Merge commit '7621e2f8dec938cf48181c8b10afc9b01f444e68' into beta

submodules/TelegramUI/Sources/PeerMediaCollectionInterfaceStateButtons.swift

@@ -0,0 +1,32 @@
+import Foundation
+import UIKit
+
+enum PeerMediaCollectionNavigationButtonAction {
+    case beginMessageSelection
+    case cancelMessageSelection
+}
+
+struct PeerMediaCollectionNavigationButton: Equatable {
+    let action: PeerMediaCollectionNavigationButtonAction
+    let buttonItem: UIBarButtonItem
+    
+    static func ==(lhs: PeerMediaCollectionNavigationButton, rhs: PeerMediaCollectionNavigationButton) -> Bool {
+        return lhs.action == rhs.action
+    }
+}
+
+func rightNavigationButtonForPeerMediaCollectionInterfaceState(_ interfaceState: PeerMediaCollectionInterfaceState, currentButton: PeerMediaCollectionNavigationButton?, target: Any?, selector: Selector?) -> PeerMediaCollectionNavigationButton? {
+    if let _ = interfaceState.selectionState {
+        if let currentButton = currentButton, currentButton.action == .cancelMessageSelection {
+            return currentButton
+        } else {
+            return PeerMediaCollectionNavigationButton(action: .cancelMessageSelection, buttonItem: UIBarButtonItem(title: interfaceState.strings.Common_Cancel, style: .plain, target: target, action: selector))
+        }
+    } else {
+        if let currentButton = currentButton, currentButton.action == .beginMessageSelection {
+            return currentButton
+        } else {
+            return PeerMediaCollectionNavigationButton(action: .beginMessageSelection, buttonItem: UIBarButtonItem(title: interfaceState.strings.Common_Select, style: .plain, target: target, action: selector))
+        }
+    }
+}