import 'dart:async';
import 'dart:convert';

import 'package:flutter/foundation.dart';
import 'package:in_app_purchase/in_app_purchase.dart';
import 'package:in_app_purchase_android/in_app_purchase_android.dart';
import 'package:pets_hero_ai/core/api/api.dart';

import '../../core/log/app_logger.dart';
import 'models/google_pay_verification_payload.dart';

/// 调起 Google Play 内购，所有内购均通过本方法发起并返回凭据用于服务端回调。
abstract final class GooglePlayPurchaseService {
  static final _log = AppLogger('GooglePlayPurchase');

  /// 发起购买并返回服务端回调所需凭据（purchaseData=originalJson, signature）。
  /// 成功返回 [GooglePayVerificationPayload]，取消/失败返回 null。调用方填入 id（federation）、userId 后组 merchant 上报。
  static Future<GooglePayVerificationPayload?> launchPurchaseAndReturnData(
      String productId) async {
    _log.d('谷歌支付请求商品 ID(helm): "$productId"');
    if (defaultTargetPlatform != TargetPlatform.android) {
      _log.d('非 Android，跳过内购');
      return null;
    }
    final iap = InAppPurchase.instance;
    if (!await iap.isAvailable()) {
      _log.w('Billing 不可用');
      return null;
    }
    final response = await iap.queryProductDetails({productId});
    if (response.notFoundIDs.isNotEmpty || response.productDetails.isEmpty) {
      _log.w(
          '商品未找到: 请求的 productId="$productId", notFoundIDs=${response.notFoundIDs}, 请核对与 Play 后台配置的「产品 ID」是否完全一致（区分大小写）');
      return null;
    }
    final product = response.productDetails.first;
    final completer = Completer<GooglePayVerificationPayload?>();
    StreamSubscription<List<PurchaseDetails>>? sub;
    sub = iap.purchaseStream.listen(
      (purchases) {
        // 把 purchases 转为 JSON 输出，方便调试
        try {
          final list = purchases.map((p) {
            final base = <String, Object?>{
              'productID': p.productID,
              'status': p.status.toString(),
              'transactionDate': p.transactionDate,
              'verificationData': {
                'serverVerificationData':
                    p.verificationData.serverVerificationData,
                'localVerificationData':
                    p.verificationData.localVerificationData,
                'source': p.verificationData.source,
              },
              'pendingCompletePurchase': p.pendingCompletePurchase,
              'error': p.error?.message,
            };
            if (p is GooglePlayPurchaseDetails) {
              final b = p.billingClientPurchase;
              base['googlePlay'] = {
                'orderId': b.orderId,
                'packageName': b.packageName,
                'purchaseTime': b.purchaseTime,
                'purchaseToken': b.purchaseToken,
                'signature': b.signature,
                'originalJson': b.originalJson,
                'isAcknowledged': b.isAcknowledged,
                'purchaseState': b.purchaseState.toString(),
              };
            }
            return base;
          }).toList();
          _log.d('Google Play purchases json: ${jsonEncode(list)}');
          logWithEmbeddedJson(jsonEncode(list));
        } catch (e) {
          _log.w('序列化 purchases 失败: $e');
        }

        for (final p in purchases) {
          if (p.productID != productId) continue;
          if (p.status == PurchaseStatus.purchased ||
              p.status == PurchaseStatus.restored) {
            _log.d('购买成功: ${p.toString()}');
            if (!completer.isCompleted) {
              GooglePayVerificationPayload? payload;
              if (p is GooglePlayPurchaseDetails) {
                final b = p.billingClientPurchase;
                payload = GooglePayVerificationPayload(
                  purchaseData: b.originalJson,
                  signature: b.signature,
                );
              }
              iap.completePurchase(p);
              completer.complete(payload);
            }
            sub?.cancel();
            return;
          }
          if (p.status == PurchaseStatus.error ||
              p.status == PurchaseStatus.canceled) {
            if (!completer.isCompleted) completer.complete(null);
            sub?.cancel();
            return;
          }
        }
      },
      onError: (e) {
        if (!completer.isCompleted) completer.complete(null);
        sub?.cancel();
      },
    );
    final success = await iap.buyConsumable(
      purchaseParam: PurchaseParam(productDetails: product),
    );
    if (!success) {
      sub.cancel();
      return null;
    }
    return completer.future.timeout(
      const Duration(seconds: 120),
      onTimeout: () {
        sub?.cancel();
        return null;
      },
    );
  }
}