<?php
namespace MazlanHalim\IntelliLanz\Detection;

use MazlanHalim\IntelliLanz\Graph\Node;

final class DatabaseDetector implements DetectorInterface {
    public function detect(): array {
        global $wpdb;
        $metadata = array( 'server_type' => null, 'server_version' => null, 'charset' => null, 'collation' => null, 'ready' => null );
        if ( is_object( $wpdb ) ) {
            // Read only these public operational fields. Never serialize the connection.
            $metadata['ready'] = isset( $wpdb->ready ) ? (bool) $wpdb->ready : null;
            foreach ( array( 'charset' => 'charset', 'collation' => 'collate' ) as $key => $property ) {
                $value = $wpdb->$property ?? null;
                $metadata[ $key ] = is_string( $value ) && preg_match( '/^[a-zA-Z0-9_]+$/D', $value ) ? $value : null;
            }
            // A ready flag is WordPress state, not a new connection/ping or health check.
            if ( $metadata['ready'] && ! empty( $wpdb->is_mysql ) ) {
                $metadata['server_type'] = 'MySQL';
                try {
                    $info = is_callable( array( $wpdb, 'db_server_info' ) ) ? $wpdb->db_server_info() : '';
                    if ( is_string( $info ) && stripos( $info, 'MariaDB' ) !== false ) {
                        $metadata['server_type'] = 'MariaDB';
                        // Ignore MariaDB's legacy 5.5.5 compatibility prefix.
                        if ( preg_match( '/(\d+\.\d+\.\d+)-MariaDB/i', $info, $match ) ) {
                            $metadata['server_version'] = $match[1];
                        }
                    }
                    if ( $metadata['server_version'] === null && is_callable( array( $wpdb, 'db_version' ) ) ) {
                        $version = $wpdb->db_version();
                        if ( is_string( $version ) && preg_match( '/^\d+(?:\.\d+)+$/D', $version ) ) {
                            $metadata['server_version'] = $version;
                        }
                    }
                } catch ( \Throwable $error ) {
                    // Unavailable server data stays unknown; never expose connection errors.
                }
            }
        }
        return array( 'nodes' => array( new Node( 'system:database', 'database', 'system', 'Database', 'unknown', 0, $metadata ) ), 'edges' => array() );
    }
}