<?php
namespace AccessNow\SimpleLMS;

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

/**
 * Saves the Course Settings meta box.
 */
class Course_Meta {

	/** Allowed values for the select-type course settings. */
	const CHOICES = array(
		'_slms_progression_mode'    => array( 'sequential', 'free' ),
		'_slms_enrollment_mode'     => array( 'self', 'admin', 'both' ),
		'_slms_content_change_mode' => array( 'off', 'lesson', 'quiz', 'both' ),
	);

	public static function init() {
		add_action( 'save_post_slms_course', array( __CLASS__, 'save' ), 10, 2 );
	}

	/**
	 * Return $value if it is an allowed choice for $key, otherwise null.
	 *
	 * @param string $key   Meta key.
	 * @param mixed  $value Submitted value.
	 * @return string|null
	 */
	public static function sanitize_choice( $key, $value ) {
		if ( '_slms_course_language' === $key ) {
			return is_string( $value ) && isset( I18n::get_supported_languages()[ $value ] ) ? $value : null;
		}
		return isset( self::CHOICES[ $key ] ) && in_array( $value, self::CHOICES[ $key ], true ) ? $value : null;
	}

	public static function save( $post_id, $post ) {
		if ( defined( 'DOING_AUTOSAVE' ) && DOING_AUTOSAVE ) {
			return;
		}
		if ( ! current_user_can( 'edit_post', $post_id ) ) {
			return;
		}
		if ( ! isset( $_POST['accessnow_slms_course_nonce'] ) || ! wp_verify_nonce( sanitize_text_field( wp_unslash( $_POST['accessnow_slms_course_nonce'] ) ), 'accessnow_slms_save_course' ) ) {
			return;
		}

		foreach ( array( '_slms_progression_mode', '_slms_enrollment_mode', '_slms_content_change_mode', '_slms_course_language' ) as $key ) {
			if ( ! isset( $_POST[ $key ] ) ) {
				continue;
			}
			$value = self::sanitize_choice( $key, sanitize_text_field( wp_unslash( $_POST[ $key ] ) ) );
			if ( null !== $value ) {
				update_post_meta( $post_id, $key, $value );
			}
		}

		Lesson_Header::save_field( $post_id );

		// Checkbox: an unticked box is not submitted, so absence means "not featured".
		update_post_meta( $post_id, '_slms_featured', empty( $_POST['_slms_featured'] ) ? 0 : 1 );
	}

	public static function get( $post_id, $key, $fallback = '' ) {
		$value = get_post_meta( $post_id, $key, true );
		return '' !== $value ? $value : $fallback;
	}
}