<?php
/**
 * Ranktim – one-time rename migration (fluxserp_* → ranktim_*).
 *
 * The plugin used to ship under the FluxSERP name and every option, transient,
 * post meta key and cron hook carried a `fluxserp` prefix. Renaming them without
 * moving the stored data would silently lose the integration key and, worse,
 * make the duplicate guard blind — every article already imported would be
 * fetched and inserted a second time. This class moves the data across once.
 *
 * It is idempotent: a version stamp in wp_options records the completed step, so
 * subsequent page loads cost a single autoloaded option read.
 *
 * @package Ranktim
 */

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

class Ranktim_Migration {

	/** Option holding the schema version this install has been migrated to. */
	const VERSION_OPTION = 'ranktim_data_version';

	/** Current data-layout version. Bump when a new migration step is added. */
	const CURRENT_VERSION = 2;

	/** Legacy WP-Cron hook, unscheduled once the new hook takes over. */
	const LEGACY_CRON_HOOK = 'fluxserp_hourly_sync';

	/** wp_options keys to move, old => new. */
	private const OPTION_MAP = array(
		// The encryption key must travel with the settings blob it unlocks,
		// otherwise the stored integration key decrypts to an empty string.
		'fluxserp_enc_key'          => 'ranktim_enc_key',
		'fluxserp_settings'         => 'ranktim_settings',
		'fluxserp_last_catchup_run' => 'ranktim_last_catchup_run',
	);

	/** Post meta keys to rename, old => new. */
	private const META_MAP = array(
		'_fluxserp_item_id'                   => '_ranktim_item_id',
		'_fluxserp_synced_at'                 => '_ranktim_synced_at',
		'_fluxserp_meta_title'                => '_ranktim_meta_title',
		'_fluxserp_meta_description'          => '_ranktim_meta_description',
		'_fluxserp_primary_keyword'           => '_ranktim_primary_keyword',
		'_fluxserp_secondary_keywords'        => '_ranktim_secondary_keywords',
		'_fluxserp_cta'                       => '_ranktim_cta',
		'_fluxserp_internal_link_suggestions' => '_ranktim_internal_link_suggestions',
		'_fluxserp_image_suggestions'         => '_ranktim_image_suggestions',
		'_fluxserp_image_url'                 => '_ranktim_image_url',
		'_fluxserp_image_alt'                 => '_ranktim_image_alt',
		'_fluxserp_outline'                   => '_ranktim_outline',
		'_fluxserp_json_ld'                   => '_ranktim_json_ld',
	);

	/**
	 * Run any migration steps this install still needs.
	 *
	 * Cheap enough to call on every admin request: the common case is one
	 * autoloaded option read that matches CURRENT_VERSION and returns.
	 */
	public static function maybe_run(): void {
		$version = (int) get_option( self::VERSION_OPTION, 0 );

		if ( $version >= self::CURRENT_VERSION ) {
			return;
		}

		if ( $version < 2 ) {
			self::migrate_fluxserp_prefix();
		}

		update_option( self::VERSION_OPTION, self::CURRENT_VERSION, true );
	}

	/**
	 * Move options, post meta and the scheduled event off the fluxserp prefix.
	 */
	private static function migrate_fluxserp_prefix(): void {
		self::migrate_options();
		self::migrate_post_meta();
		self::unschedule_legacy_cron();
		self::purge_legacy_transients();
	}

	/**
	 * Copy legacy options across. The originals are left in place so a rollback
	 * to an older plugin build keeps working; they are inert otherwise.
	 */
	private static function migrate_options(): void {
		foreach ( self::OPTION_MAP as $legacy => $current ) {
			// Never clobber a value the new-format plugin already wrote.
			if ( false !== get_option( $current, false ) ) {
				continue;
			}

			$value = get_option( $legacy, null );
			if ( null === $value ) {
				continue;
			}

			// Settings and the catch-up stamp are read on demand; only the
			// version stamp needs to autoload.
			update_option( $current, $value, false );
		}
	}

	/**
	 * Rename post meta keys in a single UPDATE per key.
	 *
	 * A meta_key rename is one indexed UPDATE on wp_postmeta, so even a site
	 * with thousands of imported articles finishes inside a normal request.
	 */
	private static function migrate_post_meta(): void {
		global $wpdb;

		foreach ( self::META_MAP as $legacy => $current ) {
			// phpcs:ignore WordPress.DB.DirectDatabaseQuery.DirectQuery, WordPress.DB.DirectDatabaseQuery.NoCaching -- One-time key rename; no core API renames meta keys in bulk.
			$wpdb->query(
				$wpdb->prepare(
					"UPDATE {$wpdb->postmeta} SET meta_key = %s WHERE meta_key = %s",
					$current,
					$legacy
				)
			);
		}

		// Meta was rewritten underneath the object cache.
		wp_cache_flush();
	}

	/**
	 * Drop the old scheduled event. The new hook is (re)scheduled by
	 * {@see Ranktim_Cron::ensure_scheduled()} on the same request.
	 */
	private static function unschedule_legacy_cron(): void {
		while ( $timestamp = wp_next_scheduled( self::LEGACY_CRON_HOOK ) ) { // phpcs:ignore WordPress.CodeAnalysis.AssignmentInCondition.FoundInWhileCondition
			wp_unschedule_event( $timestamp, self::LEGACY_CRON_HOOK );
		}
	}

	/**
	 * Delete short-lived fluxserp transients (sync lock, queue cache, ack
	 * throttles, admin notices). They all expire on their own, but clearing the
	 * lock immediately means the first sync after the upgrade is not skipped.
	 */
	private static function purge_legacy_transients(): void {
		global $wpdb;

		delete_transient( 'fluxserp_sync_lock' );

		// phpcs:ignore WordPress.DB.DirectDatabaseQuery.DirectQuery, WordPress.DB.DirectDatabaseQuery.NoCaching -- One-time cleanup of prefixed transients; there is no core API for prefix deletion.
		$wpdb->query(
			$wpdb->prepare(
				"DELETE FROM {$wpdb->options} WHERE option_name LIKE %s OR option_name LIKE %s",
				$wpdb->esc_like( '_transient_fluxserp_' ) . '%',
				$wpdb->esc_like( '_transient_timeout_fluxserp_' ) . '%'
			)
		);
	}
}