flutter_paydemo/lib/service/platform/wechat_flow.dart

/// 微信支付流程封装（fluwx 5.3.1）
library;

import 'package:fluwx/fluwx.dart' as fluwx;

import '../../constants.dart';
import '../../models/payment.dart';

/// fluwx 回调结果码
class WechatPayResultCode {
  WechatPayResultCode._();

  static const int success = 0; // 支付成功
  static const int failed = -1; // 支付失败
  static const int cancelled = -2; // 用户取消
}

/// 微信支付封装：注册 + 拉起支付 + 结果回调
class WechatFlow {
  WechatFlow._() : _fluwx = fluwx.Fluwx();

  static final WechatFlow _instance = WechatFlow._();

  /// 获取单例
  static WechatFlow get instance => _instance;

  final fluwx.Fluwx _fluwx;

  /// 支付结果回调（由 pay_service 注册，errCode: 0 成功）
  void Function(int errCode, String errStr)? onPayResult;

  /// 注册微信 SDK（App 启动时调用一次；Web 为空实现，安全跳过）
  Future<bool> init() async {
    return _fluwx.registerApi(
      appId: kWechatAppId,
      universalLink: kWechatUniversalLink,
      doOnAndroid: true,
      doOnIOS: true,
    );
  }

  /// 是否已安装微信 App
  Future<bool> isInstalled() async {
    try {
      return await _fluwx.isWeChatInstalled;
    } catch (_) {
      return false;
    }
  }

  /// 注册支付结果订阅（App 启动时调用一次）
  void subscribe() {
    _fluwx.addSubscriber((response) {
      if (response is fluwx.WeChatPaymentResponse) {
        onPayResult?.call(response.errCode ?? 0, response.errStr ?? '');
      }
    });
  }

  /// 拉起微信支付
  /// [created] 来自后端统一下单响应
  Future<bool> payWith(
    WechatPaymentCreatedResponse created,
  ) {
    return _fluwx.pay(
      which: fluwx.Payment(
        appId: created.appId!,
        partnerId: created.partnerId!,
        prepayId: created.prepayId!,
        packageValue: created.package ?? 'Sign=WXPay',
        nonceStr: created.noncestr!,
        timestamp: int.parse(created.timestamp!),
        sign: created.sign!,
      ),
    );
  }
}