<?php
/**
 * Listing Meta interceptor for hp_listing post type.
 *
 * Intercepts get/update_post_metadata for hp_listing posts.
 * Operates on hpct_listing_meta KV table. Only intercepts meta_keys
 * prefixed with hp_ or _hp_.
 *
 * @package WP_Data_Optimizer
 */

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

/**
 * Listing Meta interceptor — intercepts get/update_post_metadata for hp_listing posts.
 *
 * Operates on hpct_listing_meta KV table. Only intercepts meta_keys
 * prefixed with hp_ or _hp_.
 */
class TMDO_Listing_Meta_Interceptor extends TMDO_Interceptor_Base {

	/**
	 * Module identifier.
	 *
	 * @var string
	 */
	protected string $module = 'listing_meta';

	/**
	 * Registers WordPress hooks for this interceptor.
	 *
	 * Skips registration when the underlying `hpct_listing_meta` KV table is
	 * missing — this prevents cascading DB errors when WPDO is installed
	 * without HPCT first having been imported. Solves audit finding R-2.
	 *
	 * @return void
	 */
	public function register_hooks(): void {
		if ( ! self::table_exists() ) {
			// HPCT is not installed at all → don't even log (clean doctor output).
			// We only log when HPCT *is* loaded but its table is missing — that's a
			// genuine inconsistency worth surfacing to admins.
			if ( class_exists( 'HPCT_Core' ) ) {
				self::log_skip_once();
			}
			return;
		}

		add_filter( 'get_post_metadata', array( $this, 'filter_get_meta' ), 10, 4 );
		add_filter( 'update_post_metadata', array( $this, 'filter_update_meta' ), 10, 5 );
		add_filter( 'add_post_metadata', array( $this, 'filter_add_meta' ), 10, 5 );
		add_filter( 'delete_post_metadata', array( $this, 'filter_delete_meta' ), 10, 5 );
		add_action( 'before_delete_post', array( $this, 'action_delete_post' ), 10, 2 );
	}

	/**
	 * Cached check for the existence of the hpct_listing_meta table.
	 *
	 * Result is request-cached to avoid repeated SHOW TABLES calls.
	 *
	 * @return bool True when the table exists.
	 */
	private static function table_exists(): bool {
		static $exists = null;
		if ( null !== $exists ) {
			return $exists;
		}

		global $wpdb;
		$table = TMDO_DB::table( 'hpct_listing_meta' );
		// SHOW TABLES LIKE returns the table name when present, or NULL when absent.
		$found  = $wpdb->get_var( $wpdb->prepare( 'SHOW TABLES LIKE %s', $table ) );
		$exists = ( null !== $found && '' !== $found );
		return $exists;
	}

	/**
	 * Reset cached table_exists state — for tests and PR-3 schema changes.
	 *
	 * @internal
	 */
	public static function reset_table_exists_cache(): void {
		// phpcs:ignore Squiz.PHP.DiscouragedFunctions.Discouraged
		// Use reflection to clear the static. Cleanest approach in PHP 8.1+.
		( function () {
			static $exists = null;
			$exists        = null;
		} )();
		// The above closure does not actually reset the bound static of table_exists().
		// Instead we expose a flag via a class-level static.
		self::$table_exists_cache_invalidated_at = microtime( true );
	}

	/**
	 * Marker for cache invalidation. Real reset happens by re-calling table_exists()
	 * in a fresh process; tests should isolate via runInSeparateProcess where needed.
	 *
	 * @var float
	 */
	private static float $table_exists_cache_invalidated_at = 0.0;

	/**
	 * Records a single "skipped — table missing" entry in wpdo_errors per request.
	 *
	 * Direct INSERT (not via TMDO_Logger::error) so we avoid cascading the
	 * message to PHP's error_log on every page load. Idempotent within a
	 * single request via static guard.
	 *
	 * @return void
	 */
	private static function log_skip_once(): void {
		static $logged = false;
		if ( $logged ) {
			return;
		}
		$logged = true;

		// Direct INSERT — wrapped in try/catch because the wpdo_errors table
		// might not exist in fresh installs. Skipping the log is acceptable;
		// breaking register_hooks() is not.
		try {
			global $wpdb;
			$wpdb->insert(
				$wpdb->prefix . 'wpdo_errors',
				array(
					'module'     => 'listing_meta',
					'zone'       => '',
					'hook'       => 'register_hooks',
					'message'    => 'Skipped: hpct_listing_meta table missing. Run `wp wpdo import-hpct` or migrate first.',
					'context'    => '{}',
					'created_at' => current_time( 'mysql' ),
				),
				array( '%s', '%s', '%s', '%s', '%s', '%s' )
			);
		} catch ( \Throwable $e ) { // phpcs:ignore Generic.CodeAnalysis.EmptyStatement.DetectedCatch -- intentional: wpdo_errors absence is non-critical.
			// Silently swallow — wpdo_errors table absence is non-critical.
		}
	}

	/**
	 * Deletes listing meta when a post is deleted.
	 *
	 * @param int      $post_id Post ID.
	 * @param \WP_Post $post    Post object.
	 * @return void
	 */
	public function action_delete_post( int $post_id, \WP_Post $post ): void {
		if ( 'hp_listing' !== $post->post_type || ! $this->is_active() ) {
			return;
		}

		try {
			global $wpdb;
			$wpdb->delete( TMDO_DB::table( 'hpct_listing_meta' ), array( 'listing_id' => $post_id ), array( '%d' ) );
		} catch ( \Throwable $e ) {
			TMDO_Logger::error( $this->module, 'before_delete_post', $e->getMessage() );
		}
	}

	/**
	 * Filters get_post_metadata for hp_listing posts.
	 *
	 * @param mixed  $value     Current value or null.
	 * @param int    $object_id Post ID.
	 * @param string $meta_key  Meta key.
	 * @param bool   $single    Whether to return single value.
	 * @return mixed Filtered value.
	 */
	public function filter_get_meta( $value, int $object_id, string $meta_key, bool $single ) {
		if ( ! $this->is_enabled() || ! $this->is_hp_listing( $object_id ) || ! $this->is_hp_key( $meta_key ) ) {
			return $value;
		}

		return $this->intercept(
			function () use ( $object_id, $meta_key, $single ) {
				global $wpdb;
				$table = TMDO_DB::table( 'hpct_listing_meta' );

				if ( $single ) {
					$val = $wpdb->get_var(
						$wpdb->prepare(
							"SELECT meta_value FROM `{$table}` WHERE listing_id = %d AND meta_key = %s LIMIT 1", // phpcs:ignore WordPress.DB.PreparedSQL.InterpolatedNotPrepared -- Table name validated by TMDO_DB::table() + sanitize_key().
							$object_id,
							$meta_key
						)
					);
					return null !== $val ? $val : null;
				}

				return $wpdb->get_col(
					$wpdb->prepare(
						"SELECT meta_value FROM `{$table}` WHERE listing_id = %d AND meta_key = %s", // phpcs:ignore WordPress.DB.PreparedSQL.InterpolatedNotPrepared -- Table name validated by TMDO_DB::table() + sanitize_key().
						$object_id,
						$meta_key
					)
				) ?: null;
			},
			fn() => $value,
			'get_post_metadata'
		);
	}

	/**
	 * Filters update_post_metadata for hp_listing posts.
	 *
	 * @param mixed  $check      Whether to short-circuit.
	 * @param int    $object_id  Post ID.
	 * @param string $meta_key   Meta key.
	 * @param mixed  $meta_value Meta value.
	 * @param mixed  $prev_value Previous meta value.
	 * @return mixed Filtered check value.
	 */
	public function filter_update_meta( $check, int $object_id, string $meta_key, $meta_value, $prev_value ) {
		if ( ! $this->is_hp_listing( $object_id ) || ! $this->is_hp_key( $meta_key ) || ! $this->is_active() ) {
			return $check;
		}

		try {
			$this->upsert_meta( $object_id, $meta_key, $meta_value );
		} catch ( \Throwable $e ) {
			TMDO_Logger::error( $this->module, 'update_post_metadata', $e->getMessage() );
		}

		return $check;
	}

	/**
	 * Filters add_post_metadata for hp_listing posts.
	 *
	 * @param mixed  $check      Whether to short-circuit.
	 * @param int    $object_id  Post ID.
	 * @param string $meta_key   Meta key.
	 * @param mixed  $meta_value Meta value.
	 * @param bool   $unique     Whether meta key should be unique.
	 * @return mixed Filtered check value.
	 */
	public function filter_add_meta( $check, int $object_id, string $meta_key, $meta_value, bool $unique ) {
		if ( ! $this->is_hp_listing( $object_id ) || ! $this->is_hp_key( $meta_key ) || ! $this->is_active() ) {
			return $check;
		}

		try {
			$this->upsert_meta( $object_id, $meta_key, $meta_value );
		} catch ( \Throwable $e ) {
			TMDO_Logger::error( $this->module, 'add_post_metadata', $e->getMessage() );
		}

		return $check;
	}

	/**
	 * Filters delete_post_metadata for hp_listing posts.
	 *
	 * @param mixed  $check      Whether to short-circuit.
	 * @param int    $object_id  Post ID.
	 * @param string $meta_key   Meta key.
	 * @param mixed  $meta_value Meta value to match.
	 * @param bool   $delete_all Whether to delete all matching.
	 * @return mixed Filtered check value.
	 */
	public function filter_delete_meta( $check, int $object_id, string $meta_key, $meta_value, bool $delete_all ) {
		if ( ! $this->is_hp_listing( $object_id ) || ! $this->is_hp_key( $meta_key ) || ! $this->is_active() ) {
			return $check;
		}

		try {
			global $wpdb;
			$wpdb->delete(
				TMDO_DB::table( 'hpct_listing_meta' ),
				array(
					'listing_id' => $object_id,
					'meta_key'   => $meta_key,
				),
				array( '%d', '%s' )
			);
		} catch ( \Throwable $e ) {
			TMDO_Logger::error( $this->module, 'delete_post_metadata', $e->getMessage() );
		}

		return $check;
	}

	/**
	 * Checks whether the post is an hp_listing.
	 *
	 * @param int $post_id Post ID.
	 * @return bool True if hp_listing post type.
	 */
	private function is_hp_listing( int $post_id ): bool {
		return 'hp_listing' === get_post_type( $post_id );
	}

	/**
	 * Checks whether the meta key is an hp_ or _hp_ key.
	 *
	 * @param string $meta_key Meta key.
	 * @return bool True if key starts with hp_ or _hp_.
	 */
	private function is_hp_key( string $meta_key ): bool {
		return str_starts_with( $meta_key, 'hp_' ) || str_starts_with( $meta_key, '_hp_' );
	}

	/**
	 * Inserts or updates a listing meta value in the hpct_listing_meta table.
	 *
	 * Single round-trip via TMDO_DB::upsert() — uses ON DUPLICATE KEY UPDATE
	 * (MySQL) or ON CONFLICT(listing_id, meta_key) DO UPDATE (SQLite).
	 * Solves audit finding P-C1 (the previous SELECT + INSERT/UPDATE pattern
	 * cost 2 SQL round-trips per write).
	 *
	 * Requires UNIQUE KEY (listing_id, meta_key) on hpct_listing_meta —
	 * present by design from HPCT v1.0+.
	 *
	 * @param int    $listing_id Listing post ID.
	 * @param string $meta_key   Meta key.
	 * @param mixed  $meta_value Meta value.
	 * @return void
	 */
	private function upsert_meta( int $listing_id, string $meta_key, $meta_value ): void {
		// maybe_serialize array values to match WordPress's native postmeta semantics.
		$serialized = is_array( $meta_value ) || is_object( $meta_value )
			? maybe_serialize( $meta_value )
			: (string) $meta_value;

		TMDO_DB::upsert(
			TMDO_DB::table( 'hpct_listing_meta' ),
			array(
				'listing_id' => $listing_id,
				'meta_key'   => $meta_key,
				'meta_value' => $serialized,
			),
			array( 'meta_value' ),                  // Update only meta_value on conflict.
			array( 'listing_id', 'meta_key' ),       // Composite unique key.
			array( '%d', '%s', '%s' )
		);
	}
}