<?php
/**
 * Bounded read-only adapter for the documented Code Snippets table shape.
 *
 * @package Px320\SiteAudit
 */

declare(strict_types=1);

namespace Px320\SiteAudit\Code;

use InvalidArgumentException;
use wpdb;

final class CodeSnippetsAdapter {
	private const MAX_SNIPPETS = 1000;
	private const MAX_BYTES    = 1048576;

	private wpdb $database;
	private string $table;

	public function __construct( wpdb $database ) {
		$this->database = $database;
		$this->table    = $database->prefix . 'snippets';
	}

	public function available(): bool {
		if ( ! $this->active_plugin_declared() || 1 !== preg_match( '/^[A-Za-z0-9_]+$/', $this->table ) ) {
			return false;
		}

		// Exact table name is derived from the current-site prefix and fixed suffix.
		// phpcs:ignore WordPress.DB.DirectDatabaseQuery.DirectQuery, WordPress.DB.DirectDatabaseQuery.NoCaching
		$found = $this->database->get_var( $this->database->prepare( 'SHOW TABLES LIKE %s', $this->database->esc_like( $this->table ) ) );

		return $this->table === $found;
	}

	/**
	 * Source is returned only to the in-memory tokenizer and never to storage or UI.
	 *
	 * @return array{id:int,code:string,size_bytes:int,oversized:bool}|null
	 */
	public function next_at( int $offset ): ?array {
		if ( $offset < 0 || $offset > self::MAX_SNIPPETS ) {
			throw new InvalidArgumentException( 'invalid_snippet_cursor' );
		}
		if ( $offset >= self::MAX_SNIPPETS ) {
			return null;
		}

		// The table identifier is validated above and no callback/provider code is run.
		// phpcs:ignore WordPress.DB.DirectDatabaseQuery.DirectQuery, WordPress.DB.DirectDatabaseQuery.NoCaching, WordPress.DB.PreparedSQL.InterpolatedNotPrepared
		$row = $this->database->get_row(
			$this->database->prepare(
				"SELECT id,code FROM {$this->table} WHERE active = %d ORDER BY id ASC LIMIT 1 OFFSET %d",
				1,
				$offset
			),
			ARRAY_A
		);
		if ( ! is_array( $row ) ) {
			return null;
		}
		$code       = (string) $row['code'];
		$size_bytes = strlen( $code );
		$oversized  = $size_bytes > self::MAX_BYTES;
		if ( $oversized ) {
			$code = '';
		}

		return array(
			'id'         => (int) $row['id'],
			'code'       => $code,
			'size_bytes' => $size_bytes,
			'oversized'  => $oversized,
		);
	}

	private function active_plugin_declared(): bool {
		$active = get_option( 'active_plugins', array() );
		$active = is_array( $active ) ? $active : array();
		if ( is_multisite() ) {
			$network = get_site_option( 'active_sitewide_plugins', array() );
			$active  = array_merge( $active, is_array( $network ) ? array_keys( $network ) : array() );
		}
		foreach ( $active as $plugin ) {
			if ( is_string( $plugin ) && in_array( $plugin, array( 'code-snippets/code-snippets.php', 'code-snippets-pro/code-snippets.php' ), true ) ) {
				return true;
			}
		}

		return false;
	}
}