<?php
/**
 * Versioned, idempotent data migrations.
 *
 * @package OrbitstemSEO
 */

namespace Orbitstem\SEO\Core;

defined( 'ABSPATH' ) || exit;

/**
 * Runs numbered migration steps once each, under a lock.
 *
 * Add a step by appending the next integer to steps(). Each step must be safe
 * to run again if it is interrupted before the version is saved.
 */
class Migrations {

	const OPTION = 'orbitstem_seo_db_version';
	const LOCK   = 'orbitstem_seo_migration_lock';

	/**
	 * Migration steps keyed by the schema version they produce.
	 *
	 * @return array<int,callable>
	 */
	public static function steps() {
		return array(
			1 => array( __CLASS__, 'v1_initial_settings' ),
			2 => array( __CLASS__, 'v2_diagnostics_tables' ),
			3 => array( __CLASS__, 'v3_repair_tables' ),
			4 => array( __CLASS__, 'v4_monitor_tables' ),
			5 => array( __CLASS__, 'v5_clean_values' ),
			6 => array( __CLASS__, 'v6_page_templates' ),
			7 => array( __CLASS__, 'v7_dot_segments' ),
		);
	}

	/**
	 * Highest schema version known to this code.
	 *
	 * @return int
	 */
	public static function latest() {
		return (int) max( array_keys( self::steps() ) );
	}

	/**
	 * Stored schema version (0 when never installed).
	 *
	 * @return int
	 */
	public static function current() {
		return (int) get_option( self::OPTION, 0 );
	}

	/**
	 * Runs any pending steps. Cheap when up to date: one autoloaded option read.
	 *
	 * @return bool True when the stored version is current after the call.
	 */
	public static function maybe_run() {
		$current = self::current();
		if ( $current >= self::latest() ) {
			return true;
		}
		if ( ! Lock::acquire( self::LOCK, 120 ) ) {
			return false;
		}
		try {
			foreach ( self::steps() as $version => $step ) {
				if ( $version <= $current ) {
					continue;
				}
				call_user_func( $step );
				update_option( self::OPTION, $version, true );
				$current = $version;
			}
		} finally {
			Lock::release( self::LOCK );
		}
		return $current >= self::latest();
	}

	/**
	 * Version 1: store default settings if none exist.
	 */
	public static function v1_initial_settings() {
		add_option( Settings::OPTION, Settings::defaults(), '', true );
	}

	/**
	 * Version 2: link index and URL check tables.
	 */
	public static function v2_diagnostics_tables() {
		\Orbitstem\SEO\Diagnostics\Tables::create();
	}

	/**
	 * Version 3: redirects, 404 log and change log tables.
	 */
	public static function v3_repair_tables() {
		\Orbitstem\SEO\Diagnostics\Tables::create_v3();
	}

	/**
	 * Version 4: regression monitor snapshot tables.
	 */
	public static function v4_monitor_tables() {
		\Orbitstem\SEO\Diagnostics\Tables::create_v4();
	}

	/**
	 * Version 6: saved templates that still equal the defaults of earlier
	 * versions get the current defaults, which include %page% (so page 2 of an
	 * archive or split post has its own title). Templates someone wrote are kept.
	 */
	public static function v6_page_templates() {
		$stored = get_option( Settings::OPTION, null );
		if ( ! is_array( $stored ) ) {
			return;
		}
		$legacy = Settings::legacy_defaults();
		if ( isset( $stored['home_title'] ) && $legacy['home_title'] === $stored['home_title'] ) {
			$stored['home_title'] = Settings::defaults()['home_title'];
		}
		foreach ( isset( $stored['post_types'] ) && is_array( $stored['post_types'] ) ? array_keys( $stored['post_types'] ) : array() as $type ) {
			if ( isset( $stored['post_types'][ $type ]['title'] ) && $legacy['post_type_title'] === $stored['post_types'][ $type ]['title'] ) {
				$stored['post_types'][ $type ]['title'] = Settings::post_type_defaults( $type )['title'];
			}
		}
		update_option( Settings::OPTION, $stored );
	}

	/**
	 * Version 5: removes empty SEO field rows (left by block-editor saves in
	 * earlier versions, they counted as "set"), and re-normalizes exact redirect
	 * sources so encoded and non-Latin addresses match (e.g. /привет).
	 */
	public static function v5_clean_values() {
		global $wpdb;
		$keys   = \Orbitstem\SEO\Content\MetaRepository::meta_keys();
		$in     = implode( ',', array_fill( 0, count( $keys ), '%s' ) );
		$prefix = \Orbitstem\SEO\Content\MetaRepository::PREFIX;
		// phpcs:disable WordPress.DB.DirectDatabaseQuery, WordPress.DB.PreparedSQL.InterpolatedNotPrepared, WordPress.DB.PreparedSQLPlaceholders.ReplacementsWrongNumber, WordPress.DB.PreparedSQLPlaceholders.UnfinishedPrepare -- $in is a placeholder list built above.
		$wpdb->query( $wpdb->prepare( "DELETE FROM {$wpdb->postmeta} WHERE meta_key IN ({$in}) AND meta_value = ''", ...$keys ) );
		$wpdb->query( $wpdb->prepare( "DELETE FROM {$wpdb->termmeta} WHERE meta_key IN ({$in}) AND meta_value = ''", ...$keys ) );
		$wpdb->query( $wpdb->prepare( "DELETE FROM {$wpdb->postmeta} WHERE meta_key IN ( %s, %s ) AND meta_value = '0'", $prefix . 'noindex', $prefix . 'nofollow' ) );
		$wpdb->query( $wpdb->prepare( "DELETE FROM {$wpdb->termmeta} WHERE meta_key IN ( %s, %s ) AND meta_value = '0'", $prefix . 'noindex', $prefix . 'nofollow' ) );
		// phpcs:enable
		if ( ! wp_cache_flush_group( 'post_meta' ) ) {
			wp_cache_flush();
		}
		self::renormalize_sources();
	}

	/**
	 * Version 7: exact redirect sources are stored without "." and ".."
	 * segments or doubled slashes, so "/old/./page" matches "/old/page".
	 */
	public static function v7_dot_segments() {
		self::renormalize_sources();
	}

	/**
	 * Stores every exact redirect source in its current normalized form. A rule
	 * whose normalized source another rule already has is left as it is.
	 */
	private static function renormalize_sources() {
		global $wpdb;
		$table = \Orbitstem\SEO\Diagnostics\Tables::redirects();
		if ( ! \Orbitstem\SEO\Diagnostics\Tables::v3_ready() ) {
			return;
		}
		// phpcs:ignore WordPress.DB.DirectDatabaseQuery
		$rules = $wpdb->get_results( $wpdb->prepare( 'SELECT id, source, source_hash FROM %i WHERE is_regex = 0', $table ), ARRAY_A );
		foreach ( $rules as $rule ) {
			$source = \Orbitstem\SEO\Redirects\Repository::normalize_path( $rule['source'] );
			$hash   = \Orbitstem\SEO\Redirects\Repository::hash( $source );
			if ( '' === $source || $hash === $rule['source_hash'] ) {
				continue;
			}
			// phpcs:ignore WordPress.DB.DirectDatabaseQuery
			if ( ! $wpdb->get_var( $wpdb->prepare( 'SELECT 1 FROM %i WHERE source_hash = %s', $table, $hash ) ) ) {
				// phpcs:ignore WordPress.DB.DirectDatabaseQuery
				$wpdb->update(
					$table,
					array(
						'source'      => $source,
						'source_hash' => $hash,
					),
					array( 'id' => (int) $rule['id'] ),
					array( '%s', '%s' ),
					array( '%d' )
				);
			}
		}
		delete_option( 'orbitstem_seo_regex_redirects' );
	}
}