<?php

namespace App\Services;

use App\Exceptions\RepositoryException;
use EasyWeChat\Pay\Application;
use Illuminate\Http\Request;
use Illuminate\Support\Facades\Log;
use Throwable;

/**
 * 微信官方支付服务（APIv3 小程序 JSAPI，基于 EasyWeChat Pay）
 *
 * - 统一下单：POST /v3/pay/transactions/jsapi → prepay_id → 商户私钥签名生成 wx.requestPayment 调起参数
 * - 交易查询：GET /v3/pay/transactions/out-trade-no/{商户订单号}
 * - 支付通知：Wechatpay-Signature 验签（配置平台证书/公钥时）+ APIv3 密钥 AES-256-GCM 解密报文
 *
 * 配置优先级：后台「系统设置 → 微信官方支付」(site_config wxpay.*) > config/services.php（env）
 */
class WechatPayService
{
    /** 通知应答码：成功 / 失败（微信收到 SUCCESS 才停止重推） */
    public const string NOTIFY_ACK_OK = 'SUCCESS';
    public const string NOTIFY_ACK_FAIL = 'FAIL';

    /** 交易状态：支付成功（交易查询 / 支付通知的 trade_state） */
    public const string TRADE_STATE_SUCCESS = 'SUCCESS';

    protected ?Application $application = null;

    /**
     * 统一下单（JSAPI：小程序 / 公众号 H5 通用）
     *
     * @param string $paymentNo 商户订单号（本系统支付单号）
     * @param string $amountYuan 金额（元，两位小数）
     * @param string $openid 付款人 openid（按下单 appid 维度：小程序 openid 或公众号 openid）
     * @param string $description 订单标题
     * @param string $appid 下单应用 appid（公众号 JSAPI 传公众号 appid；留空取配置的小程序 appid）
     * @return array<string, mixed> 调起支付参数（appId/timeStamp/nonceStr/package/signType/paySign，
     *                              小程序喂 wx.requestPayment，公众号 H5 喂 WeixinJSBridge getBrandWCPayRequest，结构同构）
     * @throws RepositoryException 未配置或下单失败
     */
    public function createOrder(string $paymentNo, string $amountYuan, string $openid, string $description, string $appid = ''): array
    {
        $appid = trim($appid) !== '' ? trim($appid) : $this->appid();
        $result = $this->call('POST', '/v3/pay/transactions/jsapi', [
            'appid' => $appid,
            'mchid' => $this->config('mch_id'),
            'description' => mb_substr($description, 0, 127),
            'out_trade_no' => $paymentNo,
            'notify_url' => $this->notifyUrl(),
            'amount' => [
                'total' => (int) bcmul($amountYuan, '100'), // APIv3 金额单位：分
                'currency' => 'CNY',
            ],
            'payer' => ['openid' => $openid],
        ], '下单');

        $prepayId = (string) ($result['prepay_id'] ?? '');
        if ($prepayId === '') {
            Log::driver('pay')->error('微信支付下单应答缺少 prepay_id', ['response' => $result]);
            throw new RepositoryException('微信支付下单失败：应答缺少 prepay_id');
        }

        // buildMiniAppConfig 即 buildBridgeConfig（小程序 wx.requestPayment 与公众号 WeixinJSBridge 参数同构）
        $params = $this->app()->getUtils()->buildMiniAppConfig($prepayId, $appid);
        Log::driver('pay')->info('微信支付下单成功', ['out_trade_no' => $paymentNo, 'prepay_id' => $prepayId, 'appid' => $appid]);

        return $params;
    }

    /**
     * 交易查询（按商户订单号）
     *
     * @param string $paymentNo 商户订单号（本系统支付单号）
     * @return array<string, mixed> 微信交易报文（trade_state/transaction_id/success_time/amount.total 等）
     * @throws RepositoryException 查询失败
     */
    public function queryOrder(string $paymentNo): array
    {
        return $this->call('GET', '/v3/pay/transactions/out-trade-no/' . $paymentNo, [
            'mchid' => $this->config('mch_id'),
        ], '查询');
    }

    /**
     * 解密支付结果后台通知（配置平台证书/公钥时先验签，再以 APIv3 密钥 AES-256-GCM 解密）
     *
     * @return array<string, mixed> 解密后的交易报文（out_trade_no/trade_state/transaction_id/success_time/amount 等）
     * @throws RepositoryException 验签或解密失败
     */
    public function decryptNotify(Request $request): array
    {
        Log::driver('pay')->info('微信支付通知接收', ['body' => $request->getContent()]);

        $app = $this->app();
        $server = $app->getServer();
        $server->setRequestFromSymfonyRequest($request);

        // 配置平台证书/公钥时校验 Wechatpay-Signature；未配置时依赖 AES-GCM 认证解密（APIv3 密钥仅微信与商户持有）
        if ($this->config('platform_cert') !== '' && $this->config('platform_serial') !== '') {
            try {
                $app->getValidator()->validate($server->getRequest());
            } catch (Throwable $e) {
                throw new RepositoryException('微信支付通知验签失败：' . $e->getMessage());
            }
        }

        try {
            $message = $server->getRequestMessage();
        } catch (Throwable $e) {
            throw new RepositoryException('微信支付通知解密失败：' . $e->getMessage());
        }

        $params = $message->toArray();
        Log::driver('pay')->info('微信支付通知解密', ['params' => $params]);
        return $params;
    }

    /**
     * 支付结果后台通知地址（统一下单时上送的 notify_url）
     */
    public function notifyUrl(): string
    {
        return rtrim((string) config('app.url'), '/') . '/mini/payment/wechat-notify';
    }

    /**
     * 注入 EasyWeChat Application（测试 mock 用）
     */
    public function setApplication(Application $application): static
    {
        $this->application = $application;
        return $this;
    }

    /**
     * EasyWeChat Pay Application（按当前配置懒加载构建）
     *
     * @throws RepositoryException 必填配置缺失或密钥无法解析
     */
    public function app(): Application
    {
        if ($this->application !== null) {
            return $this->application;
        }

        $mchId = $this->config('mch_id');
        if ($mchId === '') {
            throw new RepositoryException('微信支付未配置商户号，请联系管理员');
        }

        $platformCerts = [];
        $platformCert = $this->config('platform_cert');
        $platformSerial = $this->config('platform_serial');
        if ($platformCert !== '' && $platformSerial !== '') {
            $platformCerts[$platformSerial] = $this->pemContent($platformCert, 'CERTIFICATE');
        }

        try {
            $this->application = new Application([
                'mch_id' => $mchId,
                'private_key' => $this->pemContent($this->config('private_key'), 'PRIVATE'),
                'certificate' => $this->pemContent($this->config('certificate'), 'CERTIFICATE'),
                'secret_key' => $this->config('secret_key'),
                'platform_certs' => $platformCerts,
            ]);
        } catch (RepositoryException $e) {
            throw $e;
        } catch (Throwable $e) {
            throw new RepositoryException('微信支付配置错误：' . $e->getMessage());
        }

        return $this->application;
    }

    /**
     * 调起微信 v3 接口并处理应答（通讯/业务失败统一抛 RepositoryException）
     *
     * @param array<string, mixed> $payload POST 时为 JSON 报文，GET 时为 query 参数
     * @return array<string, mixed> 应答报文
     * @throws RepositoryException
     */
    protected function call(string $method, string $uri, array $payload, string $action): array
    {
        try {
            $response = $method === 'GET'
                ? $this->app()->getClient()->get($uri, ['query' => $payload])
                : $this->app()->getClient()->postJson($uri, $payload);
        } catch (RepositoryException $e) {
            throw $e;
        } catch (Throwable $e) {
            Log::driver('pay')->error('微信支付' . $action . '通讯异常', ['uri' => $uri, 'error' => $e->getMessage()]);
            throw new RepositoryException('微信支付' . $action . '通讯异常，请稍后重试');
        }

        $body = $response->getContent(false);
        Log::driver('pay')->info('微信支付' . $action . '应答', [
            'uri' => $uri,
            'status' => $response->getStatusCode(),
            'body' => $body,
        ]);

        $result = json_decode($body, true);
        if ($response->isFailed()) {
            $message = is_array($result) ? (string) ($result['message'] ?? $result['code'] ?? '') : '';
            throw new RepositoryException('微信支付' . $action . '失败：' . ($message !== '' ? $message : '未知错误'));
        }

        return is_array($result) ? $result : [];
    }

    /**
     * 下单小程序 appid（默认取小程序自身 appid）
     */
    protected function appid(): string
    {
        $appid = $this->config('appid');
        if ($appid === '') {
            $appid = (string) site_config('wechat.mini_appid', '');
        }
        if ($appid === '') {
            $appid = (string) config('services.wechat.mini.appid', '');
        }
        return $appid;
    }

    /**
     * 密钥/证书内容归一化为 PEM：支持完整 PEM、base64 单行、file:// 路径或本地文件路径
     *
     * @throws RepositoryException 未配置
     */
    protected function pemContent(string $value, string $kind): string
    {
        $value = trim($value);
        if ($value === '') {
            $name = $kind === 'PRIVATE' ? '商户API私钥' : '证书';
            throw new RepositoryException('微信支付未配置' . $name . '，请联系管理员');
        }
        if (str_starts_with($value, 'file://') || str_contains($value, '-----BEGIN')) {
            return $value;
        }
        if (is_file($value)) {
            return 'file://' . $value;
        }
        // base64 单行内容包装为 PEM
        $header = $kind === 'PRIVATE' ? 'PRIVATE' : 'CERTIFICATE';
        return "-----BEGIN {$header}-----\n" . wordwrap($value, 64, "\n", true) . "\n-----END {$header}-----";
    }

    /**
     * 读取支付配置：后台站点配置优先，为空回退 config/services.php（env）
     */
    protected function config(string $key): string
    {
        $value = site_config('wxpay.' . $key, '');
        if ($value === null || $value === '') {
            $value = config('services.wxpay.' . $key, '');
        }
        return trim((string) $value);
    }
}