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

frontend/packages/sxchnge_wallet/lib/src/mappers/backend.dart

@@ -0,0 +1,52 @@
+import 'package:sxchnge_auth/sxchnge_auth.dart';
+
+import '../models/wallet.dart';
+import '../transport/backend.dart';
+import '../transport/wallet.dart';
+
+abstract final class BackendMapper {
+  static Map<String, Object?> request(TransferRequest r) => {
+    'kind': r.kind.name,
+    'source': r.source,
+    'destination': r.destination ?? '',
+    'amount': r.amount,
+    'recipient': r.recipient,
+  };
+  static WalletSnapshot snapshot(BackendDTO d) => WalletSnapshot(
+    accounts: d.accounts.map(WalletMapper.account).toList(),
+    operations: d.operations.map(WalletMapper.operation).toList(),
+  );
+  static Quote quote(BackendDTO d) => WalletMapper.quote(d.quoteValue);
+  static WalletOperation? operation(BackendDTO d) => d.operationValue == null
+      ? null
+      : WalletMapper.operation(d.operationValue!);
+  static AccountProfile profile(BackendDTO d) =>
+      WalletMapper.profile(ProfileDTO(d.locale));
+  static FactorChallenge challenge(
+    BackendDTO d,
+    FactorPurpose purpose,
+    String operation,
+  ) {
+    final c = d.challenge;
+    return FactorChallenge(
+      id: c.id,
+      purpose: purpose,
+      operation: operation,
+      target: c.target,
+      expiresAt: c.expires,
+      resendAt: c.resend,
+    );
+  }
+
+  static WalletError failure(BackendDTO d) =>
+      WalletError.values.where((v) => v.name == d.error).firstOrNull ??
+      WalletError.unavailable;
+  static FactorError factorFailure(BackendDTO d) => switch (d.error) {
+    'factorInvalid' => FactorError.invalid,
+    'factorExpired' || 'expiredQuote' => FactorError.expired,
+    'factorLocked' => FactorError.locked,
+    'factorCooldown' => FactorError.cooldown,
+    'factorRequired' => FactorError.required,
+    _ => FactorError.unavailable,
+  };
+}