Invoke dismiss completion when BottomSheet was dismissed programmaticly (#37)

* Invoke dismiss completion when BottomSheet was dismissed programmaticly

* Make naming more clear

* Adjust BottomSheet documentation

Author: mikhailmaslo

BottomSheetDemo/Sources/User Interface/Screens/Root/RootViewController.swift

@@ -60,7 +60,7 @@ final class RootViewController: UIViewController {
                 true
             },
             dismissCompletion: {
-                // handle dismiss completion if user closed bottom sheet by a gesture
+                // handle bottom sheet dismissal completion
             }
         )
     }

README.md

@@ -84,7 +84,7 @@ presentBottomSheet(
         true
     },
     dismissCompletion: {
-        // handle dismiss completion if user closed bottom sheet by a gesture
+        // handle bottom sheet dismissal completion
     }
 )
 ```

Sources/BottomSheet/Core/Extensions/UIViewController+Convenience.swift

@@ -50,6 +50,8 @@ public final class DefaultBottomSheetModalDismissalHandler: BottomSheetModalDism
     private let _canBeDismissed: () -> Bool
     private let dismissCompletion: (() -> Void)?
 
+    private var didInvokeDismissal = false
+
     // MARK: - Init
 
     init(
@@ -75,6 +77,14 @@ public final class DefaultBottomSheetModalDismissalHandler: BottomSheetModalDism
             // User dismissed view controller by swipe-gesture, dismiss handler wasn't invoked
             dismissCompletion?()
         }
+
+        didInvokeDismissal = true
+    }
+
+    public func didEndDismissal() {
+        guard !didInvokeDismissal else { return }
+
+        dismissCompletion?()
     }
 }
 

Sources/BottomSheet/Core/Presentation/BottomSheetModalDismissalHandler.swift

@@ -10,4 +10,6 @@ public protocol BottomSheetModalDismissalHandler {
     var canBeDismissed: Bool { get }
 
     func performDismissal(animated: Bool)
+
+    func didEndDismissal()
 }

Sources/BottomSheet/Core/Presentation/BottomSheetPresentationController.swift

@@ -144,6 +144,7 @@ public final class BottomSheetPresentationController: UIPresentationController {
             removeScrollTrackingIfNeeded()
 
             state = .dismissed
+            dismissalHandler.didEndDismissal()
         } else {
             state = .presented
         }