robotstxt-mediaaudit/includes/Privacy/DataEraser.php

<?php
/**
 * GDPR personal data eraser.
 *
 * @package MediaRightsAudit\Privacy
 */

namespace MediaRightsAudit\Privacy;

/**
 * Erases Media Audit data for a given user via the WordPress privacy tools.
 *
 * Registered via the wp_privacy_personal_data_erasers filter. Removes all rows
 * from mra_media_index, mra_media_usage, and mra_external_results that belong
 * to attachments uploaded by the requested user.
 *
 * Erasure is a hard delete: once removed, the data cannot be recovered. The
 * attachment itself (wp_posts row) is not touched — only plugin-specific data.
 */
class DataEraser {

	/**
	 * Registers this eraser with the WordPress privacy API.
	 *
	 * Hooked to wp_privacy_personal_data_erasers.
	 *
	 * @param array<string, mixed> $erasers Accumulated eraser list.
	 *
	 * @return array<string, mixed>
	 */
	public static function register( array $erasers ): array {
		$erasers['robotstxt-mediaaudit'] = array(
			'eraser_friendly_name' => __( 'Media Audit', 'robotstxt-mediaaudit' ),
			'callback'             => array( self::class, 'erase' ),
		);
		return $erasers;
	}

	/**
	 * Erases Media Audit data for the user identified by $email_address.
	 *
	 * @param string $email_address User e-mail address.
	 * @param int    $page          Pagination page (unused; all data erased in one pass).
	 *
	 * @return array{items_removed: int, items_retained: int, messages: array<mixed>, done: bool}
	 */
	public static function erase( string $email_address, int $page = 1 ): array { // phpcs:ignore Generic.CodeAnalysis.UnusedFunctionParameter.FoundAfterLastUsed -- required by WP privacy API signature
		$user = get_user_by( 'email', $email_address );
		if ( ! $user instanceof \WP_User ) {
			return self::done_response( 0 );
		}

		$attachment_ids = self::get_attachment_ids( $user->ID );
		if ( empty( $attachment_ids ) ) {
			return self::done_response( 0 );
		}

		$removed = self::delete_plugin_data( $attachment_ids );

		return self::done_response( $removed );
	}

	// -------------------------------------------------------------------------
	// Private helpers
	// -------------------------------------------------------------------------

	/**
	 * Builds a standard "done" response array.
	 *
	 * @param int $removed Number of records removed.
	 *
	 * @return array{items_removed: int, items_retained: int, messages: array<mixed>, done: bool}
	 */
	private static function done_response( int $removed ): array {
		return array(
			'items_removed'  => $removed,
			'items_retained' => 0,
			'messages'       => array(),
			'done'           => true,
		);
	}

	/**
	 * Returns all indexed attachment IDs for a given user (no pagination).
	 *
	 * @param int $user_id WordPress user ID.
	 *
	 * @return array<int, int>
	 */
	private static function get_attachment_ids( int $user_id ): array {
		global $wpdb;

		// phpcs:disable WordPress.DB.DirectDatabaseQuery,WordPress.DB.PreparedSQL.InterpolatedNotPrepared
		$raw = $wpdb->get_col(
			$wpdb->prepare(
				"SELECT p.ID
				 FROM {$wpdb->posts} p
				 INNER JOIN {$wpdb->prefix}mra_media_index mi ON p.ID = mi.attachment_id
				 WHERE p.post_type = 'attachment'
				   AND p.post_author = %d
				 ORDER BY p.ID ASC",
				$user_id
			)
		);
		// phpcs:enable WordPress.DB.DirectDatabaseQuery,WordPress.DB.PreparedSQL.InterpolatedNotPrepared

		if ( ! is_array( $raw ) ) {
			return array();
		}

		return array_map( static fn ( mixed $v ): int => is_numeric( $v ) ? (int) $v : 0, $raw );
	}

	/**
	 * Deletes all plugin data rows for the given attachment IDs.
	 *
	 * Removes records from mra_external_results, mra_media_usage, and
	 * mra_media_index. Returns the total number of affected rows.
	 *
	 * @param array<int, int> $ids Attachment IDs to delete.
	 *
	 * @return int Total rows deleted across all three tables.
	 */
	private static function delete_plugin_data( array $ids ): int {
		global $wpdb;

		$placeholders = implode( ',', array_fill( 0, count( $ids ), '%d' ) );
		$removed      = 0;

		// phpcs:disable WordPress.DB.DirectDatabaseQuery,WordPress.DB.PreparedSQL.InterpolatedNotPrepared,WordPress.DB.PreparedSQLPlaceholders.UnfinishedPrepare

		$wpdb->query(
			$wpdb->prepare(
				"DELETE FROM {$wpdb->prefix}mra_external_results WHERE attachment_id IN ({$placeholders})",
				...$ids
			)
		);
		$removed += (int) $wpdb->rows_affected;

		$wpdb->query(
			$wpdb->prepare(
				"DELETE FROM {$wpdb->prefix}mra_media_usage WHERE attachment_id IN ({$placeholders})",
				...$ids
			)
		);
		$removed += (int) $wpdb->rows_affected;

		$wpdb->query(
			$wpdb->prepare(
				"DELETE FROM {$wpdb->prefix}mra_media_index WHERE attachment_id IN ({$placeholders})",
				...$ids
			)
		);
		$removed += (int) $wpdb->rows_affected;

		// phpcs:enable WordPress.DB.DirectDatabaseQuery,WordPress.DB.PreparedSQL.InterpolatedNotPrepared,WordPress.DB.PreparedSQLPlaceholders.UnfinishedPrepare

		return $removed;
	}
}