<?php

namespace Yipresser\AdminOptimizer\Helpers;

// Exit if accessed directly.
if ( ! defined( 'ABSPATH' ) ) {
	exit;
}

/**
 * Table_Rename_Helper class
 *
 * Renames a plugin-owned table from an old prefixed name to a new one,
 * preserving all rows/indexes/auto-increment state via a metadata-only
 * `RENAME TABLE` — no data migration involved. Idempotent and safe to call
 * on every request: it only issues the rename when the old table exists and
 * the new one doesn't, so a site that has already migrated (or that only
 * ever existed under the new name, e.g. a fresh install) pays for nothing
 * beyond the two `SHOW TABLES LIKE` checks.
 *
 * This has to stay in the codebase indefinitely, not just for one release:
 * WordPress site owners can skip arbitrary numbers of plugin versions
 * between updates, so a site jumping from a pre-rename version straight to
 * a much later one still needs this step to run exactly once, whenever it
 * finally updates.
 */
class Table_Rename_Helper {

	/**
	 * Rename a table if the old name exists and the new one doesn't yet.
	 *
	 * @param string $old_table_name Fully prefixed old table name (e.g. $wpdb->prefix . 'adminoptim_redirects').
	 * @param string $new_table_name Fully prefixed new table name (e.g. $wpdb->prefix . 'ao_redirects').
	 *
	 * @return void
	 */
	public static function maybe_rename( string $old_table_name, string $new_table_name ): void {
		global $wpdb;

		if ( self::table_exists( $new_table_name ) ) {
			return;
		}

		if ( ! self::table_exists( $old_table_name ) ) {
			return;
		}

		// phpcs:ignore WordPress.DB.DirectDatabaseQuery.DirectQuery, WordPress.DB.DirectDatabaseQuery.NoCaching, WordPress.DB.PreparedSQL.InterpolatedNotPrepared, PluginCheck.Security.DirectDB.UnescapedDBParameter -- Both names are built from $wpdb->prefix plus a hardcoded literal, never user input.
		$wpdb->query( "RENAME TABLE `{$old_table_name}` TO `{$new_table_name}`" );
	}

	/**
	 * Check whether a table currently exists.
	 *
	 * @param string $table_name Fully prefixed table name.
	 *
	 * @return bool
	 */
	private static function table_exists( string $table_name ): bool {
		global $wpdb;

		$found = $wpdb->get_var( $wpdb->prepare( 'SHOW TABLES LIKE %s', $wpdb->esc_like( $table_name ) ) ); // phpcs:ignore WordPress.DB.DirectDatabaseQuery.DirectQuery, WordPress.DB.DirectDatabaseQuery.NoCaching

		return $table_name === $found;
	}
}