Ability to select all media in selection mode

Signal/src/ViewControllers/MediaGallery/MediaGalleryAccessoriesHelper.swift

@@ -27,6 +27,8 @@ protocol MediaGalleryPrimaryViewController: UIViewController {
     var isEmpty: Bool { get }
     var hasSelection: Bool { get }
     func selectionInfo() -> (count: Int, totalSize: Int64)?
+    func selectAll()
+    func selectNone()
     func disableFiltering()
     func batchSelectionModeDidChange(isInBatchSelectMode: Bool)
     func didEndSelectMode()
@@ -172,6 +174,7 @@ public class MediaGalleryAccessoriesHelper {
             updateFooterBarState()
             updateSelectionInfoLabel()
             updateSelectionModeControls()
+            updateSelectAllButton()
             updateDeleteButton()
             updateShareButton()
         }
@@ -183,6 +186,7 @@ public class MediaGalleryAccessoriesHelper {
             return
         }
         updateSelectionInfoLabel()
+        updateSelectAllButton()
         updateDeleteButton()
         updateShareButton()
     }
@@ -438,7 +442,7 @@ public class MediaGalleryAccessoriesHelper {
             case .hidden:
                 return nil
             case .selection:
-                return [ shareButton, flexibleSpace(), selectionInfoButton, flexibleSpace(), deleteButton ]
+                return [ shareButton, selectAllButton, flexibleSpace(), selectionInfoButton, flexibleSpace(), deleteButton ]
             case .regular:
                 let firstItem: UIBarButtonItem
                 if isGridViewAllowed {
@@ -569,6 +573,33 @@ public class MediaGalleryAccessoriesHelper {
         Logger.debug("")
         viewController?.shareSelectedItems(sender)
     }
+
+    // MARK: - Select All/None
+
+    private lazy var selectAllButton = UIBarButtonItem(
+        title: CommonStrings.selectAllButton,
+        style: .plain,
+        target: self,
+        action: #selector(didPressSelectAll)
+    )
+
+    @objc
+    private func didPressSelectAll(_ sender: Any) {
+      Logger.debug("")
+      if viewController?.hasSelection == false {
+        viewController?.selectAll()
+      } else {
+        viewController?.selectNone()
+      }
+
+      didModifySelection()
+    }
+
+    private func updateSelectAllButton() {
+        guard let viewController else { return }
+        selectAllButton.title =
+          viewController.hasSelection ? CommonStrings.selectNoneButton : CommonStrings.selectAllButton
+    }
 
     // MARK: - Selection Info
 

Signal/src/ViewControllers/MediaGallery/MediaTileViewController.swift

@@ -1490,6 +1490,23 @@ extension MediaTileViewController: MediaGalleryPrimaryViewController {
         }
         return false
     }
+
+    func selectAll() {
+        (0..<collectionView.numberOfSections).compactMap { (section) -> [IndexPath]? in
+            return (0..<collectionView.numberOfItems(inSection: section)).compactMap({
+                (item) -> IndexPath? in
+                return IndexPath(item: item, section: section)
+            })
+        }.flatMap { $0 }.forEach { (indexPath) in
+            collectionView.selectItem(at: indexPath, animated: true, scrollPosition: [])
+        }
+    }
+
+    func selectNone() {
+        collectionView.indexPathsForSelectedItems?.forEach({ (indexPath) in
+            collectionView.deselectItem(at: indexPath, animated: true)
+        })
+    }
 
     func selectionInfo() -> (count: Int, totalSize: Int64)? {
         guard

Signal/translations/en.lproj/Localizable.strings

@@ -646,6 +646,12 @@
 /* Button text to enable batch selection mode */
 "BUTTON_SELECT" = "Select";
 
+/* Button text to select all in batch selection mode */
+"BUTTON_SELECT_ALL" = "Select All";
+
+/* Button text to select none in batch selection mode */
+"BUTTON_SELECT_NONE" = "Select None";
+
 /* Label for the 'set' button. */
 "BUTTON_SET" = "Set";
 

SignalMessaging/utils/CommonStrings.swift

@@ -37,6 +37,14 @@ public class CommonStrings: NSObject {
     static public var selectButton: String {
         OWSLocalizedString("BUTTON_SELECT", comment: "Button text to enable batch selection mode")
     }
+
+    static public var selectAllButton: String {
+        OWSLocalizedString("BUTTON_SELECT_ALL", comment: "Button text to select all in batch selection mode")
+    }
+
+    static public var selectNoneButton: String {
+        OWSLocalizedString("BUTTON_SELECT_NONE", comment: "Button text to select none in batch selection mode")
+    }
 
     static public var doneButton: String {
         OWSLocalizedString("BUTTON_DONE", comment: "Label for generic done button.")