feat: add OpenCryptoPay support

lib/networking/http.dart

@@ -3,9 +3,13 @@ import 'dart:convert';
 import 'dart:io';
 
 import 'package:flutter/foundation.dart';
+import 'package:http/http.dart';
 import 'package:socks5_proxy/socks_client.dart';
 
+import '../app_config.dart';
+import '../services/tor_service.dart';
 import '../utilities/logger.dart';
+import '../utilities/prefs.dart';
 
 // WIP wrapper layer
 
@@ -163,3 +167,51 @@ class HTTP {
     return completer.future;
   }
 }
+
+/// HTTP client class that can be used with librairies that
+/// accept an http.Client
+class StackClient extends BaseClient {
+  StackClient({HTTP? client, this.timeout = const Duration(seconds: 30)})
+    : _client = client ?? const HTTP();
+
+  final HTTP _client;
+  final Duration timeout;
+
+  static ({InternetAddress host, int port})? _proxyInfo() {
+    if (AppConfig.hasFeature(AppFeature.tor) && Prefs.instance.useTor) {
+      return TorService.sharedInstance.getProxyInfo();
+    } else {
+      return null;
+    }
+  }
+
+  @override
+  Future<StreamedResponse> send(BaseRequest request) async {
+    final proxyInfo = _proxyInfo();
+
+    final Response response;
+    switch (request.method) {
+      case 'GET':
+        response = await _client
+            .get(
+              url: request.url,
+              headers: request.headers,
+              proxyInfo: proxyInfo,
+              connectionTimeout: timeout,
+            )
+            .timeout(timeout);
+      default:
+        throw ClientException(
+          'Unsupported HTTP method ${request.method}',
+          request.url,
+        );
+    }
+
+    return StreamedResponse(
+      ByteStream.fromBytes(response.bodyBytes),
+      response.code,
+      contentLength: response.bodyBytes.length,
+      request: request,
+    );
+  }
+}

lib/pages/open_crypto_pay/open_crypto_pay_send_handler.dart

@@ -0,0 +1,224 @@
+/*
+ * This file is part of Stack Wallet.
+ *
+ * Copyright (c) 2023 Cypher Stack
+ * All Rights Reserved.
+ * The code is distributed under GPLv3 license, see LICENSE file for details.
+ * Generated by Cypher Stack on 2023-05-26
+ *
+ */
+
+import 'dart:async';
+
+import 'package:flutter/material.dart';
+import 'package:flutter_riverpod/flutter_riverpod.dart';
+import 'package:opencryptopay/opencryptopay.dart';
+
+import '../../networking/http.dart';
+import '../../notifications/show_flush_bar.dart';
+import '../../providers/ui/preview_tx_button_state_provider.dart';
+import '../../utilities/amount/amount.dart';
+import '../../utilities/amount/amount_formatter.dart';
+import '../../utilities/logger.dart';
+import '../../utilities/show_loading.dart';
+import '../../utilities/util.dart';
+import '../../wallets/crypto_currency/crypto_currency.dart';
+import '../../widgets/stack_dialog.dart';
+
+/// Map a wallet [CryptoCurrency] (plus optional token symbol) to the
+/// library's [CryptoCoin] descriptor.
+CryptoCoin cryptoCoinFor(CryptoCurrency currency, {String? tokenSymbol}) =>
+    CryptoCoin(
+      ticker: tokenSymbol ?? currency.ticker,
+      prettyName: currency.prettyName,
+      displayName: tokenSymbol ?? currency.prettyName,
+    );
+
+class OpenCryptoPaySendHandler {
+  OpenCryptoPaySendHandler({
+    required this.ref,
+    required this.coin,
+    required this.sendToController,
+    required this.cryptoAmountController,
+    required this.setValidAddress,
+    required this.isMounted,
+    this.tokenSymbol,
+    this.tokenDecimals,
+    @visibleForTesting OpenCryptoPayController? controller,
+  }) : _controller =
+           controller ??
+           OpenCryptoPayController(
+             service: OpenCryptoPayService(client: StackClient()),
+           );
+
+  final WidgetRef ref;
+  final CryptoCurrency coin;
+  final TextEditingController sendToController;
+  final TextEditingController cryptoAmountController;
+  final void Function(String address) setValidAddress;
+  final bool Function() isMounted;
+
+  /// Set for token wallets (ERC-20, SPL, ...) so the OpenCryptoPay request
+  /// targets the token asset (ex: "USDT") instead of the chain's native coin
+  /// and amounts use the token's decimals.
+  final String? tokenSymbol;
+  final int? tokenDecimals;
+
+  int get _fractionDigits => tokenDecimals ?? coin.fractionDigits;
+
+  final OpenCryptoPayController _controller;
+  OpenCryptoPaySession? _session;
+
+  Future<void> showQuoteExpiredError(
+    BuildContext context, {
+    bool paymentNotSent = false,
+  }) => _showError(
+    context: context,
+    title: OpenCryptoPayStrings.quoteExpiredTitle,
+    message: OpenCryptoPayStrings.quoteExpiredMessage(
+      paymentNotSent: paymentNotSent,
+    ),
+  );
+
+  bool get requiresBroadcast => _session?.requiresBroadcast ?? true;
+
+  bool get isQuoteExpired => _session?.isQuoteExpired ?? false;
+
+  bool isActivePaymentFor(String? recipientAddress) =>
+      _session?.isActivePaymentFor(recipientAddress) ?? false;
+
+  Future<OpenCryptoPayResult?> _run({
+    required BuildContext context,
+    required String qrData,
+    required CryptoCoin coin,
+    required String logLabel,
+  }) async {
+    return showLoading<OpenCryptoPayResult>(
+      whileFuture: _controller.run(
+        qrData: qrData,
+        coin: coin,
+        onError: (e, s) =>
+            Logging.instance.w(logLabel, error: e, stackTrace: s),
+      ),
+      context: context,
+      rootNavigator: Util.isDesktop,
+      message: OpenCryptoPayStrings.loading,
+    );
+  }
+
+  Future<void> _showError({
+    required BuildContext context,
+    required String title,
+    required String message,
+  }) async {
+    if (!isMounted()) return;
+    await showDialog<void>(
+      context: context,
+      builder: (_) => StackOkDialog(
+        title: title,
+        message: message,
+        desktopPopRootNavigator: Util.isDesktop,
+        maxWidth: Util.isDesktop ? 600 : null,
+      ),
+    );
+  }
+
+  Future<OpenCryptoPaySuccess?> _showErrorOrSuccess(
+    BuildContext context,
+    OpenCryptoPayResult result,
+  ) async {
+    switch (result) {
+      case OpenCryptoPayFailure():
+        await _showError(
+          context: context,
+          title: result.title,
+          message: result.message,
+        );
+        return null;
+      case OpenCryptoPaySuccess():
+        return result;
+    }
+  }
+
+  Future<void> handle(BuildContext context, String qrData) async {
+    final result = await _run(
+      context: context,
+      qrData: qrData,
+      coin: cryptoCoinFor(coin, tokenSymbol: tokenSymbol),
+      logLabel: "OpenCryptoPay flow failed",
+    );
+
+    if (!isMounted() || result == null) return;
+
+    // ignore: use_build_context_synchronously
+    final success = await _showErrorOrSuccess(context, result);
+    if (success == null) return;
+
+    if (success.session.isQuoteExpired) {
+      // ignore: use_build_context_synchronously
+      await showQuoteExpiredError(context);
+      return;
+    }
+
+    _applySuccess(success);
+  }
+
+  void _applySuccess(OpenCryptoPaySuccess result) {
+    _session = result.session;
+
+    // Prefill the form in place.
+    final address = result.address;
+    sendToController.text = address;
+
+    final rawAmount = result.amountInSmallestUnit(_fractionDigits);
+    if (rawAmount != null) {
+      final parsed = Amount(
+        rawValue: rawAmount,
+        fractionDigits: _fractionDigits,
+      );
+      cryptoAmountController.text = ref
+          .read(pAmountFormatter(coin))
+          .format(parsed, withUnitName: false);
+      ref.read(pSendAmount.notifier).state = parsed;
+    }
+
+    setValidAddress(address);
+  }
+
+  Future<bool> submitProof(BuildContext context, String txProof) async {
+    final session = _session;
+    if (session == null) return true;
+
+    final result = await session.submitProof(txProof);
+    switch (result) {
+      case OpenCryptoPayProofAccepted():
+        _session = null;
+        return true;
+      case OpenCryptoPayProofQuoteExpired(:final error):
+        Logging.instance.w(
+          "OpenCryptoPay proof submission failed",
+          error: error,
+        );
+        if (!isMounted()) return false;
+        // ignore: use_build_context_synchronously
+        await showQuoteExpiredError(context, paymentNotSent: true);
+        return false;
+      case OpenCryptoPayProofFailed(:final message, :final error):
+        // The session stays active so the user can retry.
+        Logging.instance.w(
+          "OpenCryptoPay proof submission failed",
+          error: error,
+        );
+        if (!isMounted()) return false;
+        unawaited(
+          showFloatingFlushBar(
+            type: FlushBarType.warning,
+            message: message,
+            // ignore: use_build_context_synchronously
+            context: context,
+          ),
+        );
+        return false;
+    }
+  }
+}