<?php

namespace common\components;

use Yii;

/**
 * 飞鹅云打印回调验签（SHA256WithRSA）
 * 文档：http://help.feieyun.com/#/home/doc/zh;nav=1-8
 */
class feieyunCallbackUtil
{
    /**
     * 飞鹅公钥文件路径
     */
    public static function getPublicKeyPath()
    {
        return Yii::getAlias('@app/web/feieyun/public.key');
    }

    /**
     * 组装待验签字符串：剔除 sign 与空值，按参数名 ASCII 升序拼接
     */
    public static function buildSignContent(array $params)
    {
        unset($params['sign']);
        $filtered = [];
        foreach ($params as $key => $value) {
            if ($value === null || $value === '') {
                continue;
            }
            $filtered[(string)$key] = (string)$value;
        }
        ksort($filtered, SORT_STRING);

        $parts = [];
        foreach ($filtered as $key => $value) {
            $parts[] = $key . '=' . $value;
        }
        return implode('&', $parts);
    }

    /**
     * 校验飞鹅回调签名
     */
    public static function verify(array $params)
    {
        $sign = trim((string)($params['sign'] ?? ''));
        if ($sign === '') {
            return false;
        }

        $publicKeyPath = self::getPublicKeyPath();
        if (!is_file($publicKeyPath)) {
            Yii::error('飞鹅公钥文件不存在: ' . $publicKeyPath, __METHOD__);
            return false;
        }

        $publicKey = file_get_contents($publicKeyPath);
        if ($publicKey === false || trim($publicKey) === '') {
            Yii::error('飞鹅公钥文件读取失败: ' . $publicKeyPath, __METHOD__);
            return false;
        }

        $signContent = self::buildSignContent($params);
        $signature = base64_decode($sign, true);
        if ($signature === false) {
            Yii::warning('飞鹅回调 sign Base64 解码失败', __METHOD__);
            return false;
        }

        $key = openssl_pkey_get_public($publicKey);
        if ($key === false) {
            Yii::error('飞鹅公钥解析失败: ' . openssl_error_string(), __METHOD__);
            return false;
        }

        $result = openssl_verify($signContent, $signature, $key, OPENSSL_ALGO_SHA256);
        if (PHP_VERSION_ID < 80000) {
            openssl_free_key($key);
        }

        return $result === 1;
    }
}