<?php
declare(strict_types=1);
namespace plugin\saiadmin\app\service\agent;
use plugin\saiadmin\exception\ApiException;

/** Explicit hierarchy; missing historical relationships are unknown, never inferred from regions. */
final class AgentHierarchyPolicy
{
    public function levels(array $agents): array {
        $map=array_column($agents,null,'id'); $levels=[];
        foreach ($map as $id=>$agent) {
            $seen=[]; $cursor=$id; $level=0;
            while (isset($map[$cursor])) {
                if (isset($seen[$cursor])) throw new ApiException('代理上下级关系存在循环');
                $seen[$cursor]=true; $level++;
                $parent=$map[$cursor]['parent_id'];
                if ($parent===null) { $level=null; break; }
                if ((int)$parent===0) break;
                $cursor=(int)$parent;
                if (!isset($map[$cursor])) throw new ApiException('上级代理不存在');
            }
            if ($level!==null && $level>3) throw new ApiException('代理团队最多支持三级');
            $levels[$id]=$level;
        }
        return $levels;
    }

    public function validate(array $agents,int $id,?int $parent): void {
        $map=array_column($agents,null,'id');
        if ($parent!==null && $parent!==0) {
            if (!isset($map[$parent])) throw new ApiException('上级代理不存在');
            if ((int)$map[$parent]['status']!==1 && ($map[$id]['parent_id']??null)!=$parent) throw new ApiException('不能归属已停用代理');
            if (($this->levels($agents)[$parent]??null)===null) throw new ApiException('请先设置上级代理的等级');
        }
        $map[$id]=array_replace($map[$id]??['id'=>$id,'status'=>1],['parent_id'=>$parent]);
        if ($parent===null) foreach ($map as $row) if ((int)($row['parent_id']??0)===$id) throw new ApiException('存在下级代理，不能清空等级');
        $this->levels(array_values($map));
    }
}