<?php
/**
 * R2 (F2.4): counts distinct authors with at least one published post, used
 * to power the Author Archive tab's dynamic "1 author → conventionally
 * noindex the /author/ archive" recommendation. Cached briefly (a
 * COUNT DISTINCT is cheap even on a large site, but this is read on every
 * author-archive Policy Engine resolve — see
 * ABDS_SEO_Policy_Engine::type_settings_for_key()).
 *
 * @package ABDS_SEO
 */

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

/**
 * Counts published authors across the site's public post types.
 */
class ABDS_SEO_Author_Count {

	const TRANSIENT_KEY = 'abds_seo_published_author_count';
	const TRANSIENT_TTL = HOUR_IN_SECONDS;

	/**
	 * Number of distinct users with at least one published post in a
	 * public post type. Cached; the cache is not invalidated on
	 * publish/unpublish (an hour of staleness on a recommendation is
	 * harmless — the site owner can always explicitly override the
	 * Author Archive setting regardless of what this reports).
	 *
	 * @return int
	 */
	public static function published_author_count(): int {
		$cached = get_transient( self::TRANSIENT_KEY );
		if ( false !== $cached ) {
			return (int) $cached;
		}

		global $wpdb;

		$post_types = array_keys( ABDS_SEO_Taxonomy_Helper::public_post_types() );
		if ( array() === $post_types ) {
			return 0;
		}

		$placeholders = implode( ',', array_fill( 0, count( $post_types ), '%s' ) );

		// phpcs:ignore WordPress.DB.PreparedSQL.NotPrepared, WordPress.DB.DirectDatabaseQuery.DirectQuery, WordPress.DB.DirectDatabaseQuery.NoCaching -- $placeholders is a fixed-count %s list, not raw input; $wpdb->prepare() below supplies every value; the result is cached in a transient just below, not a WP object-cache group.
		$count = (int) $wpdb->get_var(
			$wpdb->prepare(
				"SELECT COUNT(DISTINCT post_author) FROM {$wpdb->posts} WHERE post_status = 'publish' AND post_type IN ({$placeholders})", // phpcs:ignore WordPress.DB.PreparedSQL.InterpolatedNotPrepared, WordPress.DB.PreparedSQLPlaceholders.UnfinishedPrepare -- table name is $wpdb->posts, not user input; {$placeholders} is a dynamically-built but fixed-count "%s,%s,..." list phpcs can't statically count, real args supplied via $post_types below.
				$post_types
			)
		);

		set_transient( self::TRANSIENT_KEY, $count, self::TRANSIENT_TTL );

		return $count;
	}
}