Build exchange workspace and shared transaction services (#28)

frontend/app/lib/workspace/copy.dart

@@ -0,0 +1,52 @@
+import 'package:flutter/material.dart';
+
+import 'package:intl/intl.dart';
+
+import 'package:sxchnge_wallet/sxchnge_wallet.dart';
+
+import '../generated/i18n/app_localizations.dart';
+
+String money(BuildContext context, CurrencyAccount account, int amount) =>
+    NumberFormat.currency(
+      locale: Localizations.localeOf(context).toLanguageTag(),
+      name: account.currency,
+      symbol: '${account.currency} ',
+      decimalDigits: account.precision,
+    ).format(amount / account.scale);
+String kindText(AppLocalizations l, TransferKind kind) => switch (kind) {
+  TransferKind.topUp => l.wTopUp,
+  TransferKind.exchange => l.wExchange,
+  TransferKind.payout => l.wPayout,
+};
+IconData kindIcon(TransferKind kind) => switch (kind) {
+  TransferKind.topUp => Icons.add_rounded,
+  TransferKind.exchange => Icons.swap_horiz_rounded,
+  TransferKind.payout => Icons.north_east_rounded,
+};
+String statusText(AppLocalizations l, OperationStatus s) => switch (s) {
+  OperationStatus.pending => l.wPending,
+  OperationStatus.completed => l.wCompleted,
+  OperationStatus.failed => l.wFailed,
+};
+String fundsText(AppLocalizations l, WalletOperation o) =>
+    switch ((o.status, o.quote.request.kind)) {
+      (OperationStatus.pending, TransferKind.topUp) => l.wPendingTopUp,
+      (OperationStatus.pending, TransferKind.exchange) => l.wPendingExchange,
+      (OperationStatus.pending, TransferKind.payout) => l.wPendingPayout,
+      (OperationStatus.completed, TransferKind.topUp) => l.wCompleteTopUp,
+      (OperationStatus.completed, TransferKind.exchange) => l.wCompleteExchange,
+      (OperationStatus.completed, TransferKind.payout) => l.wCompletePayout,
+      (OperationStatus.failed, TransferKind.topUp) => l.wFailedTopUp,
+      _ => l.wFailedOutgoing,
+    };
+String walletError(AppLocalizations l, WalletError e) => switch (e) {
+  WalletError.invalidAmount => l.wInvalidAmount,
+  WalletError.insufficientFunds => l.wInsufficient,
+  WalletError.limitExceeded => l.wLimitError,
+  WalletError.expiredQuote => l.wExpired,
+  WalletError.invalidRecipient => l.wRecipientError,
+  WalletError.unsupported => l.wUnsupported,
+  WalletError.notFound => l.wNotFound,
+  WalletError.uncertain => l.wUncertain,
+  _ => l.wUnavailable,
+};