Add date normalization methods to ForexRateApiService and handle additional error code in RentController

Signed-off-by: Hans Kokx <hans.d.kokx@gmail.com>

lib/services/open_exchange_service.dart

@@ -47,6 +47,28 @@ class ForexRateApiService {
     }
   }
 
+  DateTime _asUtcDate(DateTime value) {
+    return DateTime.utc(value.year, value.month, value.day);
+  }
+
+  DateTime _latestHistoricalDateUtc() {
+    final nowUtc = DateTime.now().toUtc();
+    final todayUtcDate = DateTime.utc(nowUtc.year, nowUtc.month, nowUtc.day);
+    return todayUtcDate.subtract(const Duration(days: 1));
+  }
+
+  DateTime _normalizeHistoricalDate(DateTime requestedDate) {
+    final requestedUtcDate = _asUtcDate(requestedDate);
+    final latestAllowed = _latestHistoricalDateUtc();
+    if (requestedUtcDate.isAfter(latestAllowed)) {
+      _log(
+        'Historical date ${DateFormat('yyyy-MM-dd').format(requestedUtcDate)} is not available yet; clamping to ${DateFormat('yyyy-MM-dd').format(latestAllowed)}.',
+      );
+      return latestAllowed;
+    }
+    return requestedUtcDate;
+  }
+
   Future<http.Response> _getWithRateLimitRetry(
     Uri uri, {
     required String operation,
@@ -78,7 +100,8 @@ class ForexRateApiService {
       throw StateError('ForexRateAPI key is not configured.');
     }
 
-    final date = DateFormat('yyyy-MM-dd').format(estDate);
+    final effectiveDate = _normalizeHistoricalDate(estDate);
+    final date = DateFormat('yyyy-MM-dd').format(effectiveDate);
     final uri = Uri.https('api.forexrateapi.com', '/v1/$date', <String, String>{
       'api_key': apiKey,
       'base': 'USD',