Merge pull request #12 from trafi/feature/presenting-during-unwind

Allow presenting during unwind
trafi · May 21, 2020 · 338c75a · 338c75a
2 parents 17c23bd + a3539b1
commit 338c75a
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Showing 3 changed files with 121 additions and 4 deletions.
diff --git a/Sources/StoryFlow/Flow/Helpers/Transition.swift b/Sources/StoryFlow/Flow/Helpers/Transition.swift
@@ -10,15 +10,31 @@ public struct Transition<To: UIViewController> {
 extension Transition {
 
     public static func custom(_: To.Type, transition: @escaping (UIViewController, To) -> ()) -> Transition {
-        return Transition(go: transition)
+        return Transition { from, to in
+            from.afterDismissingCompleted {
+                transition(from, to)
+            }
+        }
     }
 
     public static func show(_: To.Type) -> Transition {
-        return Transition { $0.show($1, sender: nil) }
+        return Transition { from, to in
+            if from.navigationController != nil {
+                from.show(to, sender: nil)
+            } else {
+                from.afterDismissingCompleted {
+                    from.show(to, sender: nil)
+                }
+            }
+        }
     }
 
     public static func present(_: To.Type, animated: Bool = true) -> Transition {
-        return Transition { $0.present($1, animated: animated) }
+        return Transition { from, to in
+            from.afterDismissingCompleted {
+                from.present(to, animated: animated)
+            }
+        }
     }
 }
 
@@ -30,6 +46,8 @@ extension Transition where To == UIViewController {
             let parentInTab = $1.parentInTabBarController
             let isWrongTab = parentInTab != $1.tabBarController?.selectedViewController
             let isPresenting = $1.presentedViewController != nil
+                && $1.presentedViewController?.isBeingPresented == false
+                && $1.presentedViewController?.isBeingDismissed == false
 
             // 1. Navigation pop
             if let nav = $1.navigationController {
@@ -55,4 +73,12 @@ private extension UIViewController {
     var parentInTabBarController: UIViewController? {
         self.parent == self.tabBarController ? self : self.parent?.parentInTabBarController
     }
+
+    func afterDismissingCompleted(_ transition: @escaping () -> ()) {
+        if presentedViewController?.isBeingDismissed == true {
+            dismiss(animated: true, completion: transition)
+        } else {
+            transition()
+        }
+    }
 }
diff --git a/Sources/StoryFlow/Flow/ImplicitFlow/ImplicitFlow.swift b/Sources/StoryFlow/Flow/ImplicitFlow/ImplicitFlow.swift
@@ -53,7 +53,7 @@ extension Flow {
             if let to = Flow<Any>.destination(for: output) {
                 let transition = TransitionInfo(from: from, producedType: output.type, receivedType: type, to: to, isUnwind: false)
                 if CustomTransition.attempt(transition) == false {
-                    from.show(to, sender: nil)
+                    Transition.show(UIViewController.self).go(from, to)
                 }
                 return
             }

diff --git a/StoryFlowTests/ImplicitFlowTests.swift b/StoryFlowTests/ImplicitFlowTests.swift
@@ -163,6 +163,33 @@ class ImplicitFlowTests: XCTestCase {
         XCTAssert(currentVc is To)
     }
 
+    // MARK: Present
+
+    func testProduce_whenDismissingPresented_itPresentsAfterDismiss() {
+
+        // Arrange
+        class T {}
+
+        class From: UIViewController, OutputProducing { typealias OutputType = T }
+        class To: UIViewController, InputRequiring { typealias InputType = T }
+
+        let from = From().visible()
+        from.present(UIViewController(), animated: true, completion: nil)
+        XCTAssert(currentVc.didAppear())
+
+        from.dismiss(animated: true, completion: nil)
+
+        let output = T()
+
+        // Act
+        from.produce(output)
+        XCTAssert(currentVc.didDismiss())
+
+        // Assert
+        XCTAssert(currentVc is To)
+
+    }
+
     // MARK: Unwind
 
     func testProduce_itUnwindsToUpdateHandlingVcAndPassesOutput() {
@@ -242,6 +269,7 @@ class ImplicitFlowTests: XCTestCase {
 
         let from = From()
         container.show(from, sender: nil)
+        XCTAssert(currentVc.didAppear())
 
         let output = T()
 
@@ -330,6 +358,68 @@ class ImplicitFlowTests: XCTestCase {
         XCTAssert(to.update === output)
     }
 
+    func testProduce_whenParentIsPresentingDuringUnwind_itUnwindsWihtoutInteruptingPresentation() {
+
+        // Arrange
+        class T {}
+
+        class From: UIViewController, OutputProducing { typealias OutputType = T }
+        class To: UIViewController, UpdateHandling {
+            func handle(update: T) {
+                self.update = update
+                self.present(UIViewController(), animated: true, completion: nil)
+            }
+            var update: T!
+        }
+
+        let to = To().visible()
+        let from = From()
+
+        to.addChild(from)
+
+        let output = T()
+
+        // Act
+        from.produce(output)
+        XCTAssert(currentVc.didAppear())
+
+        // Assert
+        XCTAssert(currentVc == to.presentedViewController!)
+        XCTAssert(to.update === output)
+    }
+
+    func testProduce_whenPresentingDuringUnwind_itUnwindsWihtoutInteruptingPresentation() {
+
+        // Arrange
+        class T {}
+
+        class From: UIViewController, OutputProducing { typealias OutputType = T }
+        class To: UIViewController, UpdateHandling {
+            func handle(update: T) {
+                self.update = update
+                self.present(UIViewController(), animated: true, completion: nil)
+            }
+            var update: T!
+        }
+
+        let to = To()
+        let from = From()
+        UINavigationController(rootViewController: to).visible()
+
+        to.show(from, sender: nil)
+        XCTAssert(currentVc.didAppear())
+
+        let output = T()
+
+        // Act
+        from.produce(output)
+        XCTAssert(currentVc.didAppear())
+
+        // Assert
+        XCTAssert(currentVc == to.presentedViewController!)
+        XCTAssert(to.update === output)
+    }
+
     func testProduce_whenSelfCanHandleUpdate_itUnwindsToPreviousVc() {
 
         // Arrange
@@ -443,6 +533,7 @@ class ImplicitFlowTests: XCTestCase {
 
         let from = From()
         currentVc.show(from, sender: nil)
+        XCTAssert(currentVc.didAppear())
 
         // TabBar
         //   - Navigation