apply scans error propagation fix

lib/services/coins/epiccash/epiccash_wallet.dart

@@ -437,7 +437,10 @@ class EpicCashWallet extends CoinServiceAPI
           ),
         );
       });
-      Logging.instance.log("result?: $result", level: LogLevel.Info);
+      Logging.instance.log(
+        "cancel $txSlateId result: $result",
+        level: LogLevel.Info,
+      );
       return result;
     } catch (e, s) {
       Logging.instance.log("$e, $s", level: LogLevel.Error);
@@ -661,25 +664,8 @@ class EpicCashWallet extends CoinServiceAPI
 
       await epicUpdateLastScannedBlock(await getRestoreHeight());
 
-      if (!await startScans()) {
-        refreshMutex = false;
-        GlobalEventBus.instance.fire(
-          NodeConnectionStatusChangedEvent(
-            NodeConnectionStatus.disconnected,
-            walletId,
-            coin,
-          ),
-        );
-        GlobalEventBus.instance.fire(
-          WalletSyncStatusChangedEvent(
-            WalletSyncStatus.unableToSync,
-            walletId,
-            coin,
-          ),
-        );
-        return;
-      }
-      await refresh();
+      await _startScans();
+
       GlobalEventBus.instance.fire(
         WalletSyncStatusChangedEvent(
           WalletSyncStatus.synced,
@@ -688,12 +674,23 @@ class EpicCashWallet extends CoinServiceAPI
         ),
       );
     } catch (e, s) {
+      GlobalEventBus.instance.fire(
+        WalletSyncStatusChangedEvent(
+          WalletSyncStatus.unableToSync,
+          walletId,
+          coin,
+        ),
+      );
+
+      Logging.instance.log(
+        "Exception rethrown from fullRescan(): $e\n$s",
+        level: LogLevel.Error,
+        printFullLength: true,
+      );
+      rethrow;
+    } finally {
       refreshMutex = false;
-      Logging.instance
-          .log("$e, $s", level: LogLevel.Error, printFullLength: true);
     }
-    refreshMutex = false;
-    return;
   }
 
   @override
@@ -1159,58 +1156,97 @@ class EpicCashWallet extends CoinServiceAPI
     // TODO: refresh anything that needs to be refreshed/updated due to epicbox info changed
   }
 
-  Future<bool> startScans() async {
+  Future<void> _startScans() async {
     try {
+      //First stop the current listener
       if (ListenerManager.pointer != null) {
+        Logging.instance
+            .log("LISTENER HANDLER IS NOT NULL ....", level: LogLevel.Info);
+        Logging.instance
+            .log("STOPPING ANY WALLET LISTENER ....", level: LogLevel.Info);
         epicboxListenerStop(ListenerManager.pointer!);
       }
-
       final wallet = await _secureStore.read(key: '${_walletId}_wallet');
 
-      var restoreHeight = epicGetRestoreHeight();
-      var chainHeight = await this.chainHeight;
-      if (epicGetLastScannedBlock() == null) {
-        await epicUpdateLastScannedBlock(await getRestoreHeight());
-      }
-      int lastScannedBlock = epicGetLastScannedBlock()!;
-      const MAX_PER_LOOP = 10000;
-      await getSyncPercent;
-      for (; lastScannedBlock < chainHeight;) {
-        chainHeight = await this.chainHeight;
-        lastScannedBlock = epicGetLastScannedBlock()!;
-        Logging.instance.log(
-            "chainHeight: $chainHeight, restoreHeight: $restoreHeight, lastScannedBlock: $lastScannedBlock",
-            level: LogLevel.Info);
-        int? nextScannedBlock;
-        await m.protect(() async {
-          ReceivePort receivePort = await getIsolate({
-            "function": "scanOutPuts",
-            "wallet": wallet!,
-            "startHeight": lastScannedBlock,
-            "numberOfBlocks": MAX_PER_LOOP,
-          }, name: walletName);
+      // max number of blocks to scan per loop iteration
+      const scanChunkSize = 10000;
 
-          var message = await receivePort.first;
-          if (message is String) {
-            Logging.instance
-                .log("this is a string $message", level: LogLevel.Error);
-            stop(receivePort);
-            throw Exception("scanOutPuts isolate failed");
+      // force firing of scan progress event
+      await getSyncPercent;
+
+      // fetch current chain height and last scanned block (should be the
+      // restore height if full rescan or a wallet restore)
+      int chainHeight = await this.chainHeight;
+      int lastScannedBlock =
+          epicGetLastScannedBlock() ?? await getRestoreHeight();
+
+      // loop while scanning in chain in chunks (of blocks?)
+      while (lastScannedBlock < chainHeight) {
+        Logging.instance.log(
+          "chainHeight: $chainHeight, lastScannedBlock: $lastScannedBlock",
+          level: LogLevel.Info,
+        );
+
+        final int nextScannedBlock = await m.protect(() async {
+          ReceivePort? receivePort;
+          try {
+            receivePort = await getIsolate({
+              "function": "scanOutPuts",
+              "wallet": wallet!,
+              "startHeight": lastScannedBlock,
+              "numberOfBlocks": scanChunkSize,
+            }, name: walletName);
+
+            // get response
+            final message = await receivePort.first;
+
+            // check for error message
+            if (message is String) {
+              throw Exception("scanOutPuts isolate failed: $message");
+            }
+
+            // attempt to grab next scanned block number
+            final nextScanned = int.tryParse(message['outputs'] as String);
+            if (nextScanned == null) {
+              throw Exception(
+                "scanOutPuts failed to parse next scanned block number from: $message",
+              );
+            }
+
+            return nextScanned;
+          } catch (_) {
+            rethrow;
+          } finally {
+            if (receivePort != null) {
+              // kill isolate
+              stop(receivePort);
+            }
           }
-          nextScannedBlock = int.parse(message['outputs'] as String);
-          stop(receivePort);
-          Logging.instance
-              .log('Closing scanOutPuts!\n  $message', level: LogLevel.Info);
         });
-        await epicUpdateLastScannedBlock(nextScannedBlock!);
+
+        // update local cache
+        await epicUpdateLastScannedBlock(nextScannedBlock);
+
+        // force firing of scan progress event
         await getSyncPercent;
+
+        // update while loop condition variables
+        chainHeight = await this.chainHeight;
+        lastScannedBlock = nextScannedBlock;
       }
-      Logging.instance.log("successfully at the tip", level: LogLevel.Info);
+
+      Logging.instance.log(
+        "_startScans successfully at the tip",
+        level: LogLevel.Info,
+      );
+      //Once scanner completes restart listener
       await listenToEpicbox();
-      return true;
     } catch (e, s) {
-      Logging.instance.log("$e, $s", level: LogLevel.Warning);
-      return false;
+      Logging.instance.log(
+        "_startScans failed: $e\n$s",
+        level: LogLevel.Error,
+      );
+      rethrow;
     }
   }
 
@@ -1490,24 +1526,7 @@ class EpicCashWallet extends CoinServiceAPI
       final int curAdd = await setCurrentIndex();
       await _getReceivingAddressForIndex(curAdd);
 
-      if (!await startScans()) {
-        refreshMutex = false;
-        GlobalEventBus.instance.fire(
-          NodeConnectionStatusChangedEvent(
-            NodeConnectionStatus.disconnected,
-            walletId,
-            coin,
-          ),
-        );
-        GlobalEventBus.instance.fire(
-          WalletSyncStatusChangedEvent(
-            WalletSyncStatus.unableToSync,
-            walletId,
-            coin,
-          ),
-        );
-        return;
-      }
+      await _startScans();
 
       unawaited(startSync());