<?php
namespace app\common\audit;

use Webman\Context;

class AuditBuffer
{
    const CTX_KEY = '__audit_buffer__';

    public array $changes = []; // 每项：['scene','object_id','field','old','new']
    public ?string $action = null; // 业务动作（可覆盖）
    public array $meta = [];       // 业务自定义元信息（如需扩展入库，可在消费者处处理）
    public array $maskFields = ['password','pwd','token','secret','access_token','refresh_token'];

    public static function instance(): self
    {
        $buf = Context::get(self::CTX_KEY);
        if (!$buf) {
            $buf = new self();
            Context::set(self::CTX_KEY, $buf);
        }
        return $buf;
    }

    public static function reset(): void
    {
        Context::set(self::CTX_KEY, new self());
    }

    public function setAction(?string $action): void
    {
        $this->action = $action;
    }

    public function setMeta(array $meta): void
    {
        $this->meta = $meta + $this->meta;
    }

    /** 模型字段级变更推送（由 Trait 调用） */
    public function pushModelChange(string $scene, $objectId, array $old, array $new): void
    {
        $keys = array_unique(array_merge(array_keys($old), array_keys($new)));
        foreach ($keys as $k) {
            $ov = $old[$k] ?? null;
            $nv = $new[$k] ?? null;
            if ($ov === $nv) continue;

            [$ovMasked, $nvMasked] = $this->maskIfNeeded($k, $ov, $nv);
            $this->changes[] = [
                'scene'     => $scene,
                'object_id' => $objectId,
                'field'     => $k,
                'old'       => $ovMasked,
                'new'       => $nvMasked,
            ];
        }
    }

    private function maskIfNeeded(string $field, $old, $new): array
    {
        foreach ($this->maskFields as $m) {
            if (stripos($field, $m) !== false) {
                return [$old===null?null:'***', $new===null?null:'***'];
            }
        }
        if (preg_match('/(mobile|phone|tel|idcard|id_card)/i', $field)) {
            $mask = function ($v) {
                if ($v === null) return null;
                $s = (string)$v;
                return mb_substr($s, 0, 3).'****'.mb_substr($s, -4);
            };
            return [$mask($old), $mask($new)];
        }
        return [$old, $new];
    }
}