			$question_count = 0;
			foreach( $questions as $question ) {

				if( $question->post_type == 'multiple_question' ) {
					$question_number = get_post_meta( $question->ID, 'number', true );
					$question_count += $question_number;
				} else {
					++$question_count;
				}

			}

			// Inner DIV
			$html .= '<div id="add-quiz-metadata"' . $quiz_class . '>';

				// Quiz ID
				$html .= '<input type="hidden" name="quiz_id" id="quiz_id" value="' . esc_attr( $quiz_id ) . '" />';

				// Default Message
				if ( 0 == $quiz_id ) {
					$html .= '<p class="save-note">';
						$html .= esc_html( __( 'Please save your lesson in order to add questions to your quiz.', 'woothemes-sensei' ) );
					$html .= '</p>';
				} // End If Statement

			$html .= '</div>';

			// Question Container DIV
			$html .= '<div id="add-question-main"' . $quiz_class . '>';
				// Inner DIV
				$html .= '<div id="add-question-metadata">';

					// Count of questions
					$html .= '<input type="hidden" name="question_counter" id="question_counter" value="' . esc_attr( $question_count ) . '" />';
					// Table headers
					$html .= '<table class="widefat" id="sortable-questions">
								<thead>
								    <tr>
								        <th class="question-count-column">#</th>
								        <th>' . __( 'Question', 'woothemes-sensei' ) . '</th>
								        <th style="width:45px;">' . __( 'Grade', 'woothemes-sensei' ) . '</th>
								        <th style="width:125px;">' . __( 'Type', 'woothemes-sensei' ) . '</th>
								        <th style="width:125px;">' . __( 'Action', 'woothemes-sensei' ) . '</th>
								    </tr>
								</thead>
								<tfoot>
								    <tr>
									    <th class="question-count-column">#</th>
									    <th>' . __( 'Question', 'woothemes-sensei' ) . '</th>
									    <th>' . __( 'Grade', 'woothemes-sensei' ) . '</th>
									    <th>' . __( 'Type', 'woothemes-sensei' ) . '</th>
									    <th>' . __( 'Action', 'woothemes-sensei' ) . '</th>
								    </tr>
								</tfoot>';

					$message_class = '';
					if ( 0 < $question_count ) { $message_class = 'hidden'; }

					$html .= '<tbody id="no-questions-message" class="' . esc_attr( $message_class ) . '">';
						$html .= '<tr>';
							$html .= '<td colspan="5">' . __( 'There are no Questions for this Quiz yet. Please add some below.', 'woothemes-sensei' ) . '</td>';
						$html .= '</tr>';
					$html .= '</tbody>';

					if( 0 < $question_count ) {
						$html .= $this->quiz_panel_questions( $questions );
					}

					$html .= '</table>';

					if( ! isset( $this->question_order ) ) {
						$this->question_order = '';
					}

					$html .= '<input type="hidden" id="question-order" name="question-order" value="' . $this->question_order . '" />';

				$html .= '</div>';

				// Question Action Container DIV
				$html .= '<div id="add-question-actions">';

					$html .= $this->quiz_panel_add();

				$html .= '</div>';

			$html .= '</div>';

		$html .= '</div>';

		return $html;

	}

	public function quiz_panel_questions( $questions = array() ) {
		global $quiz_questions;

		$quiz_questions = $questions;

		$html = '';

		if( count( $questions ) > 0 ) {

			$question_class = '';
			$question_counter = 1;

			foreach ( $questions as $question ) {

				$question_id = $question->ID;

				$question_type = Sensei()->question->get_question_type( $question_id );

				$multiple_data = array();
				$question_increment = 1;
				if( 'multiple_question' == $question->post_type ) {
					$question_type = 'category';

					$question_category = get_post_meta( $question->ID, 'category', true );
					$question_cat = get_term( $question_category, 'question-category' );

					$question_number = get_post_meta( $question->ID, 'number', true );
					$question_increment = $question_number;

					$multiple_data = array( $question_cat->name, $question_number );
				}

				if( ! $question_type ) {
					$question_type = 'multiple-choice';
				}

				// Row with question and actions
				$html .= $this->quiz_panel_question( $question_type, $question_counter, $question_id, 'quiz', $multiple_data );
				$question_counter += $question_increment;

				if( isset( $this->question_order ) && strlen( $this->question_order ) > 0 ) { $this->question_order .= ','; }
				$this->question_order .= $question_id;
			} // End For Loop
		}

		return $html;

	}

	public function quiz_panel_question( $question_type = '', $question_counter = 0, $question_id = 0, $context = 'quiz', $multiple_data = array() ) {
		global $row_counter,  $quiz_questions;

		$html = '';

		$question_class = '';
		if( 'quiz' == $context ) {
			if( ! $row_counter || ! isset( $row_counter ) ) {
				$row_counter = 1;
			}
			if( $row_counter % 2 ) { $question_class = 'alternate'; }
			++$row_counter;
		}

		if( $question_id ) {

			if( $question_type != 'category' ) {

				$question_grade = Sensei()->question->get_question_grade( $question_id );

				$question_media = get_post_meta( $question_id, '_question_media', true );
				$question_media_type = $question_media_thumb = $question_media_link = $question_media_title = '';
				$question_media_thumb_class = $question_media_link_class = $question_media_delete_class = 'hidden';
				$question_media_add_button = __( 'Add file', 'woothemes-sensei' );
				if( 0 < intval( $question_media ) ) {
					$mimetype = get_post_mime_type( $question_media );
					if( $mimetype ) {
						$mimetype_array = explode( '/', $mimetype);
						if( isset( $mimetype_array[0] ) && $mimetype_array[0] ) {
							$question_media_delete_class = '';
							$question_media_type = $mimetype_array[0];
							if( 'image' == $question_media_type ) {
								$question_media_thumb = wp_get_attachment_thumb_url( $question_media );
								if( $question_media_thumb ) {
									$question_media_thumb_class = '';
								}
							}
							$question_media_url = wp_get_attachment_url( $question_media );
							if( $question_media_url ) {
								$attachment = get_post( $question_media );
								$question_media_title = $attachment->post_title;

								if( ! $question_media_title ) {
									$question_media_filename = basename( $question_media_url );
									$question_media_title = $question_media_filename;
								}
								$question_media_link = '<a class="' . $question_media_type . '" href="' . esc_url( $question_media_url ) . '" target="_blank">' . $question_media_title . '</a>';
								$question_media_link_class = '';
							}

							$question_media_add_button = __( 'Change file', 'woothemes-sensei' );
						}
					}
				}

				$random_order = get_post_meta( $question_id, '_random_order', true );
				if( ! $random_order ) {
					$random_order = 'yes';
				}

				if( ! $question_type ) { $question_type = 'multiple-choice'; }
			}

			$html .= '<tbody class="' . $question_class . '">';

				if( 'quiz' == $context ) {
					$html .= '<tr>';
						if( $question_type != 'category' ) {
							$question = get_post( $question_id );
							$html .= '<td class="table-count question-number question-count-column"><span class="number">' . $question_counter . '</span></td>';
							$html .= '<td>' . esc_html( $question->post_title ) . '</td>';
							$html .= '<td class="question-grade-column">' . esc_html( $question_grade ) . '</td>';
							$question_types_filtered = ucwords( str_replace( array( '-', 'boolean' ), array( ' ', __( 'True/False', 'woothemes-sensei' ) ), $question_type ) );
							$html .= '<td>' . esc_html( $question_types_filtered ) . '</td>';
							$html .= '<td><a title="' . esc_attr( __( 'Edit Question', 'woothemes-sensei' ) ) . '" href="#question_' . $question_counter .'" class="question_table_edit">' . esc_html( __( 'Edit', 'woothemes-sensei' ) ) . '</a> <a title="' . esc_attr( __( 'Remove Question', 'woothemes-sensei' ) ) . '" href="#add-question-metadata" class="question_table_delete">' . esc_html( __( 'Remove', 'woothemes-sensei' ) ) . '</a></td>';

						} else {

							$end_number = intval( $question_counter ) + intval( $multiple_data[1] ) - 1;
							if( $question_counter == $end_number ) {
								$row_numbers = $question_counter;
							} else {
								$row_numbers = $question_counter . ' - ' . $end_number;
							}
							$row_title = sprintf( __( 'Selected from \'%1$s\' ', 'woothemes-sensei' ), $multiple_data[0] );

							$html .= '<td class="table-count question-number question-count-column"><span class="number hidden">' . $question_counter . '</span><span class="hidden total-number">' . $multiple_data[1] . '</span><span class="row-numbers">' . esc_html( $row_numbers ) . '</span></td>';
							$html .= '<td>' . esc_html( $row_title ) . '</td>';
							$html .= '<td class="question-grade-column"></td>';
							$html .= '<td><input type="hidden" name="question_id" class="row_question_id" id="question_' . $question_counter . '_id" value="' . $question_id . '" /></td>';
							$html .= '<td><a title="' . esc_attr( __( 'Edit Question', 'woothemes-sensei' ) ) . '" href="#question_' . $question_counter .'" class="question_table_edit" style="visibility:hidden;">' . esc_html( __( 'Edit', 'woothemes-sensei' ) ) . '</a> <a title="' . esc_attr( __( 'Remove Question(s)', 'woothemes-sensei' ) ) . '" href="#add-question-metadata" class="question_multiple_delete" rel="' . $question_id . '">' . esc_html( __( 'Remove', 'woothemes-sensei' ) ) . '</a></td>';

						}
					$html .= '</tr>';
				}

				if( $question_type != 'category' ) {

					$edit_class = '';
					if( 'quiz' == $context ) {
						$edit_class = 'hidden';
					}

					$question = get_post( $question_id );
					$html .= '<tr class="question-quick-edit ' . esc_attr( $edit_class ) . '">';
						$html .= '<td colspan="5">';
							$html .= '<span class="hidden question_original_counter">' . $question_counter . '</span>';
					    	$html .= '<div class="question_required_fields">';

						    	// Question title
						    	$html .= '<div>';
							    	$html .= '<label for="question_' . $question_counter . '">' . __( 'Question:', 'woothemes-sensei' ) . '</label> ';
							    	$html .= '<input type="text" id="question_' . $question_counter . '" name="question" value="' . esc_attr( htmlspecialchars( $question->post_title ) ) . '" size="25" class="widefat" />';
						    	$html .= '</div>';

						    	// Question description
						    	$html .= '<div>';
							    	$html .= '<label for="question_' . $question_counter . '_desc">' . __( 'Question Description (optional):', 'woothemes-sensei' ) . '</label> ';
						    	$html .= '</div>';
							    	$html .= '<textarea id="question_' . $question_counter . '_desc" name="question_description" class="widefat" rows="4">' . esc_textarea( $question->post_content ) . '</textarea>';

						    	// Question grade
						    	$html .= '<div>';
							    	$html .= '<label for="question_' . $question_counter . '_grade">' . __( 'Question grade:', 'woothemes-sensei' ) . '</label> ';
							    	$html .= '<input type="number" id="question_' . $question_counter . '_grade" class="question_grade small-text" name="question_grade" min="0" value="' . $question_grade . '" />';
						    	$html .= '</div>';

						    	// Random order
						    	if( $question_type == 'multiple-choice' ) {
						    		$html .= '<div>';
						    			$html .= '<label for="' . $question_counter . '_random_order"><input type="checkbox" name="random_order" class="random_order" id="' . $question_counter . '_random_order" value="yes" ' . checked( $random_order, 'yes', false ) . ' /> ' . __( 'Randomise answer order', 'woothemes-sensei' ) . '</label>';
						    		$html .= '</div>';
						    	}

						    	// Question media
						    	$html .= '<div>';
							    	$html .= '<label for="question_' . $question_counter . '_media_button">' . __( 'Question media:', 'woothemes-sensei' ) . '</label><br/>';
							    	$html .= '<button id="question_' . $question_counter . '_media_button" class="upload_media_file_button button-secondary" data-uploader_title="' . __( 'Add file to question', 'woothemes-sensei' ) . '" data-uploader_button_text="' . __( 'Add to question', 'woothemes-sensei' ) . '">' . $question_media_add_button . '</button>';
							    	$html .= '<button id="question_' . $question_counter . '_media_button_delete" class="delete_media_file_button button-secondary ' . $question_media_delete_class . '">' . __( 'Delete file', 'woothemes-sensei' ) . '</button><br/>';
							    	$html .= '<span id="question_' . $question_counter . '_media_link" class="question_media_link ' . $question_media_link_class . '">' . $question_media_link . '</span>';
							    	$html .= '<br/><img id="question_' . $question_counter . '_media_preview" class="question_media_preview ' . $question_media_thumb_class . '" src="' . $question_media_thumb . '" /><br/>';
							    	$html .= '<input type="hidden" id="question_' . $question_counter . '_media" class="question_media" name="question_media" value="' . $question_media . '" />';
						    	$html .= '</div>';

						    $html .= '</div>';

						    $html .= $this->quiz_panel_question_field( $question_type, $question_id, $question_counter );

						    $html .= '<input type="hidden" id="question_' . $question_counter . '_question_type" class="question_type" name="question_type" value="' . $question_type . '" />';
							$html .= '<input type="hidden" name="question_id" class="row_question_id" id="question_' . $question_counter . '_id" value="' . $question_id . '" />';

							if( 'quiz' == $context ) {
					    		$html .= '<div class="update-question">';
						    		$html .= '<a href="#question-edit-cancel" class="lesson_question_cancel" title="' . esc_attr( __( 'Cancel', 'woothemes-sensei' ) ) . '">' . __( 'Cancel', 'woothemes-sensei' ) . '</a> ';
						    		$html .= '<a title="' . esc_attr( __( 'Update Question', 'woothemes-sensei' ) ) . '" href="#add-question-metadata" class="question_table_save button button-highlighted">' . esc_html( __( 'Update', 'woothemes-sensei' ) ) . '</a>';
					    		$html .= '</div>';
					    	}

			    		$html .= '</td>';
					$html .= '</tr>';
				}

			$html .= '</tbody>';

		}

		return $html;
	}

	public function quiz_panel_add( $context = 'quiz' ) {


		$html = '<div id="add-new-question">';

			$question_types = Sensei()->question->question_types();

			$question_cats = get_terms( 'question-category', array( 'hide_empty' => false ) );

			if( 'quiz' == $context ) {
	    		$html .= '<h2 class="nav-tab-wrapper add-question-tabs">';
	    			$html .= '<a id="tab-new" class="nav-tab nav-tab-active">' . __( 'New Question'  , 'woothemes-sensei' ) . '</a>';
	    			$html .= '<a id="tab-existing" class="nav-tab">' . __( 'Existing Questions'  , 'woothemes-sensei' ) . '</a>';
                    if ( ! empty( $question_cats ) && ! is_wp_error( $question_cats )  && ! Sensei()->teacher->is_admin_teacher() ) {
	    				$html .= '<a id="tab-multiple" class="nav-tab">' . __( 'Category Questions'  , 'woothemes-sensei' ) . '</a>';
	    			}
	    		$html .= '</h2>';
	    	}

	    	$html .= '<div class="tab-content" id="tab-new-content">';

	    		if( 'quiz' == $context ) {
	    			$html .= '<p><em>' . sprintf( __( 'Add a new question to this quiz - your question will also be added to the %1$squestion bank%2$s.', 'woothemes-sensei' ), '<a href="' . admin_url( 'edit.php?post_type=question' ) . '">', '</a>' ) . '</em></p>';
	    		}

				$html .= '<div class="question">';
					$html .= '<div class="question_required_fields">';

						// Question title
						$html .= '<p><label>' . __( 'Question:'  , 'woothemes-sensei' ) . '</label> ';
	  					$html .= '<input type="text" id="add_question" name="question" value="" size="25" class="widefat" /></p>';

						// Question description
						$html .= '<p>';
							$html .= '<label for="question_desc">' . __( 'Question Description (optional):', 'woothemes-sensei' ) . '</label> ';
						$html .= '</p>';
						$html .= '<textarea id="question_desc" name="question_description" class="widefat" rows="4"></textarea>';

	  					// Question type
						$html .= '<p><label>' . __( 'Question Type:' , 'woothemes-sensei' ) . '</label> ';
						$html .= '<select id="add-question-type-options" name="question_type" class="chosen_select widefat question-type-select">' . "\n";
							foreach ( $question_types as $type => $label ) {
								$html .= '<option value="' . esc_attr( $type ) . '">' . esc_html( $label ) . '</option>' . "\n";
							} // End For Loop
						$html .= '</select></p>' . "\n";

						// Question category
						if( 'quiz' == $context ) {
							if ( ! empty( $question_cats ) && ! is_wp_error( $question_cats ) ) {
								$html .= '<p><label>' . __( 'Question Category:' , 'woothemes-sensei' ) . '</label> ';
								$html .= '<select id="add-question-category-options" name="question_category" class="chosen_select widefat question-category-select">' . "\n";
								$html .= '<option value="">' . __( 'None', 'woothemes-sensei' ) . '</option>' . "\n";
								foreach( $question_cats as $cat ) {
									$html .= '<option value="' . esc_attr( $cat->term_id ) . '">' . esc_html( $cat->name ) . '</option>';
								} // End For Loop
								$html .= '</select></p>' . "\n";
							}
						}

	  					// Question grade
						$html .= '<p><label>' . __( 'Question Grade:'  , 'woothemes-sensei' ) . '</label> ';
						$html .= '<input type="number" id="add-question-grade" name="question_grade" class="small-text" min="0" value="1" /></p>' . "\n";

						// Random order
						$html .= '<p class="add_question_random_order">';
			    			$html .= '<label for="add_random_order"><input type="checkbox" name="random_order" class="random_order" id="add_random_order" value="yes" checked="checked" /> ' . __( 'Randomise answer order', 'woothemes-sensei' ) . '</label>';
			    		$html .= '</p>';

			    		// Question media
						$html .= '<p>';
					    	$html .= '<label for="question_add_new_media_button">' . __( 'Question media:', 'woothemes-sensei' ) . '</label><br/>';
					    	$html .= '<button id="question_add_new_media_button" class="upload_media_file_button button-secondary" data-uploader_title="' . __( 'Add file to question', 'woothemes-sensei' ) . '" data-uploader_button_text="' . __( 'Add to question', 'woothemes-sensei' ) . '">' . __( 'Add file', 'woothemes-sensei' ) . '</button>';
					    	$html .= '<button id="question_add_new_media_button_delete" class="delete_media_file_button button-secondary hidden">' . __( 'Delete file', 'woothemes-sensei' ) . '</button><br/>';
					    	$html .= '<span id="question_add_new_media_link" class="question_media_link hidden"></span>';
					    	$html .= '<br/><img id="question_add_new_media_preview" class="question_media_preview hidden" src="" /><br/>';
					    	$html .= '<input type="hidden" id="question_add_new_media" class="question_media" name="question_media" value="" />';
				    	$html .= '</p>';

					$html .= '</div>';
				$html .= '</div>';

				foreach ( $question_types as $type => $label ) {
					$html .= $this->quiz_panel_question_field( $type );
				}

				if( 'quiz' == $context ) {
					$html .= '<div class="add-question">';
			    		$html .= '<a title="' . esc_attr( __( 'Add Question', 'woothemes-sensei' ) ) . '" href="#add-question-metadata" class="add_question_save button button-primary button-highlighted">' . esc_html( __( 'Add Question', 'woothemes-sensei' ) ) . '</a>';
		    		$html .= '</div>';
		    	}

		    $html .= '</div>';

		    if( 'quiz' == $context ) {

			    $html .= '<div class="tab-content hidden" id="tab-existing-content">';

			    	$html .= '<p><em>' . sprintf( __( 'Add an existing question to this quiz from the %1$squestion bank%2$s.', 'woothemes-sensei' ), '<a href="' . admin_url( 'edit.php?post_type=question' ) . '">', '</a>' ) . '</em></p>';

			    	$html .= '<div id="existing-filters" class="alignleft actions">
			    				<select id="existing-status">
			    					<option value="all">' . __( 'All', 'woothemes-sensei' ) . '</option>
			    					<option value="unused">' . __( 'Unused', 'woothemes-sensei' ) . '</option>
			    					<option value="used">' . __( 'Used', 'woothemes-sensei' ) . '</option>
			    				</select>
			    				<select id="existing-type">
			    					<option value="">' . __( 'All Types', 'woothemes-sensei' ) . '</option>';
							    	foreach ( $question_types as $type => $label ) {
										$html .= '<option value="' . esc_attr( $type ) . '">' . esc_html( $label ) . '</option>';
									}
    				$html .= '</select>
    							<select id="existing-category">
			    					<option value="">' . __( 'All Categories', 'woothemes-sensei' ) . '</option>';
				    				foreach( $question_cats as $cat ) {
										$html .= '<option value="' . esc_attr( $cat->slug ) . '">' . esc_html( $cat->name ) . '</option>';
									}
    				$html .= '</select>
    							<input type="text" id="existing-search" placeholder="' . __( 'Search', 'woothemes-sensei' ) . '" />
    							<a class="button" id="existing-filter-button">' . __( 'Filter', 'woothemes-sensei' ) . '</a>
			    			</div>';

			    	$html .= '<table id="existing-table" class="widefat">';

			    		$html .= '<thead>
									    <tr>
									        <th scope="col" class="column-cb check-column"><input type="checkbox" /></th>
									        <th scope="col">' . __( 'Question', 'woothemes-sensei' ) . '</th>
									        <th scope="col">' . __( 'Type', 'woothemes-sensei' ) . '</th>
									        <th scope="col">' . __( 'Category', 'woothemes-sensei' ) . '</th>
									    </tr>
									</thead>
									<tfoot>
									    <tr>
										    <th scope="col" class="check-column"><input type="checkbox" /></th>
									        <th scope="col">' . __( 'Question', 'woothemes-sensei' ) . '</th>
									        <th scope="col">' . __( 'Type', 'woothemes-sensei' ) . '</th>
									        <th scope="col">' . __( 'Category', 'woothemes-sensei' ) . '</th>
									    </tr>
									</tfoot>';
						$html .= '<tbody id="existing-questions">';

						$questions = $this->quiz_panel_get_existing_questions();

						$row = 1;
						foreach( $questions['questions'] as $question ) {
							$html .= $this->quiz_panel_add_existing_question( $question->ID, $row );
							++$row;
						}

						$html .= '</tbody>';

			    	$html .= '</table>';

			    	$next_class = '';
			    	if( $questions['count'] <= 10 ) {
			    		$next_class = 'hidden';
			    	}

			    	$html .= '<div id="existing-pagination">';
			    		$html .= '<input type="hidden" id="existing-page" value="1" />';
			    		$html .= '<a class="prev no-paging">&larr; ' . __( 'Previous', 'woothemes-sensei') . '</a> <a class="next ' . esc_attr( $next_class ) . '">' . __( 'Next', 'woothemes-sensei') . ' &rarr;</a>';
			    	$html .= '</div>';

			    	$html .= '<div class="existing-actions">';
			    		$html .= '<a title="' . esc_attr( __( 'Add Selected Question(s)', 'woothemes-sensei' ) ) . '" class="add_existing_save button button-primary button-highlighted">' . esc_html( __( 'Add Selected Question(s)', 'woothemes-sensei' ) ) . '</a></p>';
			    	$html .= '</div>';

			    $html .= '</div>';

			    if ( ! empty( $question_cats ) && ! is_wp_error( $question_cats ) ) {
				    $html .= '<div class="tab-content hidden" id="tab-multiple-content">';

				    	$html .= '<p><em>' . sprintf( __( 'Add any number of questions from a specified category. Edit your question categories %1$shere%2$s.', 'woothemes-sensei' ), '<a href="' . admin_url( 'edit-tags.php?taxonomy=question-category&post_type=question' ) . '">', '</a>' ) . '</em></p>';

						$html .= '<p><select id="add-multiple-question-category-options" name="multiple_category" class="chosen_select widefat question-category-select">' . "\n";
						$html .= '<option value="">' . __( 'Select a Question Category', 'woothemes-sensei' ) . '</option>' . "\n";
						foreach( $question_cats as $cat ) {
							$html .= '<option value="' . esc_attr( $cat->term_id ) . '">' . esc_html( $cat->name ) . '</option>';
						} // End For Loop
						$html .= '</select></p>' . "\n";

						$html .= '<p>' . __( 'Number of questions:', 'woothemes-sensei' ) . ' <input type="number" min="1" value="1" max="1" id="add-multiple-question-count" class="small-text"/>';

						$html .= '<a title="' . esc_attr( __( 'Add Question(s)', 'woothemes-sensei' ) ) . '" class="add_multiple_save button button-primary button-highlighted">' . esc_html( __( 'Add Question(s)', 'woothemes-sensei' ) ) . '</a></p>';

				    $html .= '</div>';
				}
			}

		$html .= '</div>';

		return $html;
	}

	public function quiz_panel_get_existing_questions( $question_status = 'all', $question_type = '', $question_category = '', $question_search = '', $page = 1 ) {

		$args = array(
			'post_type' => 'question',
			'posts_per_page' => 10,
			'post_status' => 'publish',
			'suppress_filters' => 0,
		);

		switch( $question_status ) {
			case 'unused': $quiz_status = 'NOT EXISTS'; break;
			case 'used': $quiz_status = 'EXISTS'; break;
			default: $quiz_status = ''; break;
		}

		if( $quiz_status ) {
			switch( $quiz_status ) {
				case 'EXISTS':
					$args['meta_query'][] = array(
						'key' => '_quiz_id',
						'compare' => $quiz_status,
					);
				break;

				case 'NOT EXISTS':
					$args['meta_query'][] = array(
						'key' => '_quiz_id',
						'value' => 'bug #23268',
						'compare' => $quiz_status,
					);
				break;
			}
		}

		if( $question_type ) {
			$args['tax_query'][] = array(
				'taxonomy' => 'question-type',
				'field' => 'slug',
				'terms' => $question_type,
			);
		}

		if( $question_category ) {
			$args['tax_query'][] = array(
				'taxonomy' => 'question-category',
				'field' => 'slug',
				'terms' => $question_category,
			);
		}

		if( $question_type && $question_category ) {
			$args['tax_query']['relation'] = 'AND';
		}

		if( $question_search ) {
			$args['s'] = $question_search;
		}

		if( $page ) {
			$args['paged'] = $page;
		}

		$qry = new WP_Query( $args );

        /**
         * Filter existing questions query
         *
         * @since 1.8.0
         *
         * @param WP_Query $wp_query
         */
        $qry = apply_filters( 'sensei_existing_questions_query_results', $qry );

		$questions['questions'] = $qry->posts;
		$questions['count'] = intval( $qry->found_posts );
		$questions['page'] = $page;

		return $questions;
	}

	public function quiz_panel_add_existing_question( $question_id = 0, $row = 1 ) {

		$html = '';

		if( ! $question_id ) {

            return;

        }

		$existing_class = '';
		if( $row % 2 ) {
            $existing_class = 'alternate';
        }

		$question_type = Sensei()->question->get_question_type( $question_id );

		$question_cat_list = strip_tags( get_the_term_list( $question_id, 'question-category', '', ', ', '' ) );

		$html .= '<tr class="' . esc_attr( $existing_class ) . '">
					<td class="cb"><input type="checkbox" value="' . $question_id . '" class="existing-item" /></td>
					<td>' . get_the_title( $question_id ) . '</td>
					<td>' . esc_html( $question_type ) . '</td>
					<td>' . esc_html( $question_cat_list ) . '</td>
				  </tr>';

		return $html;

	}

	public function quiz_panel_filter_existing_questions() {

		$return = '';

		//Add nonce security to the request
		$nonce = '';
		if( isset( $_POST['filter_existing_questions_nonce'] ) ) {
			$nonce = esc_html( $_POST['filter_existing_questions_nonce'] );
		} // End If Statement

		if( ! wp_verify_nonce( $nonce, 'filter_existing_questions_nonce' ) ) {
			die( $return );
		} // End If Statement

		// Parse POST data
		$data = $_POST['data'];
		$question_data = array();
		parse_str( $data, $question_data );

		if( 0 < count( $question_data ) ) {

			$question_status = '';
			if( isset( $question_data['question_status'] ) ) {
				$question_status = $question_data['question_status'];
			}

			$question_type = '';
			if( isset( $question_data['question_type'] ) ) {
				$question_type = $question_data['question_type'];
			}

			$question_category = '';
			if( isset( $question_data['question_category'] ) ) {
				$question_category = $question_data['question_category'];
			}

			$question_search = '';
			if( isset( $question_data['question_search'] ) ) {
				$question_search = $question_data['question_search'];
			}

			$question_page = 1;
			if( isset( $question_data['question_page'] ) ) {
				$question_page = intval( $question_data['question_page'] );
			}

			$questions = $this->quiz_panel_get_existing_questions( $question_status, $question_type, $question_category, $question_search, $question_page );

			$row = 1;
			$html = '';
			foreach( $questions['questions'] as $question ) {
				$html .= $this->quiz_panel_add_existing_question( $question->ID, $row );
				++$row;
			}

			if( ! $html ) {
				$html = '<tr class="alternate">
								<td class="no-results" colspan="4"><em>' . __( 'There are no questions matching your search.', 'woothemes-sensei' ) . '</em></td>
							  </tr>';
			}

			$return['html'] = $html;
			$return['count'] = $questions['count'];
			$return['page'] = $questions['page'];

			wp_send_json( $return );
		}

		die( $return );
	}

	public function quiz_panel_question_field( $question_type = '', $question_id = 0, $question_counter = 0 ) {

		$html = '';

		if( $question_type ) {

			$right_answer = '';
			$wrong_answers = array();
			$answer_order_string = '';
			$answer_order = array();
			if( $question_id ) {
				$right_answer = get_post_meta( $question_id, '_question_right_answer', true);
				$wrong_answers = get_post_meta( $question_id, '_question_wrong_answers', true);
				$answer_order_string = get_post_meta( $question_id, '_answer_order', true );
				$answer_order = array_filter( explode( ',', $answer_order_string ) );
				$question_class = '';
			} else {
				$question_id = '';
				$question_class = 'answer-fields question_required_fields hidden';
			}

			switch ( $question_type ) {
				case 'multiple-choice':
					$html .= '<div class="question_default_fields multiple-choice-answers ' . str_replace( ' hidden', '', $question_class ) . '">';

						$right_answers = (array) $right_answer;
						// Calculate total right answers available (defaults to 1)
						$total_right = 0;
						if( $question_id ) {
							$total_right = get_post_meta( $question_id, '_right_answer_count', true );
						}
						if( 0 == intval( $total_right ) ) {
							$total_right = 1;
						}
						for ( $i = 0; $i < $total_right; $i++ ) {
							if ( !isset( $right_answers[ $i ] ) ) { $right_answers[ $i ] = ''; }
							$right_answer_id = $this->get_answer_id( $right_answers[ $i ] );
							// Right Answer
							$right_answer = '<label class="answer" for="question_' . $question_counter . '_right_answer_' . $i . '"><span>' . __( 'Right:' , 'woothemes-sensei' ) . '</span> <input rel="' . esc_attr( $right_answer_id ) . '" type="text" id="question_' . $question_counter . '_right_answer_' . $i . '" name="question_right_answers[]" value="' . esc_attr( $right_answers[ $i ] ) . '" size="25" class="question_answer widefat" /> <a class="remove_answer_option"></a></label>';
							if( $question_id ) {
								$answers[ $right_answer_id ] = $right_answer;
							} else {
								$answers[] = $right_answer;
							}
						}

				    	// Calculate total wrong answers available (defaults to 4)
				    	$total_wrong = 0;
				    	if( $question_id ) {
				    		$total_wrong = get_post_meta( $question_id, '_wrong_answer_count', true );
				    	}
				    	if( 0 == intval( $total_wrong ) ) {
				    		$total_wrong = 1;
				    	}

                        // Setup Wrong Answer HTML
                        foreach ( $wrong_answers as $i => $answer ){

                            $answer_id = $this->get_answer_id( $answer );
                            $wrong_answer = '<label class="answer" for="question_' . $question_counter . '_wrong_answer_' . $i . '"><span>' . __( 'Wrong:' , 'woothemes-sensei' ) ;
                            $wrong_answer .= '</span> <input rel="' . esc_attr( $answer_id ) . '" type="text" id="question_' . $question_counter . '_wrong_answer_' . $i ;
                            $wrong_answer .= '" name="question_wrong_answers[]" value="' . esc_attr( $answer ) . '" size="25" class="question_answer widefat" /> <a class="remove_answer_option"></a></label>';
                            if( $question_id ) {

                                $answers[ $answer_id ] = $wrong_answer;

                            } else {

                                $answers[] = $wrong_answer;

                            }

                        } // end for each

				    	$answers_sorted = $answers;
				    	if( $question_id && count( $answer_order ) > 0 ) {
				    		$answers_sorted = array();
				    		foreach( $answer_order as $answer_id ) {
				    			if( isset( $answers[ $answer_id ] ) ) {
				    				$answers_sorted[ $answer_id ] = $answers[ $answer_id ];
				    				unset( $answers[ $answer_id ] );
				    			}
				    		}

				    		if( count( $answers ) > 0 ) {
						    	foreach( $answers as $id => $answer ) {
						    		$answers_sorted[ $id ] = $answer;
						    	}
						    }
				    	}

						foreach( $answers_sorted as $id => $answer ) {
				    		$html .= $answer;
				    	}

				    	$html .= '<input type="hidden" class="answer_order" name="answer_order" value="' . $answer_order_string . '" />';
				    	$html .= '<span class="hidden right_answer_count">' . $total_right . '</span>';
				    	$html .= '<span class="hidden wrong_answer_count">' . $total_wrong . '</span>';

				    	$html .= '<div class="add_answer_options">';
					    	$html .= '<a class="add_right_answer_option add_answer_option button" rel="' . $question_counter . '">' . __( 'Add right answer', 'woothemes-sensei' ) . '</a>';
					    	$html .= '<a class="add_wrong_answer_option add_answer_option button" rel="' . $question_counter . '">' . __( 'Add wrong answer', 'woothemes-sensei' ) . '</a>';
				    	$html .= '</div>';

                        $html .= $this->quiz_panel_question_feedback( $question_counter, $question_id , 'multiple-choice' );

			    	$html .= '</div>';
				break;
				case 'boolean':
					$html .= '<div class="question_boolean_fields ' . $question_class . '">';
						if( $question_id ) {
							$field_name = 'question_' . $question_id . '_right_answer_boolean';
						} else {
							$field_name = 'question_right_answer_boolean';
							$right_answer = 'true';
						}
						$html .= '<label for="question_' . $question_id . '_boolean_true"><input id="question_' . $question_id . '_boolean_true" type="radio" name="' . $field_name . '" value="true" '. checked( $right_answer, 'true', false ) . ' /> ' . __( 'True', 'woothemes-sensei' ) . '</label>';
						$html .= '<label for="question_' . $question_id . '_boolean_false"><input id="question_' . $question_id . '_boolean_false" type="radio" name="' . $field_name . '" value="false" '. checked( $right_answer, 'false', false ) . ' /> ' . __( 'False', 'woothemes-sensei' ) . '</label>';

                    $html .= $this->quiz_panel_question_feedback( $question_counter, $question_id, 'boolean' );

					$html .= '</div>';
				break;
				case 'gap-fill':
					$gapfill_array = explode( '||', $right_answer );
					if ( isset( $gapfill_array[0] ) ) { $gapfill_pre = $gapfill_array[0]; } else { $gapfill_pre = ''; }
					if ( isset( $gapfill_array[1] ) ) { $gapfill_gap = $gapfill_array[1]; } else { $gapfill_gap = ''; }
					if ( isset( $gapfill_array[2] ) ) { $gapfill_post = $gapfill_array[2]; } else { $gapfill_post = ''; }
					$html .= '<div class="question_gapfill_fields ' . $question_class . '">';
						// Fill in the Gaps
						$html .= '<label>' . __( 'Text before the Gap:' , 'woothemes-sensei' ) . '</label> ';
						$html .= '<input type="text" id="question_' . $question_counter . '_add_question_right_answer_gapfill_pre" name="add_question_right_answer_gapfill_pre" value="' . $gapfill_pre . '" size="25" class="widefat gapfill-field" />';
	  					$html .= '<label>' . __( 'The Gap:' , 'woothemes-sensei' ) . '</label> ';
	  					$html .= '<input type="text" id="question_' . $question_counter . '_add_question_right_answer_gapfill_gap" name="add_question_right_answer_gapfill_gap" value="' . $gapfill_gap . '" size="25" class="widefat gapfill-field" />';
	  					$html .= '<label>' . __( 'Text after the Gap:' , 'woothemes-sensei' ) . '</label> ';
	  					$html .= '<input type="text" id="question_' . $question_counter . '_add_question_right_answer_gapfill_post" name="add_question_right_answer_gapfill_post" value="' . $gapfill_post . '" size="25" class="widefat gapfill-field" />';
	  					$html .= '<label>' . __( 'Preview:' , 'woothemes-sensei' ) . '</label> ';
	  					$html .= '<p class="gapfill-preview">' . $gapfill_pre . '&nbsp;<u>' . $gapfill_gap . '</u>&nbsp;' . $gapfill_post . '</p>';
	  				$html .= '</div>';
				break;
				case 'multi-line':
					$html .= '<div class="question_multiline_fields ' . $question_class . '">';
						// Guides for grading
						if( $question_counter ) {
							$field_id = 'question_' . $question_counter . '_add_question_right_answer_multiline';
						} else {
							$field_id = 'add_question_right_answer_multiline';
						}
						$html .= '<label>' . __( 'Guide/Teacher Notes for grading the answer' , 'woothemes-sensei' ) . '</label> ';
						$html .= '<textarea id="' . $field_id . '" name="add_question_right_answer_multiline" rows="4" cols="40" class="widefat">' . $right_answer . '</textarea>';
					$html .= '</div>';
				break;
				case 'single-line':
					$html .= '<div class="question_singleline_fields ' . $question_class . '">';
						// Recommended Answer
						if( $question_counter ) {
							$field_id = 'question_' . $question_counter . '_add_question_right_answer_singleline';
						} else {
							$field_id = 'add_question_right_answer_singleline';
						}
						$html .= '<label>' . __( 'Recommended Answer' , 'woothemes-sensei' ) . '</label> ';
						$html .= '<input type="text" id="' . $field_id . '" name="add_question_right_answer_singleline" value="' . $right_answer . '" size="25" class="widefat" />';
					$html .= '</div>';
				break;
				case 'file-upload':
					$html .= '<div class="question_fileupload_fields ' . $question_class . '">';
						if( $question_counter ) {
							$right_field_id = 'question_' . $question_counter . '_add_question_right_answer_fileupload';
							$wrong_field_id = 'question_' . $question_counter . '_add_question_wrong_answer_fileupload';
						} else {
							$right_field_id = 'add_question_right_answer_fileupload';
							$wrong_field_id = 'add_question_wrong_answer_fileupload';
						}

						$wrong_answer = '';
						if( isset( $wrong_answers[0] ) ) {
							$wrong_answer = $wrong_answers[0];
						}
						$html .= '<label>' . __( 'Description for student explaining what needs to be uploaded' , 'woothemes-sensei' ) . '</label> ';
						$html .= '<textarea id="' . $wrong_field_id . '" name="add_question_wrong_answer_fileupload" rows="4" cols="40" class="widefat">' . $wrong_answer . '</textarea>';

						// Guides for grading
						$html .= '<label>' . __( 'Guide/Teacher Notes for grading the upload' , 'woothemes-sensei' ) . '</label> ';
						$html .= '<textarea id="' . $right_field_id . '" name="add_question_right_answer_fileupload" rows="4" cols="40" class="widefat">' . $right_answer . '</textarea>';
					$html .= '</div>';
				break;
			}
		}

		return $html;
	}

	public function quiz_panel_question_feedback( $question_counter = 0, $question_id = 0, $question_type = '' ) {

        // default field name
        $field_name = 'answer_feedback';
        if( 'boolean' == $question_type ){

            $field_name = 'answer_feedback_boolean';

        }elseif( 'multiple-choice' == $question_type ){

            $field_name = 'answer_feedback_multiple_choice';

        }// end if

		if( $question_counter ) {
			$field_name = 'answer_' . $question_counter . '_feedback';
		}

		$feedback = '';
		if( $question_id ) {
			$feedback = get_post_meta( $question_id, '_answer_feedback', true );
		}

		$html = '<p title="' . __( 'This feedback will be automatically displayed to the student once they have completed the quiz.', 'woothemes-sensei' ) . '">';
		$html .= '<label for="' . $field_name . '">' . __( 'Answer Feedback' , 'woothemes-sensei' ) . ':</label>';
		$html .= '<textarea id="' . $field_name . '" name="' . $field_name . '" rows="4" cols="40" class="answer_feedback widefat">' . $feedback . '</textarea>';
		$html .= '</p>';

		return $html;
	}

	public function question_get_answer_id() {
		$data = $_POST['data'];
		$answer_data = array();
		parse_str( $data, $answer_data );
		$answer = $answer_data['answer_value'];
		$answer_id = $this->get_answer_id( $answer );
		echo $answer_id;
		die();
	}

	public function get_answer_id( $answer = '' ) {

		$answer_id = '';

		if( $answer ) {
			$answer_id = md5( $answer );
		}

		return $answer_id;

	}

	/**
	 * lesson_quiz_meta_box_content function.
	 *
	 * @access public
	 * @return void
	 */
	public function lesson_quiz_meta_box_content () {
		global $post;

		// Get quiz panel
		$quiz_id = 0;
		$quizzes = array();
		if ( 0 < $post->ID ) {
			$quiz_id = $this->lesson_quizzes( $post->ID, 'any' );
		}

		echo $this->quiz_panel( $quiz_id );

	} // End lesson_quiz_meta_box_content()

	/**
	 * Quiz settings metabox
	 * @return void
	 */
	public function lesson_quiz_settings_meta_box_content() {
		global $post;

		$html = '';

		// Get quiz panel
		$quiz_id = 0;
		$lesson_id = $post->ID;
		$quizzes = array();
		if ( 0 < $lesson_id ) {
			$quiz_id = $this->lesson_quizzes( $lesson_id, 'any' );
		}

		if( $quiz_id ) {
			$html .= $this->quiz_settings_panel( $lesson_id, $quiz_id );
		} else {
			$html .= '<p><em>' . __( 'There is no quiz for this lesson yet - please add one in the \'Quiz Questions\' box.', 'woothemes-sensei' ) . '</em></p>';
		}

		echo $html;
	}

	public function quiz_settings_panel( $lesson_id = 0, $quiz_id = 0 ) {


		$html = '';

		if( ! $lesson_id && ! $quiz_id ) return $html;

		$settings = $this->get_quiz_settings( $quiz_id );

		$html = Sensei()->admin->render_settings( $settings, $quiz_id, 'quiz-settings' );

		return $html;

	}

	public function get_quiz_settings( $quiz_id = 0 ) {

		$disable_passmark = '';
		$pass_required = get_post_meta( $quiz_id, '_pass_required', true );
		if( ! $pass_required ) {
			$disable_passmark = 'hidden';
		}

		// Setup Questions Query
		$questions = array();
		if ( 0 < $quiz_id ) {
			$questions = $this->lesson_quiz_questions( $quiz_id );
		}

		// Count questions
		$question_count = 0;
		foreach( $questions as $question ) {
			if( $question->post_type == 'multiple_question' ) {
				$question_number = get_post_meta( $question->ID, 'number', true );
				$question_count += $question_number;
			} else {
				++$question_count;
			}
		}

		$settings = array(
			array(
				'id' 			=> 'pass_required',
				'label'			=> __( 'Pass required to complete lesson', 'woothemes-sensei' ),
				'description'	=> __( 'The passmark must be achieved before the lesson is complete.', 'woothemes-sensei' ),
				'type'			=> 'checkbox',
				'default'		=> '',
				'checked'		=> 'on',
			),
			array(
				'id' 			=> 'quiz_passmark',
				'label'			=> __( 'Quiz passmark percentage', 'woothemes-sensei' ),
				'description'	=> '',
				'type'			=> 'number',
				'default'		=> 0,
				'placeholder'	=> 0,
				'min'			=> 0,
				'max'			=> 100,
				'class'			=> $disable_passmark,
			),
			array(
				'id' 			=> 'show_questions',
				'label'			=> __( 'Number of questions to show', 'woothemes-sensei' ),
				'description'	=> __( 'Show a random selection of questions from this quiz each time a student views it.', 'woothemes-sensei' ),
				'type'			=> 'number',
				'default'		=> '',
				'placeholder'	=> __( 'All', 'woothemes-sensei' ),
				'min'			=> 1,
				'max'			=> $question_count,
			),
			array(
				'id' 			=> 'random_question_order',
				'label'			=> __( 'Randomise question order', 'woothemes-sensei' ),
				'description'	=> '',
				'type'			=> 'checkbox',
				'default'		=> 'no',
				'checked'		=> 'yes',
			),
			array(
				'id' 			=> 'quiz_grade_type',
				'label'			=> __( 'Grade quiz automatically', 'woothemes-sensei' ),
				'description'	=> __( 'Grades quiz and displays answer explanation immediately after completion. Only applicable if quiz is limited to Multiple Choice, True/False and Gap Fill questions. Questions that have a grade of zero are skipped during autograding.', 'woothemes-sensei' ),
				'type'			=> 'checkbox',
				'default'		=> 'auto',
				'checked'		=> 'auto',
			),
			array(
				'id' 			=> 'enable_quiz_reset',
				'label'			=> __( 'Allow user to retake the quiz', 'woothemes-sensei' ),
				'description'	=> __( 'Enables the quiz reset button.', 'woothemes-sensei' ),
				'type'			=> 'checkbox',
				'default'		=> '',
				'checked'		=> 'on',
			),
		);

		return apply_filters( 'sensei_quiz_settings', $settings );
	}

	/**
	 * enqueue_scripts function.
	 *
	 * @access public
	 * @return void
	 */
	public function enqueue_scripts( $hook ) {
		global  $post_type;

		$allowed_post_types = apply_filters( 'sensei_scripts_allowed_post_types', array( 'lesson', 'course', 'question' ) );
		$allowed_post_type_pages = apply_filters( 'sensei_scripts_allowed_post_type_pages', array( 'edit.php', 'post-new.php', 'post.php', 'edit-tags.php' ) );
		$allowed_pages = apply_filters( 'sensei_scripts_allowed_pages', array( 'sensei_grading', 'sensei_analysis', 'sensei_learners', 'sensei_updates', 'woothemes-sensei-settings', 'lesson-order' ) );

		// Test for Write Panel Pages
		if ( ( ( isset( $post_type ) && in_array( $post_type, $allowed_post_types ) ) && ( isset( $hook ) && in_array( $hook, $allowed_post_type_pages ) ) ) || ( isset( $_GET['page'] ) && in_array( $_GET['page'], $allowed_pages ) ) ) {

			$suffix = defined( 'SCRIPT_DEBUG' ) && SCRIPT_DEBUG ? '' : '.min';

			// Load the lessons script
            wp_enqueue_media();
			wp_enqueue_script( 'sensei-lesson-metadata', Sensei()->plugin_url . 'assets/js/lesson-metadata' . $suffix . '.js', array( 'jquery', 'sensei-core-select2' ,'jquery-ui-sortable' ), Sensei()->version, true );
			wp_enqueue_script( 'sensei-lesson-chosen', Sensei()->plugin_url . 'assets/chosen/chosen.jquery' . $suffix . '.js', array( 'jquery' ), Sensei()->version, true );
			wp_enqueue_script( 'sensei-chosen-ajax', Sensei()->plugin_url . 'assets/chosen/ajax-chosen.jquery' . $suffix . '.js', array( 'jquery', 'sensei-lesson-chosen' ), Sensei()->version, true );

            // Load the bulk edit screen script
            if( 'edit.php' == $hook && 'lesson'==$_GET['post_type'] ) {
                wp_enqueue_script( 'sensei-lessons-bulk-edit', Sensei()->plugin_url . 'assets/js/admin/lesson-bulk-edit' . $suffix . '.js', array( 'jquery' ), Sensei()->version , true);
            }

			// Localise script
			$translation_strings = array( 'right_colon' => __( 'Right:', 'woothemes-sensei' ), 'wrong_colon' => __( 'Wrong:', 'woothemes-sensei' ), 'add_file' => __( 'Add file', 'woothemes-sensei' ), 'change_file' => __( 'Change file', 'woothemes-sensei' ), 'confirm_remove' => __( 'Are you sure you want to remove this question?', 'woothemes-sensei' ), 'confirm_remove_multiple' => __( 'Are you sure you want to remove these questions?', 'woothemes-sensei' ), 'too_many_for_cat' => __( 'You have selected more questions than this category contains - please reduce the number of questions that you are adding.', 'woothemes-sensei' ) );
			$ajax_vars = array( 'lesson_update_question_nonce' => wp_create_nonce( 'lesson_update_question_nonce' ), 'lesson_add_course_nonce' => wp_create_nonce( 'lesson_add_course_nonce' ), 'lesson_update_grade_type_nonce' => wp_create_nonce( 'lesson_update_grade_type_nonce' ), 'lesson_update_question_order_nonce' => wp_create_nonce( 'lesson_update_question_order_nonce' ), 'lesson_update_question_order_random_nonce' => wp_create_nonce( 'lesson_update_question_order_random_nonce' ), 'lesson_add_multiple_questions_nonce' => wp_create_nonce( 'lesson_add_multiple_questions_nonce' ), 'lesson_remove_multiple_questions_nonce' => wp_create_nonce( 'lesson_remove_multiple_questions_nonce' ), 'lesson_add_existing_questions_nonce' => wp_create_nonce( 'lesson_add_existing_questions_nonce' ), 'filter_existing_questions_nonce' => wp_create_nonce( 'filter_existing_questions_nonce' ) );
			$data = array_merge( $translation_strings, $ajax_vars );
			wp_localize_script( 'sensei-lesson-metadata', 'woo_localized_data', $data );

			// Chosen RTL
			if ( is_rtl() ) {
				wp_enqueue_script( 'sensei-chosen-rtl', Sensei()->plugin_url . 'assets/chosen/chosen-rtl' . $suffix . '.js', array( 'jquery' ), Sensei()->version, true );
			}

		}

	} // End enqueue_scripts()

	/**
	 * Load in CSS styles where necessary.
	 *
	 * @access public
	 * @since  1.4.0
	 * @return void
	 */
	public function enqueue_styles ( $hook ) {
		global  $post_type;

		$allowed_post_types = apply_filters( 'sensei_scripts_allowed_post_types', array( 'lesson', 'course', 'question', 'sensei_message' ) );
		$allowed_post_type_pages = apply_filters( 'sensei_scripts_allowed_post_type_pages', array( 'edit.php', 'post-new.php', 'post.php', 'edit-tags.php' ) );
		$allowed_pages = apply_filters( 'sensei_scripts_allowed_pages', array( 'sensei_grading', 'sensei_analysis', 'sensei_learners', 'sensei_updates', 'woothemes-sensei-settings' ) );

		// Test for Write Panel Pages
		if ( ( ( isset( $post_type ) && in_array( $post_type, $allowed_post_types ) ) && ( isset( $hook ) && in_array( $hook, $allowed_post_type_pages ) ) ) || ( isset( $_GET['page'] ) && in_array( $_GET['page'], $allowed_pages ) ) ) {
			wp_enqueue_style( 'woothemes-sensei-settings-api', esc_url( Sensei()->plugin_url . 'assets/css/settings.css' ), '', Sensei()->version );
		}

	} // End enqueue_styles()

	/**
	 * Add column headings to the "lesson" post list screen.
	 * @access public
	 * @since  1.0.0
	 * @param  array $defaults
	 * @return array $new_columns
	 */
	public function add_column_headings ( $defaults ) {

This method seems to be duplicated in your project.

		$new_columns['cb'] = '<input type="checkbox" />';
		$new_columns['title'] = _x( 'Lesson Title', 'column name', 'woothemes-sensei' );
		$new_columns['lesson-course'] = _x( 'Course', 'column name', 'woothemes-sensei' );
		$new_columns['lesson-prerequisite'] = _x( 'Pre-requisite Lesson', 'column name', 'woothemes-sensei' );
		if ( isset( $defaults['date'] ) ) {
			$new_columns['date'] = $defaults['date'];
		}
		return $new_columns;
	} // End add_column_headings()

	/**
	 * Add data for our newly-added custom columns.
	 * @access public
	 * @since  1.0.0
	 * @param  string $column_name
	 * @param  int $id
	 * @return void
	 */
	public function add_column_data ( $column_name, $id ) {
		global $wpdb, $post;

		switch ( $column_name ) {
			case 'id':
				echo $id;
			break;
			case 'lesson-course':

This code seems to be duplicated across your project.

				$lesson_course_id = get_post_meta( $id, '_lesson_course', true);
				if ( 0 < absint( $lesson_course_id ) ) {
					echo '<a href="' . esc_url( get_edit_post_link( absint( $lesson_course_id ) ) ) . '" title="' . esc_attr( sprintf( __( 'Edit %s', 'woothemes-sensei' ), get_the_title( absint( $lesson_course_id ) ) ) ) . '">' . get_the_title( absint( $lesson_course_id ) ) . '</a>';
				} // End If Statement
			break;
			case 'lesson-prerequisite':

This code seems to be duplicated across your project.

				$lesson_prerequisite_id = get_post_meta( $id, '_lesson_prerequisite', true);
				if ( 0 < absint( $lesson_prerequisite_id ) ) {
					echo '<a href="' . esc_url( get_edit_post_link( absint( $lesson_prerequisite_id ) ) ) . '" title="' . esc_attr( sprintf( __( 'Edit %s', 'woothemes-sensei' ), get_the_title( absint( $lesson_prerequisite_id ) ) ) ) . '">' . get_the_title( absint( $lesson_prerequisite_id ) ) . '</a>';
				} // End If Statement
			break;
			default:
			break;
		} // End Switch Statement
	} // End add_column_data()

	/**
	 * lesson_add_course function.
	 *
	 * @access public
	 * @return void
	 */
	public function lesson_add_course () {
		global $current_user;
		//Add nonce security to the request
		if ( isset($_POST['lesson_add_course_nonce']) ) {
			$nonce = esc_html( $_POST['lesson_add_course_nonce'] );
		} // End If Statement
		if ( ! wp_verify_nonce( $nonce, 'lesson_add_course_nonce' )
            || ! current_user_can( 'edit_lessons' ) ) {
			die('');
		} // End If Statement
		// Parse POST data
		$data = $_POST['data'];
		$course_data = array();
		parse_str($data, $course_data);
		// Save the Course
		$updated = false;

$updated is not used, you could remove the assignment.

		$current_user = wp_get_current_user();
		$question_data['post_author'] = $current_user->ID;
		$updated = $this->lesson_save_course($course_data);

It seems like $course_data can also be of type null; however, Sensei_Lesson::lesson_save_course() does only seem to accept array, maybe add an additional type check?

		echo $updated;
		die(); // WordPress may print out a spurious zero without this can be particularly bad if using JSON
	} // End lesson_add_course()

	/**
	 * lesson_update_question function.
	 *
	 * @access public
	 * @return void
	 */
	public function lesson_update_question () {
		global $current_user;
		//Add nonce security to the request
		if ( isset($_POST['lesson_update_question_nonce']) ) {
			$nonce = esc_html( $_POST['lesson_update_question_nonce'] );
		} // End If Statement
		if ( ! wp_verify_nonce( $nonce, 'lesson_update_question_nonce' )
            ||  ! current_user_can( 'edit_questions' )) {

			die('');

		} // End If Statement

		// Parse POST data
		// WP slashes all incoming data regardless of Magic Quotes setting (see wp_magic_quotes()), which means that
		// even the $_POST['data'] encoded with encodeURIComponent has it's apostrophes slashed.
		// So first restore the original unslashed apostrophes by removing those slashes
		$data = wp_unslash( $_POST['data'] );
		// Then parse the string to an array (note that parse_str automatically urldecodes all the variables)
		$question_data = array();
		parse_str($data, $question_data);
		// Finally re-slash all elements to ensure consistancy for lesson_save_question()
		$question_data = wp_slash( $question_data );
		// Save the question
		$return = false;
		// Question Save and Delete logic
		if ( isset( $question_data['action'] ) && ( $question_data['action'] == 'delete' ) ) {
			// Delete the Question
			$return = $this->lesson_delete_question($question_data);
		} else {
			// Save the Question
			if ( isset( $question_data['quiz_id'] ) && ( 0 < absint( $question_data['quiz_id'] ) ) ) {
				$current_user = wp_get_current_user();
				$question_data['post_author'] = $current_user->ID;
				$question_id = $this->lesson_save_question( $question_data );
				$question_type = Sensei()->question->get_question_type( $question_id );

				$question_count = intval( $question_data['question_count'] );
				++$question_count;

				$return = $this->quiz_panel_question( $question_type, $question_count, $question_id );
			} // End If Statement
		} // End If Statement

		echo $return;

		die();
	} // End lesson_update_question()

	public function lesson_add_multiple_questions() {

		$return = '';

		//Add nonce security to the request
		$nonce = '';
		if( isset( $_POST['lesson_add_multiple_questions_nonce'] ) ) {
			$nonce = esc_html( $_POST['lesson_add_multiple_questions_nonce'] );
		} // End If Statement

		if( ! wp_verify_nonce( $nonce, 'lesson_add_multiple_questions_nonce' )
            || ! current_user_can( 'edit_lessons' ) ) {
			die( $return );
		} // End If Statement

		// Parse POST data
		$data = $_POST['data'];
		$question_data = array();
		parse_str( $data, $question_data );

		if( is_array( $question_data ) ) {
			if( isset( $question_data['quiz_id'] ) && ( 0 < absint( $question_data['quiz_id'] ) ) ) {

				$quiz_id = intval( $question_data['quiz_id'] );
				$question_number = intval( $question_data['question_number'] );
				$question_category = intval( $question_data['question_category'] );

				$question_counter = intval( $question_data['question_count'] );
				++$question_counter;

				$cat = get_term( $question_category, 'question-category' );

				$post_data = array(
					'post_content' => '',
					'post_status' => 'publish',
					'post_title' => sprintf( __( '%1$s Question(s) from %2$s', 'woothemes-sensei' ), $question_number, $cat->name ),
					'post_type' => 'multiple_question'
				);

				$multiple_id = wp_insert_post( $post_data );

				if( $multiple_id && ! is_wp_error( $multiple_id ) ) {
					add_post_meta( $multiple_id, 'category', $question_category );
					add_post_meta( $multiple_id, 'number', $question_number );
					add_post_meta( $multiple_id, '_quiz_id', $quiz_id, false );
					add_post_meta( $multiple_id, '_quiz_question_order' . $quiz_id, $quiz_id . '000' . $question_counter );
					$lesson_id = get_post_meta( $quiz_id, '_quiz_lesson', true );
					update_post_meta( $lesson_id, '_quiz_has_questions', '1' );
					$return = $this->quiz_panel_question( 'category', $question_counter, $multiple_id, 'quiz', array( $cat->name, $question_number ) );
				}
			}
		}

		echo $return;

		die();
	}

	public function lesson_remove_multiple_questions() {

		//Add nonce security to the request
		$nonce = '';
		if( isset( $_POST['lesson_remove_multiple_questions_nonce'] ) ) {
			$nonce = esc_html( $_POST['lesson_remove_multiple_questions_nonce'] );
		} // End If Statement

		if( ! wp_verify_nonce( $nonce, 'lesson_remove_multiple_questions_nonce' )
        || ! current_user_can( 'edit_lessons' ) ) {
			die('');
		} // End If Statement

		// Parse POST data
		$data = $_POST['data'];
		$question_data = array();
		parse_str( $data, $question_data );

		if( is_array( $question_data ) ) {
			wp_delete_post( $question_data['question_id'], true );
		}

		die( 'Deleted' );
	}

	public function get_question_category_limit() {

		// Set default
		$return = 1;

		// Parse POST data
		$data = $_POST['data'];
		$cat_data = array();
		parse_str( $data, $cat_data );

		if( isset( $cat_data['cat'] ) && '' != $cat_data['cat'] ) {
			$cat = get_term( $cat_data['cat'], 'question-category' );
			if( isset( $cat->count ) ) {
				$return = $cat->count;
			}
		}

		echo $return;

		die('');
	}

	public function lesson_add_existing_questions() {

		//Add nonce security to the request
		$nonce = '';
		if( isset( $_POST['lesson_add_existing_questions_nonce'] ) ) {
			$nonce = esc_html( $_POST['lesson_add_existing_questions_nonce'] );
		} // End If Statement

		if( ! wp_verify_nonce( $nonce, 'lesson_add_existing_questions_nonce' )
        || ! current_user_can( 'edit_lessons' ) ) {
			die('');
		} // End If Statement

		// Parse POST data
		$data = $_POST['data'];
		$question_data = array();
		parse_str( $data, $question_data );

		$return = '';

		if( is_array( $question_data ) ) {

			if( isset( $question_data['questions'] ) && '' != $question_data['questions'] ) {

				$questions = explode( ',', trim( $question_data['questions'], ',' ) );
				$quiz_id = $question_data['quiz_id'];
				$question_count = intval( $question_data['question_count'] );

				foreach( $questions as $question_id ) {

					++$question_count;

					$quizzes = get_post_meta( $question_id, '_quiz_id', false );
					if( ! in_array( $quiz_id, $quizzes ) ) {
			    		add_post_meta( $question_id, '_quiz_id', $quiz_id, false );
						$lesson_id = get_post_meta( $quiz_id, '_quiz_lesson', true );
						update_post_meta( $lesson_id, '_quiz_has_questions', '1' );
			    	}

			    	add_post_meta( $question_id, '_quiz_question_order' . $quiz_id, $quiz_id . '000' . $question_count );
					$question_type = Sensei()->question->get_question_type( $question_id );

					$return .= $this->quiz_panel_question( $question_type, $question_count, $question_id );
				}
			}
		}

		echo $return;

		die('');
	}

	public function lesson_update_grade_type() {
		//Add nonce security to the request
		if ( isset($_POST['lesson_update_grade_type_nonce']) ) {

			$nonce = esc_html( $_POST['lesson_update_grade_type_nonce'] );

		} // End If Statement

		if ( ! wp_verify_nonce( $nonce, 'lesson_update_grade_type_nonce' )
        || ! current_user_can( 'edit_lessons' ) ) {

			die('');

		} // End If Statement

		// Parse POST data
		$data = $_POST['data'];
		$quiz_data = array();
		parse_str($data, $quiz_data);
		update_post_meta( $quiz_data['quiz_id'], '_quiz_grade_type', $quiz_data['quiz_grade_type'] );
		die();
	}

	public function lesson_update_question_order() {
		// Add nonce security to the request
		if ( isset($_POST['lesson_update_question_order_nonce']) ) {
			$nonce = esc_html( $_POST['lesson_update_question_order_nonce'] );
		} // End If Statement

        if ( ! wp_verify_nonce( $nonce, 'lesson_update_question_order_nonce' )
            ||! current_user_can( 'edit_lessons' ) ) {
			die('');
		} // End If Statement

		// Parse POST data
		$data = $_POST['data'];
		$quiz_data = array();
		parse_str($data, $quiz_data);
		if( strlen( $quiz_data['question_order'] ) > 0 ) {
			$questions = explode( ',', $quiz_data['question_order'] );
			$o = 1;
			foreach( $questions as $question_id ) {
				update_post_meta( $question_id, '_quiz_question_order' . $quiz_data['quiz_id'], $quiz_data['quiz_id'] . '000' . $o );
				++$o;
			}
			update_post_meta( $quiz_data['quiz_id'], '_question_order', $questions );
		}
		die();
	}

	public function lesson_update_question_order_random() {
		//Add nonce security to the request
		if ( isset($_POST['lesson_update_question_order_random_nonce']) ) {
			$nonce = esc_html( $_POST['lesson_update_question_order_random_nonce'] );
		} // End If Statement
		if ( ! wp_verify_nonce( $nonce, 'lesson_update_question_order_random_nonce' )
            || ! current_user_can( 'edit_lessons' ) ) {

			die('');

		} // End If Statement
		// Parse POST data
		$data = $_POST['data'];
		$quiz_data = array();
		parse_str($data, $quiz_data);
		update_post_meta( $quiz_data['quiz_id'], '_random_question_order', $quiz_data['random_question_order'] );
		die();
	}

	/**
	 * lesson_save_course function.
	 *
	 * @access private
	 * @param array $data (default: array())
	 * @return integer|boolean $course_id or false
	 */
	private function lesson_save_course( $data = array() ) {
		global $current_user;
		$return = false;
		// Setup the course data
		$course_id = 0;
		$course_content = '';
		$course_title = '';
		$course_prerequisite = 0;

$course_prerequisite is not used, you could remove the assignment.

		$course_category = 0;

$course_category is not used, you could remove the assignment.

		if ( isset( $data[ 'course_id' ] ) && ( 0 < absint( $data[ 'course_id' ] ) ) ) {

This code seems to be duplicated across your project.

			$course_id = absint( $data[ 'course_id' ] );
		} // End If Statement
		if ( isset( $data[ 'course_title' ] ) && ( '' != $data[ 'course_title' ] ) ) {
			$course_title = $data[ 'course_title' ];
		} // End If Statement
		$post_title = $course_title;
		if ( isset($data[ 'post_author' ]) ) {
			$post_author = $data[ 'post_author' ];

$post_author is not used, you could remove the assignment.

		} else {
			$current_user = wp_get_current_user();
			$post_author = $current_user->ID;

$post_author is not used, you could remove the assignment.

		} // End If Statement
		$post_status = 'publish';
		$post_type = 'course';
		if ( isset( $data[ 'course_content' ] ) && ( '' != $data[ 'course_content' ] ) ) {
			$course_content = $data[ 'course_content' ];
		} // End If Statement
		$post_content = $course_content;
		// Course Query Arguments
		$post_type_args = array(	'post_content' => $post_content,
  		    						'post_status' => $post_status,
  		    						'post_title' => $post_title,
  		    						'post_type' => $post_type
  		    						);
  		// Only save if there is a valid title
  		if ( $post_title != '' ) {
  		    // Check for prerequisite courses & product id
  		    $course_prerequisite_id = absint( $data[ 'course_prerequisite' ] );
  		    $course_woocommerce_product_id = absint( $data[ 'course_woocommerce_product' ] );
  		    $course_category_id = absint( $data[ 'course_category' ] );
  		    if ( 0 == $course_woocommerce_product_id ) { $course_woocommerce_product_id = '-'; }
  		    // Insert or Update the Lesson Quiz
		    if ( 0 < $course_id ) {
		    	$post_type_args[ 'ID' ] = $course_id;
		    	$course_id = wp_update_post($post_type_args);
		    	update_post_meta( $course_id, '_course_prerequisite', $course_prerequisite_id );
		    	update_post_meta( $course_id, '_course_woocommerce_product', $course_woocommerce_product_id );
		    	if ( 0 < $course_category_id ) {
		    		wp_set_object_terms( $course_id, $course_category_id, 'course-category' );
		    	} // End If Statement
		    } else {
		    	$course_id = wp_insert_post($post_type_args);
		    	add_post_meta( $course_id, '_course_prerequisite', $course_prerequisite_id );
		    	add_post_meta( $course_id, '_course_woocommerce_product', $course_woocommerce_product_id );
		    	if ( 0 < $course_category_id ) {
		    		wp_set_object_terms( $course_id, $course_category_id, 'course-category' );
		    	} // End If Statement
		    } // End If Statement
		} // End If Statement
  		// Check that the insert or update saved by testing the post id
  		if ( 0 < $course_id ) {
  			$return = $course_id;
  		} // End If Statement
  		return $return;
  	} // End lesson_save_course()


	/**
	 * lesson_save_question function.
	 *
	 * @access private
	 * @param array $data (default: array())
	 * @return integer|boolean $question_id or false
	 */
	public function lesson_save_question( $data = array(), $context = 'quiz' ) {
		$return = false;
		// Save the Questions
		// Setup the Question data
		$question_id = 0;
		$question_text = '';
		$question_right_answer = '';
		$question_wrong_answers = $question_right_answers = array();
		$question_type = 'multiple-choice';
		$question_category = '';

		// Handle Question Type
		if ( isset( $data[ 'question_type' ] ) && ( '' != $data[ 'question_type' ] ) ) {
			$question_type = $data[ 'question_type' ];
		} // End If Statement

		if ( isset( $data[ 'question_category' ] ) && ( '' != $data[ 'question_category' ] ) ) {
			$question_category = $data[ 'question_category' ];
		} // End If Statement

		if ( isset( $data[ 'question_id' ] ) && ( 0 < absint( $data[ 'question_id' ] ) ) ) {

This code seems to be duplicated across your project.

			$question_id = absint( $data[ 'question_id' ] );
		} // End If Statement
		if ( isset( $data[ 'question' ] ) && ( '' != $data[ 'question' ] ) ) {
			$question_text = $data[ 'question' ];
		} // End If Statement
		$post_title = $question_text;

$post_title is not used, you could remove the assignment.

		// Handle Default Fields (multiple choice)
		if ( 'multiple-choice' == $question_type && isset( $data[ 'question_right_answers' ] ) && ( '' != $data[ 'question_right_answers' ] ) ) {
			$question_right_answers = $data[ 'question_right_answers' ];
		} // End If Statement
		elseif ( 'multiple-choice' == $question_type && isset( $data[ 'question_right_answer' ] ) && ( '' != $data[ 'question_right_answer' ] ) ) {
			$question_right_answer = $data[ 'question_right_answer' ];
		} // End If Statement
		if ( 'multiple-choice' == $question_type && isset( $data[ 'question_wrong_answers' ] ) && ( '' != $data[ 'question_wrong_answers' ] ) ) {
			$question_wrong_answers = $data[ 'question_wrong_answers' ];
		} // End If Statement
		// Handle Boolean Fields - Edit
		if ( 'boolean' == $question_type && isset( $data[ 'question_' . $question_id . '_right_answer_boolean' ] ) && ( '' != $data[ 'question_' . $question_id . '_right_answer_boolean' ] ) ) {
			$question_right_answer = $data[ 'question_' . $question_id . '_right_answer_boolean' ];
		} // End If Statement
		// Handle Boolean Fields - Add
		if ( 'boolean' == $question_type && isset( $data[ 'question_right_answer_boolean' ] ) && ( '' != $data[ 'question_right_answer_boolean' ] ) ) {
			$question_right_answer = $data[ 'question_right_answer_boolean' ];
		} // End If Statement
		// Handle Gap Fill Fields
		if ( 'gap-fill' == $question_type && isset( $data[ 'add_question_right_answer_gapfill_gap' ] ) && '' != $data[ 'add_question_right_answer_gapfill_gap' ] ) {
			$question_right_answer = $data[ 'add_question_right_answer_gapfill_pre' ] . '||' . $data[ 'add_question_right_answer_gapfill_gap' ] . '||' . $data[ 'add_question_right_answer_gapfill_post' ];
		} // End If Statement
		// Handle Multi Line Fields
		if ( 'multi-line' == $question_type && isset( $data[ 'add_question_right_answer_multiline' ] ) && ( '' != $data[ 'add_question_right_answer_multiline' ] ) ) {
			$question_right_answer = $data[ 'add_question_right_answer_multiline' ];
		} // End If Statement
		// Handle Single Line Fields
		if ( 'single-line' == $question_type && isset( $data[ 'add_question_right_answer_singleline' ] ) && ( '' != $data[ 'add_question_right_answer_singleline' ] ) ) {
			$question_right_answer = $data[ 'add_question_right_answer_singleline' ];
		} // End If Statement
		// Handle File Upload Fields
		if ( 'file-upload' == $question_type && isset( $data[ 'add_question_right_answer_fileupload' ] ) && ( '' != $data[ 'add_question_right_answer_fileupload' ] ) ) {
			$question_right_answer = $data[ 'add_question_right_answer_fileupload' ];
		} // End If Statement
		if ( 'file-upload' == $question_type && isset( $data[ 'add_question_wrong_answer_fileupload' ] ) && ( '' != $data[ 'add_question_wrong_answer_fileupload' ] ) ) {
			$question_wrong_answers = array( $data[ 'add_question_wrong_answer_fileupload' ] );
		} // End If Statement

		// Handle Question Grade
		if ( isset( $data[ 'question_grade' ] ) && ( '' != $data[ 'question_grade' ] ) ) {
			$question_grade = $data[ 'question_grade' ];
		} // End If Statement

		// Handle Answer Feedback
		$answer_feedback = '';
		if ( isset( $data[ 'answer_feedback_boolean' ] ) && !empty( $data[ 'answer_feedback_boolean' ] ) ) {

            $answer_feedback = $data[ 'answer_feedback_boolean' ];

		}elseif( isset( $data[ 'answer_feedback_multiple_choice' ] ) && !empty( $data[ 'answer_feedback_multiple_choice' ] ) ){

            $answer_feedback = $data[ 'answer_feedback_multiple_choice' ];

        }elseif( isset( $data[ 'answer_feedback' ] )  ){

            $answer_feedback = $data[ 'answer_feedback' ];

        } // End If Statement

		$post_title = $question_text;
		$post_author = $data[ 'post_author' ];

$post_author is not used, you could remove the assignment.

		$post_status = 'publish';
		$post_type = 'question';
		// Handle the extended question text
		if ( isset( $data[ 'question_description' ] ) && ( '' != $data[ 'question_description' ] ) ) {
			$post_content = $data[ 'question_description' ];
		}
		else {
			$post_content = '';
		}
		// Question Query Arguments
		$post_type_args = array(	'post_content' => $post_content,
  		    						'post_status' => $post_status,
  		    						'post_title' => $post_title,
  		    						'post_type' => $post_type
  		    						);

  		// Remove empty values and reindex the array
  		if ( is_array( $question_right_answers ) && 0 < count($question_right_answers) ) {
  			$question_right_answers_array = array_values( array_filter( $question_right_answers, 'strlen' ) );
  			$question_right_answers = array();

  			foreach( $question_right_answers_array as $answer ) {
  				if( ! in_array( $answer, $question_right_answers ) ) {
  					$question_right_answers[] = $answer;
  				}
  			}
  			if ( 0 < count($question_right_answers) ) {
  				$question_right_answer = $question_right_answers;
  			}
  		} // End If Statement
  		$right_answer_count = count( $question_right_answer );

		// Remove empty values and reindex the array
  		if ( is_array( $question_wrong_answers ) ) {
  			$question_wrong_answers_array = array_values( array_filter( $question_wrong_answers, 'strlen' ) );
  			$question_wrong_answers = array();
  		} // End If Statement

  		foreach( $question_wrong_answers_array as $answer ) {
  			if( ! in_array( $answer, $question_wrong_answers ) ) {
  				$question_wrong_answers[] = $answer;
  			}
  		}

  		$wrong_answer_count = count( $question_wrong_answers );

  		// Only save if there is a valid title
  		if ( $post_title != '' ) {

  			// Get Quiz ID for the question
  		    $quiz_id = $data['quiz_id'];

  		    // Get question media
			$question_media = $data['question_media'];

  		    // Get answer order
  		    $answer_order = '';
  		    if( isset( $data['answer_order'] ) ) {
				$answer_order = $data['answer_order'];
			}

			// Get random order selection
			$random_order = 'no';
			if( isset( $data['random_order'] ) ) {
				$random_order = $data['random_order'];
			}

  		    // Insert or Update the question
  		    if ( 0 < $question_id ) {

  		    	$post_type_args[ 'ID' ] = $question_id;
		    	$question_id = wp_update_post( $post_type_args );

		    	// Update poast meta
		    	if( 'quiz' == $context ) {
		    		$quizzes = get_post_meta( $question_id, '_quiz_id', false );
		    		if( ! in_array( $quiz_id, $quizzes ) ) {
			    		add_post_meta( $question_id, '_quiz_id', $quiz_id, false );
			    	}
		    	}

		    	update_post_meta( $question_id, '_question_grade', $question_grade );
		    	update_post_meta( $question_id, '_question_right_answer', $question_right_answer );
		    	update_post_meta( $question_id, '_right_answer_count', $right_answer_count );
		    	update_post_meta( $question_id, '_question_wrong_answers', $question_wrong_answers );
		    	update_post_meta( $question_id, '_wrong_answer_count', $wrong_answer_count );
		    	update_post_meta( $question_id, '_question_media', $question_media );
		    	update_post_meta( $question_id, '_answer_order', $answer_order );
		    	update_post_meta( $question_id, '_random_order', $random_order );

		    	if( 'quiz' != $context ) {
		    		wp_set_post_terms( $question_id, array( $question_type ), 'question-type', false );
		    	}
				// Don't store empty value, no point
				if ( !empty($answer_feedback) ) {
					update_post_meta( $question_id, '_answer_feedback', $answer_feedback );
				}

		    } else {
				$question_id = wp_insert_post( $post_type_args );
				$question_count = intval( $data['question_count'] );
				++$question_count;

				// Set post meta
				if( 'quiz' == $context ) {
					add_post_meta( $question_id, '_quiz_id', $quiz_id, false );
					$lesson_id = get_post_meta( $quiz_id, '_quiz_lesson', true );
					update_post_meta( $lesson_id, '_quiz_has_questions', '1' );
				}

				if( isset( $question_grade ) ) {
		    		add_post_meta( $question_id, '_question_grade', $question_grade );
		    	}
		    	add_post_meta( $question_id, '_question_right_answer', $question_right_answer );
		    	add_post_meta( $question_id, '_right_answer_count', $right_answer_count );
		    	add_post_meta( $question_id, '_question_wrong_answers', $question_wrong_answers );
		    	add_post_meta( $question_id, '_wrong_answer_count', $wrong_answer_count );
		    	add_post_meta( $question_id, '_quiz_question_order' . $quiz_id, $quiz_id . '000' . $question_count );
		    	add_post_meta( $question_id, '_question_media', $question_media );
		    	add_post_meta( $question_id, '_answer_order', $answer_order );
		    	add_post_meta( $question_id, '_random_order', $random_order );
				// Don't store empty value, no point
				if ( !empty($answer_feedback) ) {
					add_post_meta( $question_id, '_answer_feedback', $answer_feedback );
				}

		    	// Set the post terms for question-type
			    wp_set_post_terms( $question_id, array( $question_type ), 'question-type' );

			    if( $question_category ) {
	    			wp_set_post_terms( $question_id, array( $question_category ), 'question-category' );
	    		}

		    } // End If Statement
		} // End If Statement
  		// Check that the insert or update saved by testing the post id
  		if ( 0 < $question_id ) {
  			$return = $question_id;
  		} // End If Statement
  		return $return;
  	} // End lesson_question_save()


	/**
	 * lesson_delete_question function.
	 *
	 * @access private
	 * @param array $data (default: array())
	 * @return boolean
	 */
	private function lesson_delete_question( $data = array() ) {

		// Get which question to delete
		$question_id = 0;
		if ( isset( $data[ 'question_id' ] ) && ( 0 < absint( $data[ 'question_id' ] ) ) ) {

This code seems to be duplicated across your project.

			$question_id = absint( $data[ 'question_id' ] );
		} // End If Statement
		// Delete the question
		if ( 0 < $question_id ) {
			$quizzes = get_post_meta( $question_id, '_quiz_id', false );

			foreach( $quizzes as $quiz_id ) {
				if( $quiz_id == $data['quiz_id'] ) {
					delete_post_meta( $question_id, '_quiz_id', $quiz_id );
				}
			}

			return true;
		} // End If Statement
		return false;
	} // End lesson_delete_question()


	/**
	 * lesson_complexities function.
	 *
	 * @access public
	 * @return array $lesson_complexities
	 */
	public function lesson_complexities() {

		// V2 - make filter for this array
        $lesson_complexities = array( 	'easy' => __( 'Easy', 'woothemes-sensei' ),
									'std' => __( 'Standard', 'woothemes-sensei' ),
									'hard' => __( 'Hard', 'woothemes-sensei' )
									);

		return $lesson_complexities;

	} // End lesson_complexities


	/**
	 * lesson_count function.
	 *
	 * @access public
	 * @param string $post_status (default: 'publish')
	 * @return int
	 */
	public function lesson_count( $post_status = 'publish', $course_id = false ) {

		$post_args = array(	'post_type'         => 'lesson',
							'posts_per_page'    => -1,
//							'orderby'           => 'menu_order date',
//							'order'             => 'ASC',
							'post_status'       => $post_status,
							'suppress_filters'  => 0,
							'fields'            => 'ids',
							);
		if( $course_id ) {
			$post_args['meta_query'][] = array(
				'key' => '_lesson_course',
				'value' => $course_id,
			);
		}
		else {
			// Simple check for connection to a Course
			$post_args['meta_query'][] = array(
				'key' => '_lesson_course',
				'value' => 0,
				'compare' => '>=',
			);
		}

		// Allow WP to generate the complex final query, just shortcut to only do an overall count
//		add_filter( 'posts_clauses', array( 'WooThemes_Sensei_Utils', 'get_posts_count_only_filter' ) );
		$lessons_query = new WP_Query( apply_filters( 'sensei_lesson_count', $post_args ) );
//		remove_filter( 'posts_clauses', array( 'WooThemes_Sensei_Utils', 'get_posts_count_only_filter' ) );

		return count( $lessons_query->posts );
	} // End lesson_count()


	/**
	 * lesson_quizzes function.
	 *
	 * @access public
	 * @param int $lesson_id (default: 0)
	 * @param string $post_status (default: 'publish')
	 * @param string $fields (default: 'ids')
	 * @return int $quiz_id
	 */
	public function lesson_quizzes( $lesson_id = 0, $post_status = 'any', $fields = 'ids' ) {

		$posts_array = array();

$posts_array is not used, you could remove the assignment.

		$post_args = array(	'post_type' 		=> 'quiz',
							'posts_per_page' 		=> 1,
							'orderby'         	=> 'title',
    						'order'           	=> 'DESC',
    						'post_parent'      	=> $lesson_id,
    						'post_status'		=> $post_status,
							'suppress_filters' 	=> 0,
							'fields'            => $fields
							);
		$posts_array = get_posts( $post_args );
        $quiz_id = array_shift($posts_array);

		return $quiz_id;
	} // End lesson_quizzes()


	/**
	 * Fetches all the questions for a quiz depending on certain conditions.
     *
     * Determine which questions should be shown depending on:
     * - admin/teacher selected questions to be shown
     * - questions shown to a user previously (saved as asked questions)
     * - limit number of questions lesson setting
	 *
     * @since 1.0
	 * @param int $quiz_id (default: 0)
	 * @param string $post_status (default: 'publish')
	 * @param string $orderby (default: 'meta_value_num title')
	 * @param string $order (default: 'ASC')
     *
	 * @return array $questions { $question type WP_Post }
	 */
	public function lesson_quiz_questions( $quiz_id = 0, $post_status = 'any', $orderby = 'meta_value_num title', $order = 'ASC' ) {

		$quiz_id = (string) $quiz_id;
        $quiz_lesson_id = Sensei()->quiz->get_lesson_id( $quiz_id );

        // setup the user id
        if( is_admin() ) {
            $user_id = isset( $_GET['user'] ) ? $_GET['user'] : '' ;
        } else {
            $user_id = get_current_user_id();
        }

        // get the users current status on the lesson
        $user_lesson_status = Sensei_Utils::user_lesson_status( $quiz_lesson_id, $user_id );

		// Set the default question order if it has not already been set for this quiz
		$this->set_default_question_order( $quiz_id );

		// If viewing quiz on the frontend then show questions in random order if set
		if ( ! is_admin() ) {
			$random_order = get_post_meta( $quiz_id, '_random_question_order', true );
			if( $random_order && $random_order == 'yes' ) {
				$orderby = 'rand';
			}
		}

		// Get all questions and multiple questions
		$question_query_args = array(
			'post_type' 		=> array( 'question', 'multiple_question' ),
			'posts_per_page' 	=> -1,
			'meta_key'        	=> '_quiz_question_order' . $quiz_id,
			'orderby'         	=> $orderby,
			'order'           	=> $order,
			'meta_query'		=> array(
				array(
					'key'       => '_quiz_id',
					'value'     => $quiz_id,
				)
			),
			'post_status'		=> $post_status,
			'suppress_filters' 	=> 0
		);

        //query the questions
		$questions_query = new WP_Query( $question_query_args );

        // Set return array to initially include all items
        $questions = $questions_query->posts;

        // set the questions array that will be manipulated within this function
        $questions_array = $questions_query->posts;

		// If viewing quiz on frontend or in grading then only single questions must be shown
		$selected_questions = false;
		if( ! is_admin() || ( is_admin() && isset( $_GET['page'] ) && 'sensei_grading' == $_GET['page'] && isset( $_GET['user'] ) && isset( $_GET['quiz_id'] ) ) ) {

			// Fetch the questions that the user was asked in their quiz if they have already completed it
			$questions_asked_string = !empty( $user_lesson_status->comment_ID) ? get_comment_meta( $user_lesson_status->comment_ID, 'questions_asked', true ) : false;
			if( !empty($questions_asked_string) ) {

				$selected_questions = explode( ',', $questions_asked_string );

				// Fetch each question in the order in which they were asked
				$questions = array();
				foreach( $selected_questions as $question_id ) {
					if( ! $question_id ) continue;
					$question = get_post( $question_id );
					if( ! isset( $question ) || ! isset( $question->ID ) ) continue;
					$questions[] = $question;
				}

			} else {

				// Otherwise, make sure that we convert all multiple questions into single questions

				$multiple_array = array();
				$existing_questions = array();

				// Set array of questions that already exist so we can prevent duplicates from appearing
				foreach( $questions_array as $question ) {
					if( 'question' != $question->post_type ) continue;
					$existing_questions[] = $question->ID;
				}

				// Include only single questions in the return array
				$questions_loop = $questions_array;
				$questions_array = array();
				foreach( $questions_loop as $k => $question ) {

					// If this is a single question then include it
					if( 'question' == $question->post_type ) {
						$questions_array[] = $question;
					} else {

						// If this is a multiple question then get the specified amount of questions from the specified category
						$question_cat = intval( get_post_meta( $question->ID, 'category', true ) );
						$question_number = intval( get_post_meta( $question->ID, 'number', true ) );

						$qargs = array(
							'post_type' 		=> 'question',
							'posts_per_page' 		=> $question_number,
							'orderby'         	=> $orderby,
							'tax_query'			=> array(
								array(
									'taxonomy'  => 'question-category',
									'field'     => 'term_id',
									'terms'		=> $question_cat
								)
							),
							'post_status'		=> $post_status,
							'suppress_filters' 	=> 0,
							'post__not_in'		=> $existing_questions,
						);
						$cat_questions = get_posts( $qargs );

						// Merge results into return array
						$questions_array = array_merge( $questions_array, $cat_questions );

						// Add selected questions to existing questions array to prevent duplicates from being added
						foreach( $questions_array as $cat_question ) {
							if( in_array( $cat_question->ID, $existing_questions ) ) continue;
							$existing_questions[] = $cat_question->ID;
						}
					}
				}

				// Set return data
				$questions = $questions_array;
			}
		}

		// If user has not already taken the quiz and a limited number of questions are to be shown, then show a random selection of the specified amount of questions
		if( ! $selected_questions ) {

			// Only limit questions like this on the frontend
			if( ! is_admin() ) {

				// Get number of questions to show
				$show_questions = intval( get_post_meta( $quiz_id, '_show_questions', true ) );
				if( $show_questions ) {

					// Get random set of array keys from selected questions array
					$selected_questions = array_rand( $questions_array, $show_questions );

					// Loop through all questions and pick the the ones to be shown based on the random key selection
					$questions = array();
					foreach( $questions_array as $k => $question ) {

						// Random keys will always be an array, unless only one question is to be shown
						if( is_array( $selected_questions ) ) {
							if( in_array( $k, $selected_questions ) ) {
								$questions[] = $question;
							}
						} elseif( 1 == $show_questions ) {
							if ( $selected_questions == $k ) {
								$questions[] = $question;
							}
						}
					}
				}
			}
		}

        // Save the questions that will be asked for the current user
        // this happens only once per user/quiz, unless the user resets the quiz
        if( ! is_admin() ){

            if( $user_lesson_status ) {

                $questions_asked = get_comment_meta($user_lesson_status->comment_ID, 'questions_asked', true);
                if ( empty($questions_asked) && $user_lesson_status) {

                    $questions_asked = array();
                    foreach ($questions as $question) {

                        $questions_asked[] = $question->ID;

                    }

                    // save the questions asked id
                    $questions_asked_csv = implode(',', $questions_asked);
                    update_comment_meta($user_lesson_status->comment_ID, 'questions_asked', $questions_asked_csv);

                }
            }
        }

        /**
         * Filter the questions returned by Sensei_Lesson::lessons_quiz_questions
         *
         * @hooked Sensei_Teacher::allow_teacher_access_to_questions
         * @since 1.8.0
         */
		return apply_filters( 'sensei_lesson_quiz_questions', $questions,  $quiz_id  );

	} // End lesson_quiz_questions()

	/**
	 * Set the default quiz order
	 * @param integer $quiz_id ID of quiz
	 */
	public function set_default_question_order( $quiz_id = 0 ) {

		if( $quiz_id ) {

			$question_order = get_post_meta( $quiz_id, '_question_order', true );

			if( ! $question_order ) {

				$args = array(
					'post_type' 		=> 'question',
					'posts_per_page' 		=> -1,
					'orderby'         	=> 'ID',
					'order'           	=> 'ASC',
					'meta_query'		=> array(
						array(
							'key'       => '_quiz_id',
							'value'     => $quiz_id
						)
					),
					'post_status'		=> 'any',
					'suppress_filters' 	=> 0
				);
				$questions = get_posts( $args );

				$o = 1;
				foreach( $questions as $question ) {
					add_post_meta( $question->ID, '_quiz_question_order' . $quiz_id, $quiz_id . '000' . $o, true );
					$o++;
				}
			}
		}

	}

	/**
	 * lesson_image function.
	 *
	 * Handles output of the lesson image
	 *
	 * @access public
	 * @param int $lesson_id (default: 0)
	 * @param string $width (default: '100')
	 * @param string $height (default: '100')
	 * @return string
	 */
	public function lesson_image( $lesson_id = 0, $width = '100', $height = '100', $widget = false ) {

		$html = '';

		// Get Width and Height settings
		if ( ( $width == '100' ) && ( $height == '100' ) ) {

			if ( is_singular( 'lesson' ) ) {

				if ( ! $widget && ! Sensei()->settings->settings[ 'lesson_single_image_enable' ] ) {

					return '';

				} // End If Statement

				$image_thumb_size = 'lesson_single_image';
				$dimensions = Sensei()->get_image_size( $image_thumb_size );
				$width = $dimensions['width'];
				$height = $dimensions['height'];
				$crop = $dimensions['crop'];

			} else {

				if ( ! $widget && ! Sensei()->settings->settings[ 'course_lesson_image_enable' ] ) {

					return '';
				} // End If Statement

				$image_thumb_size = 'lesson_archive_image';
				$dimensions = Sensei()->get_image_size( $image_thumb_size );
				$width = $dimensions['width'];
				$height = $dimensions['height'];
				$crop = $dimensions['crop'];

			} // End If Statement

		} // End If Statement

		$img_url = '';

		if ( has_post_thumbnail( $lesson_id ) ) {

   			// Get Featured Image
   			$img_url = get_the_post_thumbnail( $lesson_id, array( $width, $height ), array( 'class' => 'woo-image thumbnail alignleft') );

 		} else {

This code seems to be duplicated across your project.

 			// Display Image Placeholder if none
			if ( Sensei()->settings->settings[ 'placeholder_images_enable' ] ) {

                $img_url = apply_filters( 'sensei_lesson_placeholder_image_url', '<img src="http://placehold.it/' . $width . 'x' . $height . '" class="woo-image thumbnail alignleft" />' );

			} // End If Statement

		} // End If Statement

		$html .= '<a href="' . get_permalink( $lesson_id ) . '" title="' . esc_attr( get_post_field( 'post_title', $lesson_id ) ) . '">' . $img_url . '</a>';

		return $html;

	} // End lesson_image()

    /**
     * Ooutpu the lesson image
     *
     * @since 1.9.0
     * @param integer $lesson_id
     */
    public static function the_lesson_image( $lesson_id = 0 ){

        echo Sensei()->lesson->lesson_image( $lesson_id );

    }

	/**
	 * Returns the the lesson excerpt.
	 *
	 * @param WP_Post $lesson
     * @param bool $add_p_tags should the excerpt be wrapped by calling wpautop()
	 * @return string
	 */
	public static function lesson_excerpt( $lesson = null, $add_p_tags = true ) {
		$html = '';
		if ( is_a( $lesson, 'WP_Post' ) && 'lesson' == $lesson->post_type ) {

            $excerpt =  $lesson->post_excerpt;

            // if $add_p_tags true wrap with <p> else return the excerpt as is
            $html =  $add_p_tags ? wpautop( $excerpt ) : $excerpt;

		}
		return apply_filters( 'sensei_lesson_excerpt', $html );

	} // End lesson_excerpt()

    /**
     * Returns the course for a given lesson
     *
     * @since 1.7.4
     * @access public
     *
     * @param int $lesson_id
     * @return int|bool $course_id or bool when nothing is found.
     */
     public function get_course_id( $lesson_id ){

         if( ! isset( $lesson_id ) || empty( $lesson_id )
         ||  'lesson' != get_post_type( $lesson_id ) ){
             return false;
         }

         $lesson_course_id = get_post_meta( $lesson_id, '_lesson_course', true);

         // make sure the course id is valid
         if( empty( $lesson_course_id )
             || is_array( $lesson_course_id )
             || intval( $lesson_course_id ) < 1
             || 'course' != get_post_type( $lesson_course_id ) ){

             return false;

         }

         return $lesson_course_id;

     }// en get_course_id

    /**
     * Add the admin all lessons screen edit options.
     *
     * The fields in this function work for both quick and bulk edit. The ID attributes is used
     * by bulk edit javascript in the front end to retrieve the new values set byt the user. Then
     * name attribute is will be used by the quick edit and submitted via standard POST. This
     * will use this classes save_post_meta function to save the new field data.
     *
     * @hooked quick_edit_custom_box
     * @hooked bulk_edit_custom_box
     *
     * @since 1.8.0
     *
     * @param string $column_name
     * @param string $post_type
     * @return void
     */
    public function all_lessons_edit_fields( $column_name, $post_type ) {

        // only show these options ont he lesson post type edit screen
        if( 'lesson' != $post_type || 'lesson-course' != $column_name
            || ! current_user_can( 'edit_lessons' ) ) {
            return;
        }

        ?>
        <fieldset class="sensei-edit-field-set inline-edit-lesson">
            <div class="sensei-inline-edit-col column-<?php echo $column_name ?>">
                    <?php
                    echo '<h4>' . __('Lesson Information', 'woothemes-sensei') . '</h4>';
                    // create a nonce field to be  used as a security measure when saving the data
                    wp_nonce_field( 'bulk-edit-lessons', '_edit_lessons_nonce' );
                    wp_nonce_field( 'sensei-save-post-meta','woo_' . $this->token . '_nonce'  );

                    // unchanged option - we need this in because
                    // the default option in bulk edit should not be empty. If it is
                    // the user will erase data they didn't want to touch.
                    $no_change_text = '-- ' . __('No Change', 'woothemes-sensei') . ' --';

                    //
                    //course selection
                    //
                    $courses =  WooThemes_Sensei_Course::get_all_courses();
                    $course_options = array();
                    if ( count( $courses ) > 0 ) {
                        foreach ($courses as $course ){
                            $course_options[ $course->ID ] = get_the_title( $course->ID );
                        }
                    }
                    //pre-append the no change option
                    $course_options['-1']=  $no_change_text;
                    $course_attributes = array( 'name'=> 'lesson_course', 'id'=>'sensei-edit-lesson-course' , 'class'=>' ' );
                    $course_field =  Sensei_Utils::generate_drop_down( '-1', $course_options, $course_attributes );
                    echo $this->generate_all_lessons_edit_field( __('Lesson Course', 'woothemes-sensei'),   $course_field  );

                    //
                    // lesson complexity selection
                    //
                    $lesson_complexities =  $this->lesson_complexities();
                    //pre-append the no change option
                    $lesson_complexities['-1']=  $no_change_text;
                    $complexity_dropdown_attributes = array( 'name'=> 'lesson_complexity', 'id'=>'sensei-edit-lesson-complexity' , 'class'=>' ');
                    $complexity_filed =  Sensei_Utils::generate_drop_down( '-1', $lesson_complexities, $complexity_dropdown_attributes );
                    echo $this->generate_all_lessons_edit_field( __('Lesson Complexity', 'woothemes-sensei'),   $complexity_filed  );

                    ?>

                    <h4><?php _e('Quiz Settings', 'woothemes-sensei'); ?> </h4>

                    <?php

                    //
                    // Lesson require pass to complete
                    //
                    $pass_required_options = array(
                        '-1' => $no_change_text,
                         '0' => __('No','woothemes'),
                         '1' => __('Yes','woothemes'),
                    );

                    $pass_required_select_attributes = array( 'name'=> 'pass_required',
                                                                'id'=> 'sensei-edit-lesson-pass-required',
                                                                'class'=>' '   );
                    $require_pass_field =  Sensei_Utils::generate_drop_down( '-1', $pass_required_options, $pass_required_select_attributes, false );
                    echo $this->generate_all_lessons_edit_field( __('Pass required', 'woothemes-sensei'),   $require_pass_field  );

                    //
                    // Quiz pass percentage
                    //
                    $quiz_pass_percentage_field = '<input name="quiz_passmark" id="sensei-edit-quiz-pass-percentage" type="number" />';
                    echo $this->generate_all_lessons_edit_field( __('Pass Percentage', 'woothemes-sensei'), $quiz_pass_percentage_field  );

                    //
                    // Enable quiz reset button
                    //
                    $quiz_reset_select__options = array(
                        '-1' => $no_change_text,
                        '0' => __('No','woothemes'),
                        '1' => __('Yes','woothemes'),
                    );
                    $quiz_reset_name_id = 'sensei-edit-enable-quiz-reset';
                    $quiz_reset_select_attributes = array( 'name'=> 'enable_quiz_reset', 'id'=>$quiz_reset_name_id, 'class'=>' ' );
                    $quiz_reset_field =  Sensei_Utils::generate_drop_down( '-1', $quiz_reset_select__options, $quiz_reset_select_attributes, false );
                    echo $this->generate_all_lessons_edit_field( __('Enable quiz reset button', 'woothemes-sensei'), $quiz_reset_field  );

                    ?>
            </div>
        </fieldset>
    <?php
    }// all_lessons_edit_fields

    /**
     * Create the html for the edit field
     *
     * Wraps the passed in field and title combination with the correct html.
     *
     * @since 1.8.0
     *
     * @param string $title that will stand to the left of the field.
     * @param string $field type markup for the field that must be wrapped.
     * @return string $field_html
     */
    public function generate_all_lessons_edit_field( $title  ,$field ){

        $html = '';
        $html = '<div class="inline-edit-group" >';
        $html .=  '<span class="title">'. $title .'</span> ';
        $html .= '<span class="input-text-wrap">';
        $html .= $field;
        $html .= '</span>';
        $html .= '</label></div>';

        return $html ;

    }//end generate_all_lessons_edit_field

    /**
     * Respond to the ajax call from the bulk edit save function. This comes
     * from the admin all lesson screen.
     *
     * @since 1.8.0
     * @return void
     */
    function save_all_lessons_edit_fields() {

        // verify all the data before attempting to save
        if( ! isset( $_POST['security'] ) || ! check_ajax_referer( 'bulk-edit-lessons', 'security' )
            ||  empty( $_POST[ 'post_ids' ] )  || ! is_array( $_POST[ 'post_ids' ] ) ) {
            die();
        }

        // get our variables
        $new_course = sanitize_text_field(  $_POST['sensei_edit_lesson_course'] );
        $new_complexity = sanitize_text_field(  $_POST['sensei_edit_complexity'] );
        $new_pass_required = sanitize_text_field(  $_POST['sensei_edit_pass_required'] );
        $new_pass_percentage = sanitize_text_field(  $_POST['sensei_edit_pass_percentage'] );
        $new_enable_quiz_reset = sanitize_text_field(  $_POST['sensei_edit_enable_quiz_reset'] );
        // store the values for all selected posts
        foreach( $_POST[ 'post_ids' ] as $lesson_id ) {

            // get the quiz id needed for the quiz meta
            $quiz_id = Sensei()->lesson->lesson_quizzes( $lesson_id );

            // do not save the items if the value is -1 as this
            // means it was not changed

            // update lesson course
            if( -1 != $new_course ){
                update_post_meta( $lesson_id, '_lesson_course', $new_course );
            }
            // update lesson complexity
            if( -1 != $new_complexity ){
                update_post_meta( $lesson_id, '_lesson_complexity', $new_complexity );
            }

            // Quiz Related settings
            if( isset( $quiz_id) && 0 < intval( $quiz_id ) ) {

                // update pass required
                if (-1 != $new_pass_required) {

                    $checked = $new_pass_required  ? 'on' : '';
                    update_post_meta($quiz_id, '_pass_required', $checked);
                    unset( $checked );
                }

                // update pass percentage
                if( !empty( $new_pass_percentage) && is_numeric( $new_pass_percentage ) ){

                        update_post_meta($quiz_id, '_quiz_passmark', $new_pass_percentage);

                }

                //
                // update enable quiz reset
                //
                if (-1 != $new_enable_quiz_reset ) {

                    $checked = $new_enable_quiz_reset ? 'on' : ''  ;
                    update_post_meta($quiz_id, '_enable_quiz_reset', $checked);
                    unset( $checked );

                }


            } // end if quiz

        }// end for each

        die();

    } // end save_all_lessons_edit_fields

    /**
     * Loading the quick edit fields defaults.
     *
     * This function will localise the default values along with the script that will
     * add these values to the inputs.
     *
     * NOTE: this function runs for each row in the edit column
     *
     * @since 1.8.0
     * @return void
     */
    public function set_quick_edit_admin_defaults( $column_name, $post_id ){

        if( 'lesson-course' != $column_name ){
            return;
        }
        // load the script
        $suffix = defined( 'SCRIPT_DEBUG') && SCRIPT_DEBUG ? '' : '.min';
        wp_enqueue_script( 'sensei-lesson-quick-edit', Sensei()->plugin_url . 'assets/js/admin/lesson-quick-edit' . $suffix . '.js', array( 'jquery' ), Sensei()->version, true );

        // setup the values for all meta fields
        $data = array();
        foreach( $this->meta_fields as $field ){

            $data[$field] =  get_post_meta( $post_id, '_'.$field, true );

        }
        // add quiz meta fields
        $quiz_id = Sensei()->lesson->lesson_quizzes( $post_id );
        foreach( Sensei()->quiz->meta_fields as $field ){

            $data[$field] =  get_post_meta( $quiz_id, '_'.$field, true );

        }

        wp_localize_script( 'sensei-lesson-quick-edit', 'sensei_quick_edit_'.$post_id, $data );

    }// end quick edit admin defaults

    /**
     * Filter the classes for lessons on the single course page.
     *
     * Adds the nesecary classes depending on the user data
     *
     * @since 1.9.0
     * @param array $classes
     * @return array $classes
     */
    public static function single_course_lessons_classes( $classes ){

        if(  is_singular('course') ){

            global $post;
            $course_id = $post->ID;

            $lesson_classes = array( 'course', 'post' );
            if ( is_user_logged_in() ) {

                // Check if Lesson is complete
                $single_lesson_complete = Sensei_Utils::user_completed_lesson( get_the_ID(), get_current_user_id() );
                if ( $single_lesson_complete ) {

                    $lesson_classes[] = 'lesson-completed';

                } // End If Statement

            } // End If Statement

            $is_user_taking_course = Sensei_Utils::user_started_course( $course_id, get_current_user_id() );
            if (  Sensei_Utils::is_preview_lesson( get_the_ID() ) && !$is_user_taking_course ) {

                $lesson_classes[] = 'lesson-preview';

            }

            $classes = array_merge( $classes, $lesson_classes  );

        }

        return $classes;

    }// end single_course_lessons_classes

    /**
     * Output the lesson meta for the given lesson
     *
     * @since 1.9.0
     * @param $lesson_id
     */
    public static function the_lesson_meta( $lesson_id ){

        global $wp_query;
        $loop_lesson_number = $wp_query->current_post + 1;

        $course_id = Sensei()->lesson->get_course_id( $lesson_id );
        $single_lesson_complete = false;
        $is_user_taking_course = Sensei_Utils::user_started_course( $course_id, get_current_user_id() );

        // Get Lesson data
        $complexity_array = Sensei()->lesson->lesson_complexities();

        $lesson_complexity = get_post_meta( $lesson_id, '_lesson_complexity', true );
        if ( '' != $lesson_complexity ) {

            $lesson_complexity = $complexity_array[$lesson_complexity];

        }
        $user_info = get_userdata( absint( get_post()->post_author ) );
        $is_preview = Sensei_Utils::is_preview_lesson( $lesson_id);
        $preview_label = '';
        if ( $is_preview && !$is_user_taking_course ) {

            $preview_label = Sensei()->frontend->sensei_lesson_preview_title_text( $lesson_id);
            $preview_label = '<span class="preview-heading">' . $preview_label . '</span>';

        }


        $count_markup= '';
        /**
         * Filter for if you want the $lesson_count to show next to the lesson.
         *
         * @since 1.0
         * @param bool default false.
         */
        if( apply_filters( 'sensei_show_lesson_numbers', false ) ) {

            $count_markup =  '<span class="lesson-number">' . $loop_lesson_number. '</span>';

        }

        $heading_link_title = sprintf( __( 'Start %s', 'woothemes-sensei' ), get_the_title( $lesson_id ) );

        ?>
        <header>
            <h2>
                <a href="<?php echo esc_url_raw( get_permalink( $lesson_id ) ) ?>"
                   title="<?php esc_attr_e( $heading_link_title ) ?>" >
                    <?php echo $count_markup. get_the_title( $lesson_id ) . $preview_label; ?>
                </a>
            </h2>

            <p class="lesson-meta">

                <?php

                $meta_html = '';
                $user_lesson_status = Sensei_Utils::user_lesson_status( get_the_ID(), get_current_user_id() );

                $lesson_length = get_post_meta( $lesson_id, '_lesson_length', true );
                if ( '' != $lesson_length ) {

                    $meta_html .= '<span class="lesson-length">' .  __( 'Length: ', 'woothemes-sensei' ) . $lesson_length . __( ' minutes', 'woothemes-sensei' ) . '</span>';

                }

                if ( Sensei()->settings->get( 'lesson_author' ) ) {

                    $meta_html .= '<span class="lesson-author">' .  __( 'Author: ', 'woothemes-sensei' ) . '<a href="' . get_author_posts_url( absint( get_post()->post_author ) ) . '" title="' . esc_attr( $user_info->display_name ) . '">' . esc_html( $user_info->display_name ) . '</a></span>';

                } // End If Statement
                if ( '' != $lesson_complexity ) {

                    $meta_html .= '<span class="lesson-complexity">' .  __( 'Complexity: ', 'woothemes-sensei' ) . $lesson_complexity .'</span>';

                }

                if ( $single_lesson_complete ) {

                    $meta_html .= '<span class="lesson-status complete">' .__( 'Complete', 'woothemes-sensei' ) .'</span>';

                } elseif ( $user_lesson_status ) {

                    $meta_html .= '<span class="lesson-status in-progress">' . __( 'In Progress', 'woothemes-sensei' ) .'</span>';

                } // End If Statement

                echo $meta_html;

                ?>

            </p> <!-- lesson meta -->

        </header>

    <?php

    } // end the_lesson_meta

    /**
     * Output the lessons thumbnail
     *
     * 1.9.0
     *
     * @param $lesson_id
     */
    public static function the_lesson_thumbnail( $lesson_id ){

        if( empty( $lesson_id ) ){

            $lesson_id = get_the_ID();

        }

        if( 'lesson' != get_post_type( $lesson_id ) ){
            return;
        }

        echo Sensei()->lesson->lesson_image( $lesson_id );
    }


    /**
     * Alter the sensei lesson excerpt.
     *
     * @since 1.9.0
     * @param string $excerpt
     * @return string $excerpt
     */
    public static function alter_the_lesson_excerpt( $excerpt ) {

        if ('lesson' == get_post_type(get_the_ID())){

            // remove this hooks to avoid an infinite loop.
            remove_filter( 'get_the_excerpt', array( 'WooThemes_Sensei_Lesson','alter_the_lesson_excerpt') );

            return WooThemes_Sensei_Lesson::lesson_excerpt( get_post( get_the_ID() ) );
        }

        return $excerpt;

    }// end the_lesson_excerpt

    /**
     * Returns the lesson prerequisite for the given lesson id.
     *
     * @since 1.9.0
     *
     * @param $current_lesson_id
     * @return mixed | bool | int $prerequisite_lesson_id or false
     */
    public static function get_lesson_prerequisite_id( $current_lesson_id  ){

        $prerequisite_lesson_id = get_post_meta( $current_lesson_id , '_lesson_prerequisite', true );

        // set ti to false if not a valid prerequisite lesson id
        if(  empty( $prerequisite_lesson_id )
            || 'lesson' != get_post_type( $prerequisite_lesson_id )
            || $prerequisite_lesson_id == $current_lesson_id  ) {

            $prerequisite_lesson_id = false;

        }

        return apply_filters( 'sensei_lesson_prerequisite', $prerequisite_lesson_id, $current_lesson_id );

    }

    /**
     * This function requires that you pass in the lesson you would like to check for
     * a pre-requisite and not the pre-requisite. It will check if the
     * lesson has a pre-requiste and then check if it is completed.
     *
     * @since 1.9.0
     *
     * @param $lesson_id
     * @param $user_id
     * @return bool
     */
    public  static function is_prerequisite_complete( $lesson_id, $user_id  ){

        if( empty( $lesson_id ) || empty( $user_id )
        || 'lesson' != get_post_type( $lesson_id )
        ||  ! is_a( get_user_by( 'id', $user_id ), 'WP_User' )){

            return false;

        }

        $pre_requisite_id = (string) self::get_lesson_prerequisite_id( $lesson_id );

        // not a valid pre-requisite so pre-requisite is completed
        if( 'lesson' != get_post_type( $pre_requisite_id )
            || ! is_numeric( $pre_requisite_id ) ){

            return true;

        }

        return  Sensei_Utils::user_completed_lesson( $pre_requisite_id, $user_id );

    }// end is_prerequisite_complete

    /**
     * Show the user not taking course message if it is the case
     *
     * @since 1.9.0
     */
    public  static function user_not_taking_course_message(){

        $lesson_id = get_the_ID();

        if( 'lesson' != get_post_type( $lesson_id ) ){
            return;
        }

        $is_preview = Sensei_Utils::is_preview_lesson( $lesson_id );
        $pre_requisite_complete = self::is_prerequisite_complete( $lesson_id , get_current_user_id() );
        $lesson_course_id = get_post_meta( $lesson_id, '_lesson_course', true );
        $user_taking_course = Sensei_Utils::user_started_course( $lesson_course_id, get_current_user_id() );

        if ( $pre_requisite_complete && $is_preview && !$user_taking_course ) {


        }// end if

    } // end user_not_taking_course_message

    /**
     * Outputs the lessons course signup lingk
     *
     * This hook runs inside the single lesson page.
     *
     * @since 1.9.0
     */
    public static function course_signup_link( ){

        $course_id =  Sensei()->lesson->get_course_id( get_the_ID() );

        if ( empty( $course_id ) || 'course' != get_post_type( $course_id ) || sensei_all_access() ) {

            return;

        }

        ?>

        <section class="course-signup lesson-meta">

            <?php

            global $current_user;
            $wc_post_id = (int) get_post_meta( $course_id, '_course_woocommerce_product', true );

            if ( Sensei_WC::is_woocommerce_active() && Sensei_WC::is_course_purchasable( $course_id ) ) {

                if( is_user_logged_in() && ! Sensei_Utils::user_started_course( $course_id, $current_user->ID )  ) {

	                    $a_element = '<a href="' . esc_url( get_permalink( $course_id ) ) . '" title="' . __( 'Sign Up', 'woothemes-sensei' )  . '">';
	                    $a_element .= __( 'course', 'woothemes-sensei' );
	                    $a_element .= '</a>';

	                    if( Sensei_Utils::is_preview_lesson( get_the_ID()  ) ){

		                    $message = sprintf( __( 'This is a preview lesson. Please purchase the %1$s before starting the lesson.', 'woothemes-sensei' ), $a_element );

	                    }else{

		                    $message = sprintf( __( 'Please purchase the %1$s before starting the lesson.', 'woothemes-sensei' ), $a_element );

	                    }

	                    Sensei()->notices->add_notice( $message, 'info' );

                }

	            if( ! is_user_logged_in() ) {

	                $a_element = '<a href="' . esc_url( get_permalink( $course_id ) ) . '" title="' . __( 'Sign Up', 'woothemes-sensei' )  . '">';
	                $a_element .= __( 'course', 'woothemes-sensei' );
	                $a_element .= '</a>';

	                if( Sensei_Utils::is_preview_lesson( get_the_ID()  ) ){

						$message = sprintf( __( 'This is a preview lesson. Please purchase the %1$s before starting the lesson.', 'woothemes-sensei' ), $a_element );

					}else{

						$message = sprintf( __( 'Please purchase the %1$s before starting the lesson.', 'woothemes-sensei' ), $a_element );

					}

					Sensei()->notices->add_notice( $message, 'alert' );

	            }

            } else { ?>

	            <?php if( ! Sensei_Utils::user_started_course( $course_id, get_current_user_id() ) &&  sensei_is_login_required() )  : ?>

	                <div class="sensei-message alert">
	                    <?php
	                    $course_link =  '<a href="'
	                                        . esc_url( get_permalink( $course_id ) )
	                                        . '" title="' . __( 'Sign Up', 'woothemes-sensei' )
	                                        . '">' . __( 'course', 'woothemes-sensei' )
	                                    . '</a>';

						if ( Sensei_Utils::is_preview_lesson( get_the_ID( ) ) ) {

							echo sprintf( __( 'This is a preview lesson. Please sign up for the %1$s to access all lessons.', 'woothemes-sensei' ),  $course_link );

						} else {

							echo sprintf( __( 'Please sign up for the %1$s before starting the lesson.', 'woothemes-sensei' ),  $course_link );

						}

	                    ?>
	                </div>

	            <?php endif; ?>

            <?php } // End If Statement ?>

        </section>

        <?php
    }// end course_signup_link

    /**
     * Show a message telling the user to complete the previous message if they haven't done so yet
     *
     * @since 1.9.0
     */
    public  static function prerequisite_complete_message(){

        $lesson_prerequisite =  WooThemes_Sensei_Lesson::get_lesson_prerequisite_id( get_the_ID() );
        $lesson_has_pre_requisite = $lesson_prerequisite > 0;
        if ( ! WooThemes_Sensei_Lesson::is_prerequisite_complete(  get_the_ID(), get_current_user_id() ) && $lesson_has_pre_requisite ) {

            $prerequisite_lesson_link  = '<a href="' . esc_url( get_permalink( $lesson_prerequisite ) ) . '" title="' . esc_attr(  sprintf( __( 'You must first complete: %1$s', 'woothemes-sensei' ), get_the_title( $lesson_prerequisite ) ) ) . '">' . get_the_title( $lesson_prerequisite ). '</a>';
            echo sprintf( __( 'You must first complete %1$s before viewing this Lesson', 'woothemes-sensei' ), $prerequisite_lesson_link );

        }

    }

    /**
     * Deprecate the sensei_lesson_archive_header hook but keep it
     * active for backwards compatibility.
     *
     * @deprecated since 1.9.0
     */
    public static function deprecate_sensei_lesson_archive_header_hook(){

        sensei_do_deprecated_action('sensei_lesson_archive_header', '1.9.0', 'sensei_loop_lesson_inside_before');

    }

    /**
     * Outputs the the lesson archive header.
     *
     * @since  1.9.0
     * @return void
     */
    public function the_archive_header( ) {

        $before_html = '<header class="archive-header"><h1>';
        $after_html = '</h1></header>';
        $html = $before_html .  __( 'Lessons Archive', 'woothemes-sensei' ) . $after_html;

        echo apply_filters( 'sensei_lesson_archive_title', $html );

    } // sensei_course_archive_header()

    /**
     * Output the title for the single lesson page
     *
     * @global $post
     * @since 1.9.0
     */
    public static function the_title(){

        global $post;

        ?>
        <header>

            <h1>

                <?php
                /**
                 * Filter documented in class-sensei-messages.php the_title
                 */
                echo apply_filters( 'sensei_single_title', get_the_title( $post ), $post->post_type );
                ?>

            </h1>

        </header>

        <?php

    }//the_title

    /**
     * Flush the rewrite rules for a lesson post type
     *
     * @since 1.9.0
     *
     * @param $post_id
     */
    public static function flush_rewrite_rules( $post_id ){

        if (defined('DOING_AUTOSAVE') && DOING_AUTOSAVE){

            return;

        }


        if( 'lesson' == get_post_type( $post_id )  ){

            Sensei()->initiate_rewrite_rules_flush();

        }

    }

    /**
     * Output the quiz specific buttons and messaging on the single lesson page
     *
     *
     * @since 1.0.0 moved here from frontend class
     *
     * @param int $lesson_id
     * @param int $user_id
     */
    public static function footer_quiz_call_to_action( $lesson_id = 0, $user_id = 0 ) {


        $lesson_id                 =  empty( $lesson_id ) ?  get_the_ID() : $lesson_id;
        $user_id                   = empty( $lesson_id ) ?  get_current_user_id() : $user_id;


	    if ( ! sensei_can_user_view_lesson( $lesson_id, $user_id ) ) {
		    return;
	    }

        $lesson_prerequisite       = (int) get_post_meta( $lesson_id, '_lesson_prerequisite', true );
        $lesson_course_id          = (int) get_post_meta( $lesson_id, '_lesson_course', true );
        $quiz_id                   = Sensei()->lesson->lesson_quizzes( $lesson_id );
        $has_user_completed_lesson = Sensei_Utils::user_completed_lesson( intval( $lesson_id ), $user_id );
        $show_actions              = is_user_logged_in() ? true : false;

        if( intval( $lesson_prerequisite ) > 0 ) {

            // If the user hasn't completed the prereq then hide the current actions
            $show_actions = Sensei_Utils::user_completed_lesson( $lesson_prerequisite, $user_id );

        }

        ?>

        <footer>

            <?php
            if( $show_actions && $quiz_id && Sensei()->access_settings() ) {

                $has_quiz_questions = get_post_meta( $lesson_id, '_quiz_has_questions', true );
                if( $has_quiz_questions ) {
                    ?>

                    <p>

                        <a class="button"
                           href="<?php echo esc_url_raw( get_permalink( $quiz_id ) ); ?>"
                           title="<?php _e( 'View the Lesson Quiz', 'woothemes-sensei'  ); ?>">

                            <?php  _e( 'View the Lesson Quiz', 'woothemes-sensei' ); ?>

                        </a>

                    </p>

                    <?php
                }

            } // End If Statement

            if ( $show_actions && ! $has_user_completed_lesson ) {

                sensei_complete_lesson_button();

            } elseif( $show_actions ) {

                sensei_reset_lesson_button();

            } // End If Statement
            ?>

        </footer>

        <?php
    } // End sensei_lesson_quiz_meta()

    /**
     * Show the lesson comments. This should be used in the loop.
     *
     * @since 1.9.0
     */
    public static function output_comments(){

        if( ! is_user_logged_in() ){
            return;
        }

        $pre_requisite_complete = Sensei()->lesson->is_prerequisite_complete( get_the_ID(), get_current_user_id() );
        $course_id = Sensei()->lesson->get_course_id( get_the_ID() );
        $allow_comments = Sensei()->settings->settings[ 'lesson_comments' ];
        $user_taking_course = Sensei_Utils::user_started_course($course_id );

        $lesson_allow_comments = $allow_comments && $pre_requisite_complete  && $user_taking_course;

        if (  $lesson_allow_comments || is_singular( 'sensei_message' ) ) {

            comments_template();

        } // End If Statement

    } //output_comments

    /**
     * Display the leeson quiz status if it should be shown
     *
     * @param int $lesson_id defaults to the global lesson id
     * @param int $user_id defaults to the current user id
     *
     * @since 1.9.0
     */
    public static function user_lesson_quiz_status_message( $lesson_id = 0, $user_id = 0){

        $lesson_id                 =  empty( $lesson_id ) ?  get_the_ID() : $lesson_id;
        $user_id                   = empty( $lesson_id ) ?  get_current_user_id() : $user_id;
        $lesson_course_id          = (int) get_post_meta( $lesson_id, '_lesson_course', true );
        $quiz_id                   = Sensei()->lesson->lesson_quizzes( $lesson_id );
        $has_user_completed_lesson = Sensei_Utils::user_completed_lesson( intval( $lesson_id ), $user_id );


        if ( $quiz_id && is_user_logged_in()
            && Sensei_Utils::user_started_course( $lesson_course_id, $user_id ) ) {

            $no_quiz_count = 0;
            $has_quiz_questions = get_post_meta( $lesson_id, '_quiz_has_questions', true );

            // Display lesson quiz status message
            if ( $has_user_completed_lesson || $has_quiz_questions ) {
                $status = Sensei_Utils::sensei_user_quiz_status_message( $lesson_id, $user_id, true );
                echo '<div class="sensei-message ' . $status['box_class'] . '">' . $status['message'] . '</div>';
                if( $has_quiz_questions ) {
                   // echo $status['extra'];
                } // End If Statement
            } // End If Statement

        }

    }

    /**
     * On the lesson archive limit the number of words the show up if the access settings are enabled
     *
     * @since 1.9.0
     * @param $content
     * @return string
     */
    public static function limit_archive_content ( $content ){

        if( is_archive('lesson') && Sensei()->settings->get('access_permission') ){

            return wp_trim_words( $content, $num_words = 30, $more = '…' );
        }

        return $content;

    } // end limit_archive_content

    /**
     * Returns all publised lesson ID's
     *
     * @since 1.9.0
     * @return array
     */
    public static function get_all_lesson_ids(){

        return get_posts( array(
            'post_type'=>'lesson',
            'fields'=>'ids',
            'post_status' => 'publish',
            'numberposts' => 4000, // legacy support
            'post_per_page' => 4000
        ));

    }

} // End Class

/**
 * Class WooThemes_Sensei_Lesson
 * @ignore only for backward compatibility
 * @since 1.9.0
 */
class WooThemes_Sensei_Lesson extends Sensei_Lesson{}