fix: #85 unreliable torch

Fixes an issue where the CaptureSession became unresponsive while the torch was on or where the CaptureSession wouldn't properly start at all when the torch was on by default.

Author: nitricware

Sources/CodeScanner/ScannerViewController.swift

@@ -416,12 +416,14 @@ extension CodeScannerView {
         #endif
 
         func updateViewController(isTorchOn: Bool, isGalleryPresented: Bool, isManualCapture: Bool, isManualSelect: Bool) {
-            if let backCamera = AVCaptureDevice.default(for: AVMediaType.video),
-               backCamera.hasTorch
-            {
-                try? backCamera.lockForConfiguration()
-                backCamera.torchMode = isTorchOn ? .on : .off
-                backCamera.unlockForConfiguration()
+            guard let videoCaptureDevice = parentView.videoCaptureDevice ?? fallbackVideoCaptureDevice else {
+                return
+            }
+            
+            if videoCaptureDevice.hasTorch {
+                try? videoCaptureDevice.lockForConfiguration()
+                videoCaptureDevice.torchMode = isTorchOn ? .on : .off
+                videoCaptureDevice.unlockForConfiguration()
             }
 
             if isGalleryPresented && !isGalleryShowing {