Don't let horizontal and vertical gestures run simultaneously

Tetris/ContentView.swift

@@ -17,6 +17,7 @@ struct ContentView: View {
         return c
     }()
     @State var timer: Timer?
+    @State var gestureState: GestureState = .none
     @State var initialXPosition: Int?
 
     var body: some View {
@@ -73,26 +74,40 @@ struct ContentView: View {
     func horizDragGesture(geometry: GeometryProxy) -> some Gesture {
         DragGesture(coordinateSpace: .global)
             .onChanged { (state) in
-                guard case .playing(.normal) = self.controller.state,
+                guard self.gestureState != .vertical,
+                    case .playing(.normal) = self.controller.state,
                     let currentPiece = self.controller.currentPiece else { return }
                 if self.initialXPosition == nil {
                     self.initialXPosition = currentPiece.topLeft.0
                 }
                 var moved = currentPiece
                 let xPosition = self.initialXPosition! + Int((state.translation.width / (geometry.size.width / 10)).rounded())
+                
+                if xPosition != self.initialXPosition {
+                    self.gestureState = .horizontal
+                }
                 moved.topLeft = (xPosition, currentPiece.topLeft.1)
                 if !self.controller.overlapsAny(moved) {
                     self.controller.currentPiece = moved
                 }
             }.onEnded { (state) in
                 self.initialXPosition = nil
+                if self.gestureState == .horizontal {
+                    self.gestureState = .none
+                }
             }
     }
     
     var verticalDragGesture: some Gesture {
         DragGesture()
+            .onChanged({ (state) in
+                guard self.gestureState != .horizontal else { return }
+                
+            })
             .onEnded { (state) in
+                guard self.gestureState != .horizontal else { return }
                 if abs(state.translation.height) > 80 {
+                    self.gestureState = .none
                     if state.translation.height > 0 {
                         self.onSwipeDown()
                     } else {
@@ -133,6 +148,10 @@ struct ContentView: View {
     }
 }
 
+enum GestureState: Equatable {
+    case none, horizontal, vertical
+}
+
 struct ContentView_Previews: PreviewProvider {
     static var previews: some View {
         ContentView()