<?php
namespace AccessNow\SimpleLMS;

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

// This class reads and writes the plugin's own {prefix}slms_* tables, so direct
// queries are required; the data is per-user and changes on every action, so it is
// not cached. Table names are built from $wpdb->prefix and fixed strings, and every
// value goes through $wpdb->prepare() or $wpdb->insert/update/delete.
// phpcs:disable WordPress.DB.DirectDatabaseQuery.DirectQuery, WordPress.DB.DirectDatabaseQuery.NoCaching

class Certificates {

	public static function init() {
		add_action( 'init', array( __CLASS__, 'register_rewrite' ) );
		add_action( 'template_redirect', array( __CLASS__, 'handle_certificate_view' ) );
	}

	public static function register_rewrite() {
		add_rewrite_rule( '^certificate/([a-zA-Z0-9]+)/?$', 'index.php?accessnow_slms_certificate=$matches[1]', 'top' );
		add_rewrite_tag( '%accessnow_slms_certificate%', '([a-zA-Z0-9]+)' );
	}

	public static function handle_certificate_view() {
		$code = get_query_var( 'accessnow_slms_certificate' );
		if ( ! $code ) {
			return;
		}

		$cert = self::get_by_code( $code );
		if ( ! $cert || ! get_userdata( $cert->user_id ) || ! get_post( $cert->course_id ) ) {
			wp_die( esc_html__( 'Certificate not found.', 'accessnow-lms' ), 404 );
		}

		// The certificate is a standalone page (no theme header/footer), so its
		// assets are printed directly by the template.
		wp_register_style( 'slms-certificate', ACCESSNOW_SLMS_PLUGIN_URL . 'assets/css/slms-certificate.css', array(), ACCESSNOW_SLMS_VERSION );
		wp_register_script( 'slms-certificate', ACCESSNOW_SLMS_PLUGIN_URL . 'assets/js/slms-certificate.js', array(), ACCESSNOW_SLMS_VERSION, true );

		$template = locate_template( 'single-slms_certificate.php' );
		if ( ! $template ) {
			$template = ACCESSNOW_SLMS_PLUGIN_DIR . 'templates/single-slms_certificate.php';
		}
		/**
		 * The template a certificate page is rendered from: the theme's single-slms_certificate.php,
		 * else the plugin's. The template prints its own assets (slms-certificate is registered).
		 *
		 * @since 1.1.0
		 *
		 * @param string $template Full path.
		 * @param object $cert     Certificate row (user_id, course_id, certificate_code, issued_at...).
		 */
		$template = apply_filters( 'accessnow_slms_certificate_template', $template, $cert );
		include is_string( $template ) && file_exists( $template ) ? $template : ACCESSNOW_SLMS_PLUGIN_DIR . 'templates/single-slms_certificate.php';
		exit;
	}

	public static function issue( $user_id, $course_id, $enrollment_id = 0 ) {
		global $wpdb;
		$table = $wpdb->prefix . 'slms_certificates';

		$existing = self::get_for_enrollment( $enrollment_id, $course_id );
		if ( $existing ) {
			return $existing;
		}

		$code = wp_generate_password( 16, false );

		$wpdb->insert(
			$table,
			array(
				'user_id'          => $user_id,
				'course_id'        => $course_id,
				'enrollment_id'    => $enrollment_id,
				'certificate_code' => $code,
				'issued_at'        => current_time( 'mysql', true ),
			),
			array( '%d', '%d', '%d', '%s', '%s' )
		);

		$certificate = self::get_by_code( $code );
		if ( $certificate ) {
			/**
			 * A certificate was issued (once per enrolment; a reopened enrolment keeps its certificate).
			 *
			 * @since 1.0.0
			 *
			 * @param object $certificate   Certificate row (certificate_code, issued_at, ...).
			 * @param int    $user_id       User ID.
			 * @param int    $course_id     Course ID.
			 * @param int    $enrollment_id Enrolment ID.
			 */
			do_action( 'accessnow_slms_certificate_issued', $certificate, (int) $user_id, (int) $course_id, (int) $enrollment_id );
		}
		return $certificate;
	}

	/**
	 * The certificate already issued for an enrolment, if any.
	 *
	 * @param int $enrollment_id Enrolment ID.
	 * @param int $course_id     Course ID.
	 * @return object|null
	 */
	public static function get_for_enrollment( $enrollment_id, $course_id ) {
		global $wpdb;
		return $wpdb->get_row(
			$wpdb->prepare(
				"SELECT * FROM {$wpdb->prefix}slms_certificates WHERE enrollment_id = %d AND course_id = %d",
				$enrollment_id,
				$course_id
			)
		);
	}

	public static function get_by_code( $code ) {
		global $wpdb;
		return $wpdb->get_row(
			$wpdb->prepare(
				"SELECT * FROM {$wpdb->prefix}slms_certificates WHERE certificate_code = %s",
				$code
			)
		);
	}

	public static function get_user_certificates( $user_id ) {
		global $wpdb;
		return $wpdb->get_results(
			$wpdb->prepare(
				"SELECT * FROM {$wpdb->prefix}slms_certificates WHERE user_id = %d ORDER BY issued_at DESC",
				$user_id
			)
		);
	}

	public static function get_certificate_url( $code ) {
		return home_url( 'certificate/' . $code );
	}
}