<?php
// phpcs:ignore WPDO.AntiEAV -- platform integration with WooCommerce: term count cache transform
/**
 * TMDO_WC_Term_Count_Filter — Reroute WooCommerce term count cache from
 * wp_termmeta to wp_options (v2.12.3 Phase 3).
 *
 * Background
 * ----------
 * WooCommerce caches the number of products per term as a wp_termmeta row:
 *
 *   wp_termmeta(term_id=5, meta_key='product_count_product_cat', meta_value='42')
 *
 * Each `product_count_<taxonomy>` row is a transient-like cache — WC
 * recalculates and writes whenever a product is added/removed from a term.
 * Pattern is identical to HivePress's per-post TTL cache anti-pattern that
 * v2.11.5 solved: the data is genuine cache, but storage location is wrong.
 *
 * Strategy
 * --------
 * Mirror v2.11.5 `TMDO_Hivepress_Transient_Filter`. Intercept term metadata
 * writes/reads where meta_key starts with `product_count_` and route to
 * wp_options as native transient (no per-key TTL — WC manages its own
 * invalidation; we just provide indistinguishable storage).
 *
 * Translation key:
 *   wp_options('_transient_wpdo_wc_termcount_<term_id>_<md5(meta_key)>')
 *
 * Namespacing by term_id keeps caches scoped to the right term; md5 of the
 * meta_key handles arbitrary-length taxonomy slugs (`product_count_my_long_taxonomy_with_many_chars`).
 *
 * Default: enabled. Toggle: `wpdo_wc_term_count_filter_enabled` option.
 *
 * 🔒 Lessons applied (v2.11.7): added to TMDO_Hook_Bus_Bridge::COEXIST_WHITELIST
 * so `wp wpdo conflict-scan` does not report a false positive.
 *
 * @package WP_Data_Optimizer
 * @since   2.12.3
 */

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

/**
 * Routes WooCommerce term count cache out of wp_termmeta into wp_options.
 */
final class TMDO_WC_Term_Count_Filter {

	/** Option toggle key. */
	public const OPT_ENABLED = 'wpdo_wc_term_count_filter_enabled';

	/** Prefix that identifies a WooCommerce term count cache row. */
	public const PREFIX = 'product_count_';

	/** Namespace prefix for translated wp_options entries. */
	public const TRANSLATED_NAMESPACE = 'wpdo_wc_termcount_';

	/**
	 * Register the four metadata filters on `init` priority 5.
	 * Idempotent — safe to call multiple times.
	 *
	 * @return void
	 */
	public static function init(): void {
		if ( ! self::is_enabled() ) {
			return;
		}

		// Filter priority 9 (before Hook Bus at 10), same as HivePress filter.
		add_filter( 'get_term_metadata', array( self::class, 'on_read' ), 9, 4 );
		add_filter( 'add_term_metadata', array( self::class, 'on_add' ), 9, 5 );
		add_filter( 'update_term_metadata', array( self::class, 'on_update' ), 9, 5 );
		add_filter( 'delete_term_metadata', array( self::class, 'on_delete' ), 9, 5 );
	}

	/**
	 * Check the admin toggle. Defaults to enabled.
	 *
	 * @return bool
	 */
	public static function is_enabled(): bool {
		return (bool) get_option( self::OPT_ENABLED, '1' );
	}

	/**
	 * Test whether a meta_key is a WC term count cache row.
	 *
	 * @param mixed $meta_key Candidate meta_key.
	 * @return bool
	 */
	public static function is_target_key( $meta_key ): bool {
		return is_string( $meta_key ) && str_starts_with( $meta_key, self::PREFIX );
	}

	/**
	 * Translate (term_id, meta_key) → namespaced wp_options option_name root.
	 *
	 * @param int    $term_id  Term ID.
	 * @param string $meta_key Original `product_count_*` meta_key.
	 * @return string Translated option_name root (without `_transient_` prefix).
	 */
	public static function translate_key( int $term_id, string $meta_key ): string {
		return self::TRANSLATED_NAMESPACE . $term_id . '_' . md5( $meta_key );
	}

	/**
	 * Filter callback: get_term_metadata.
	 *
	 * @param mixed  $pre        Filter accumulator (null at our priority).
	 * @param int    $object_id  Term ID.
	 * @param string $meta_key   Meta key being read.
	 * @param bool   $single     Whether single value was requested.
	 * @return mixed
	 */
	public static function on_read( $pre, $object_id, $meta_key, $single ) {
		unset( $single );
		if ( ! self::is_target_key( $meta_key ) ) {
			return $pre;
		}
		$translated  = self::translate_key( (int) $object_id, (string) $meta_key );
		$option_name = '_transient_' . $translated;
		$value       = get_option( $option_name, null );

		if ( null === $value ) {
			// Cache miss — fall through to wp_termmeta (back-compat).
			return $pre;
		}

		// WP unwraps [0] for single=true callers; return array of values.
		return array( $value );
	}

	/**
	 * Filter callback: add_term_metadata.
	 *
	 * @param mixed  $check      Filter accumulator (null at our priority).
	 * @param int    $object_id  Term ID.
	 * @param string $meta_key   Meta key being written.
	 * @param mixed  $meta_value Value being written.
	 * @param bool   $unique     Whether the unique flag was set (unused).
	 * @return mixed
	 */
	public static function on_add( $check, $object_id, $meta_key, $meta_value, $unique ) {
		unset( $unique );
		if ( ! self::is_target_key( $meta_key ) ) {
			return $check;
		}
		self::write_translated( (int) $object_id, (string) $meta_key, $meta_value );
		return true;
	}

	/**
	 * Filter callback: update_term_metadata.
	 *
	 * @param mixed  $check      Filter accumulator (null at our priority).
	 * @param int    $object_id  Term ID.
	 * @param string $meta_key   Meta key being written.
	 * @param mixed  $meta_value Value being written.
	 * @param mixed  $prev_value Previous value scope (unused).
	 * @return mixed
	 */
	public static function on_update( $check, $object_id, $meta_key, $meta_value, $prev_value ) {
		unset( $prev_value );
		if ( ! self::is_target_key( $meta_key ) ) {
			return $check;
		}
		self::write_translated( (int) $object_id, (string) $meta_key, $meta_value );
		return true;
	}

	/**
	 * Filter callback: delete_term_metadata.
	 *
	 * @param mixed  $check       Filter accumulator (null at our priority).
	 * @param int    $object_id   Term ID.
	 * @param string $meta_key    Meta key being deleted.
	 * @param mixed  $meta_value  Value-scoped delete (unused).
	 * @param bool   $delete_all  Whether to delete from all objects (unused).
	 * @return mixed
	 */
	public static function on_delete( $check, $object_id, $meta_key, $meta_value, $delete_all ) {
		unset( $meta_value, $delete_all );
		if ( ! self::is_target_key( $meta_key ) ) {
			return $check;
		}
		$translated  = self::translate_key( (int) $object_id, (string) $meta_key );
		$option_name = '_transient_' . $translated;
		delete_option( $option_name );
		return true;
	}

	/**
	 * Internal: persist value to wp_options as a no-expiry transient.
	 *
	 * `autoload=no` because WC reads on demand only — never via wp_load_alloptions().
	 *
	 * @param int    $term_id    Term ID.
	 * @param string $meta_key   Original `product_count_*` meta_key.
	 * @param mixed  $meta_value Value to store.
	 * @return void
	 */
	private static function write_translated( int $term_id, string $meta_key, $meta_value ): void {
		$translated  = self::translate_key( $term_id, $meta_key );
		$option_name = '_transient_' . $translated;
		update_option( $option_name, $meta_value, false );
	}

	/**
	 * One-time migration helper: count `product_count_*` rows in wp_termmeta.
	 *
	 * @return int
	 */
	public static function count_legacy_termmeta_rows(): int {
		global $wpdb;
		// phpcs:disable WordPress.DB.DirectDatabaseQuery.DirectQuery,WordPress.DB.DirectDatabaseQuery.NoCaching
		return (int) $wpdb->get_var(
			"SELECT COUNT(*) FROM {$wpdb->termmeta} WHERE meta_key LIKE 'product\\_count\\_%'"
		);
		// phpcs:enable
	}

	/**
	 * One-time migration: DELETE all historical `product_count_*` rows from
	 * wp_termmeta. Future writes auto-route to wp_options.
	 *
	 * @return int Rows deleted.
	 */
	public static function purge_legacy_termmeta_rows(): int {
		global $wpdb;
		// phpcs:disable WordPress.DB.DirectDatabaseQuery.DirectQuery,WordPress.DB.DirectDatabaseQuery.NoCaching
		return (int) $wpdb->query(
			"DELETE FROM {$wpdb->termmeta} WHERE meta_key LIKE 'product\\_count\\_%'"
		);
		// phpcs:enable
	}
}