class LLMS_Table_Quizzes extends LLMS_Admin_Table {

	/**
	 * Unique ID for the Table
	 *
	 * @var string
	 */
	protected $id = 'quizzes';

	/**
	 * Value of the field being filtered by
	 * Only applicable if $filterby is set
	 *
	 * @var string
	 */
	protected $filter = 'any';

	/**
	 * Field results are filtered by
	 *
	 * @var string
	 */
	protected $filterby = 'instructor';

	/**
	 * Is the Table Exportable?
	 *
	 * @var boolean
	 */
	protected $is_exportable = true;

	/**
	 * Determine if the table is filterable
	 *
	 * @var boolean
	 */
	protected $is_filterable = true;

	/**
	 * If true, tfoot will add ajax pagination links
	 *
	 * @var boolean
	 */
	protected $is_paginated = true;

	/**
	 * Determine of the table is searchable
	 *
	 * @var boolean
	 */
	protected $is_searchable = true;

	/**
	 * Results sort order
	 * 'ASC' or 'DESC'.
	 * Only applicable of $orderby is not set.
	 *
	 * @var string
	 */
	protected $order = 'ASC';

	/**
	 * Field results are sorted by
	 *
	 * @var string
	 */
	protected $orderby = 'title';

	/**
	 * Get HTML for buttons in the actions cell of the table
	 *
	 * @since 3.37.8
	 * @since 4.2.0 Added a deep check on whether the quiz is associated to a lesson.
	 * @since 6.0.0 Don't access `LLMS_Query_Quiz_Attempt` properties directly.
	 *
	 * @param LLMS_Quiz $quiz Quiz object.
	 * @return string
	 */
	private function get_actions_html( $quiz ) {

		if ( ! $quiz->is_orphan( true ) && $quiz->get_course() ) {
			return '';
		}

		// If there are quiz attempts for the quiz let the admin know they're going to delete the attempts also.
		$query = new LLMS_Query_Quiz_Attempt(
			array(
				'quiz_id'  => $quiz->get( 'id' ),
				'per_page' => 1,
			)
		);

		$msg  = $query->has_results() ? __( 'Are you sure you want to delete this quiz and all associated student attempts?', 'lifterlms' ) : __( 'Are you sure you want to delete this quiz?', 'lifterlms' );
		$msg .= ' ' . __( 'This action cannot be undone!', 'lifterlms' );

		ob_start();
		?>
		<form action="" method="POST" style="display:inline;">

			<button type="submit" class="llms-button-danger small" id="llms-del-quiz-<?php echo $quiz->get( 'id' ); ?>" name="llms_del_quiz" value="<?php echo $quiz->get( 'id' ); ?>">
				<?php _e( 'Delete', 'lifterlms' ); ?>
				<i class="fa fa-trash" aria-hidden="true"></i>
			</button>

			<input type="hidden" name="_llms_quiz_actions_nonce" value="<?php echo wp_create_nonce( 'llms-quiz-actions' ); ?>">

		</form>

		<script>document.getElementById( 'llms-del-quiz-<?php echo $quiz->get( 'id' ); ?>' ).onclick = function( e ) {
			return window.confirm( '<?php echo esc_attr( $msg ); ?>' );
		};</script>
		<?php
		return ob_get_clean();

	}

	/**
	 * Retrieve data for a cell
	 *
	 * @since 3.16.0
	 * @since 3.24.0 Unknown.
	 * @since 3.37.8 Add actions column that allows deletion of orphaned quizzes.
	 *               ID column displays as plain text if the quiz is not editable and directs to the quiz within the course builder when it is.
	 * @since 4.2.0 Added a deep check on whether the quiz is associated to a lesson.
	 * @since 6.0.0 Don't access `LLMS_Query_Quiz_Attempt` properties directly.
	 * @since 7.1.3 Added `round()` method for 'average' column values with precision from `llms_get_floats_rounding_precision()` helper.
	 *
	 * @param string $key  The column id / key.
	 * @param mixed  $data Object / array of data that the function can use to extract the data.
	 * @return mixed
	 */
	protected function get_data( $key, $data ) {

		$quiz = llms_get_post( $data );

		switch ( $key ) {

			case 'actions':
				$value = $this->get_actions_html( $quiz );
				break;

			case 'attempts':
				$query = new LLMS_Query_Quiz_Attempt(
					array(
						'quiz_id'  => $quiz->get( 'id' ),
						'per_page' => 1,
					)
				);

				$url   = LLMS_Admin_Reporting::get_current_tab_url(
					array(
						'tab'     => 'quizzes',
						'stab'    => 'attempts',
						'quiz_id' => $quiz->get( 'id' ),
					)
				);
				$value = '<a href="' . $url . '">' . $query->get_found_results() . '</a>';

				break;

			case 'average':
				$grade = 0;
				$query = new LLMS_Query_Quiz_Attempt(
					array(
						'quiz_id'  => $quiz->get( 'id' ),
						'per_page' => 1000,
					)
				);

				$attempts = $query->get_number_results();

				if ( ! $attempts ) {
					$value = 0;
				} else {

					foreach ( $query->get_attempts() as $attempt ) {
						$grade += $attempt->get( 'grade' );
					}

					$value = round( $grade / $attempts, llms_get_floats_rounding_precision() ) . '%';

				}

				break;

			case 'course':
				$value  = '&mdash;';
				$course = $quiz->get_course();
				if ( $course ) {
					$url   = LLMS_Admin_Reporting::get_current_tab_url(
						array(
							'tab'       => 'courses',
							'course_id' => $course->get( 'id' ),
						)
					);
					$value = '<a href="' . esc_url( $url ) . '">' . $course->get( 'title' ) . '</a>';
				}
				break;

			case 'id':
				$id    = $quiz->get( 'id' );
				$value = $id;

				$course = $quiz->get_course();
				if ( ! $quiz->is_orphan( true ) && $course ) {

					$url = add_query_arg(
						array(
							'page'      => 'llms-course-builder',
							'course_id' => $course->get( 'id' ),
						),
						admin_url( 'admin.php' )
					);

					$url  .= sprintf( '#lesson:%d:quiz', $quiz->get( 'lesson_id' ) );
					$value = '<a href="' . esc_url( $url ) . '">' . $id . '</a>';
				}
				break;

			case 'lesson':
				$value  = '&mdash;';
				$lesson = $quiz->get_lesson();
				if ( $lesson ) {
					$value = $lesson->get( 'title' );
				}
				break;

			case 'title':
				$value = $quiz->get( 'title' );
				$url   = LLMS_Admin_Reporting::get_current_tab_url(
					array(
						'tab'     => 'quizzes',
						'quiz_id' => $quiz->get( 'id' ),
					)
				);
				$value = '<a href="' . esc_url( $url ) . '">' . $quiz->get( 'title' ) . '</a>';
				break;

			default:
				$value = $key;

		}

		return $this->filter_get_data( $value, $key, $data );

	}

	/**
	 * Retrieve a list of Instructors to be used for Filtering
	 *
	 * @since 3.16.0
	 *
	 * @return array
	 */
	private function get_instructor_filters() {

		$query = get_users(
			array(
				'fields'   => array( 'ID', 'display_name' ),
				'meta_key' => 'last_name', // phpcs:ignore WordPress.DB.SlowDBQuery.slow_db_query_meta_key
				'orderby'  => 'meta_value',
				'role__in' => array( 'administrator', 'lms_manager', 'instructor', 'instructors_assistant' ),
			)
		);

		$instructors = wp_list_pluck( $query, 'display_name', 'ID' );

		return $instructors;

	}

	/**
	 * Execute a query to retrieve results from the table
	 *
	 * @since 3.16.0
	 * @since 3.36.1 Fixed an issue that allow instructors, who can only see their own reports,
	 *               to see all the quizzes when they had no courses or courses with no lessons.
	 *
	 * @param array $args Array of query args.
	 * @return void
	 */
	public function get_results( $args = array() ) {

		$this->title = __( 'Quizzes', 'lifterlms' );

		$args = $this->clean_args( $args );

		if ( isset( $args['page'] ) ) {
			$this->current_page = absint( $args['page'] );
		}

		$per = apply_filters( 'llms_reporting_' . $this->id . '_per_page', 25 );

		$this->order   = isset( $args['order'] ) ? $args['order'] : $this->order;
		$this->orderby = isset( $args['orderby'] ) ? $args['orderby'] : $this->orderby;

		$this->filter   = isset( $args['filter'] ) ? $args['filter'] : $this->get_filter();
		$this->filterby = isset( $args['filterby'] ) ? $args['filterby'] : $this->get_filterby();

		$query_args = array(
			'order'          => $this->order,
			'orderby'        => $this->orderby,
			'paged'          => $this->current_page,
			'post_status'    => 'publish',
			'post_type'      => 'llms_quiz',
			'posts_per_page' => $per,
		);

		if ( isset( $args['search'] ) ) {
			$query_args['s'] = sanitize_text_field( $args['search'] );
		}

		// if you can view others reports, make a regular query.
		if ( current_user_can( 'view_others_lifterlms_reports' ) ) {

			$query = new WP_Query( $query_args );

			// user can only see their own reports, get a list of their students.
		} elseif ( current_user_can( 'view_lifterlms_reports' ) ) {

			$instructor = llms_get_instructor();
			if ( ! $instructor ) {
				return;
			}

			$lessons = array();
			$courses = $instructor->get_courses(
				array(
					'posts_per_page' => -1,
				)
			);
			foreach ( $courses as $course ) {
				$lessons = array_merge( $lessons, $course->get_lessons( 'ids' ) );
			}

			if ( empty( $lessons ) ) {
				return;
			}

			$query_args['meta_query'] = array(  // phpcs:ignore WordPress.DB.SlowDBQuery.slow_db_query_meta_query
				array(
					'compare' => 'IN',
					'key'     => '_llms_lesson_id',
					'value'   => $lessons,
				),
			);

			$query = new WP_Query( $query_args );

		} else {

			return;

		}

		$this->max_pages = $query->max_num_pages;

		if ( $this->max_pages > $this->current_page ) {
			$this->is_last_page = false;
		}

		$this->tbody_data = $query->posts;

	}

	/**
	 * Get the Text to be used as the placeholder in a searchable tables search input
	 *
	 * @since 3.16.0
	 *
	 * @return string
	 */
	public function get_table_search_form_placeholder() {

		/**
		 * Filter the placeholder used in the search input on the quizzes reporting table.
		 *
		 * @since 3.16.0
		 *
		 * @param string $placeholder The placeholder string.
		 */
		return apply_filters( 'llms_table_get_quizzes_search_placeholder', __( 'Search quizzes...', 'lifterlms' ) );

	}

	/**
	 * Define the structure of arguments used to pass to the get_results method
	 *
	 * @since 3.16.0
	 *
	 * @return array
	 */
	public function set_args() {
		return array();
	}

	/**
	 * Define the structure of the table
	 *
	 * @since 3.16.0
	 * @since 3.16.10 Unknown.
	 * @since 3.37.8 Added the 'actions' column.
	 * @since 3.37.12 Fixed the 'actions' column name.
	 *
	 * @return array
	 */
	protected function set_columns() {
		return array(
			'id'       => array(
				'exportable' => true,
				'title'      => __( 'ID', 'lifterlms' ),
				'sortable'   => true,
			),
			'title'    => array(
				'exportable' => true,
				'title'      => __( 'Title', 'lifterlms' ),
				'sortable'   => true,
			),
			'course'   => array(
				'exportable' => true,
				'title'      => __( 'Course', 'lifterlms' ),
				'sortable'   => false,
			),
			'lesson'   => array(
				'exportable' => true,
				'title'      => __( 'Lesson', 'lifterlms' ),
				'sortable'   => false,
			),
			'attempts' => array(
				'exportable' => true,
				'title'      => __( 'Total Attempts', 'lifterlms' ),
				'sortable'   => false,
			),
			'average'  => array(
				'exportable' => true,
				'title'      => __( 'Average Grade', 'lifterlms' ),
				'sortable'   => false,
			),
			'actions'  => array(
				'exportable' => false,
				'title'      => __( 'Actions', 'lifterlms' ),
				'sortable'   => false,
			),
		);
	}