<?php
declare(strict_types=1);

namespace Soon\Api\Services;

use Soon\Api\Core\Config;

/**
 * 支付宝 PC 网站支付（页面跳转）。
 */
final class AlipayClient
{
    /** @return array{gateway: string, params: array<string, string>} */
    public static function pagePayForm(string $orderNo, int $amountCents, string $subject): array
    {
        $cfg = Config::get('alipay', []);
        $params = [
            'app_id' => (string)($cfg['app_id'] ?? ''),
            'method' => 'alipay.trade.page.pay',
            'charset' => 'utf-8',
            'sign_type' => 'RSA2',
            'timestamp' => date('Y-m-d H:i:s'),
            'version' => '1.0',
            'notify_url' => (string)Config::get('site.base_url', '') . '/api/v1/pay/alipay/notify',
            'return_url' => (string)Config::get('site.front_base_url', Config::get('site.base_url', ''))
                . '/pages/member.web.html?paid=' . rawurlencode($orderNo),
            'biz_content' => json_encode([
                'out_trade_no' => $orderNo,
                'product_code' => 'FAST_INSTANT_TRADE_PAY',
                'total_amount' => number_format($amountCents / 100, 2, '.', ''),
                'subject' => $subject,
            ], JSON_UNESCAPED_UNICODE),
        ];
        $params['sign'] = self::sign($params, (string)($cfg['private_key'] ?? ''));
        $gateway = ($cfg['sandbox'] ?? false)
            ? 'https://openapi.alipaydev.com/gateway.do'
            : 'https://openapi.alipay.com/gateway.do';
        return ['gateway' => $gateway, 'params' => $params];
    }

    public static function pagePay(string $orderNo, int $amountCents, string $subject): string
    {
        $form = self::pagePayForm($orderNo, $amountCents, $subject);
        return $form['gateway'] . '?' . http_build_query($form['params']);
    }

    public static function verifyNotify(array $params): bool
    {
        $cfg = Config::get('alipay', []);
        $sign = (string)($params['sign'] ?? '');
        if ($sign === '') {
            return false;
        }
        unset($params['sign'], $params['sign_type']);
        ksort($params);
        $query = '';
        foreach ($params as $k => $v) {
            if ($v === '' || $v === null) {
                continue;
            }
            $query .= $k . '=' . $v . '&';
        }
        $query = rtrim($query, '&');
        return self::verifyNotifySign($query, $sign, (string)($cfg['public_key'] ?? ''));
    }

    public static function verifyNotifySign(string $content, string $signBase64, string $alipayPublicKey): bool
    {
        $pub = openssl_get_publickey(self::normalizePem($alipayPublicKey, 'PUBLIC KEY'));
        if ($pub === false) {
            return false;
        }
        $sig = base64_decode($signBase64, true);
        if ($sig === false) {
            openssl_free_key($pub);
            return false;
        }
        $ok = openssl_verify($content, $sig, $pub, OPENSSL_ALGO_SHA256);
        openssl_free_key($pub);
        return $ok === 1;
    }

    private static function sign(array $params, string $privateKey): string
    {
        ksort($params);
        $query = '';
        foreach ($params as $k => $v) {
            if ($v === '' || $v === null) {
                continue;
            }
            $query .= $k . '=' . $v . '&';
        }
        $query = rtrim($query, '&');
        $res = openssl_get_privatekey(self::normalizePem($privateKey, 'PRIVATE KEY'));
        if ($res === false) {
            return '';
        }
        $signature = '';
        openssl_sign($query, $signature, $res, OPENSSL_ALGO_SHA256);
        openssl_free_key($res);
        return base64_encode($signature);
    }

    public static function refund(string $orderNo, int $amountCents): bool
    {
        $cfg = Config::get('alipay', []);
        $appId = (string)($cfg['app_id'] ?? '');
        $privateKey = (string)($cfg['private_key'] ?? '');
        if ($appId === '' || $privateKey === '') {
            return false;
        }
        $params = [
            'app_id' => $appId,
            'method' => 'alipay.trade.refund',
            'charset' => 'utf-8',
            'sign_type' => 'RSA2',
            'timestamp' => date('Y-m-d H:i:s'),
            'version' => '1.0',
            'biz_content' => json_encode([
                'out_trade_no' => $orderNo,
                'refund_amount' => number_format($amountCents / 100, 2, '.', ''),
            ], JSON_UNESCAPED_UNICODE),
        ];
        $params['sign'] = self::sign($params, $privateKey);
        $gateway = ($cfg['sandbox'] ?? false)
            ? 'https://openapi.alipaydev.com/gateway.do'
            : 'https://openapi.alipay.com/gateway.do';
        $ch = curl_init($gateway);
        curl_setopt_array($ch, [
            CURLOPT_RETURNTRANSFER => true,
            CURLOPT_POST => true,
            CURLOPT_POSTFIELDS => http_build_query($params),
            CURLOPT_TIMEOUT => 20,
        ]);
        $resp = curl_exec($ch);
        curl_close($ch);
        if (!is_string($resp) || $resp === '') {
            return false;
        }
        $data = json_decode($resp, true);
        $key = 'alipay_trade_refund_response';
        return is_array($data) && ($data[$key]['code'] ?? '') === '10000';
    }

    private static function normalizePem(string $key, string $type): string
    {
        $key = trim($key);
        if (str_contains($key, 'BEGIN')) {
            return $key;
        }
        $body = chunk_split(preg_replace('/\s+/', '', $key), 64, "\n");
        return "-----BEGIN {$type}-----\n{$body}-----END {$type}-----\n";
    }
}