<?php
namespace Relay\Multisite;

/** Which of a network's tables belong to one subsite (spec 2026-10-16 §3.1). */
final class SubsiteTables
{
    /**
     * $prefix is the subsite's table prefix ("wp_3_", or the base prefix for the main site). The shared users and
     * usermeta tables and the network's own tables never belong to a subsite.
     *
     * @param string[] $tables
     * @return string[]
     */
    public static function of(string $prefix, string $base, array $tables): array
    {
        $out = [];
        foreach ($tables as $t) {
            if (strpos($t, $prefix) !== 0) {
                continue;
            }
            $suffix = substr($t, strlen($prefix));
            if ($prefix === $base && (preg_match('/^[0-9]+_/', $suffix) || in_array($suffix, Network::TABLES, true))) {
                continue; // another subsite's table, or the network's
            }
            if (in_array($suffix, ['users', 'usermeta'], true)) {
                continue;
            }
            $out[] = $t;
        }
        return $out;
    }

    /**
     * Whether a table coming in may be written as $table on $scope: one of its own tables, or its incoming users
     * tables (they wait for the user merge and never go live). Never another subsite's or the network's.
     */
    public static function accepts(Scope $scope, string $table): bool
    {
        if (!$scope->is_subsite()) {
            return true;
        }
        return self::of($scope->prefix, $scope->base_prefix, [$table]) === [$table] || in_array($table, [$scope->prefix . 'users', $scope->prefix . 'usermeta'], true);
    }
}