Customize modal presentation style via modal-style

In the path configuration, set "modal-style" to:

* "medium" to present a small, half-screen modal.
* "large" to present a normal sized modal, filling the screen.
* "full" to present a modal that can't be swiped to dismiss.

If the property is missing or doesn't exactly match one of these three
options then `large` is used.

Source/Turbo Navigator/Extensions/UINavigationControllerExtension.swift

@@ -5,4 +5,20 @@ extension UINavigationController {
         let viewControllers = viewControllers.dropLast()
         setViewControllers(viewControllers + [viewController], animated: false)
     }
+
+    func setModalPresentationStyle(via proposal: VisitProposal) {
+        switch proposal.modalStyle {
+        case .medium:
+            modalPresentationStyle = .automatic
+            if #available(iOS 15.0, *) {
+                if let sheet = sheetPresentationController {
+                    sheet.detents = [.medium(), .large()]
+                }
+            }
+        case .large:
+            modalPresentationStyle = .automatic
+        case .full:
+            modalPresentationStyle = .fullScreen
+        }
+    }
 }

Source/Turbo Navigator/Extensions/VisitProposalExtension.swift

@@ -1,3 +1,5 @@
+import UIKit
+
 public extension VisitProposal {
     var context: TurboNavigation.Context {
         if let rawValue = properties["context"] as? String {
@@ -13,6 +15,13 @@ public extension VisitProposal {
         return .default
     }
 
+    var modalStyle: TurboNavigation.ModalStyle {
+        if let rawValue = properties["modal-style"] as? String {
+            return TurboNavigation.ModalStyle(rawValue: rawValue) ?? .large
+        }
+        return .large
+    }
+
     /// Used to identify a custom native view controller if provided in the path configuration properties of a given pattern.
     ///
     /// For example, given the following configuration file:

Source/Turbo Navigator/Helpers/TurboNavigation.swift

@@ -13,4 +13,10 @@ public enum TurboNavigation {
         case replaceRoot = "replace_root"
         case none
     }
+
+    public enum ModalStyle: String {
+        case medium
+        case large
+        case full
+    }
 }

Source/Turbo Navigator/TurboNavigationHierarchyController.swift

@@ -18,8 +18,8 @@ class TurboNavigationHierarchyController {
 
     func navController(for navigationType: NavigationStackType) -> UINavigationController {
         switch navigationType {
-            case .main: navigationController
-            case .modal: modalNavigationController
+        case .main: navigationController
+        case .modal: modalNavigationController
         }
     }
 
@@ -82,6 +82,7 @@ class TurboNavigationHierarchyController {
                 pushOrReplace(on: modalNavigationController, with: controller, via: proposal)
             } else {
                 modalNavigationController.setViewControllers([controller], animated: true)
+                modalNavigationController.setModalPresentationStyle(via: proposal)
                 navigationController.present(modalNavigationController, animated: true)
             }
             if let visitable = controller as? Visitable {
@@ -146,6 +147,7 @@ class TurboNavigationHierarchyController {
                 modalNavigationController.replaceLastViewController(with: controller)
             } else {
                 modalNavigationController.setViewControllers([controller], animated: false)
+                modalNavigationController.setModalPresentationStyle(via: proposal)
                 navigationController.present(modalNavigationController, animated: true)
             }
             if let visitable = controller as? Visitable {