Connect customer quotations and payment execution to Sendico (#50)

frontend/packages/sxchnge_wallet/lib/src/providers/transfer.dart

@@ -19,6 +19,8 @@ class TransferProvider extends ChangeNotifier {
             .firstOrNull
             ?.id ??
         'usd';
+    wallet.addListener(_walletChanged);
+    _syncAccounts();
     final op = recorder.begin(
       journey,
       JourneyStep.transferDraft,
@@ -26,6 +28,30 @@ class TransferProvider extends ChangeNotifier {
     );
     recorder.finish(op, simulated: wallet.service.isSimulated);
   }
+  void _syncAccounts() {
+    final accounts = wallet.data?.accounts;
+    if (accounts == null ||
+        accounts.isEmpty ||
+        busy ||
+        uncertain ||
+        quote != null)
+      return;
+    if (!accounts.any((a) => a.id == source)) source = accounts.first.id;
+    if (!accounts.any((a) => a.id == destination) || destination == source) {
+      destination = accounts.where((a) => a.id != source).firstOrNull?.id;
+    }
+    if (!wallet.service.isSimulated && kind == TransferKind.payout) {
+      recipient = wallet.account(source)?.payoutMethod ?? '';
+    }
+  }
+
+  void _walletChanged() {
+    if (_disposed) return;
+    final previous = source;
+    _syncAccounts();
+    if (source != previous) notifyListeners();
+  }
+
   final WalletProvider wallet;
   final TransferKind kind;
   final JourneyRecorder recorder;
@@ -45,7 +71,8 @@ class TransferProvider extends ChangeNotifier {
     TransferKind.exchange => JourneyKind.exchange,
     TransferKind.payout => JourneyKind.payout,
   };
-  bool get hasDraft => amount.isNotEmpty || recipient.isNotEmpty;
+  bool get hasDraft =>
+      amount.isNotEmpty || (wallet.service.isSimulated && recipient.isNotEmpty);
   bool get expired =>
       quote != null && !DateTime.now().isBefore(quote!.expiresAt);
   void change({
@@ -59,6 +86,7 @@ class TransferProvider extends ChangeNotifier {
     this.destination = destination ?? this.destination;
     this.amount = amount ?? this.amount;
     this.recipient = recipient ?? this.recipient;
+    if (source != null) _syncAccounts();
     quote = null;
     noSubmission = false;
     error = null;
@@ -171,6 +199,7 @@ class TransferProvider extends ChangeNotifier {
     error = null;
     factorError = null;
     notifyListeners();
+    _key ??= approval?.token;
     _key ??= List.generate(
       16,
       (_) => Random.secure().nextInt(256).toRadixString(16).padLeft(2, '0'),
@@ -266,6 +295,7 @@ class TransferProvider extends ChangeNotifier {
   @override
   void dispose() {
     _disposed = true;
+    wallet.removeListener(_walletChanged);
     recipient = '';
     if (!_handedOff) recorder.dispose();
     super.dispose();